I just put together a 6.8 upper using an ARP 16" midlength barrel on a complete Sionics lower. The lower was on a 16" 5.56 middy and ran great. Just wondering if I need to change anything or if I can go to an H2 or H3 to soften recoil impulse. I know Ill have to shoot it to confirm but any help from people with the same barrel would be appreciated.
You should be fine running an H2 buffer in your rifle. Just FYI, the guy who owns AR Performance recommends you start with a regular H buffer and adjust accordingly. Of course this all depends on what round you are shooting and if you ever plan on loading your own pills.
It depends on the loads. Remington and Federal 90gr gold dots are weak and may not cycle with an H2. Hornady and the old SSA with 110-120gr bullets should run fine with a regular H buffer. Hot handloads may need an H2 or 3 to slow the cycle speed. I would start with a standard buffer an adjust as needed depending on the ammo.
I put an A5 kit with Vltors standard buffer (A5H2 I think) on mine and it runs like a champ. Constructor there can probably give you a better idea how good an idea that is since my upper is an old Titan Xtreme and IIRC he had a hand in the shared design. That’s been a damn long time ago so I can’t remember the details.
I bought quite a few 110 gr S&B vmax from a buddy for cheap so I’ll mostly be shooting that. I understand it is fairly hot so I will just take a h, h2, and carbine and see what works best. I appreciate the help and will report back when I get some range time.
I am running a H buffer for my 18" mid-length 6.8. No issues with any of the factory ammo I’ve shot so far. I mostly shoot 120 SST, 115 fusions and some 110 FMJ for plinking.
I am using a super heavy 7 oz. Spikes tungsten buffer and a 15% extra power spring and mine runs like a top, even with 90 grainers. My 6.8 SPC has very short barrel (7.5" Noveski Diplomat upper) so I can’t really speak to the reliability of this set up in a 16" upper like yours.
I run a Vltor A5 with the standard buffer and an adjustable gas block with a suppressor on a 16" Wilson Combat barrel.
Soon to be an SBR.
I’ve used a rifle length buffer system and a H2 buffer with my 18" middy upper with no problems.