Have been out of the loop fr awhile and seems the info is lacking. I was thinking about a micro SBR but redone in 300 blk... Just a thought.

have you checked out delta arms?  seems to be the current golden boy for the 300blk right now.

Check with Bookhound. He may be able to help you out.

Not looking for a AR 15 base. Seems the XCR micro would be more conveniently compact. A true PDW. For an AR bases one, I'd just build it myself. An E3 KAC lower would be nice for that.

Site is still up...shoot an email?

I think you mean delta company arms,i have an 9" upper built on their 300blk barrel that i traded for.When i inquired about load data for the 9" i was told that if i have any issues with the barrel they would take care of it.I told them in my original email i got it in trade due to lack of funds to build a new one so i was amazed by his customer service.If you go ar platform i highly recommend them.I have not finished my pistol build so i cannot attest to its functionality but the previous owner did fire a few rounds through it to test subsonics with out a suppressor.