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Posted: 10/10/2016 1:25:28 PM EST
[Last Edit: 10/10/2016 1:28:39 PM EST by delta-10]
Like the title says, what is the difference between "Tested" and "Untested" bolt carrier groups. PSA had a deal where you could buy a 120 pack of Federal 62gr green tip 5.56 and an "Untested" AR-15 full-auto bolt carrier group for $99.00. I bought several of these and the only difference I can see is that the edges around the front aren't rounded off like on a "regular" bolt carrier group. I have seen some of the Nickel boron groups that look like that with the edges not rounded, but that is it. I took the bolt out of the carrier and it was dark and not shiny with chrome lining, but PSA says that the "untested" groups are chrome lined, phosphate finished. Sorry if this is a dupe, but I couldn't find anything about these so I figured that I would ask here.

The Specs for the group in question:
Bolt Steel:9310
Bolt Finish:Mag Phosphate
Bolt Testing:No
Carrier Steel:8620, Chrome lined
Carrier ProfileFull-auto
Carrier Finish:Chrome-lined, Phosphate Coated
Gas key Finish:Chrome-lined, Phosphate Coated
Gas Key Screws:Grade 8
Staked gas key:Yes
Link Posted: 10/10/2016 1:30:50 PM EST
[Last Edit: 10/10/2016 1:31:30 PM EST by 021411]
Tested usually means high pressure testing and then magnetic partical inspection. A high pressure round is fired from the bolt and then checked for cracks in laymans terms.
Link Posted: 10/10/2016 1:46:35 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 021411:
Tested usually means high pressure testing and then magnetic partical inspection. A high pressure round is fired from the bolt and then checked for cracks in laymans terms.
View Quote



HPT/MPI. It is desirable, but not required.
Link Posted: 10/10/2016 4:09:07 PM EST
The bolt itself has the MPI stamping if I recall. I am at work and I see that the bolt carrier in the new Ruger AR-556 looks the same way with the what I will call "facets" towards the front. The ruger even has more pronounced machine marks on it than the PSA bolt carriers that I am questioning.
Link Posted: 10/10/2016 5:16:52 PM EST
The chromed inside of the bolt carrier will not be shiny reflective like a bumper on an old car. It appears kind of flat silver/grey color, that's perfectly normal GTG!
Link Posted: 10/10/2016 6:23:28 PM EST
9310 is not the "mil-spec" if I am not mistaken if that matters to you. I belive the spec is for C-158? I have used 9310 bolts form Aim, C-158 bolts from PSA and BCM all with great results. You will probably never have an issue and I've even heard arguments and 9310 being superior.
Link Posted: 10/10/2016 6:32:21 PM EST
[Last Edit: 10/10/2016 6:32:53 PM EST by Darkamek]
You missed out on the other daily deal they had where they were doing the premium BCG.
Link Posted: 10/10/2016 6:40:54 PM EST
[Last Edit: 10/10/2016 6:41:21 PM EST by dalle0001]
No HPT / MPI tests make the bolt/carrier a little less expensive. You get a price reduction by a small amount.
Link Posted: 10/10/2016 10:39:57 PM EST
~$20
Link Posted: 10/10/2016 11:01:26 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Darkamek:
You missed out on the other daily deal they had where they were doing the premium BCG.
View Quote


Yeah, I saw that
Link Posted: 10/11/2016 1:00:55 AM EST
[Last Edit: 10/11/2016 1:01:50 AM EST by defendtexas]
From my brother-in-law who works in the industry.

"If parts are made to meet a specific standard and the maker knows they will be tested individually they normally go out of their way to make sure their product will meet and exceed the expectations of the end user"

Link Posted: 10/13/2016 5:20:01 PM EST
I bought a few of these specials and all of my bolts are marked MPI on them so it seems they got some testing at least, or they over sold and i got "upgrades".
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