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Posted: 12/17/2007 9:55:14 AM EDT
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When using iron sights is it better to keep the front sight attached to the barrel or is it OK to use a flip-up/folding front sight on a rail that extends passed the gas-block? I am thinking I will eventually want optics but it might be a while before I can afford them so I may need something to make my gun shootable in the meantime. |
The sights don't tell the bullet where to go, they just predict it. The barrel does the work. |
Sorry I was fishing for more responses :D |
No need to be sorry.  One of the main reasons I put flip-up sights on the free-float rail is because I like to use a low profile gas block in conjunction with a free float tube that extends past the gas block.
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The shooter has no credible interface or understanding of the barrel's pointing. It is the sights we use to "do the work". It is for this reason that ANYTHING that interferes with a strict relationship between sight alignment/sight picture and barrel pointing is to be avoided. When the sights are barrel-mounted, the two are synonymous. When the sights are rail mounted, you get the problem I originally described. |
This is a ridiculous statemnt... you know that right? Flexing of the barrel? Come on. |
OMG my scope and barrel do not coincide! If the barrel moves my optic does not! We should all drop our optics and use irons attached to the barrel till they make barrel mounted optics!  This is ridiculous. Anyone with any experience using rail mounted BUIS knows they work just fine. This is more of that internet commando theoretical bullshit arfcom is known for. If you have a stiff rail you will never be able to tell the difference. Any walking the barrel might do is no worse than a non FF barrel with an optic. Those work just fine too. |
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I don't know what you are talking about, Bud. I have seen POI change with sling tension. Have you not? If not, what criteria were you using to evaluate your targets? I can't imagine shooting at 200, 300 or 600 yards and not seeing the effect of varying sling tension on POI. You can easily see POI changes with differing pressure on the barrel. if it is not free-floated. Where are you coming from with these comments? |
So if the barrel is free-floated what will alter the POI, just the heat from shooting?? |
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How many guys actually use enough "sling tension" when using a free float railed type set up with a rail mounted buis? I have no problems getting decent hits with my rail mounted front sight. It is not the optimum but I don't know if there is such a thing. There are alot of guys running around with optics and no free float system, and as devil said, that would not be much different either. Using a rest or a bipod, your barrel may move but your optic doesn't. But I don't think it's going to make that big of a difference for minute of man. If you're doing varminting, shooting prairie dogs, then yes, you may have problem and need to go with an appropriate set up. For Defense at most ranges, it's nothing to worry about. That's my 2 cents. Somehow the marines get away with using slings and no free float and shoot to 500 meters. I know my 20"er changes poi with sling tension, so I'm not sure how they do it. Either way, it's something you need to understand, but it doesn't render your rifle useless. "not hitting a broad side of a barn with a railed front sight" is a ridiculous statement. |
If your barrel is free floated, if you have rock solid sights, if the problem isn't the shooter and still the POI moves, then you have a problem with your barrel. It probably has a lot of unrelieved internal stress and is warping as the temperature varies. I'd send it back to the manufacturer and request a new barrel. The key factor is to be sure it is not the shooter. Let several different people shoot it to ensure it's not the shooter. Have the shooters shoot a known good rifle, too. This will allow you to isolate the barrel as the cause. |
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If you get 8" of pull off your target with sling tension, then you either need to lay off the sling or see if your barrel nut, scope/sights are tight. I shoot a scoped lightweight non-freefloat 16" barrel and after about 30 consecutive rounds I get about a 1" drift from the normal 1-2" groups at 100 yards because of the heat and that's it. 8" is extreme! |
To the original post: IMO, you take the $200-$400+ that you would spend on a freefloat tube, gas block, and rail mounted front sight and apply that to the optic you want. Then, after you have used the optic on the standard setup, decide if the above is necessary for what you need. I've had a lot of cool stuff like expensive rails and fold down sights and for my needs it was nothing but cool stuff so it got sold off to fund the best optics I can afford. I have to have a cost/performance rationale these days. On the other hand, if it was a hotrod you were putting together and you said you didn't need to paint it because it wouldn't make it run any faster, I would say you were crazy! |
