SS-109/M855 duplicate with RL-15?

[dangertree]

Looking to load some 62grain 5.56mm. Wasn't able to get any H335 or BL-C2, choices came down to RL-15 or IMR-4895. I know the RL15 will work well with the 69gn bullets, but is anyone able to offer any thoughts on these two in an attempt to duplicate 5.56NATO? The RL15 is in hand, the 4895 is quickly available.

Thanks in advance,
DT

 

[ZuluMike]

I shot 7 C-8's, 1 C8HB and 1 C7 over a cronogragh last month with issue IVI ammo, average velocity for the C8's were 2865, the C8HB average velocity was 2911 and the C7 was at 3123fps. Fired 10 rounds from each rifle to get the average. See if those powders can duplicate these velocities with out excess pressure and you will have duplicate 5.56NATO loads.

 

[dangertree]

Thanks ZM, that's good info, and in the barrel lengths required.

I've got some loads made up with 24-26 grains to start with, I'll go from there and see what does what. I finally found my Lyman book, which lists 27.5gn as max load.

 

[Popurhedoff]

I use 24gr of R-15 which gives me about 3100fps from a 20" barrel.

 

[dangertree]

I use 24gr of R-15 which gives me about 3100fps from a 20" barrel.

I wish I read that yesterday.

Interesting the variance between that number and the Lyman manual.
For 24" barrel, 63gn bullet:
Starting 24.7gn 2892fps (36.5K CUP)
Max 27.5 3210fps. (51.2K CUP)

As per that I reckoned I'd still be fairly moderate at 26gn. I'll keep a close eye for pressure, and get that chrony.

Thanks.

 

[NSRA Member]

Speer Manual

The Speer Manual gives the following data

62 grain FMJ-BT bullet, ballistic coefficient of 0.307, COL 2.255"

RL-15
23.0 grains gives 2549 fps
25.5 grains (compressed charge) gives 2955 fps
from a 22" test barrel

The highest velocity given is for 26.5(C) grains of AA 2520 and 3025 fps.

I have never seen AA 2520 for sale and I don't know anything about it.

Good Luck