Armory Sponsor
Posted: 9/14/2009 4:45:27 PM EDT
|
OK... so i just turned out about 5 round tonight. Used some Sierra 77gr MK's on LC brass…. swaged, trimmed, primed powered charged and dropped the bullets in. One thing I'm noticeing is my OAL length is varying. Nothing larger than 2.260" but I'm hitting in an around the 2.253-2.58 range. My first question is does being under the OAL pose any issues? Secondly what can I do to better control the ammo? I assume it all starts back at the FL resizing die and then works out from there. I run all Hornady dies, except for a Lee crimp die, but I don't have any cannulure bullets yet.
I basically went through about 30 cases, getting the trimming ,F/L and Seating die in check, a few primers here and there and about 10 or so bullets. Overall I can say FOR SURE.. that I am HOOKED! As I stated above there are a lot of variances in my ammo production. Should I worry about them or just keep on trucking through? I’m not shooting for match here, I just go the range allot and also do allot of training that is more focuses on technique rather than shooting ultra tight groupings. I think the added QC of hand reloading coupled with a good powder like Varget and the other added benefits of reloading will weight out to be more than enough increase in accuracy for my purposes. That being said I would, at some point like to get into Handgun reloading… and that would be slightly more beneficial as I do get into IDPA and such. What would you guys suggest to retool my setup and attempt to make things more uniform? |
|
The irregular hollowpoint tip will cause a few thousandths overall length variance. The ogive of the bullet should be very close to the same dimensions if measuring ogive length. Some people go to the trouble with match hollowpoint bullets to use a meplat uniformer which cuts the hollowpoint tips evenly an makes the tip pefectly square. Not a problem with your lengths. I'd just make sure the longest doesn't go over the 2.260" and make sure they feed in your rifle at that length.
Here's an article on meplat uniforming: http://www.davidtubb.com/tcom_images/reloading/bmu_one.html |
|
Quoted:
OK... so i just turned out about 5 round tonight. Used some Sierra 77gr MK's on LC brass. Swaged, trimmed, primed powered charded and dropped the bullets in. One thing I'm noticeing is my OAL length is varying. Nothing larger than 2.260" but I'm hitting in an around the 2.253-2.58 range. Is varies a little bit. My first question is does being under the OAL pose any issues? No Secondly what can I do to better control the ammo? It's the bullets, totally normal. I assume it all starts back at the FL resizing die and then works out from there. I run all Hornady dies, except for a Lee crimp die, but I don't have any cannulure bullets yet. Measure OAL on some factory ammo. |
| To answer you question about seating depth, yes seating deeper than the recommended OAL will usually raise pressure. I like to decide on a seating depth first, before I play around with the powder charges. I've been using a metplat trimmer sold by Sinclair. I trim about 0.015" off the tip of the bullets before loading. This gives me a little more room in the magazine without having to seat deeper. |
|
Quoted:
The irregular hollowpoint tip will cause a few thousandths overall length variance. The ogive of the bullet should be very close to the same dimensions if measuring ogive length. Some people go to the trouble with match hollowpoint bullets to use a meplat uniformer which cuts the hollowpoint tips evenly an makes the tip pefectly square. Not a problem with your lengths. I'd just make sure the longest doesn't go over the 2.260" and make sure they feed in your rifle at that length. Here's an article on meplat uniforming: http://www.davidtubb.com/tcom_images/reloading/bmu_one.html I agree with rg1. |
| See the shaving of the bullets is a bit extreme for me. I got into reloading cause I needed a winter time hobby and with the volume I shoot I can make up some money…somewhat. See a majority of the training I do is all focused on technique and shooting from various positions. Everything being equal the guys I train with have the same weapons. There all 14.5” M4’s and our training ammo is 55gr XM192 stuff. For actual life and death shooting we use the infamous Mk262 rounds. So in these classes when everyone is using roughly the same guns and the same ammo were all pretty consistent. However, one day we switched up from the 55gr stuff to 77grMK262 and it was unreal the difference. Our rifles are 1x7 so it really makes a difference. Some of the guys bring their personal guns out. There running 16” barrels with 1x9 twists and are have good effect on target with 55 grain stuff. I opted to reload 77gr’s and get a load comparable to the price of 55gr stuff. We get so much MK262 allotted for training then were on our own or gotta get XM192 So I opted to make 77 gr stuff to more accurately simulate what is used in reality, plus i find all of this extremely interesting. |
|
You'll find other bullet types will have much better control of their length - BTHP match bullets can be aggravating while getting the length set for magazines. I shoot for 2.26 inches in USGI magazines, but let them sneak out to 2.265 and have never had a problem.
