Running into some cycling issues unsuppressed with supers and subs. Ran a handful of different ammo with the upper. Some 220gr Rem subs, 205gr Sig tipped subs, 194gr LeHigh Def max expansion subs (2 different makers), some 120gr Sig SBR supers, and some 115gr Sig Open Tip supers. All but the 115gr Open Tips behaved like single shots while the 115gr ran fine though I do not remember if the 115’s allowed lrbho. Using an A5 equipped lower with an H2 weight buffer (5.3oz) and Springco Green spring. Ordered an A5 “H” (3.8oz) buffer, see what happens.

Looking at the LWRCI website, the only 300BLK at 10.5" is a DI gun.  Is that correct?    They ship with an H2 buffer so it seems what they expect you to use.

Can't hurt to change buffers.  I had almost the same issues on a KAC SR-30 and had to send it back.  Turns out it was a leaking carrier key.

It is the 10.5” DI. It isn’t L-Dubs fault since I’m positive I am using it outside their intended purpose, that is to say suppressed and will guess it would run 100% as such with the supplied H2 carbine buffer. Since I am already using a the A5 buffer setup I thought I’d might as well try a lighter buffer and see if that’ll alleviate the short-stroking.

The A5H0 buffer (3.8oz) arrived and was able to make it to the range today. Results were Supers ran great with LRBHO but Subs were still a no-go.