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Posted: 10/21/2003 7:45:16 PM EDT
[#1]
I heard a vicious rumor.....
That putting a PRI front post designed for a rifle on a 14.5inch barrel would require the use of a different front post. (supposedly there is made a taller front post specifically designed for M4's). The dealer told me that if I didn't buy the taller post I would have problems zeroing at 50yds. [b]Well I never bought the post and there was no problem and that is all a bunch of bullshit. The barrel is on the same axis... the sights are on the same axis... the problem makes no sense[/b] |
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Posted: 10/21/2003 7:48:45 PM EDT
[#2]
Yeah, that's the other thing I heard. I guess COLT uses a different SIGHT POST on their M4's, in order to compensate for the shorter sight radius (?). I don't think Bushmaster does this for their M4 barrels, though...
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Posted: 10/22/2003 7:10:14 AM EDT
[#3]
I may be confused, but it looks like he's saying there are no flat top Colt's in 1/7? Or perhaps he's excluding the M4's because of what you requested...
I believe the front sight post is a different thickness on the shorter guns. |
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Posted: 10/22/2003 7:55:42 AM EDT
[#4]
Man, lots of bad info here.
OK, first off: Colt uses front sight bases that are a different height on their barrels that are intended for use on flat top uppers. These FSBs will have an "F" stamped on the left side of the gas tube bracket forward of the gas tube roll pin. If the photo server ever comes up again I'll post a pic. There is a link to the pic in the Glossary and FAQ at the Troubleshooting Forum. I thought this was common knowledge. Two, The M4 (as in the one Sam gives away) uses the same front sight post as the M16A2. Sam does this out of a concern for logistics. Colt's carbines use a different front sight post. It is thinner, not taller, due to the shorter sight radius of the carbines. Those companies trying to sell taller front sight posts to make up for screwy sight alignment are simply aggravating the problem. |
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Posted: 10/22/2003 8:26:04 AM EDT
[#5]
Quoted: Those companies trying to sell taller front sight posts to make up for screwy sight alignment are simply aggravating the problem. Bushy sell the 0.040" taller front sight post, because they use the A2 front sight base on their flat tops receivers not a Colt flattop spec front sight base. So if a person wants to use the GG&G or ARMS#40 rear sights that were setup for Colt's higher sight plane on their Bushy flattop the need a taller front sight post to properly get a zero. |
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Posted: 10/22/2003 8:47:04 AM EDT
[#6]
Quoted: So if a person wants to use the GG&G or ARMS#40 rear sights that were setup for Colt's higher sight plane on their Bushy flattop the need a taller front sight post to properly get a zero. I have a #40 and had absolutely no problem with the height of my front sight post. It seems that the majority of people don't have any trouble. |
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Posted: 10/22/2003 11:14:11 AM EDT
[#7]
". It is thinner, not taller, due to the shorter sight radius of the carbines."
Thinner front posts would make sense. That front post on my issue M4 is really large... It complicates zeroing by making it hard to see the target, and consequently, hard to get a tight group. I never had a problem zeroing a M16 in 9 rounds but the M4 irons took me more than 18rds. (the sights adjustments also seem to have no correlation with the graduation lines on the paper, and groups required a lot more concentration- as soon as aimpoints went on most shooters zeroed in 9rds. |
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Posted: 10/22/2003 1:01:02 PM EDT
[#8]
Anyone know the width of the front sight post used on Colt's carbine rifles?