I had a feeling you were going to through HiPower shooting out there. First off, it doesnt even relate to this topic. That is specialized type of shooting. Note, they use FF tubes with FSBases on the barrel. Therefore doesnt matter how much sling tension you have, the sights and barrel shouldnt move. This is very different shooting than defense and combat type shooting. Again, show me a grunt that is in a firefight that has a leather coat on, a hat with a visor, and a 20 round mag. The op was clearly talking about FF rails with front sights on it. The mission of rifles set up that way is not HiPower shooting. You are using hyperbole and extreme example to prove a point. It is not necessary. The question is about running front sight on a FF tube and if it will work. Or even yet he asked about a gas block. What is the reason for the question, OP. Are you building a HiPower rig? If so, I stand corrected and forget everything I said.  Oh, I just read his initial post and it seems apparent to me the mission of his rifle is probably not HiPower competition. Most guys shoot at 25 and 100 yards. He will be fine. |
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I was thinking about the the generic free float versus not and here's what I came up with. Every rifle I own that is free floated is more accurate and consistently more accurate than any rifle I own that is now free floated. Every rifle I own that is not free floated has exhibited POI shifts with varying load on the fore end or barrel. Several inaccurate rifles I have I have fixed by floating the barrel. The basic steps to accurizing all rifles is to free float the barrel - M1, M1A, AR15, bolt actions, all of them. One rifle was inaccurate even after free floating the barrel. That rifle was sold. Back to the OP:
Given my experiences related above, I'd say, yes, it is better to have the sights attached to a free floated barrel. It takes a variable out of the system. It is okay to rail mount them,... but why? I have never heard or read anything to suggest rail mounted sights are better than barrel mounted sights on a free floated barrel. I reiterate, it is better to have barrel mounted sights. In asking if one is "better" but is the other "okay", are you just asking for validation to rail mount them? The longer the rail, the longer the sight radius, the greater the shift in POI with change in load. The change in load can come from many sources, not the least of which are changes in: sling tension, weight of rifle on a bag/bipod versus not on a bag/bipod, lights, lasers, ... I was not inferring or implying his rifle is for high power competition, not at all. JJREA may disparage the experience one gains in high power shooting, or IPSC-style rifle shooting but I have done a lot of shooting and I get real-time feedback from it. I know what works for me and what does not. It is that experience that I am relaying to you in my answer to your question. Free floating your barrel works. Keeping your sights on the barrel works. Honest questions here - Why would you put the sights on the rail if you had a choice? Is it a style you are after, or is there some functionality you gain by doing so? Does that functionality outweigh the possible aiming error? These are the kinds of questions you have to answer for yourself to determine which is the way to go. |
I am building a range/paper/tin can/coyote/prairie dog gun. I was thinking of only using BUIS until I can afford good optics; I am not interested in competition. The main reason I asked this question was because I see a bunch of setups with the BUIS on the FF-rail, but I assumed having the sights on the barrel would be more accurate. But then that raises the point that (most) scopes are not mounted to the barrel. [I have heard that scout mounted scopes are inherently more accurate since they are mounted on the barrel, but that is hearsay and forget I mentioned it. (I have a feeling others have strong feelings about that topic also)] So basically I am looking for information on my build, weighing different opinions and deciding what would be the best set up for me. Thank you all for your input, feel free to add more if you would like, but I apologize for bringing up a sensitive topic. |
Mike, FWIW, I don't disagree with you as to which is better. What got me was people acting like a rail mounted front sight is going to get you terrible accuracy. My experience tells me that it's not so. For the most part, people put BUIS on the rail because it is primarily a rifle set up with an optic and the BUIS is "back up", hence the name, therefore not the primary sighting mechanism. And because it's primarily set up for optics, the fold down type obviously leave the sight picture totally clear. Some lower powered optics will allow you to see the front sight. And the extra rail leaves more room for a bipod. Is a fixed front sight on the barrel and the barrel free floated a better set up? Yes, for the purpose of the irons sights I would say of course. For the OP's intended purpose, if your main sighting system is going to be irons, this is the way to go. Of course I realize HiPower shooters know a thing or two about how to get their rifles to shoot well. However, if you're just going to plink or shoot coyotes and prairie dogs, any BUIS you come up with will be fine, because it's not your primary sight. This is not rocket science. |