Be sure to check the length your magazines will tolerate however. I have a commercial magazine I won in a contest here that will not operate with 2.26 COAL, but works perfectly with 2.25 inch ammo. |
|
Quoted:
See the shaving of the bullets is a bit extreme for me. I got into reloading cause I needed a winter time hobby and with the volume I shoot I can make up some money…somewhat. See a majority of the training I do is all focused on technique and shooting from various positions. Everything being equal the guys I train with have the same weapons. There all 14.5” M4’s and our training ammo is 55gr XM192 stuff. For actual life and death shooting we use the infamous Mk262 rounds. So in these classes when everyone is using roughly the same guns and the same ammo were all pretty consistent. However, one day we switched up from the 55gr stuff to 77grMK262 and it was unreal the difference. Our rifles are 1x7 so it really makes a difference. Some of the guys bring their personal guns out. There running 16” barrels with 1x9 twists and are have good effect on target with 55 grain stuff. I opted to reload 77gr’s and get a load comparable to the price of 55gr stuff. We get so much MK262 allotted for training then were on our own or gotta get XM192 So I opted to make 77 gr stuff to more accurately simulate what is used in reality, plus i find all of this extremely interesting. You may look into the 69gr SMK's, they are a very nice bullet for the 1/7 twist rifles. I'm also testing some Hornady 75gr BTHP's that from what I hear shoot to the same point of impact and almost the exact same load data as the 77gr bullets and are a good bit cheaper than the 77gr SMK's as well. |
|
For actual life and death shooting we use the infamous Mk262 rounds
Some of us, including me, may never get to touch the Mk262 stuff. Do you pick up the M193 and the Mk262 brass at the range? It would be interesting to map the once fired condition of both of those product streams. I have heard all sorts of rumors about the Mk262, chamber pressures way above SAAMI MAP, primer pockets loose after 1x, trim lengths way over 1.760, etc. |
| Negative on the brass picking up. I'm not allowed to touch the stuff. We already shot our quota of MK262 stuff for the year so I wont be seeing that anytime soon(at least in the training arena). The XM193 stuff we shoot is what any joe blow can buy at the store. Its all non Nato head stamped. I was not all "up" on ammo until recently and by that time it was to late. I didnt even know how rare the MK stuff was out in the civilian world. The only thing I know is that some of the MK262 stuff has no case markings. I typically did not pay attention to anything and just loaded up ammo and went about my business. The no case markings stuff was interesting. I assume they make it for various SPECWAR and SPECOPS people who are in countries they should not be. |
|
Spectre...
Thanks for the info. Here is probably more than you ever wanted to know about the 75 and 77 gn OTMs in 5.56 / .223 ammo from BH, and HDY. http://www.box.net/public/static/a5yybdgztv.pdf |
|
A few thousandths of an inch variance is not a problem in seating depth. I would be concerned if it was a hundredth or more. In rifles even a hundredth may not be significant but it is not hard to tune and compensate so I play it safe. What I do is figure out approximately what load I want to put together. Then I run a few cartridges through after initial adjustments and see how much variance there is. Then I make a final decision on the powder charge based on the shortest overall length. Also, 2.260" is the very max length for the cartridge and just fits inside the mags. I like to seat a little under this to give a little more room for the tip to slide up the mags in case of any grit that gets in there. More like 2.220. A lot of factory ammo is 2.200 or shorter. Of course this is counter to what you want for best accuracy, which is to seat as far out as the mag and throat allow. But I will trade a bit of accuracy for more reliability. |
|
Quoted:
Spectre... Thanks for the info. Here is probably more than you ever wanted to know about the 75 and 77 gn OTMs in 5.56 / .223 ammo from BH, and HDY. http://www.box.net/public/static/a5yybdgztv.pdf Thanks, i'll take a look at that. There is a ton of info and things I didnt no even know existed. Ammo production is a cool little science, like high performance race car engines. Two people can make the same engine but they can be completely different. I have it pretty good, my buddy is a police officer back home and they were shooting wolf ammo in there guns. I dont know if thats there carry stuff or what. Scary stuff man. |
| When I first started loading the 77gr. Sierra MatchKing bullets, I tried to get as close to 2.260" COAL as possible. Went to an out-of-state shoot and a few rounds were hanging up in USGI mags turning my rifle into a single-shot. Major PIA as it was a 2 week shoot. All it took was one over-mag-length round somewhere in the mag. So I measured some factory Black Hills MK 262 MOD 1 to see what COAL the factory settled on to guarantee 100% reliability. They are shorter than you would think@ 2.243"-2.249" with 2.245" average COAL. Doesn't appear to matter whether you measure 1st quality Black Hills MK 262 MOD 1, 1st quality BH commercial, or BH SECONDS. Measure a few for yourself. I settled on a COAL of 2.250" to err on the side of caution. Have not had any further feeding problems in the last few years and accuracy is right at 0.5 MOA@100yds. |
Armory Sponsor