I think the standard rifle's post is .072" wide, am I correct? |
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Posted: 10/22/2003 1:31:44 PM EDT
[#9]
Quoted: I have a #40 and had absolutely no problem with the height of my front sight post. It seems that the majority of people don't have any trouble. Do you have a Bushmaster flattop upper with their mil-spec A2 front sight base??? Quoted: ". It is thinner, not taller, due to the shorter sight radius of the carbines." No the sight in question is taller, not thinner... Here is a link to Bushmaster selling the [url=http://www.bushmaster.com/shopping/scopes/arms40.asp]ARMS #40[/url] Posted on Bushmaster website Due to aperture height, you should order the .040 higher front sight. This is in regards to if you are using one of their upper assemblies w/ an mil-spec A2 front sight base... Here is a link to Bushmaster selling the [url=http://www.bushmaster.com/shopping/scopes/9349056-m.asp]Taller front sight post[/url] Posted on Bushmaster website Because the Colt A3 carry handle is taller than mil spec. It requires this modified .040 front sight post. This sight post should also be used with the ARMS #40. Here is the reply I got from Bushmaster when I asked them about this after noticing it on their website before ordering my 16" pre-ban M4gery A3 Flattop complete upper receiver assembly & ARMS #40... Subject: Sight Heights When Colt came out with the A3 design with the detachable carry handle they made the front and rear sights .040" higher than the sights used on A1 and A2 rifles. The front sight forging is the same but the front sight post when set for mechanical zero is even with the top of the sight ears instead of below them as the plane for the sight post is milled higher. You will notice on 20" A3 barrels there are two raised bands on the barrel under the handguards. This designates that the barrel has the front sight base with the front sight that is milled high for the front sight post. Colt parts lists have a different part number for the higher front sight base barrels and sight bases for A3 and M4 barrels. We decided when we began to build the A3 models with detachable carry handles that we would keep the sight heights the same for all models. Our A3 handle, Flat-top Rear Sight and Rear Flip Up Sight has the same rear sight aperture height as on the A1 and A2 receivers so that all barrels with standard height front sight bases will interchange. The Mark Brown Flat Top Mount also uses this same rear sight height. The A.R.M.S. Swan Sleeve and # 40 Flip Up Rear Sights have the higher rear sight aperture height. When used with standard height front sight bases the front sight post must be turned out to the .040" higher position where it is even with the top of the sight base ears for mechanical zero. We now carry a .040" taller front sight post, part number 9349056-M for $4.95, to correct this difference. Coincidentally, I tried to zero my carbine with the short front sight post just to see if it would work, and it would not… I needed the taller front sight post, which luckily I didn’t listen to people around here and ordered anyway… To get the proper zero the front sight post was so far out of the front sight base, that the post detent base was out of the front sight base so far the detent barely engaged… I'm not saying everybody needs it the taller front sight post to work with the GG&G A2 or MAD or ARMS #40 sights; just everybody who uses a Bushmaster mil-spec A2 front sight base and wants their flattops w/ ARMS#40 to zero correctly... |
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Posted: 10/22/2003 1:50:03 PM EDT
[#10]
Quoted: I'm not saying everybody needs it the taller front sight post to work with the GG&G A2 or MAD or ARMS #40 sights; just everybody who uses a Bushmaster mil-spec A2 front sight base and wants their flattops w/ ARMS#40 to zero correctly... Sorry too many people (including myself) have the same setup and didn't need the taller front sight post. If you could review the old threads in the Bushmaster forum you would see this. It seems some Bushy's need it and some don't. I don't see any rhyme or reason for it. |
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Posted: 10/22/2003 2:02:13 PM EDT
[#11]
Quoted: Anyone know the width of the front sight post used on Colt's carbine rifles? I think the standard rifle's post is .072" wide, am I correct? Also if anyone could post the sight radius of the Carbine vs. the rifle that would be great. Edited: Nevermind the sight-radius request, found out the rifle is 19.75" and carbine is 14.5". Still wondering about front sight post width. |
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Posted: 10/22/2003 2:15:23 PM EDT
[#12]
I like Forest, and many others, don't have this problem with this set up. As for rhyme or reason, I considered it could be the sight picture we see/use is different. ??? Thanks.....Chad
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Posted: 10/22/2003 3:27:44 PM EDT
[#13]
So how do you fix the problem if you can't replace the front sight base (i.e. permanently attached muzzle brake) with a higher base?
