Thread: 55gr CMJs

How fast are people pushing these and through what twist rates?
Anyone experienced jacket separations?

22grs of AR2206H is causing jacket separations through my Spikes 14.5" 1/7.

Sent from my XT535

Are these the Frontier projectiles? If so I have trialled over 26grs of 2206h behind them while working up a load and have had no problems at all.
Cannot think what would be causing that.
I use a Stag with a 20" barrel, 1 in 7,so perhaps that is the difference?
Haven't had a chance to crony it yet tho.

Bugger I meant a 1 in 9 twist.
Hopefully someone more clued up will jump on.

I have a Stag model 4 coming tomorrow, so this looks interesting as I'll want to reload. I expected that the heavier projectiles like 69gr would be more suited than 55gr? Im hoping I get to test it next weekend with factory ammo, after that Im looking for projectiles to buy.

I believe the 1 in 7 twist may be too quick for the 55 gr pills. The jackets are thinner than on the heavier weights and at that speed (approx. 300,000rpm) the jacket pulls itself apart. I may be wrong though, wouldn't be the first time either.

A lot of guys in our club run these for 3 gun and I've started using them.
The advice I'd been given was that for an identical powder weight these will push higher velocity, similar to lead projectile.
Everyone has had to drop their loads after chrono'ing them,

haven't chrono'd mine yet but they shoot fine at much lower loads than I usually load to

Are these the Frontier projectiles? If so I have trialled over 26grs of 2206h behind them while working up a load and have had no problems at all.
Cannot think what would be causing that.
I use a Stag with a 20" barrel, 1 in 9,so perhaps that is the difference?

Yeah, the Frontier projectiles. I've run them with 26 grains of 2206H through my NEA 14.5" 1/7 with no separation. I guess the polygonal rifling in the NEA doesn't damage the jacket during engraving as much as conventional rifling.

haven't chrono'd mine yet but they shoot fine at much lower loads than I usually load to

Is this through a 1/7?

Yeah Cmmg 16"

What load are you using?

Through my 14.5" 1/9 twist no name ar15, I get a small cloud appearing about 25 meters down range as the jackets part company. The bullets still hit the target accurately surprisingly but a get 1 in 40 that hit sideways. Many of the holes in the paper targets have a noticeable lead coloured swirl around the bullet hole which confirms the jacket is not 100% intact.

Through my 18" 1/9 twist Remington R15 and 20" 1/8 twist Windham Weaponry I have no issues and its a load that I shoot all the time as its accurate and very cost effective.

My load is 26.2gr of CFE223.
Out of the 14.5" barrel, speed is 2650fps. Out of the 20" barrel the speed was bang on 3000 fps so a mild load.
Initially I thought the twist may be the reason the jackets part company too but I think its more to do with the length of the barrel.

Interesting Simon, we wondered why the guys with 20" Windham's never had trouble but that may be what we're experiencing.

My load is around 23gr of BM2