Why pistol length gas for 16 inch barrels?

[SgtCottle]

I spent the good part of 2 months experimenting on this issue. I had a 16" AR barrel from Montana Rifleman with the gas in the Carbine position. It would shoot supers all day long very accurately. When it came to subsonics - it was hit and miss. Unless I ran the heaviest bullets I could get with a fairly slow powder - it would not work. Even being subsonic; the heavier powders made quite a bit of noise.

I finally trashed the carbine system gas idea .... I want a gun that is reliable and doesn't have to be handled with kid gloves to run. I put together a pistol gas system with a selectable gas block and it made things very very interesting. Reliability is 100% and being able to use the faster powders has reduced noise signature significantly. Even with the reduced gas from the faster powders the gun cycles great. I even have some 168g bullets that I use when I shoot subsonic so it doesn't cost a fortune to play around. There is no way your going to get that on a carbine gas system.

Sarg

[BWE Firearms]

I have a couple of 300/221 barrels laying around the shop with the gas system in the carbine position that people have given me. They simply don't work reliably for what the 300 Whisper was designed for. When I was designing our 338 THUMPER I didn't care about supersonic, my main concern was could I get the 300 grain bullets going 1050 FPS quietly. Once that was accomplished we figured lets see how fast we can get the 160 grain bullets going which is 2100 FPS, but it is what it is and I wouldn't change the design to get more speed because that is not the point of either one of these cartridges.

To cycle subs reliably and as quiet as possible and use the full range of powders the gas system has to be in the pistol position You must then use a three position or an adjustable gas block to choke it down to cycle supersonic loads.

There are better supersonic cartridges out there if you want mostly supersonic. Its just an added bonus of the Thumper and the Whisper.