My flat-top carbine (from a J&T kit) must have the standard A2 front sight base. The front sight IS much taller than on my 20" A2, and must be adjusted almost as high as the protective "ears" as Omega stated. It kind of drives me nuts because the two ARs I have with open sights have radically different sight pictures. Would a Bushy detachable carry handle/ rear sight work, or is it possible to replace the rear sight on the J&T carry handle? Thanks for any advice. Scot |
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Posted: 10/22/2003 3:34:49 PM EDT
[#14]
Quoted: Sorry too many people (including myself) have the same setup and didn't need the taller front sight post. Could it be that Bushy installed the taller front sight before the upper left the factory? Could you measure how tall your sight post is and let us know, when I get home tonight I'll measure both my regular and my tall and we can compare. |
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Posted: 10/22/2003 4:01:53 PM EDT
[#15]
Mine is a Rock River. A good friend of mine has a #40 on his BM and didn't need the taller post either. Colt should be the only odd-ball. Like Forest said, some do, some don't.
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Posted: 10/22/2003 4:06:14 PM EDT
[#16]
So,.....
Does this mean a Colt removable handle rear sight is .040 higher than a Bushie rear handle sight? Since none of these handles/sights are marked, how in tarnation do you tell what you have? Also, what is Rock River doing with their sight height? Will a 20" barrel "work" on a flat top, which sight to use? Now I am really confused..... |
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Posted: 10/22/2003 5:26:09 PM EDT
[#17]
There are two different height flat top uppers floating around as well as their corresponding handles. Combined with the barrels using different height FSBs you got a lot of possible combos, some of which cancel out.
If the PRI sight was destined for use with Colt flat tops it will be the same height as the "F" marked FSBs. A taller front sight post is not a solution as the post is susceptible to damage because it is not as well protected by the ears of the FSB. |
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Posted: 10/22/2003 5:42:33 PM EDT
[#18]
I plan on fixing mine by installing a GG&G flip up front sight, and if I ever down the road decided to get a carry handle (which I doubt) I'll get a Colt spec carry handle.
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Posted: 10/22/2003 5:54:44 PM EDT
[#19]
One thing to consider as well. If a Bushy owner zeros an ARMS #40, etc. with the small aperture, the front post will end up flush with the sight ears. If you zero with the large aperture, the post will be at normal height. I found this out by using the Santose IBZ, zeroing with the small aperture per my understanding of the directions. I later found out that I should have zeroed with the large aperture. This brought the front post height back down to normal.
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Posted: 10/22/2003 7:48:52 PM EDT
[#20]
Ok just to clarify, this is what I understand from the previous comments:
Bushmaster and all other manufacturers except for Colt: Use A2 height front sight bases on all models whether they have A2 uppers or flattop uppers. The removable carry handle on flattop uppers is made to put the sights at the same height as fixed A2 upper sights. Colt: Use the A2 height front sight base on fixed sight upper receiver models. For flattop models (A3/A4), whether they have 20", 16", or 14.5" barrels, they install the higher front sight base, have flattop upper receivers with the same rail height as the other manufactureres and use a different carry handle that puts the sights on a higher plane. If this is correct then the only real difference between Colt and the other manufacturers when it comes to flattop models is the front sight base and removable carry handle. Is this right or are the removable carry handles made by Colt and the others the same in dimension and Colt uses a flattop upper receiver with a higher rail? It would be nice if Colt made a different dimensioned flattop upper receiver so that removable carry handles were interchangable between manufacturers since I would like to pick up a cheaper carry handle to cut down for use as a BUIS. Please let me know if and where I am wrong, thanks. |
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Posted: 10/23/2003 6:44:03 AM EDT
[#21]
My Bushy upper/ ARMS 40 works fine without a higher front sight. The 40 has an AO same plane aperture.
