I've got one of those Colt upper parts for IRG and it's got a 1-7 twist barrel. I know that 75gr and the heavier ones would be ideal but what kind of performance are some of you getting with the 55gr FMJ or maybe the 62gr Speers with said twist???
AR Reloading
- Thread starter Katana
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Most of the FMJ projectiles won't be fabulous accuracy. If you want to go cheap find a bulk SP projectile and reload that,
youl'll get a lot more accuracy with only a modest increase in unit cost.
Hornady, Win and Rem (among others) have .224 dia SP in 55g for example.
youl'll get a lot more accuracy with only a modest increase in unit cost.
Hornady, Win and Rem (among others) have .224 dia SP in 55g for example.
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- The Orion Arm
1 in 7 will stabilize both the 55 and the 62 and everything else as well.
It theoretically is possible that a 55gr zipping through a 1/7 might shed some of its jacket, but that usually means a crappy projectile if that kind of separation occurs. I haven't seen it once in all the years and matches I've gone to, nor have I even heard a story from someone who knew someone who heard it from a guy who's best friend's brother was talking to a guy who.....
Both my ARs are 1/7 and I shoot nothing but 55gr except if hunting.
It theoretically is possible that a 55gr zipping through a 1/7 might shed some of its jacket, but that usually means a crappy projectile if that kind of separation occurs. I haven't seen it once in all the years and matches I've gone to, nor have I even heard a story from someone who knew someone who heard it from a guy who's best friend's brother was talking to a guy who.....
Both my ARs are 1/7 and I shoot nothing but 55gr except if hunting.
Trini - What kinds of groups are you getting? I'm working up a load for my new AR using the Hornady 55 FMJs as well (over IMR4895) and so far it seems insensitive to the load. The first 5 rounds go into 1" to 1.2", then open to around 2" if I shoot in one string.
I'm starting to branch out to some other bullets and powders but I've got thousands of the 55's and Lbs of 4895.
This is some load testing I did on my last range session with that rifle. I was using a 1-4x optic on it but changed it out to a higher magnification scope (my eyes ain't what they used to be) to try it at 100yrds on my next range session. I'm guessing it'll be about 1.5" - 2" at 100yrds which I'll be happy with since that's no match grade barrel in that rifle. Shooting skills need some work but 24gr of Varget seems to be the powder load for me.
The pic shows H4895 but should actually be Varget.
The pic shows H4895 but should actually be Varget.
Thanks. LOL...You had me all jealous for a second until I noticed that was at 50 yards. Those are great results out of a standard DD barrel. Makes me wonder why I paid extra for my Ultramatch. Have to get out to try my Varget loads.
That is pretty typical for any FMJ. Results vary considerably from group to group.
The easiest solution to shrink that variation and firm up consistency is to:
A) use a 'match' type seater die that will very likely reduce the overall runout of the round to two thou to zero, and
B) switch to a match or varmint type bullet offering that will invariably have more consistency from bullet to bullet than will the FMJ.
Match dies pay for themselves fairly quickly and if you factor the extra cost of a match bullet over FMJ per 1000 rounds, it often isn't that much more in the grand scheme of things - of course your shooting style, distance, etc. all factor into whether it is worth it.
The easiest solution to shrink that variation and firm up consistency is to:
A) use a 'match' type seater die that will very likely reduce the overall runout of the round to two thou to zero, and
B) switch to a match or varmint type bullet offering that will invariably have more consistency from bullet to bullet than will the FMJ.
Match dies pay for themselves fairly quickly and if you factor the extra cost of a match bullet over FMJ per 1000 rounds, it often isn't that much more in the grand scheme of things - of course your shooting style, distance, etc. all factor into whether it is worth it.
Just keep in mind the 75gr. AMax needs to be seated longer than the typical 2.260" max. OAL for magazine loaded rounds - you'll be feeding them one at a time.
Pushing them into the case to 2.260" and shorter, renders the brass casing sticking out past the bearing length of the bullet into the ogive, potentially creating a dangerous situation with high probability of bullets being set back into the case.
What does it being 14.5 inch have to do with your accuracy expectations?
Accuracy potential is determined by the quality of the ammo and the quality of the barrel. It has nothing to do with length. My 12 inch AR can shoot sub moa at 100yds with quality ammo and a 4 power optic. Even my 6.5 inch barrel showed me sub 2 moa with match ammo.
I wasn't sure if it would make a difference but some one posted there results with an 18 in barrel so I thought I would add it. I know that accuracy does get affected with barrels shorter than 18 in from the reports that I've read.
It seems counterintuitive but every quantitative test that I've seen which measures the relationship between barrel length and accuracy indicates that barrel length is irrelevant to accuracy. There is some argument that in piston operated, semi-auto rifles the improved stiffness of shorter barrels may even yield improved accuracy but I've not seen any empirical evidence of this theory.
http://www.thetruthaboutguns.com/20...t-barrel-length-muzzle-velocity-and-accuracy/
I have a 223AI bolt rifle that I had built. It has a 1-7 twist as I planned on shooting 90 VLDs out of it. When I first got it, I loaded a box of nearly 100 Speer 52gr HP for fire forming the brass. I have a few video clips of them disintegrating approximately 10-15 yards out of the muzzle. I can't post them but I can e-mail them if someone wishes to post them.
