Vag,
Sounds like you are on the edge of being undergassed.
If everything works fine, except when using the heavy A2 rifle buffer, then maybe the available gas does not have enough pressure to cycle the full distance required for a mag catch.
A 5oz A2 rifle buffer is equivalent to an H3 carbine buffer - the heaviest you can get. There's not the carbine range of rifle buffers but JP does sell a lower weight A2 buffer which is 3oz.
https://www.brownells.com/rifle-parts/re...27116.aspx
Obviously the tension in the spring would also be part of the equation but a 3oz rifle buffer is about the weight of a MILSPEC carbine buffer.
FYI, on another forum people have weighed difference between SA15 and full mass FA16 carriers. It's anything between 0.2-0.7oz depending on manufacturer.
You can also look at bleeding more gas or changing out your powder if you hand-load.
That's if it is gas and not a faulty lower.
Sounds like you are on the edge of being undergassed.
If everything works fine, except when using the heavy A2 rifle buffer, then maybe the available gas does not have enough pressure to cycle the full distance required for a mag catch.
A 5oz A2 rifle buffer is equivalent to an H3 carbine buffer - the heaviest you can get. There's not the carbine range of rifle buffers but JP does sell a lower weight A2 buffer which is 3oz.
https://www.brownells.com/rifle-parts/re...27116.aspx
Obviously the tension in the spring would also be part of the equation but a 3oz rifle buffer is about the weight of a MILSPEC carbine buffer.
FYI, on another forum people have weighed difference between SA15 and full mass FA16 carriers. It's anything between 0.2-0.7oz depending on manufacturer.
You can also look at bleeding more gas or changing out your powder if you hand-load.
That's if it is gas and not a faulty lower.