kenk

thank you for that, totally explains my worry there. I knew the difference was very slight, and that the kind of thread made up for most of it, but the picture takes away all doubt. You guys are great, thanks again.

having to replace the extension (buffer tube) because of excessive scarring on the threads from a buddy "showing me how" to use an armorers wrench that was too small.... I do fully understand the difference in stock sizes though, milspec on milspec tube com on com, unless you have a shim you want to try, easy enough. but 98z5v answered my question perfectly, it was on weather the slight thread difference would make any functional difference when exchanging tubes, thank you guys.

Thanks again guys, just one more thing. using the schematic provided by jtallen83, and other reiterations of the same info, I see that the threaded (receiver) side of the receiver extension is different between the commercial and MILSPEC versions. 1.170" com vs 1.185 M.S to be exact, now I know that the "teeth" or threads on the M.S versions are supposedly "sharper" and those on the commercial are "flatter" is this what allows the two to fit up as you say? My receiver extension is 7 5/8" long, and 1.70" in diameter (basically at both ends), when purchasing a new one online I am running into only ones labeled as MILSPEC, so to clarify, to your knowledge as long as the buffer kit is for .308 cal, I can put it on this rifle?(I know no one is liable, just clarifying) Or am I totally missing it again? So I have the 7 5/8" receiver extension, buffer, and spring that goes with it, If I replace the receiver extension with a 7" MILSPEC one how do I get the right size spring, the one I have would be too long right? and all of the ones I am seeing just say rifle or carbine, but..... as I am seeing I have a carbine receiver extension that is different dimensions than some...... thanks again guys, swear I am not an Idiot, just trying to eliminate room for error.......

Thanks guys, I am still at a loss, maybe dpms did some weird stuff, I dunno. My buffer tube is definitely commercial, as it is the slanted and slightly longer one. However the diameter.... is exactly the same as the MILSPEC b.s for the ar15 that my local bass pros shop carries...... is this possible or is the buffer tube they have labeled wrong? I guess I need to measure it with calipers to be certain, the reason I say they are exactly the same is the buffer tube nut off of mine fit the tube and threads perfectly for the "ar 15 mill spec" one. Sorry for my bumbling here guys, but one more time for my slow self...... on several forums folks have suggested that if you use the correct buffer and spring, then the tubes are interchangeable, this is INCORRECT right? I am attempting to learn more, this is not my intro to guns or anything, just my first a.r platform rifle, and there is a LOT of misinformation available out there.

O.k guys, total noob here in the a.r category, as far as parts and fit. So a little clarification please, on a MILSPEC part, just the part, are the sizes and or fit, totally different? The reason I ask is specifically the buffer tube, I own a DPMS lr 308, when I look up parts every damned thing says MILSPEC, is this a gimmick, will it fit? I thought no MILSPEC 308s? just don't want wrong size parts, thanks for any help.