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Posted: 6/8/2009 1:00:09 PM EDT
| I thought partof the MP process involved firing a hot test round before running the bolt throught the magnetic testing? If that is the case, should a bolt marked MP show signs of having been fired? The reason I ask is a just received one that is squeeky clean. No marks on the bolt face at all. All of the other bolts I have received had signs of test firing (granted I have only purchased complete upperr/rifles to this point no spare parts.) I was just asking to see if I really have an MP bolt. Thank you for the help. |
| MP is magnetic particle inspection, which is supposed to reveal any micro cracks in the metal part being inspected. HPT (high pressure) testing is separate and would involve firing the part with a high pressure proof load. To my knowledge, only Colt, LMT, and S&W high pressure test EVERY bolt, and only Colt, LMT, and Noveske HPT test EVERY barrel. Most of the others do batch HPT testing, meaning they will select a number of bolts or barrels from the entire production batch and HPT test them. Although HPT of every bolt is probably the best, it adds a lot of cost to do so much testing and some very high quality AR manufacturers including Sabre Defense and Noveske HPT batch test their bolts. |
| MP testing isn't as good as Magna Flux testing, I've seen flaws show by MF testing that passed the MP inspection. I have a friend that X-Ray's pipe lines and Magna Flux tests some of the thing that are really important that wont even show on an X-Ray, I had him X-ray and Magna Flux test both of my bolts and carriers and they checked out perfect, one a CMT BCG and the other a DPMS BCG, I need to get him to test my Colt BCG and see if it's up to par with the other two. |
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Quoted:
MP testing isn't as good as Magna Flux testing, I've seen flaws show by MF testing that passed the MP inspection. I have a friend that X-Ray's pipe lines and Magna Flux tests some of the thing that are really important that wont even show on an X-Ray, I had him X-ray and Magna Flux test both of my bolts and carriers and they checked out perfect, one a CMT BCG and the other a DPMS BCG, I need to get him to test my Colt BCG and see if it's up to par with the other two. I thought MagnaFlux was a form of magnetic particle testing. |
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Actually, the M stands for magnetic particle testing. The P is supposed to be for proofed.
If your bolt is squeaky clean, then it wasn't proofed And the BS in the sftermaket continues 
Which is precisely why I will use nothing but Colt bolts/carriewrs, no matter who made the rest of the piece  .
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Quoted:
Actually, the M stands for magnetic particle testing. The P is supposed to be for proofed. If your bolt is squeaky clean, then it wasn't proofed And the BS in the sftermaket continues
Which is precisely why I will use nothing but Colt bolts/carriewrs, no matter who made the rest of the piece .I actually posted this question over in the Colt forum. I purchased a complete Colt group and the bolt face was "squeaky clean", no marks what so ever just like the OP's. |
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Quoted:
Quoted:
Actually, the M stands for magnetic particle testing. The P is supposed to be for proofed. If your bolt is squeaky clean, then it wasn't proofed And the BS in the sftermaket continues
Which is precisely why I will use nothing but Colt bolts/carriewrs, no matter who made the rest of the piece .I actually posted this question over in the Colt forum. I purchased a complete Colt group and the bolt face was "squeaky clean", no marks what so ever just like the OP's. And it was marked "MP"? If so , then I guess Colt has joiuned the "to hell with honesty" crew. Well, what else awaits us in the oncoming Commu'Fascist world we're headed into?
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