I have a BCM mid length upper I am building a lower for and I am planning on using a fixed stock. If I use a rifle length spring and a rifle buffer, will that work with a broad range of ammunition? Do I need to use a carbine buffer with carbine spring and one of those spacers? Please help!
Read gotm4 post it covers it https://www.m4carbine.net/showthread.php?t=23001
I did. I didn’t see an exact answer to my question. Maybe I am just stupid.
The midlength gas system being longer lowers the amount of gas pressure at the gas port thus heavier buffers aren’t required. CAR would work fine, H will work but with weaker ammo or a dirtier gun it will likely jam (short stroke, running to slowing to feel as good as a faster cycling gun).
Quoting Gotm4’s post
OH SNAP:eek: I just re read it sorry you just use the rifle buffer and standard rifle spring sorry:o
The rifle buffer isn’t too heavy?
With the mid-length gas system you will have more gas pressure going to the BCG than with a rifle length gas system.
So the rifle will actually cycle a little faster than it would with a rifle length gas system.
If anything you might try a stiffer rifle spring but I would try the standard one first.
Should run fine with the standard spring and buffer. I run a carbine buffer in my middie and H buffers in my SBR’s. Many many rounds down range and so far no snags with either setup.
My Larue Stealth midlength uses a H buffer. Works fine with Wolf and Brown Bear ammo.
With a fixed length rifle stock the rifle length buffer and spring will work just fine.
If you wanted to you could use a delrin spacer and a CAR or H buffer and spring.
There’s people who do this… but I don’t know why.
If you have a rifle stock, why not run the less finnicky rifle buffer system?
More options.
Someone may already own a CAR buffer w/spring and own a rifle stock but not a rifle buffer and spring.