Let's see what Colt has screwed up on this weapon over the years. Wrong height sights, large hole uppers, large diameter trigger pins, sear blocks, unchromed bores and plastic trapdoors. Did I forget anything? I love my Bushmaster more than my preban Colt! That says it all. |
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Posted: 10/23/2003 8:38:38 AM EDT
[#22]
Quoted: Could it be that Bushy installed the taller front sight before the upper left the factory? No for several reasons 1) I didn't ask for it (its not like they give them out for free). 2) I bought my ARMS #40 from a different vedor - so they had no way of know I was going that route. 3) I didn't purchase an upper from them - I purchased parts, and they were purchased under different orders at different times. |
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Posted: 10/23/2003 10:13:13 AM EDT
[#23]
Quoted: 3) I didn't purchase an upper from them - I purchased parts, and they were purchased under different orders at different times. So you don't have a Bushy assembled upper which is what I have been talking about all along.[banghead] What front sight base did you get and where did you get it from??? |
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Posted: 10/23/2003 11:38:54 AM EDT
[#24]
Quoted: So you don't have a Bushy assembled upper which is what I have been talking about all along.[banghead] I have a bushmaster barrel and a bushmaster upper. Only difference is I turned the wrench rather than a Bushmaster employee. If that is the difference that makes a height difference then Bushmaster must be employing monkeys to do the install. What front sight base did you get and where did you get it from??? All Bushmaster barrels come with the Bushmaster front sight base (unless you specify something else - and Bushy only has 1 size fixed front sight). All my barrels have Bushshmaster forged fixed front sight bases. |
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Posted: 10/23/2003 12:45:50 PM EDT
[#25]
Well Forest, it sounds like you should start your own company seeing as how you know more than Bushmaster about Bushmaster rifles, upper assemblies, and components...
Why can't we buy a Forest, FR-15's??? [ROFL] There is definitley a reason for the difference but you are more interested in [bs] than figuring out what it is so I'm done with this thread [wave] |
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Posted: 10/23/2003 1:00:08 PM EDT
[#26]
Quoted: Quoted: So if a person wants to use the GG&G or ARMS#40 rear sights that were setup for Colt's higher sight plane on their Bushy flattop the need a taller front sight post to properly get a zero. I have a #40 and had absolutely no problem with the height of my front sight post. It seems that the majority of people don't have any trouble. I had to buy the taller sight post. I almost screwed the standard out of the base to zero with the ARMS #40, I normally have to go "down" to zero not "up" With the taller post, I had to go "up" one click vs almost out of the hole. |
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Posted: 10/23/2003 1:02:50 PM EDT
[#27]
Quoted: There are two different height flat top uppers floating around as well as their corresponding handles. In measuring 2 dozen uppers (7 Colts and a variety of others), the height of the flattop UPPER RECEIVER was identical. If this was different, there would be issues mounting products like the ARMS SIR, which isn't the case. We DID indeed find variation in the front sight bases as you stated (F-marked Colt bases were slightly different), and some variation in height with the detachable carry handles. I just wanted to make it clear, though, that the upper receiver itself does not change from brand to brand, at least among the major players. We know that very early, pre-Picatinny Olys, and non-forged uppers like the DPMS Lo-Pro, ARE different, but these are obviously not standardized uppers in the first place. -Troy |
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Posted: 10/23/2003 3:54:25 PM EDT
[#28]
Quoted: Quoted: Those companies trying to sell taller front sight posts to make up for screwy sight alignment are simply aggravating the problem. Bushy sell the 0.040" taller front sight post, because they use the A2 front sight base on their flat tops receivers not a Colt flattop spec front sight base. So if a person wants to use the GG&G or ARMS#40 rear sights that were setup for Colt's higher sight plane on their Bushy flattop the need a taller front sight post to properly get a zero. You would only need the taller front post if you were zeroing with the small aperture. The A2 sight system is designed to be zeroed using the small aperture, but the ARMS 40's, GGG's, etc. are zeroed with the large aperture. This lowers the rear sight thus lowering the front sight. |
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Posted: 10/23/2003 4:50:48 PM EDT
[#29]
I noticed my non-colt removable carry handles all have sight bases with a bottom thickness .040" less than the sight bases in my non-colt A2 fixed upper receivers.
Could it be... that Colt chose to use a taller front sight tower with the standard A2 rear sight base and ... everyone else uses a standard front sight with a shorter A2 rear sight base? That would make all upper receiver and removable carry handle forgings the same. Colt sucks! |
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Posted: 10/23/2003 4:51:56 PM EDT
[#30]
TROY IS RIGHT ON THE MONEY, AS USUAL!
