I just did a barrel swap, from a mid gas rainier arms barrel to a carbine gassed Ballistic Advantage with all other parts remaining the same. BA does hint on their sight that their barrels are lightly gassed.

Shot the new barrel last night, and it is super soft shooting for carbine gas. too soft though. It felt like a good middie, without the snap of my DD carbine. I did check the gas block with a can of compressed air, feeling for flow and leaks while the wife sprayed it down the tube. Everything seems aligned and tight.

With some Cheaper 55g 5.56, it would pick up the next round about 50% of the time

With Hornady 75g. it was a single shot affair with an occasional exception.

It is ejecting fine, just not picking up a round.

I want it to stay soft, so I'm debating which buffer to swap to. the standard is 5.33 ounces. options in the lighter direction are 4.56 and 3.80

Do you think the 4.56 will make enough of a difference or should i go straight to the 3.80

i do tend to shoot things like Rem UMC 223 and such so they might cause even less buffer movement, so i was leaning towards the 3.80. I haven't tuned a buffer before so I don't have experience on how much weight makes how much of a difference

What say you?

go with the heaviest buffer you can use that works on all the ammo you use.

It's all trail and error so just go progressively to H1 first before going straight to H0.

You can open up the buffer and swap out the tungsten weights for steel ones(if you have an extra buffer with steel weights) to create a lighter buffer, H1 and H0, instead of buying new ones.

You also have the option of running a semi auto carrier to drop some mass.

Sounds like the gas port is too small.

From what you describe probably would go with the 3.80.   Its kind of hard to believe that BA barrels would be gassed that light, we are are talking about a 16" carbine gas system barrel?  My 11.5" and 12.5" carbine Daniel Defense (know for moderating gas port sizes) run fine on the A5 system with the standard weight, and I had to turn down the adjustable gas block on a 14.5" middy way down before I stopped picking up rounds with the A5.

Yeah these are both 14.5 carb gas ,One is  a Daniel Defense and its snappy. This BA barrel feels smooth like a middy but isnt picking up the next round.

Trial and error indeed but these buffers are closer to $40 so I don't want a drawer of them

I'm going to try the 3.80, it'll be 1.5 ounce lighter. The other choice would only have been .75 that's why I wasn't sure if it was going to be a big enough change.

I'm not complaining about the gas port size yet, because right now it has a pretty heavy buffer, heavier than most any factory carbine would come with. This could be one smooth shooting carbine if the buffer gives me just a tad more bolt travel.

I should mention also that the BA equiped gun also has a heavy YM match bolt, the DD has a regular full auto bolt

I see no reason to run the vltor a5 on anything but a 20".  I had my 14.5 m4 set up with an a5 for awhile and changed it back to a carbine due to erratic cycling. Just when i thought i had it, cold weather set in that year and it started shorting again. Just too much spring i think.

if it was short stroking due to the spring being to long I doubt that making the spring shorter would solve the short stroking issue.

Sounds like you had the same issue as the OP, to much reciprocating mass.