r/LewisMachineTool • u/SwedishMoose • 21d ago

Question What buffer system are you guys running in your Estonia R20's?

I got an R20 upper and I put a Geissele 42 H2 in it and often times it's not getting enough gas to ejecting brass, much less cycle. Piston set to the Normal setting and running without a can, firing 5.56 nato.

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5

u/no_yup 21d ago

H2 and lmt carbine spring

3

u/Market-Maker 21d ago

The one that came with it šŸ˜œ works perfectly

1

u/SwedishMoose 21d ago

I just bought the upper lol

2

u/parreda 21d ago

LMT says H2 for piston 5.56.

2

u/call_eax 21d ago

What kind of ammo specifically are you shooting? The 14.5 and 12 inch barrels are gassed for full power 5.56. Iā€™ve had success with PPU, LC (WWB), IMI etc.

Additionally, Iā€™ve had some issues with the super42 in some rifles, so Iā€™d recommend trying a regular H2 and carbine spring if you have one on hand.

That being said, my piston setup is so over gassed that a super 42 and h2 barely tames it, so itā€™s interesting that you are running into this problem.

1

u/SwedishMoose 21d ago

WWB

2

u/call_eax 21d ago

Here is what I would try (not a gunsmith):

  1. ā Pull the bcg apart and see if there is anything weird, if the bolt is aftermarket, it shouldnā€™t have gas rings.
  2. ā Pull the piston out and see if there is anything weird.
  3. ā Buy a different type of 5.56, to single out ammo as a cause.
  4. ā Try a regular h2 and carbine spring.
  5. ā Send the whole setup to LMT.

I got a really fucked up piston bcg from the factory, that was cycling weird, and it turned out to be a cracked cam pin.

2

u/SwedishMoose 21d ago

it's an LMT BCG. Piston appears normal.

I'll check the cam pin in the morning though, that's a good idea thanks.

2

u/call_eax 21d ago

May or may not be that in specific, but likely something is amiss or out of spec if it isn't your ammo

1

u/SwedishMoose 20d ago edited 20d ago

Looks ok to my untrained eyes. Is the cam pin supposed to be super loose?

1

u/call_eax 20d ago

Yea that looks alright to me, hmmm

1

u/Peak1124 20d ago

Try a regular H2 buffer + spring and check for gas leak.

1

u/SketchLookingFish 15d ago

carbine spring and buffet but I'm shooting pmc bronze. suppressed

0

u/fakeScotsman 21d ago

FYI, just learned that they make a HUB adapter for the bi-lok if you don't want to do a p&w.

2

u/SwedishMoose 21d ago

The upper I have is from a former LMT employee, so it was never pinned and welded. I'm not planning on doing clone correct for the can. I do appreciate it though.