I want only experienced Smiths about gas port size, location and cartridge specific to help out this/these question/s please. Other people with 1st hand knowledge can/could help also IF they know their port size! Some of my barrels I know port size on only due to manufacturer list it and depends on gas system length thereof. While I have many 6.5creeds in AR's, not all function well with standard carbine/rifle buffers and springs. This also translates to other 308 based cartridges of .473 bolts (anything with that bolt face, but not necessarily 308 based). Aero Precision is THE only company I've bought from with 100% reliability in rifle length gas systems with barrels from 20-24" with standard weight buffers and springs. I also have "camgas" systems (+2) in 260rem and 6.5creed that DOESN'T function as well until other mods are done. Is there a good way to find out what the port size is without going to a Smith? The recoil is fine with the AP: barrels and gas length with standard weight recoil components. I have a CBI barrel that shoots bug holes, but is in need on mod work (I haven't had time to do it yet) that has a rifle gas system 22" barrel that's overgassed (for now) as it pops factory ammo's primers (Hornady 123a-max and sst's), but the AP barrels work 100% perfect. I might have the port opened up more or just increase buffer weight (in the works when I have time). I do have several buffers I can change out as not to mess with taking apart buffer in the field. Has anyone used a + gas with a 308win? Port size and location is EXTREMELY important on non-308win's is what I've come to learn the difficult way. Sure, throw in a h3/h2/h4 and call it good, but I'd rather have answers to the questions. This isn't a debate or p i s s i n g match, so keep it calm as some can't help themselves! If you have a factory complete gun or upper and know what specs are as far as port size, location and cartridge goes (non-308 type) feel free to chime in!