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Posted: 9/7/2014 10:11:46 PM EDT
Ive never even considered this before. but shot a new upper today with an AIM 9310 BCG and PSA upper and the marks on the PSA barrel extension are marking the face of the bolt carrier.
The four dimples as shown on this pic are creating a matching mark on the front face of the AIM Bolt Carrier. 
Edited to add bot carrier face photos. 
this is after firing 60-rounds of XM193 |
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Posted: 9/8/2014 12:02:00 AM EDT
[#1]
It certainly does.
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Posted: 9/8/2014 12:04:11 AM EDT
[#2]
Normal. It will wear in and stop making further ugly marks.
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Posted: 9/8/2014 12:04:21 AM EDT
[#3]
What else is going to stop its forward movement?
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Posted: 9/8/2014 3:12:28 PM EDT
[#4]
Yes, bolt to barrel breach area, and carrier to face of barrel extension with mate to each other on bolt lock up.
But to back it up, Why the fuck does the front of the carrier surface have a protrusion/bump on it since it will mate up with the front of the barrel extension on lock up. The front side of the carrier should be flush/smooth as a babies ass, and I would get Aim on the phone for at least a replacement B/C since the one you have has a factory flaw on it, if not a new barrel as well due to the damage that the defective B/C did to the barrel extension as well. 
P.S, Post a Photo of the front of your carrier. I want to see if its a factory flaw when the carrier was milled, or if it was debris that was on the face of the bolt that was encapsulated when the carrier was plated instead. |
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Posted: 9/8/2014 3:14:23 PM EDT
[#5]
Quote HistoryQuoted:
Yes, bolt to barrel breach area, and carrier to face of barrel extension with mate to each other on bolt lock up. But to back it up, Why the fuck does the front of the carrier surface have a protrusion/bump on it since it will mate up with the front of the barrel extension on lock up. The front side of the carrier should be flush/smooth as a babies ass, and I would get Aim on the phone for at least a replacement B/C since the one you have has a factory flaw on it, if not a new barrel as well due to the damage that the defective B/C did to the barrel extension as well. http://www.dillonprecision.com/uimages//JP_Bolt_Carrier.jpg https://4b1e874935ea5d25a97e-f099844d0e354c7ab50c55a966be6870.ssl.cf2.rackcdn.com/product/XAIMNIBBDGBCG.jpg What carrier is that in the first pic? |
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Posted: 9/8/2014 3:22:05 PM EDT
[#6]
Quote HistoryQuoted:
What carrier is that in the first pic? JP low mass, and only used the photo since its the first one that found that showed the front of a carrier that should be flush; and not to merit the value or quality of JP low mass carrier instead instead. |
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Posted: 9/8/2014 3:25:47 PM EDT
[#7]
The 4 "dimples" in the OP's post almost look like the imprints from a Brinell hardness test. If they were in fact impressions from that test, perhaps the front of the BCG is showing some "ghost" marking on the front of it as a result of the rest of the carrier contacting the extension, but not those 4 areas.
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Posted: 9/8/2014 3:51:51 PM EDT
[#8]
Nice cleaning job. It's spotless. What did you use?
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Posted: 9/8/2014 3:55:50 PM EDT
[#9]
Quote HistoryQuoted:
The 4 "dimples" in the OP's post almost look like the imprints from a Brinell hardness test. If they were in fact impressions from that test, perhaps the front of the BCG is showing some "ghost" marking on the front of it as a result of the rest of the carrier contacting the extension, but not those 4 areas. +1 |
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Posted: 9/8/2014 10:13:14 PM EDT
[#10]
I can see grabbing a raw barrel extension to do hardness test on for the batch lot, but to throw the "dimpled to hell" hardness tested barrel extension (in a bearing area) back into the batch to be used to actually produce a barrel with, just wrong in so many ways.
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Posted: 9/9/2014 12:07:06 AM EDT
[#11]
Quote HistoryQuoted:
I can see grabbing a raw barrel extension to do hardness test on for the batch lot, but to throw the "dimpled to hell" hardness tested barrel extension (in a bearing area) back into the batch to be used to actually produce a barrel with, just wrong in so many ways. Just curious why you feel that way. It doesn't appear to affect function or strength, and other than cosmetic issues, wouldn't be a problem. I don't know the specifics of the extension in terms of material and heat treat, but know a lot of precision parts for other industries have a brinell check to confirm proper heat treat. It is usually done in an area where it won't affect function but can serve as a good visual indicator that it went through the QC process. |
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Posted: 9/9/2014 5:14:54 AM EDT
[#12]
Not uncommon to see single ball testing show up on non bearing areas on say the side of a carrier, but to test a part over and over again 4 times on a bearing area, then put it back into the lot to be used in production, way over the top from even a cosmetic stand point.
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Posted: 9/9/2014 3:58:04 PM EDT
[#13]
If I remember correctly, there have been a couple of posts in other forums and I think the PSA industry form about these dimples. I'm not sure if PSA or anyone else provided a reason for them. Is it Colt that stamps M4 on their extension? OP, how about a photo, in focus please, of the front of your carrier. |
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Posted: 9/9/2014 7:32:17 PM EDT
[#14]
Quote HistoryQuoted:
If I remember correctly, there have been a couple of posts in other forums and I think the PSA industry form about these dimples. I'm not sure if PSA or anyone else provided a reason for them. Is it Colt that stamps M4 on their extension? OP, how about a photo, in focus please, of the front of your carrier. I'll bet this. Colt stamps a 4 on their M4 barrel extensions at the 3 o'clock position. Perhaps PSA places 4 evenly spaced dimples on their M4 extensions at the 9 o'clock position? |
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Posted: 9/9/2014 10:40:37 PM EDT
[#15]
Out of curiosity, I just looked at 5 AR's, including 1 from PSA, and none had these marks. I still wouldn't worry too much about it, but might be worth a call to the manufacturer to confirm.
