What is the difference between A3 and A4?

[xrMike]

Actually, my "terminology" may have been off. But you don't"think" a .223/5.56 rifle is capable of launching a bullet fast enough to do this? Well, they definitely are.For a 55gr. projectile traveling @ 3100+ fps, 1/7" is too fast. They DO rip their jackets apart as they leave the muzzle, & accuracy (in loads that don't destroy themselves before reaching target is sh***y at best. I've tried shooting AE 55g FMJ's (>3100 fps.) through 1/7" BBLs, that's how I know it is true - ESPECIALLY after using the same ammo in 1/9" BBL with sub-MOA accuracy. Oh, by the way(as far as "where I got this info from"): before seeing it before my very eyes, I "got this info" (about .223 FMJ's literally ripping themselves apart @ muzzle w/ too fast a twist rate - 55gr.;1/7") from at LEAST two of the top authorities on the subject: RELOADING MANUALS. I own the latest ones from each of these industry giants:Barnes, Hornady, Lapua, Lee, Nosler, & Speer. IIRC, this info came from the Speer & Hornady Books. Aside from my little "terminology error," I do believe my explanation was indeed CORRECT

Hey Supersonic, I'm not trying to argue needlessly here, but my experience with 55 grainers coming out of a 1:7 20" barrel is not the same as yours. I've had pretty good results, with no evidence of jacket separation ever seen in my paper targets.

I'm referring specifically to the following combination of stuff:

-- 55 grain Remington ammo (cheapo green box stuff from SprawlMart)
-- White Oak Armament Service Rifle upper (20-inch stainless with 1:7 twist)

Here's a typical 5-shot bull, 100 yards, iron sights, fom a rest:



No signs of fragmentation or keyholing. Pretty good accuracy (my eyes are the limiting factor here, more than the gun or ammo).

I've got another image still in the camera but not transferred to laptop yet where there are 20 rounds fired, with 9 Xs, 7 tens, and 4 flyers just barely in the 9 ring. No signs of fragmentation or keyholing anywhere there either.

There may be some combos of 55 grain ammo and 1:7 barrels that produce fragmentation, but some people get away with it and even get decent results.

[Sgt Raven]

Hey Supersonic, I'm not trying to argue needlessly here, but my experience with 55 grainers coming out of a 1:7 20" barrel is not the same as yours. I've had pretty good results, with no evidence of jacket separation ever seen in my paper targets.

I'm referring specifically to the following combination of stuff:

-- 55 grain Remington ammo (cheapo green box stuff from SprawlMart)
-- White Oak Armament Service Rifle upper (20-inch stainless with 1:7 twist)

Here's a typical 5-shot bull, 100 yards, iron sights, fom a rest:



No signs of fragmentation or keyholing. Pretty good accuracy (my eyes are the limiting factor here, more than the gun or ammo).

I've got another image still in the camera but not transferred to laptop yet where there are 20 rounds fired, with 9 Xs, 7 tens, and 4 flyers just barely in the 9 ring. No signs of fragmentation or keyholing anywhere there either.

There may be some combos of 55 grain ammo and 1:7 barrels that produce fragmentation, but some people get away with it and even get decent results.

The Army wouldn't have switched to 1:7 and not been able to still use the M193 they had in stockpiles.

[bobfried]

That 55gr comment not stabalizing out of 1:7 is just plain crazy. just because you had a bullet tear itself apart has nothing to do with it not stabalizing. That's just crappy or improper ammo.

Just because it's a .223 caliber doesn't mean it was designed to be shot out of an AR type rifle. I have not owned anything in a 1:9 twist in awhile now and all my 1:7 works perfectly fine with all sort of ammo weight down to 55 gr. I have NEVER heard of or seen any report of anyone tearing jackets apart on any 55gr FMJ round made to mil-spec standard. Heck, if a random company in Russia can make it, ANYONE ELSE CAN. If you don't believe me, go buy a few box of 55gr FMJ Wolf and see if it will shoot through a 1:7 twist barrel or not, IT WILL.

As far as CMMG over RRA, well first was the twist rate, than the chrome lining, than the mid-length. RRA offer's all of the above now, but none of that comes standard, whilst CMMG is a standard fare. If I wanted a medium priced/performance upper my money goes to CMMG.

As far as A3/4, it's sort of mute in the civilian market, we can go into the details of the history as much as we want, but as a civilian they are essentially the same thing. You should be asking more relevant questions:

1:7 vs 1:8 vs 1:9 vs 1:12
Chromelined vs non-chromlined
Stainless vs Chromoly
CAR vs Middy vs Rifle gas system
M4 ramps vs non-ramped
5.56 vs. Wylde chamber
Regular vs polygonal rifling

And so on and so on.........

[Prc329]

The RRA is actually cheaper when not buying direct. 10% has them for Under $500 and I believe Pete at AR15sales.com can get them as well for a similar price. CMMG is around $20 to $30 more.