Good shootin, Jack |
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Posted: 10/23/2003 10:15:18 PM EDT
[#31]
Quoted: In measuring 2 dozen uppers (7 Colts and a variety of others), the height of the flattop UPPER RECEIVER was identical. Troy, I'm not sure what I've done to get on your bad side but, trust me, it was not intentional. Here is the data I've collected from several members of the AR15-L. Some of these guys were on the original list. I never said that certain companies used certain height uppers. I said that there are two different height flattop upper floating around. i still run across them at gun shows and on rifles. The parts are still available and as such will continue to turn up on rifles. 1.721” 1.844” BM flattop Nick 1.720” 1.843” Colt M4 Unipro 1.721” 1.842” Colt flattop Rick from El Paso 1.720” 1.838” Colt M4 Ron N 1.724” 1.840” Colt M4 Ron N 1.763” 1.875” Armalite Paul 1.757” 1.871” OAI Picatinny 13 slots Tweak 1.945” 2.450” OAI Weaver 8 slots Tweak The first column is the height from the bottom of the receiver to the bottom of the to the bottom of the slot. The second column is the height from the bottom of the receiver to the top of the slot/top of rail. The third column is the name of the person submitting the numbers. Like so many of the different styles and sizes of parts available (RRA flattops being a recent reminder) the difference was is not doubt due to a change in the prints after tooling was made. At OAI we had a print on the wall for the XXX flattops we were using at the time. It perfectly (XXX does good work) matched the uppers they were sending. Unfortunately it didn't match the Colt uppers I had mic'd. |
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Posted: 10/24/2003 11:24:54 AM EDT
[#32]
"Coincidentally, I tried to zero my carbine with the short front sight post just to see if it would work, and it would not… I needed the taller front sight post, which luckily I didn’t listen to people around here and ordered anyway… To get the proper zero the front sight post was so far out of the front sight base, that the post detent base was out of the front sight base so far the detent barely engaged…"
Good for you. I was able to zero my Bushy 14.5 with PRI front and ARMS #40 rear also (fine) it wasn't having the same detent problem. I zeroed at 25M. [b]And well yes I did post this but I did not say it first (the "" are there to let you know it is someone-elses words NOT MINE I still think the thinner square front post would be a good idea.[/b] "-------------------------------------------------------------------------------- Quoted: ". It is thinner, not taller, due to the shorter sight radius of the carbines." -------------------------------------------------------------------------------- No the sight in question is taller, not thinner... Here is a link to Bushmaster selling the ARMS #40" |
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Posted: 10/24/2003 1:59:24 PM EDT
[#33]
Quoted: Troy, I'm not sure what I've done to get on your bad side but, trust me, it was not intentional. I appologize if I've given you that impression; that isn't the case at all. I've learned a TON of stuff from you over the years, starting back in those AR15-L days. Between you and Chuck Santose, and a few other folks like rambo, a lot of us "experts" [:P]learned much of what we know about ARs. I was agreeing with virtually everything you said, except that (and here's the part I guess I didn't make clear enough) MODERN A3/A4 forged uppers are generally all machined to the same spec. I noted that there were a number of known exceptions, especially from back in the day before the 1913 spec was standardized. Here is the data I've collected from several members of the AR15-L. Some of these guys were on the original list. I never said that certain companies used certain height uppers. I said that there are two different height flattop upper floating around. i still run across them at gun shows and on rifles. The parts are still available and as such will continue to turn up on rifles. 1.721” 1.844” BM flattop Nick 1.720” 1.843” Colt M4 Unipro 1.721” 1.842” Colt flattop Rick from El Paso 1.720” 1.838” Colt M4 Ron N 1.724” 1.840” Colt M4 Ron N 1.763” 1.875” Armalite Paul 1.757” 1.871” OAI Picatinny 13 slots Tweak 1.945” 2.450” OAI Weaver 8 slots Tweak The first column is the height from the bottom of the receiver to the bottom of the to the bottom of the slot. The second column is the height from the bottom of the receiver to the top of the slot/top of rail. The third column is the name of the person submitting the numbers. Like so many of the different styles and sizes of parts available (RRA flattops being a recent reminder) the difference was is not doubt due to a change in the prints after tooling was made. At OAI we had a print on the wall for the XXX flattops we were using at the time. It perfectly (XXX does good work) matched the uppers they were sending. Unfortunately it didn't match the Colt uppers I had mic'd. I remember these posts. You were the first one who clued me into the F-stamped Colt front sight posts, and are therefore responsbile for me examining and measuring parts for the next couple of years. I'll be honest in that I didn't remember the Armalites being different, but I know that the ones made over the last 3 years or so are standard spec. I don't know how old Paul's rifle was, but IIRC, this post was from '97-'98. Even when I *disagree* with your posts, I always find them both interesting and full of facts. And I'm not always right, and when someone can prove to me that I'm wrong, I'll admit it (and have, publicly, at least a dozen times). I've been under a lot of stress lately between my job and my side business, so if I seem a little harsh on folks, it isn't intentional. [:D] -Troy |
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Posted: 10/24/2003 9:04:05 PM EDT
[#34]
I read this thread 2 times now and I'm still flustered.