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Here's a question which I hope is relevant and helps shed some light on the topic, otherwise I've just wasted more bandwidth and I ask for forgiveness up front. Do barrel mounted front sights which fold all attach via cross-slot screws or set screws and dimples, or can they be pinned, like a standard FSB? Reason I ask is probably 99% or buyers who are going to contemplate a rail mounted front sight will be looking at folders. Folders have the perceived advantage of cleaning up the sight picture (I say perceived, because in my limited experience with a 2 - 7x, the std FSB doesn't interfere with my sight picture, but I digress), so if you really are interested in folders, then the debate comes down to folding rail mounted vs folding barrel mounted. Std fixed FSBs are pinned on the barrel, and when properly installed, those bastards will stay put. They can take some bumps and such and they aren't moving. But when I think of barrel mounted folders, I think of set screws and dimples and split halves secured with loctited screws, or cross-slot screws, which aren't quite as secure. Not saying they can't be made secure, I'm just saying compared to the two installation methods, pinning is better. If the folders can be installed only via set screw/dimples, then the debate comes down to picatinny attachment on a rail vs set screws/dimples/locktite. In that debate I'd probably opt for a railmounted sight because it would be more secure, or at least it wouldn't as prone to getting knocked around if it takes a good bump. I still say though that a fixed, std FSB does not screw with your sight picture, so unless like Molon pointed out earlier (you want to extend your sight picture, so you use a lo-pro gas block under a rail with the rail extending beyond, and your sight mounted at the end of the rail) I'd suggest just going with a std, fixed, pinned FSB. |
Not for me, I have found all the opinions very helpful. |
You're right. Instead of bickering about the matter, I should've chided the OP to just go shoot his rifle and see what he thinks about it. So many people ask questions on here wanting to get answers that they could just as easily get for themselves. I swear someone is going to ask how to zero, pretend he did it like we said at home, and think his rifle is zero'd somehow magically because the internet told him how to do it. Experience is the best teacher. |
Feel Free to chide him then. And I am sure the OP would have said he is unable to shoot his rifle, because he is in the research/design process of building it. Then economics comes into play: * Why spend the various amounts on a front sight, and however much for a low profile gas block? * Why spend $200+ on a free floating rail that extends over the gas block, then another $200+ free floating rail that doesn't, only to see which one shoots better?
You're right, that is why I am calling on y'all's experience to help out an inexperienced guy. I don't have the funds to try various configurations, and I don't know anybody who will let me shoot his configurations, so I am basically SOL and am looking for information from a forum. Isn't that what internet forums are for, to share experiences to help newbies like me from making the same, costly mistakes that were made time and time again? I guess nobody should be allowed to ask any type of question on here and only use this place to post pictures of people's guns. |
| It wasn't clear to me that you didn't actually had the rifle together yet. It was a little vague in your original post. I assumed you had something together already. Sorry about that. That does change things a little. If it was me, I'd go with a FF rail and a FSB IF, IF you think you will do any amount of shooting with irons as a mainstay. If you think it will be a dedicated Aimpoint / ACOG or whatever optic gun, then fold downs are AOK and will work well for back up. And they would even work in the interim. If it is CQB or HD that you would be needing irons for, they don't have to be super precision anyways. Just as so they don't fall off. With quality ones, that shouldn't be a problem. |
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Here are a few of my experiences. PRI flips... they wiggle fore and aft when locked at the top. The screws and come loose on set screwed versions unless you do something like Rocksett them. GGG... its pinned and does not move. It locks firmly in the up position. It was great to use but I found it "ugly" as if that means anything...  I have a pinned gas block and a rail that goes over it right now. Because there is no heat on the BUIS vs the barrel mounted version simple blue locktite will hold it in place. I never have noticed any kind of wandering zero. |
Thanks. I apologize for my tone in my last post. |
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I haven't built anything yet. I have something similar to what you want, but a little different. My barrel profile is almost identical. But it's WOA and I don't think it gets thicker like that towards the chamber. WOA upper Bolt, BCH etc. and barrel like I said. Not sure what gas block DD 9.5 FF rail w/ and LMT front sight rig RRA Cut Carry handle, I did see below RRA lower with 2 stage trigger. Makes shooting for groups alot nicer. Just easier all around. Larue SPR EER mount with Leupy 3 x 9 VXII. Nothing special besides the mount. If I had to do it over again, I'd probably just get the FSB because I don't ever take it off of there and I look shooting with the irons. I'd of have to use a different rail though. But, it is pretty accurate with the irons and I don't have a wandering zero. It's pretty much dead nuts all the time. That barrel shoots different ammo to a similar POI, which makes it worth it's weight in Gold. Oh yeah, I forgot to tell you. The upper was built by ADCO. My brother has their match carbine, which is FFloated Wilson carbine Hbar barrel 1/8 with an RRA upper I believe. It's pretty nice too. I can't get the pic to come up though. |
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I dont shoot my ARs with slings FWIW. I shoot off a rest or bipod and carbine, midlength, and rifle length rails have no detectable POI shift for me if using rail mounted irons. I dont see it as a real world issue for that type of shooting at 300 yards and under. I dont use rear BUIS that are adjustable so beyond 300m is meaningless to me. |
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