Anyone familiar with this AR15 build? This round appeals to me more so than the 300 blackout. Simpler reloading in that just a neck re-sizing is all that is needed. Other than the barrel, uses .223 parts and magazines. Bullet weights up to 100 gr. can be used. With a 90 gr. bullet, holds around 800 ft.-lbs. out to 300 yards compared to about 625 for a 55 gr. .223 bullet at 300 yards. Might be a fun round to play with. Any feedback?