I have a Colt LW 1/9 16" barrel mounted to a DPMS standard flat top upper with a DPMS detachable rear sight (not the carry handle). The FSB is marked D98 (RI inside a circle)2. I have to raise the post almost out of the ears to get it to zero. I assume this means my receiver and/or rear sight are to high. What should I do? My receiver measures 1.869 from the bottom to the top of the rail. Brick |
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Posted: 10/25/2003 12:45:40 AM EDT
[#35]
Earlier in this thread someone asked how wide the front sight post was on a Colt M4 carbine. Acording to my caliper it is .073 inches.
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Posted: 10/25/2003 7:04:15 AM EDT
[#36]
I gotta take the time to re-read all of this 'cuz I'm still freaking confused!
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Posted: 10/25/2003 1:27:27 PM EDT
[#37]
Quoted: Earlier in this thread someone asked how wide the front sight post was on a Colt M4 carbine. Acording to my caliper it is .073 inches. On the M4 it is the same width as the M16's (.073") for consistency's sake. However, Colt's other carbines taper the end down to a smaller width (I THINK .052") to make up for the shorter sight radius. I'd really like to know the width of this front sight post. |
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Posted: 10/27/2003 12:04:52 AM EDT
[#38]
Quoted: I apologize if I've given you that impression; that isn't the case at all. Just checking Troy, we've all had those days. |
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Posted: 10/27/2003 12:28:14 AM EDT
[#39]
Quoted: I gotta take the time to re-read all of this 'cuz I'm still freaking confused! Which part UK? Brick, Sounds like you're using one of the "old, not encounted much around here anymore" taller flattop upper receivers. You can see how your measurement (bottom of receiver to bottom of rail notch is the called dimension, bottom of receiver to top of receiver dimension is an estimate BTW) corresponds to the ones I posted earlier. In addition it sounds like the front sight base on your barrel is the standard (shorter, non flattop) height. The distance from the bore centerline to the flat where the "UP" is stamped should be 2.285"+/-0.010". The "F" marked FSBs are in the 2.34" range. Here's the pic I promised earlier. [img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=16149[/img] Note the stamped "F" on the gas tube bracket forward of the gas tube roll pin. Edited to add there is/was a wide variation in FSB heights last time I put out the call for measurements. Colt showed the least (narrowest range) variation and the dimensions went down hill from there. This also corresponds with my experience. Some of the numbers were so far afield that I question their validity esp when I look at the measurements that one person sent for corresponding barrel diameters. I have been too lazy to follow up on that tho. Congrats, you all just made the [url=http://ar15.com/forums/announcement.html?b=3&f=66&id=185]Troubleshooting FAQ II[/url]. |
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Posted: 10/27/2003 6:32:21 AM EDT
[#40]
The distance from the bore centerline to the flat where the "UP" is stamped should be 2.285"+/-0.010". The "F" marked FSBs are in the 2.34" range. If this is true.. 1. Does this mean that the "F" FSBs and the A1/A2 FSBs are both milled from the same blanks? 2. Wouldn't this mean that the protective ears are the same height from bore centerline? If these are true, then those of us that have A1/A2 height FSBs with a flat-top & ARMS #40 (or other BUIS built to Colt F-marked FSB spec) and have to back out our front sights way out (or use extended front sight posts) shouldn't have any less of a protected front sight post than those using F-marked FSBs, is this correct? Basically I'm asking if your front sight post is as protected in "F" marked FSBs as they are in A1/A2 height FSBs when using a flat-top upper and a BUIS built to colt flat-top FSB spec? I've heard others say it's not as protected, but I don't see how that can be if all colt does is mill the FSBs from the same blanks and just cut down the "UP"-flat less. The tip of the front sight post is still going to be the same height from bore centerline regardless of which base you use. And if all the ears are the same height from bore centerline (which they would be if both FSBs are milled from the same blank), then there should be no more protection for the front sight post with either base. The only way the ears would be to a different height from centerline between the "F" FSBs and the A1/A2 FSBs is if they were milled to a specific height in relation to the "UP" flat, rather than milled to a specific height from bore centerline. |
