Buffer system

[johnjohn]

I'm running Lilja 20" AR740 barrel. I went with a mil-spec collapsible stock, with Tubbs CS flatwire springs and a non-adj gas block. What buffer weight should I use for best performance, H2 or H3 or less? Don't want to buy more buffers then I have to.

Thanks

John

[LRRPF52]

It will be load dependent on the margins if you have a buffer and recoil spring weight that is more tailored for one type of charge weight and bullet weight.

With the RLGS and a .094" port, they are usually pretty forgiving, so that anything from a carbine 2.9oz buffer, up to an H3 will work.

Since you have the Tubbs spring, I think a carbine or H2 will be fine. I use H2's with the 16" MLGS, .078" gas port, with a SAAMI chamber done by AA. I think Bill A. said he has good results with that combo as well.

I have seen plenty of 20" guns that run well with carbine springs and 2.9oz carbine buffers, and I have also seen 20" guns run well with standard rifle buffers (5.2oz), as well as JP SCS, and Enidine buffers with the Tubbs spring. Since the port pressure is more tame on a RLGS, and the volume and dwell time are good with .094" port/20" pipe, it seems to be more stable than say an 18" MLGS.

When you buffer it up and go to the range, use Hornady 123gr A-MAX or SST as your baseline if you can. Start with one round in the magazine, and see if it chambers ok, fires, extracts, ejects, and locks the bolt face back against the bolt catch, not the bolt carrier face.

Then look specifically at what clock direction the brass has ejected to diagnose your gas system and cyclic rate. You preferably want 3:30-4:00 ejection pattern.

[Slappy]

I just changed a couple things around on my 24" rifle I went back or to a low pro gas block, anywhos I have a standard carbine buffer that I can send you to try if you promise to send it back or maybe even buy it. That should solve a couple little things right off the bat. Going to the range in the AM to check out and make sure things are normal and if so I can get it in the mail by Friday so you can try it. Send me a message and let me know. BANG BANG!!

[johnjohn]

Thank you LRRPF52 for your in depth explanation.

Slappy - Thanks for your offer. I spoke to my cousin and he has a receiver extension kit on the way which included a carbine buffer. I can test using his buffer.

Again thanks for the explanation and offers. Very cool and knowledgeable people on this forum.....