James95

Sorry for the very delayed update, but I finally got around to drilling and testing. I drilled my gas port to 0.0945" and with the 5.3oz buffer/springco orange spring it cycled cheap 150grain Tula ammo beautifully, 100 rounds no malfunctions. It was throwing the steel 4-5 oclock, so I decided to drill out to 0.096", and it threw the Tula 3-4 oclock but with surprisingly MUCH greater recoil. I'm going to be using a suppressor so plan to put an adjustable gas block on anyway, but I'm helping some family with identical builds and am recommending 0.0945" for their 18" aero uppers. Anyone else experience such difference on recoil with such a small change in gas port diameter? Anyways, thanks again all for the advice and help! Ain't nothing quite like a 308 ar build!

Thank you for the great info. I bought the springco orange spring and 5.3 oz buffer from KAK, Expo arms, and AR stoner (for comparison, will return the ones I don’t use), haven’t gotten the AR one yet but the other two both weight 5.1-5.15oz. Is this an issue? Also have you heard any issues with any of the 3 products? Doesn’t seem it matters a ton as long as weight and size are to specs for the buffer? I also noticed the light buffers are underweighted by .1oz. On that note, since the bcg is the vast majority of the reciprocating mass, shouldn’t I be taking that into account when figuring out what buffer and spring I need? Or are all standard bcgs the same weight? I couldn’t find Armalites bcg weight.. My gas port is as Aero says, 0.089”. I bought drill bits ranging from 0.093-0.1” and will hopefully get to drilling it out soon. Is it possible to drill it to a size where it will reliably cycle pretty much any ammo, or do I need to drill bigger and put on an adjustable gas block to do it? If so, do I just start at a 0.093” hole and test it to work my way up?

Thanks for the link, ton of good info. I think I’m following. So to clarify, any 308 ar needs at least a 5.4oz buffer to reliably cycle different types of ammo and by using the lighter buffer, it has a small window of pressures/ammo it can handle in order to properly cycle since it cycles faster? -my gas tube looks centered -my buffer tube looks to be 7” but is a tad shy of being flush with the upper receiver Do you think there would be a big difference between using the armalite carbine system vs the 2.5” 5.4 oz buffer with a springco orange spring?

Thanks! Is there a noticeable difference between doing an armalite carbine buffer system and doing the 5.4oz 2.5” buffer with AR15 tube or are they pretty similar? also, what is it that makes these superior to the carbine 3.8oz buffer that came with Aero’s setup?

Hi, before I found this forum, I built an AR308 (DPMS) rifle. I knew there was a difference between the AR10 and AR308, so I stuck to a pretty much complete Aero Precision build, but I've definitely learned a ton since reading some info on this forum! So thank you all for the great info! Here's my problem: I took it to the range, and it doesn't cycle properly. I was using Norma 150 grain fmj ammo. It was discharging the brass at 3oclock, but it never locked back on an empty mag and either was closed on an empty chamber (most of the time) or would catch the next bullet halfway and get it stuck against the lower receiver. Here's my build: Aero 18" 308 CMV rifle length barrel (bought as a complete upper from Aero) Aero nitride 308 BCG and charging handle Magpul gen 3 PMags Here's the part I think is causing the issues: I bought the Aero 308 carbine buffer system: (standard Ar15 tube with the 2.5" 308 buffer and matching spring) I reached out to Aero, and they said they tune the rifle length gas system to their rifle length buffer tube system and vice versa. AKA I can't use the carbine buffer system with the rifle gas system. They recommended buying the rifle length buffer system. I'm planning on putting the PRS lite (if it ever comes out haha) on this build, so I'd really prefer to stick to the carbine buffer system. I know every build is a bit different, but I was surprised considering others have done exactly my build with no issues. Has anyone else had the same issues I have? Now after reading this forum a bit, I've read that the 2.5" 3.8oz buffer is crap for the 308, and I'm not understanding why? Either way, I saw my options as these and really didn't like either for the reasons above: -Swap to rifle buffer sytem -drill out gas port more Is there an option 3 where I can use a carbine buffer system that will properly cycle a rifle length gas system? I.e. can I use the Armalite carbine buffer system with my build? Thanks for the help!!