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Posted: 10/27/2003 9:09:55 AM EDT
[#41]
Tweak:
Sorry to have ask for more clarification, but I'm just trying to make sense of all this! Okay, here it goes ([b]by the way, my rifle is 16" FLAT TOP BUSHY DISSIPATOR with a chopped BUSHY carry handle[/b]): 1) Colt uses a different (i.e. taller) FSB for their FLAT TOPS becuse their removable handles raise the REAR SIGHT UP A BIT? 2) Technically speaking, my PRI sight that's mounted on my 16" BUSHY DISSIPATOR FLAT TOP should have given me problems (should have used a taller front sight post), right? [i]But I had no problems in using the IMPROVED BATTLESIGHT ZERO with my set up.[/i] [b]Nevermind, I was off on this comment![/b] 3) I can see the need for a thinner post in the sight base on the M4's, but this isn't necessary for the 16" plus barrels, right? 4) I may, or may not, experince problems in using an ARMS #40 rear sight in conjunction with my PRI front sight on BUSHY FLAT TOP? Supposedly, I would need a taller front sight post in order to properly zero? [b]I guess I won't because my PRI sight is spec'd to Colt's flat-top specs.[/b] 5) If the next upper that I buy is a FLAT TOP COLT, then I won't have to worry about all this sutff! I apologize if these observations/questions are redundant, but I was just getting lost trying to re-read all of this...[>:/] |
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Posted: 10/27/2003 10:21:43 AM EDT
[#42]
Quoted: 1) Colt uses a different (i.e. taller) FSB for their FLAT TOPS becuse their removable handles raise the REAR SIGHT UP A BIT? Yes. 2) Technically speaking, my PRI sight that's mounted on my 16" BUSHY DISSIPATOR FLAT TOP should have given me problems (should have used a taller front sight post), right? [i]But I had no problems in using the IMPROVED BATTLESIGHT ZERO with my set up. The PRI Flip-ups are made to Colt flat-top spec. If you have a Colt height-spec rear sight (such as ARMS #40 or Colt Carry Handle) you shouldn't have any problems. You won't necessarily have problems mixing and matching either, but you _might_. Your mechanical zero will give you a much different POI compared to non-mixed, but most people have enough adjustment to zero just fine. 3) I can see the need for a thinner post in the sight base on the M4's, but this isn't necessary for the 16" plus barrels, right? It's never "necessary". The 16" M4 barrels have the same sight radius as the 14.5", so yes, you would want the thinner front sight post. On dissipators the sight radius is the same (or atleast very close to, not sure which) as the 20" barrels (19.75" sight radius). Thus, the thinner post is not "necessary". 4) I may, or may not, experince problems in using an ARMS #40 rear sight in conjunction with my PRI front sight on BUSHY FLAT TOP? Supposedly, I would need a taller front sight post in order to properly zero? No, both items are made to Colt flat-top spec. They should zero correctly. 5) If the next upper that I buy is a FLAT TOP COLT, then I won't have to worry about all this sutff! Not necessarily. If you purchase a rear sight that is not to Colt's flat-top spec, you probably will have enough adjustment to zero. But if you don't, then you will have the opposite problem.. needing a shorter post. [b]EDITED TO ADD[/b]: I just spoke with a PRI rep and asked about the compatability of the ARMS #40 and their PRI sight. He stated that SOME people do have problems and call in for a taller front post. SO, as long as I'm running my chopped BUSHY handle and the PRI front sight I'LL BE A-OKAY! Hmmm... from what I've read the PRI is made to Colt's flat-top spec (.040 higher). That's odd.. Anyway, I THINK all my information is correct. But by no means am I Colt factory worker or a TM writer. |
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Posted: 10/27/2003 10:26:29 AM EDT
[#43]
I'm just repeating what the PRI guy told me. Maybe, their front sight was spec'd to match the FSB's on COLT's non-flat top models? Maybe that's why I had ZERO PROBLEMS in "zeroing" my rifle with the BUSHY rear aperature?
