My 300 build is finally up and running!

[alorton]

It is a beautifully crafted upper. The parts fit well and the action is very smooth. I like the side charging handle very much but it does take some getting used to if you are accustomed to a standard AR. I chose it for this build for a very specific reason, to cycle the weapon with the gas turned off while prone using a bipod. It is also very handy for not having clearance issues with a scope.

Since it is non-reciprocating you don't have to worry about getting your fingers in the way with one notable exception. If you manually cycle the bolt on an empty mag the charging handle will stay back with the bolt. Then if you hit the release, the lever slams forward right where the release is and can bite you. When I manually cycle the bolt and it locks back, I push the handle forward and fold it in. That way, when I push the release the handle is already forward and this isn't a problem. If you don't push the handle forward as I do then you could use the handle to release the bolt when you put in a fresh magazine, much like it is taught to pull the slide on a handgun as opposed to pushing the slide release lever. This would also prevent problems.

Another issue is it does make locking the bolt open manually (as you would for a double feed clearance drill) a bit tricky. It is also a good idea when you rack in the first round to fold the handle back down afterward. This keeps the floating charging handle locked in place.

These are all minor issues for me as I won't be using one on every AR I put together (the ASA side charger is a bit pricey). But if you want something unique and well made, it is a good choice.

As for use with a suppressed rifle, it definitely seems to have less gas in the face compared to shooting my 223 rifles suppressed. I think the ASA has something to to with that, but it could also be that the full power 223 rounds vent more gas back than the lower pressure subsonic 300's.

I think it would make a great upper for a long range build like a 6.5 Grendel as well. It works well with optics and allows you to cycle the weapon prone without using your firing hand.