Did a little load testing today with H110 subs and 1680.

[RockyRiver]

Ran through a few dozen rounds today . 8.5" barrel SBR using Silencerco Specwar. Aimpoint Patrol with el cheapo 3X magnifier at 75 yards.

I bought 4 loads to try out. All held about 2" or less at 75 yards which is about as good as I can shoot with a red dot. 75 degrees, no wind perfect conditions.

7.4 grains H110 with 200 grain gas check hard cast lead with hi tec coating. 825 fps with 12 fps standard variation. No bolt lock back but full function. Nice quiet easy shooting load.

9 grains H110 with the same 200 grain lead bullets . 1100 FPS with no sonic crack. 16 fps standard deviation. Full bolt lock back. Slightly louder than the previous load.

9 grains H110 with 225 grain Hornady BTHP . 12 FPS SD 1100 FPS Best groups of the session and full cycling.

11 grains 1680 220 grain BTHP Nosler. Full cycling 1025 FPS with 7 FPS SD.

[RockyRiver]

Took the 10.3" SBR out today with the H110 9 grain 220 BTHP loads. It has a proper scope on it. At 75 yards I had 3/4" groups with 6 bullet holes touching each other closely. The more I wring out this load the more I like it

[rippr334]

Using a carbine buffer or heavy buffer?

Thanks for sharing the load. You prefer the H110 or 1680?

[RockyRiver]

I'm using the carbine buffer. Just whatever came with the kit. Nothing fancy. At this point I prefer the H110. Its cheap enough, it works, its readily available and its very consistent and it meters great. Ive been using it in my magnum level 45 colt loads for years and supersonic 300 blk 150's but I didnt think to try it in subs.

I broke open some commercial 300 BLK subs from LAX ammo using MAST brass Iv'e had for a while and tried to figure out what powder they were using because that stuff cycled everything I had and was quiet and burned clean. I thought it had to be 1680. Turned out it was H110 and guess what ? There were 9 grains of it .

[KTMRacer]

Good H110 info.
I went to the range with a friend this weekend who had also worked up some H110 - 208 AMAX sub loads. I don't recall the grain (guess I can ask and get back with ya) but he was running a 8.5" CMMG with standard carbine buffer and a AAC SD. His also were a little quick thru the chrono but we didn't hear the crack. Maybe the old tire berm at 30 yds had something to do with it.
Anyway, fed and functioned well but no BHO with a G2 PMag. It did hold back with a Lancer.

[RockyRiver]

Let me know what he was running. I just bought a shitload of Amax 208's. I'm thinking 8.5 grains will do it.

[certifiable]

The last couple of years, H110/W296 has been my go to sub powder for pistol gas.
My 208 Max load is 8.9gr, 2.224" OAL with a CCI 400 primer in an LC converted case.
Clocks 1020 fps out of my 9" AAC barrel and locks the bolt suppressed

[njogi]

I had on this Saturday time to shoot some 208 Amax and 208 BTHPs witn 296

I did not have my chrono with me ...

8.9->9.0g 208 Amax 2.24 AOL 8.5 Gas pistol SBR with specwar sup. Cycled good and was very quite compare to some 4198, 5744 and 1680 with 190g I shot the same day- Lancer mag. My 11.0 -11.5 H4198 190g Noslers were I think transonic with a lot of Gas Blowback . No blowback experienced with 296 208 Bullet loads.

but with 7.62 SDN 6 on another SBR 8.5 - The next round did not load via Pmag - same issue with Lancer mag too - I might need to load some 208 or 190 with 9.3g of 296 and give it shot on this setup.

208 Amax 296 loads and 190g Nosler with 10.5 g of 5744 were the quietest loads I shot. The 190 nosler Blems were shot with 2.12 AOL.

Once fired LC brass - Light crimp via Lee Crimp Die.

[VinnAY]

Thanks for the data on H110

[RockyRiver]

Did a little more testing with the H110, 1680 and , 220's, 240's and AMAX 208's today.

7.5" Anderson 300 BLK barrel and whatever el cheapo buffer that came with the butt stock kit. SpecWar silencer. All rounds fired were 1 1/2" or less at 60 yards with 5X red dot scope.

8.5 grains of H110 208 AMAX hovered right around 1100 FPS . Didnt lock the bolt back every time. Very quiet.
9 grains H110 right around 1150 FPS with the 208 AMAX . No sonic crack full function with bolt hold open every time.

11 grains 1680 220 HPBT . 1000 FPS +/- 20 FPS . Full function but not as quiet as the H110.
12 grains 1680 240 leatherheads 1100 FPS . Quiet and full function. The least accurate of the bunch but I think my silencer might have loosened a bit.