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Posted: 10/27/2003 10:36:45 AM EDT
[#44]
Quoted: Hmmm... from what I've read the PRI is made to Colt's flat-top spec (.040 higher). That's odd.. Anyway, I THINK all my information is correct. But by no means am I Colt factory worker or a TM writer. YOU ARE CORRECT. Just called PRI again and the guy stated that they are indeed spec'd to COLT's flat-top specs. Hmm...so why did my combo work (PRI sight with chopped Bushy handle)? I guess it's more of a problem when one has a non-COLT spec front sight and is trying to use an ARMS #40 than using a PRI front sight and a non-spec detach handle! |
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Posted: 10/27/2003 11:27:35 AM EDT
[#45]
Quoted: YOU ARE CORRECT. Just called PRI again and the guy stated that they are indeed spec'd to COLT's flat-top specs. Hmm...so why did my combo work (PRI sight with chopped Bushy handle)? Like I said, your mechanical zero will have a POI way off from what you'd normally see when the two heights are not mixed & matched. However, you SHOULD have enough adjustment to get it to zero properly. Especially when you can adjust elevation in the front and the rear. With ARMS #40, you only have whatever adjustment the front elevation will give you to work with. So yes, it is a bigger problem with flip-up BUIS. I'm still hoping Tweak or someone can weigh in on my questions. If what I am asking is true, then the whole "your front post isn't protected enough" issue goes right out the window. Then the only concern really would be zeroing and having adjustment left-over. |
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Posted: 10/27/2003 12:07:32 PM EDT
[#46]
Thanks for the information. I guess I didn't read your reply closely enough. I'm in the middle of writing some reports, so I was skimming through everything.
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Posted: 10/27/2003 12:16:33 PM EDT
[#47]
Quoted: Thanks for the information. I guess I didn't read your reply closely enough. I'm in the middle of writing some reports, so I was skimming through everything. No no no! Please don't take my post as me yelling or being frusterated or anything. That's just the way I converse in typing.. I can see how the "Like I said" and stuff like that can make it seem that way. I don't mind clarifying my words.. I try not to be cryptic but sometimes I can say things a little screwy. I guess I have some public relations skills to work on when posting to these boards. [:D] |
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Posted: 10/27/2003 3:46:12 PM EDT
[#48]
No, I didn't take it the wrong way. I was just acknowledging the fact that you had already answered my question, and that I should've taken the time to read your post more thoroughly. No offense taken. [:)]
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Posted: 10/27/2003 10:46:44 PM EDT
[#49]
Tweak,
I read the FAQII and it stated, [b]Going to a taller front sight post is not a solution[/b] I got the same problem with my front sight post almost screwed all the way out for zero with the big rear aperture on an M4gry. Please don't get frustrated with some of us trying to understand. What would be the best way to fix this problem if going to a taller front sight post is not the solution? The rear flip up sight has no elevation adjustment otherwise I would just lower the rear sight. Also I do not see a taller FSB for sale on any internet sights. With options available it looks like the taller post is the only alternative... Man I'm lost... Dan |
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Posted: 10/28/2003 6:16:56 AM EDT
[#50]
Also I do not see a taller FSB for sale on any internet sights. With options available it looks like the taller post is the only alternative... I think what Tweak means is that it's not the "correct" solution, but it will work, and it's cheap. In an ideal world, everyone would be on the same page. Colt would be making everything to mil-spec heights or everyone would be making their parts to Colt flat-top spec heights and the mil-spec for flattops would be changed. |
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