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Posted: 9/9/2014 10:42:21 PM EDT
[#16]
Quote HistoryQuoted:
I can see grabbing a raw barrel extension to do hardness test on for the batch lot, but to throw the "dimpled to hell" hardness tested barrel extension (in a bearing area) back into the batch to be used to actually produce a barrel with, just wrong in so many ways. I have an m&p with 3 test dimples. I assume they do it at steps in progression like machining,heat treat/ tempering and after melonite? |
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Posted: 9/9/2014 10:54:27 PM EDT
[#17]
Quote HistoryQuoted:
Out of curiosity, I just looked at 5 AR's, including 1 from PSA, and none had these marks. I still wouldn't worry too much about it, but might be worth a call to the manufacturer to confirm. Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway) From Joe Weir: On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN. |
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Posted: 9/9/2014 10:58:14 PM EDT
[#18]
Quote HistoryQuoted:
Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway) From Joe Weir: On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN. Quote HistoryQuoted:
Quoted:
Out of curiosity, I just looked at 5 AR's, including 1 from PSA, and none had these marks. I still wouldn't worry too much about it, but might be worth a call to the manufacturer to confirm. Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway) From Joe Weir: On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN. That is interesting. The upper was in fact a "Premium" Upper and just shipped end of last week. It was a "blem" according to the website, but I don't see anything wrong with it. Maybe the blem is not having the dimples??? I haven't shot it yet, so the thing was very clean, and clearly no dimpled. Better call and complain.... 
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Posted: 9/10/2014 8:12:35 AM EDT
[#19]
I would have guessed it was something left from the way it was clamped/secured in the machine making it. Part of keeping it from rotating and in alignment through the process.
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Posted: 9/10/2014 10:46:27 PM EDT
[#20]
Quote HistoryQuoted:
Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway) From Joe Weir: On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN. Synyster06Gates, Please post photo's, (Also StevenH, I still waiting to see photo's of the front of your carrier, since if the impacting denting is bad enough to the front of carrier, could cause the carrier plating to flake off). I would like to see if the indents are consistency on the left hand lug location of all (such as in part of the barrel extension installing process to the barrel), or if these marking are more of a cosmetic identifier on the barrel extension instead (why, i don't know, since the barrel extension feed ramps are visually different on a M-4 barrel extension verses a standard barrel extension so they really don't need to be marked in this fashion on a bearing surface). On a standard barrel extension, the feed ramps start point are flush to the OD face of the barrel extension line, while on a M-4, the start line of the ramps are recessed back down from the OD face line instead. 
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Posted: 9/10/2014 11:13:26 PM EDT
[#21]
Quote HistoryQuoted:
What else is going to stop its forward movement? I guess the cam track could but the pin would bust in a few rounds. |
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Posted: 9/14/2014 12:50:29 PM EDT
[#22]
Quote HistoryQuoted:
Synyster06Gates, Please post photo's, (Also StevenH, I still waiting to see photo's of the front of your carrier, since if the impacting denting is bad enough to the front of carrier, could cause the carrier plating to flake off). Quote HistoryQuoted:
Quoted:
Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway) From Joe Weir: On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN. Synyster06Gates, Please post photo's, (Also StevenH, I still waiting to see photo's of the front of your carrier, since if the impacting denting is bad enough to the front of carrier, could cause the carrier plating to flake off). Had a hard time getting photos. This is the best I could do. This is after only firing 60-rounds of XM193.
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Posted: 9/14/2014 12:58:42 PM EDT
[#23]
Quote HistoryQuoted:
The 4 "dimples" in the OP's post almost look like the imprints from a Brinell hardness test. If they were in fact impressions from that test, perhaps the front of the BCG is showing some "ghost" marking on the front of it as a result of the rest of the carrier contacting the extension, but not those 4 areas. Thats what it seems like to me. |
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Posted: 9/14/2014 9:25:46 PM EDT
[#24]
Quote HistoryQuoted:
Thats what it seems like to me. Quote HistoryQuoted:
Quoted:
The 4 "dimples" in the OP's post almost look like the imprints from a Brinell hardness test. If they were in fact impressions from that test, perhaps the front of the BCG is showing some "ghost" marking on the front of it as a result of the rest of the carrier contacting the extension, but not those 4 areas. Thats what it seems like to me. Agreed and nothing to be concerned about |
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Posted: 9/15/2014 11:05:00 PM EDT
[#25]
After viewing the topic pics I'm gonna say the dimples on the barrel extension do NOT match the marks on the Carrier. The ones on the carrier are further apart while the dimples on the extension are in a smaller(shorter distance) cluster.
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Posted: 9/16/2014 3:47:55 AM EDT
[#26]
Quote HistoryQuoted:
After viewing the topic pics I'm gonna say the dimples on the barrel extension do NOT match the marks on the Carrier. The ones on the carrier are further apart while the dimples on the extension are in a smaller(shorter distance) cluster. In the chicken verses the egg, and which came first game, the barrel extension in this case was peen tested/marked for some reason unknown, which will raise the surface around the barrel extension indents, and these surface indent higher surrounding areas caused the pressure wear that you see to the front of the carrier now. Is there a harm/foul, really the only downfall is that the the coating that was put on the carrier to prevent it from rusting, has been pressure worn off now (the face of the receiver bright silver finish, which is bare untreated metal). |
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