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Just saw this Thread about Stag stepping up quality.
What’s kind of neat is that the info on their Website for the “Plus Package” is a line item list of what is in The Chart.
Hopefully it all proves true.
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Wondering if Stag is just offering the PLUS package so they can mark all the right boxes on the chart… Then shortly after discontinue that package while the chart lives on with their high marks. If they just offer the right stuff on one model gun i hope it doesnt give the impression on the chart that all their products hold up to the same quality.
The plus package thing is bullshit. It’s not plus it’s meeting the bare minimum, they are a bunch of tards :rolleyes:
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?
It is inspected.
Can you elaborate on the inspection process you use?
Visual inspection followed by function testing.
Ever had one fail?
No, even proof testing an AR is pointless as they never fail. I believe proof testing only makes sense for new and unproven designs.
From a metallurgical stand point, proofing them then visually inspecting them makes no sense. Microscopic cracks can and will form in metal from stress and fatigue. These can lead to failures. MPI tests for these cracks and imperfections in the metal. So if you’re proofing the barrels without MPI’ing them, that would lead to the potential of sending out a damaged barrel or one with other invisible flaws.
It has been stated (and I cannot find the post at this time) that even the top end parts makers have some amount of bolts that do not pass the proof-mpi. Pair this with the recent rash of busted bolt images circulating the forums as of late and I will gladly pay the $20 premium that comes with a BCM or Daniel Defense bolt.
And for “new and unproven designs…”, despite that fact that some companies know exactly how do make an AR work, they still test and inspect. Testing is not an extra developmental step, it is a verification that good parts are going into the gun.
One has no idea if a bolt is good or bad based on an MPI test. I have found many bolts out of spec dimensionally that have passed MPI but I am not aware of any in spec bolts which have failed MPI. You would be much better off taking that $20 and having someone spend 30 minutes gauging as many critical dimensions as possible or doing an extended firing/function check. MPI is something Colt got stuck with contractually. The HK416 and Sig 551 - two awesome rifles - are not MPI as far as I know. If you want an M4, buy a Colt M4. Nothing else is an M4. If you think MPI is important for non-M4s, then better have all the pistons in your car MPI and send your 416 out to a lab. Or you could just shoot it.
Let me explain this another way… Everyone has a QC procedure (or lack thereof) and QC budget. I am not sure exactly, but say we spend $50 per upper for QC. If we consume $15 of that on MPI, then that means less of the budget can be used for test firing and gauging. It is easy to just pay the $15 and get to the left of the chart. The chart has no column for number of rounds used in test firing, how many dimensions are gauged, how much high speed video is done, or how the parts are heat treated.
Who said anything about being OK with parts that are not dimensionally correct?
Dimensional tolerances and metallurgical integrity are two completely separate issues. The fact that parts do fail and there is a rejection rate alone suggests there should be hpt/mpi for certain applications.
Correct, both of which cannot be ignored. In this particular application both matter.
Testing is incredibly important. But testing to me means:
Hardness testing.
Gauging.
Function testing.
Ask each company how many rounds they fire on each upper before shipping. That is much more useful than MPI. But live fire testing is also expensive.
I can understand why you would think that way.
I think that way because we employ actual engineers who went to college.
Is that implying posters in this thread are not engineers? I mean the actual posters, not one of their friends.