Status of NEW Comparison Chart of Commercial M4-pattern carbines

[rob_s]

@rsilvers

What I wish the chart had is the percentage of important functional parts that are dimensionally correct and correctly heat treated.

This data is unfortunately extremely expensive to gather, but that is one way we screen subcontractors. If they send out of spec parts we replace them with another subcontractor.

You could be buying some rifle that had an MPI barrel and think it is all cool and never realize that your cam pins are slightly oversized. We HPT every barrel but don’t MPI them, and would rather put the QC budget into checking parts for dimensional accuracy. Why? Because such testing actually sometimes finds out of spec parts buy one never fails a barrel from MPI (unless it fails, but they never do). So frankly, MPI is Colt’s problem. It is mil spec for an M4. It is not mil spec for a 416, G36, or Sig 551. So demand it if you want, but please consider that what really matters is getting bolt and trigger parts that are within the tolerances stated on the engineering drawings.

The issue of the FCG parts is always one that exists, but as you know hard to verify.

I’m curious about HPT without MPI. You stress the barrel but then don’t do anything to survey the effects of that stress?