[Pryde]

The Army wouldn't have switched to 1:7 and not been able to still use the M193 they had in stockpiles.

I'm pretty sure the Army was against the 1/7 from the getgo. The marines wanted the 1/7, the Army wanted a 1/9 or to keep the A1.

FWIW the decision to go 1/7 was ultimately decided because the 1/7 was needed to shoot the new LONG tracer round.

If you aren't shooting tracers or 77 grain $2 a round ammo, then 1/9 will be superior for you accuracy needs.

99% of people shoot 99% 55gr. 1/7 shoots 55gr fine, its just that 1/9 will shoot it more accurately.

[caduckgunner]

The RRA is actually cheaper when not buying direct. 10% has them for Under $500 and I believe Pete at AR15sales.com can get them as well for a similar price. CMMG is around $20 to $30 more.

I bought my RRA from Pete @ AR15sales.com and it was in the low $400. It came with a chrome lined barrel, mid-lenght gas system, flat top w/ A2 front sight and M4 feed ramps. I think they are both quality, but I keep seeing people say one is better than the other just because they own one or they read this or that on the internet.

[Prc329]

I personally love RRA and have shot the CMMG before and honestly they didn't seem to much different.

[mike452]

I say 1/9 twist all the way.. what ever the brand..

CMMG recommends 75gr and 77gr ammo for my 1/8 twist SPR barrel.
It all depends how much you have for ammo.

[supersonic]

Hey Supersonic, I'm not trying to argue needlessly here, but my experience with 55 grainers coming out of a 1:7 20" barrel is not the same as yours. I've had pretty good results, with no evidence of jacket separation ever seen in my paper targets.

I'm referring specifically to the following combination of stuff:

-- 55 grain Remington ammo (cheapo green box stuff from SprawlMart)
-- White Oak Armament Service Rifle upper (20-inch stainless with 1:7 twist)

Here's a typical 5-shot bull, 100 yards, iron sights, fom a rest:



No signs of fragmentation or keyholing. Pretty good accuracy (my eyes are the limiting factor here, more than the gun or ammo).

I've got another image still in the camera but not transferred to laptop yet where there are 20 rounds fired, with 9 Xs, 7 tens, and 4 flyers just barely in the 9 ring. No signs of fragmentation or keyholing anywhere there either.

There may be some combos of 55 grain ammo and 1:7 barrels that produce fragmentation, but some people get away with it and even get decent results.

Hey, if you can get away with what is commonly known as problematic, the more power to you! But I still won't try something again that I've seen fail many times & the evidence is also published by industry leaders.

[supersonic]

The RRA is actually cheaper when not buying direct. 10% has them for Under $500 and I believe Pete at AR15sales.com can get them as well for a similar price. CMMG is around $20 to $30 more.

EXACTLY.

[supersonic]

I'm pretty sure the Army was against the 1/7 from the getgo. The marines wanted the 1/7, the Army wanted a 1/9 or to keep the A1.

FWIW the decision to go 1/7 was ultimately decided because the 1/7 was needed to shoot the new LONG tracer round.

If you aren't shooting tracers or 77 grain $2 a round ammo, then 1/9 will be superior for you accuracy needs.

99% of people shoot 99% 55gr. 1/7 shoots 55gr fine, its just that 1/9 will shoot it more accurately.

I wil agree w/ MOST of this.

[supersonic]

I say 1/9 twist all the way.. what ever the brand..

CMMG recommends 75gr and 77gr ammo for my 1/8 twist SPR barrel.
It all depends how much you have for ammo.

YOU AND CMMG would be definitely in the ballpark, if not typically correct! BTW, if anyone else feels this needs any more attention, PLEASE, by all means: knock yourself out. My fingers have suddenly fallen assleeee.......................p Peace!

[ar15barrels]

I bought my RRA from Pete @ AR15sales.com and it was in the low $400. It came with a chrome lined barrel, mid-lenght gas system, flat top w/ A2 front sight and M4 feed ramps. I think they are both quality, but I keep seeing people say one is better than the other just because they own one or they read this or that on the internet.

You did not get actual M4 feedramps, you got a hand-dremeled blending of rifle feedramps into the receiver.
It's better than no blending, but it's NOT M4 feedramps.

[Spodeley]

Just curious: why were you shooting 52gr. match loads out of a 20"; 1/7" twist BBL? I'm guessing it was before you knew about what it would get you?

You're not confused, I WAS! I didn't know - it's new to me. Someone ( a Canadian) pointed out to me (on my blog) that "At 1:7 twist at your stated 3250fps, the round will spin up to 334,286rpm." Disintegration just waiting to happen. My buddy with a 1:9 twist, his bullet rpm is 260,000rpm. I was always bad at math. We do learn, don't we?