I am VERY fond of my AR180B, and I like the basic design of the rifle better than that of the AR15. The gas-piston system keeps the breech/receiver MUCH cleaner after heavy shooting. The bolt carrier is significantly heavier than that of the AR15, which means that it has more momentum during the feeding/extracting cycle and thus ejects and locks-up more reliably. The inner dimensions of the receiver and the recoil-spring set-up are such that there is VERY little bolt carrier-to-receiver contact, and plenty of room for trash, gunk and fouling to get pushed out of the way. When fed from GOOD magazines(the other AR15 bugaboo), my AR180B runs like a top and can make a 6" steel plate dance at almost 200yds.
Apart from the action, though, the AR15 has certain features that I can only wish had been incorporated into the AR180B design, such as:
- A port-side external bolt hold-open/release lever
- Rigid handguards w/aluminum heat shield(found on original AR-180)
- Spring-loaded dust cover(also found on original AR-180)
- Elevation/BDC-adjustable rear sight
- Picatinny rail on top, instead of the proprietary scope-mounting-plate
- Chrome-lined barrel/chamber
- Positive safety-lever detent
On balance, these minor details tend to make the AR15 somewhat more "shooter-friendly" IMO than the AR-180B, but not by much...