View Full Version : 1/7 twist barrel and ammo question
Rbcrusher15
02-07-15, 16:13
Sorry for the semi misleading title gentlemen. And let me say this is NOT a complaint thread, I know the rules. A little back story. I recently purchased a PSA CHF M4A1 1/7 twist Upper, mostly because I wanted a hammer forged barrel, and figured since I hear they outsource most of their branded barrels from FN, it would be as good as any. My other choice was a Daniel Defense, but since it only came with the barrel and fsp for $299, the entire psa upper seemed like a more cost effective option for the same price. I really only wanted the barrel, fsp, delta ring assembly and gas tube from it, and I'm planning on putting it on a mega arms stripped upper, but I digress.
Anyway I went shooting today to see what grain ammo it liked best, and sight in a 1-4x24 scope. I went with fiocchi 50 gr vmax, a bunch of different 5.56 and .223 55 gr ball, some 62 gr soft point, and some ssa 77 gr smk's. My question is this. Is it normal for one to blow the 1/2 in square out of multiple targets, about dime size groups at 25 yards, with 50 gr vmax ammo out of a 1/7 twist barrel, and open those up to 1-1.5 in groups with heavier ammo? I wasn't shooting with a vice or anything, just sitting down at the bench basically using the mag as a mono-pod. I know this is far from the ideal way to do this, but you use the tools you have on hand. I apologize for the long winded question, but i was just curious if its normal or if those vmax bullets are just that good
50 gr vmax bullets are silly accurate. So that's no surprise. But you really need to stretch out to 100 yards and get a solid rest/pack to size up the gun's likes.
Rbcrusher15
02-07-15, 17:23
this is true. hopefully i'll be able to do that soon. my uncle is a member at a range, and sadly thats the only one near me that i dont have to be a member at. i'll probably join one sooner or later. but ya that ammo out of that barrel just kinda took me by surprise. i'm hoping i can get the groups to shrink with heavier grain ammo though.
Every barrel is a law unto itself. Just remember, bullet weight has little to do with how much spin i needed to stabilize a bullet- it's bullet length and shape
Rbcrusher15
02-08-15, 11:06
Fair enough gentlemen, I'm gonna do that as soon as I get the chance. Another question then, and one that has been absolutely beaten to death on probably every forum known to man, so I'm going to be a bit more specific in my question. I'm going to get a complete upper with tax money, and I've narrowed it down to 2 choices. BCM is selling a 16 in M4 SOCOM upper with free bcg and mod 0 comp for $439 right now. Providing they still have them by the end of the week, this is one option. The other is a Daniel Defense basic M4 chf upper w/o bcg for $459 from brownells. The BCM sounds like a faaar better deal. Am i really actually gaining anything with the DD chf barrel? Considering the fact that the filthy 14 rifle had a basic barrel, and has far more rounds through it than i will probably ever shoot from all of my rifles combined. The reason I'm asking this is because this is the last time I'm going to be able to spend any money on guns for probably quite some time, and I want to do it right. I know for my purpose either will serve me just fine, but based on anyones experience, is their a preference for one over the other?
I think you would be happy with either choice. The DD has the option of a mid-length gas system if that matters to you.
That free BCG screams "buy me" however.
Get what you want. Do you want the heavier SOCOM barrel profile and it's superior capability to handle heat? Or do you want something lighter and nimbler? Neither choice is wrong. But, if you really want light & nimble, the extra weight of the SOCOM will bother you long after the glow of a free BCG has dimmed
Rbcrusher15
02-08-15, 11:53
Get what you want. Do you want the heavier SOCOM barrel profile and it's superior capability to handle heat? Or do you want something lighter and nimbler? Neither choice is wrong. But, if you really want light & nimble, the extra weight of the SOCOM will bother you long after the glow of a free BCG has dimmed
Both of you are correct, and the SOCOM profile isn't the only one they have. Lighter and nimbler is nice, and I usually don't shoot fast enough for the extra metal to really make a difference with heat now that I think about it... So the BCM standard M4 profile is probably a better option. The weight doesn't bother me at all though, in fact weird as it is I kinda like it. That being said though, I'm not out humping miles on end with it, at which point I'm sure my choice of a heavier barrel would probably make make me face palm if I could still lift my arm enough to do it. Both companies have reputations that speak volumes about their quality, I just don't know if chf is superior to mil-spec enough to sway me one way or the other. There's just something about hammer forged barrels that makes me stop and think. If someone wants to reach through the screen and smack me feel free to...
You're over thinking it. None of the M4s coming out of the Hartford plant use a CHF barrel
Rbcrusher15
02-08-15, 12:10
Lol thank you. I'm going to go with the BCM upper and be happy with it. Also nice to support a Big 10 conference company. GBR!
Good choice, but why not another bcm option?
As for ammo. 50 gr vmax is possibly the most accurate short range bullet out there.
That said, 25 yds won't tell you much.
Rbcrusher15
02-09-15, 09:13
Good choice, but why not another bcm option?
As for ammo. 50 gr vmax is possibly the most accurate short range bullet out there.
That said, 25 yds won't tell you much.
I assume you're referring to a mid length upper? Always an option. I really don't have a whole lot of experience with them, as I've only owned one. Muzzle stayed flat as hell and shot really soft, but I just attributed that to the surefire comp. Did the mid length help muzzle climb at all? I've looked online quite a few times, but its always two sided and I'm really not sure which side is right lol
Hard to say with muzzle climb as my mid upper is very different than my carbine. For a 16" barrel, there is no reason to go carbine.
I was mainly referring to barrel profile, though. Most people, myself included prefer lw barrels. Bcm has lw hammer forged barrels. If you want the weight, get it, but think about it first.
There is always noveske and centurion barrels too. Both hammer forged.
Rbcrusher15
02-15-15, 09:49
So finally got lucky and found a mid length upper in stock. I decided to go with the BCM standard mid length upper. I'm going to go out and shoot it today and see how she works. I appreciate the input fellas
sgtstinger
02-16-15, 08:11
I've always been happy with BCM stuff, especially their barrels...
In a related vein, how well overall does typical 55 grain M193 perform from a 1/7 twist barrel?
In a related vein, how well overall does typical 55 grain M193 perform from a 1/7 twist barrel?
I don't think you can tell the difference between 193 from a 1/7, 1-9, or even 1/12. You'll get crap groups with all 3, haha. Seriiusly, probably 2-3" on average.
Faster twist doesn't effect accuracy of lighter bullets. I hear you can frag them out the barrel with the super light vermin loads, but people have shot 1" groups with 40 gr out of a 1/7.
Failure2Stop
02-16-15, 21:26
In a related vein, how well overall does typical 55 grain M193 perform from a 1/7 twist barrel?
Just fine.
Jack Leuba
Military/Govt Product Liaison
Knight's Armament Company
Director of Shooting Stuff
F2S Consulting
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