I started building and working on AR's in the 1980's (before it was cool, before this site, before the internet). Olys (along with SGWs and PWAs) were the most problematic, piss-poor, POS AR's I ever dealt with. Nothing in recent memory comes close except the trash that idiot ross rogio was cobbling together in Fayetteville, NC a few years back (2009-ish?) It got to the point that I didn't even want to assemble kits from those companies that other people got me to put together for them that they were buying from shotgun news or wherever they were getting them (which I would typically do for a case of beer if I knew you) all in the name of saving a little $. The guns would almost always have problems and it would look like I put it together wrong. Uppers and lowers that didn't fit right, plastic buffers filled with bird shot, crappy BCGs and components, gas tubes of inferior gauge metal, on and on. Even if Oly worked out their problems and totally changed EVERYTHING, I still have nothing for them. I would advise you to get with someone who really knows what he's doing and build a DI pistol AR with a 10" barrel and carbine gas tube out of quality components, if you want a pistol. Just my 2 cents.