Ok, I'll pontificate on a subject regarding your (308 gas gun) rifle. Mainly two points. The recoil system and I'll briefly touch on the gas system. I would also listen to what
@KurtM has to say; we also have a mutual friend down in TX that is a repository of really good Gas Gun info. If it can be answered, he's the one to answer it. Or Kurt
For right now, you have a DPMS pattern rifle (AR308) and not an Armalite pattern rifle (AR10). There is a difference and some folks say tomato-tomotto, but it can really matter sometimes especially with fitment shit.
Anyway,
Recoil System:
What are you sporting on there? A standard carbine Extension (buffer tube) and a shorty buffer with a short (probably cut down) spring?
Or an A5/AR10 carbine extension with a standard Carbine buffer and spring?
My personal preference is the latter. I don't ever use shorty buffers and springs. I know some folks use them and really like them and I don't mean to take away from them. But, here's why I don't ever use them. The only shorty buffer/spring combo that I've ever seen work is DPMS. DPMS is basically the ones who started using shorty buffers and springs prolifically. To my knowledge, they are the only ones that had a purpose made short recoil spring. Everyone else just cuts a carbine spring and calls it good. I have purchased short springs only to find that they've been cut. If someone else knows of a shorty spring maker that actually works, please post away. I don't trust any company out there to be competent enough to make one. But that's just me. Plenty of time with them and pretty much all bad.
Usually, when people cut these springs, in order for them to function, they will also stack up - which means the spring coils are smashed together in the tube and stop moving. Then you have BCG bounce and short stroking, bolt override, etc. Not long enough, they can short stroke, slow return, fail to feed, extreme BCG bounce and excessive recoil. Then the fix is to stretch the spring and voila! you fucked up it's spring tension and it still does all the above but worse. I'd say ask
@rockchalk06 about spring stack.
Another neat trick people do is use an A5 Extension with a shorty buffer...not a good thing.
I don't have any shorty buffers or springs. If I can't sell them, then I chunk 'em in the trash because they're useless as a retired wheelchair repairman on O2.
Here's the secret to a good big bore gas gun recoil system:
A5/AR10 Extension
H2 Carbine Buffer
Tubbs spring or a heavy carbine spring (usually painted red)
I think JP has a system that works well too but I haven't ever used it so I cannot say anything good or bad.
@KurtM knows about these
Gas System:
Here's one of the subjects that makes everyone mad AF so I don't say much anymore on it.
IMO, if it was mine, with an 18"-20" barrel, I'd port it to .093 +/- .001. .095 is fine too. Otherwise hunt down a table for 16" mid or carbine gas.
I will say that if you have an adjustable gas block, remember that it's only going to work up the gas port in the barrel. That's why most people waste the $$$ on these adjustable gas blocks that don't do shit three turns from closed no matter how much they open them up. If I run an adjustable gas block, I will open the gas port to a minimum as large as the largest opening on the gas block I think I'll need. Otherwise you are wasting money with an adjustable gas block.
Now, if you think you have to learn the hard way and find out for yourself and make sure you spend a lot of time and money, then completely disregard anything I said.
