Good morning folks! I just got this barrel at a reasonable price and was wanting to use it in an AR build. It is a varmint profile at 24 inches and is chambered in 22/250. I want to re-chamber to 223 Wylde, shorten to 20 in., maybe as short as 16 in. In either case, can I assume a carbine length gas system would be best or what would be the longest gas system that could be used? My boolit is 61 grain, Elvis powder coated. 1800 fps min. would be my goal. Thanks for any input!