A couple questions about recommended buffer weight/ spring setups. I only have experience with proper rifle length buffer systems and H1, H2 and H3 Carbine systems but am willing to venture out if the A5 is really that good...

1) I am building an 18” rifle for my girlfriend’s dad. It has an 18” Criterion Barrel (CORE series) with rifle length gas tube. Not sure what the gas port diameter it is.

I’m thinking Springco Green spring with A5H2 buffer? Maybe I could go H3?

2) I have an 11.5” Barrett REC7 upper. It has suppressed and un-suppressed gas settings and I plan to purchase my first suppressor for use on this upper (SOCOM RC2).

For this I’m thinking Wolff XP Spring and A5H4 Buffer?

I would rather have the weapons be slightly over-gassed and be able to function with all ammo (I.E. low powered stuff like PMC Bronze) but am wanting them to be tuned as best as I can get them. What says the forum?

Honestly I would buy two of the H2's and a 3 pack of the tungsten weights on ebay here Tungsten weights
Then you can fine tune it as needed.
I don't think you'll need an AH4 in your 11.5 but I could be wrong.
It all depends on your port size and how strong the buffer spring is.
Running an 11.5 with a port size of .050" and an AH2 with geissele super 42 spring and it runs great.
My 10.3 with a port size of .062" and an AH3 with geissele super 42 spring also runs great.
Hopefully that'll help you get close to what you need.

That is a good idea, I just don’t know I’ll have the time to tune his rifle with such detail as to swap out individual buffer weights. All of the parts are being collected at his place and will probably be put together over Christmas or something.

I would think the AH2 would be okay on the 18" not to sure if the AH4 on the shorter one would work good. I'd try an AH3 first. But that's just me.

I ordered the A5H2 for his gun with a springco green and VLTOR tube.

For my piston shorty, I’m going to order a springco green, a Wolff XP and the A5H3 and H4 with and use a POF 7 position tube with carrier support. I figure I’ll try out the combos and use what works best. Whatever I don’t use, I have plenty of other rifles to put them on.

Taken from SOLGW FAQ Section:
https://sonsoflibertygw.com/frequently-asked-questions/

Any barrel length 556 ?- A5 Systems are Green and A5H2 unless run with a law tactical folder. If using the Law Tactical folder drop to a A5H1.

11.5” ?Milspec: Blue Spring/H2 (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)
12.5” ?Milspec: Blue Spring/H2 (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)
13.7” ?Milspec: Blue Spring/H (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)
13.9” Milspec: Blue Spring/H (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)
14.5” ?Milspec: Blue Spring/H (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)
16” ? Milspec: Blue Spring/H (LAW Folder H), A5: Green Spring A5H2 (LAW A5H1)

300 BLACKOUT
9”: Blue Spring and H2 (can use a white hot as well)

Good info. I saw their video about the A5. Don't know if that factors in piston use and a suppressor. Thanks for the help!

I will never buy from TD materials again.
They sat on my order for a week before shipping, then shipped short....

A5H2 mimics the Original buffer weight pretty closely and uses springs designed for rifle buffer system.  The rifle buffer system is what the AR15 rifle was designed around.  

20yrs ago at MG shoots it was common to see short barrel M16’s with A2 stocks.   When I inquired why I was told because they work,  there’s no bolt bounce and the ROF is a bit slower.   That stuck with me.  

Even before the A5 system was born I liked to run 5oz 9mm buffers in the carbine buffer system as they’re about the same weight as A2 and now A5H2 buffers.

Thanks for the input. I did as I said above. For the 18”, I ordered a rifle spring (springco green) and the A5H2. For my piston gun, I am going to play around a bit. I ordered a springco green, wolf XP spring, and the A5H3 and H4. We’ll see what works out.

Now, based on what you were saying with the “original” buffer weight... I am quite the AR “purist” (despite having a piston gun lol) and tend to think that Mr. Stoner did many things right the first time around. (If you peek into the retro forum, you’ll find me there in many places, and I own more early ARs than I know what to do with lol.)

I am very well versed in the minute details of the AR system and the early faults, etc. Based on what I know, the A5 system does seem to be a legitimate improvement over the standard carbine setup, moving the “carbine” back closer to the original design parameters (ie rifle spring and buffer weight).