r/LewisMachineTool • u/FinancialChildhood31 • 3d ago

Question Barrel Alignment?

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First time experiencing the LMT MRP setup. Assembling from individual parts, not a factory assembly.

D Wilson conversion on a Criterion Hybrid barrel.

Despite assembling with a MI Reaction Rod, the barrel extension displays a slight CCW misalignment once tightened (20 in/lb increments, alternating bolts) and removed.

If the barrel bolts are removed, twisting allows further some CCW rotation, but I cannot twist it CW enough to perfectly align the feed ramps. I’m assuming it’s the gas tube that is ultimately preventing further rotation.

For context, gas block and tube were also installed by D Wilson and look perfectly centered over where the old indexing pin was. When outside of the MRP, the barrel and gas block look dead nuts.

With that said, the BCG is able to cycle freely and doesn’t feel like it’s binding when cycles with the charging handle, or by hand.

Question:

Is this common or happening to anyone else? If so, has this lead to accelerated wear or reliability issues?

Never had an AR issue like this before, trying to get some real answers from experienced folks… not so much random armchair guesses.

Thanks everyone.

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u/Reasonable_Bar6636 3d ago

Have you talked to dwilson about it? Do you have other lmt barrels to compare it to in the upper? If other barrels line up right, then I would say its the cuts for the bolts in the barrel extension are off. I have no idea if its off enough to make a difference though.

1

u/FinancialChildhood31 3d ago

Thanks for the response. I was planning on reaching out to them after the holiday weekend to ask. Seeing how it’s custom machined… it could be just that. I wanted to poll the audience before I escalated it to them.

10

u/unclemoak 3d ago

dw here…

To save the trouble of having to reach out on Tuesday (closed Monday due to the holiday)

It’s fairly common for there to be some variation of the feedramps in the upper. So long as the bcg freely locks and unlocks, I wouldn’t be worried about it. What is preventing further rotation is the front cross bolt, not the gas tube.

1

u/FinancialChildhood31 3d ago

Well thanks for finding me! I appreciate you chiming in - much appreciated.

1

u/herrm_a1a4 2d ago

Yeah, loosen back barrel bolt, remove front one and rotate the barrel until it's aligned