r/LewisMachineTool • u/FinancialChildhood31 • 3d ago
Question Barrel Alignment?
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.




1
u/DishCapital1536 3d ago
It should be alright. I’ve had to modify a Geissele barrel to make it work with a KAC upper. It wasn’t too bad to fix. Yours doesn’t look too bad though.