Shay1911 Posted January 13, 2009 Share Posted January 13, 2009 Just a warning from personal experience. I have around 600 rounds of PMC ammo through my AR. It burnt the ____ out of the first chamber of my comp. It is pitted with lots of erosion. I'd rather not say which comp it is, but it is a top quality one. I hope this helps someone. Link to comment Share on other sites More sharing options...
lmccrock Posted January 13, 2009 Share Posted January 13, 2009 I have run hundreds (500+) of PMC Bronze through my comp'ed rifle. While the comp has been blackened inside, it is no worse than the other ammo I have run (mostly Remington UMC and Fed XM193). Have you run any other ammo through it? Contacted the comp vendor? I wonder if PMC changed their powder formula. If you have a borescope, look at the chamber. If the comp is eroding, the throat might be bad. Lee Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 I have run hundreds (500+) of PMC Bronze through my comp'ed rifle. While the comp has been blackened inside, it is no worse than the other ammo I have run (mostly Remington UMC and Fed XM193).Have you run any other ammo through it? Contacted the comp vendor? I wonder if PMC changed their powder formula. If you have a borescope, look at the chamber. If the comp is eroding, the throat might be bad. Lee Yea, I contacted the comp vendor, very reputable, and they said it was the ammo. No, I have not run anything else through the rifle. The bore and the chamber actually look fine with the naked eye, I have no tried a borescope but will. This is not just blackening, it is erosion of the metal, enough to create a dent and pitting in it. Comp is stainless steel. I am sure the comp still functions fine, but I am not going to shoot that ammo any more. Link to comment Share on other sites More sharing options...
JThompson Posted January 13, 2009 Share Posted January 13, 2009 Yikes! Link to comment Share on other sites More sharing options...
Tom S. Posted January 13, 2009 Share Posted January 13, 2009 If it did that to the comp, what did it do to the barrel? Are you sure you're not looking at some deposits that are making it look rough? Link to comment Share on other sites More sharing options...
Gregory_k Posted January 13, 2009 Share Posted January 13, 2009 POST PICS Link to comment Share on other sites More sharing options...
George Posted January 13, 2009 Share Posted January 13, 2009 Yeah, this I gotta' see, please post pics. 500 rounds of anything etching a stainless brake is pretty strange. There will always be some erosion after a thou or so rounds, but heavy pitting after 500 rounds, hmmm! Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 (edited) This is in no way a complaint against the manufacturer of the comp. I do think its the ammo. Is this normal? Should I be expecting this? I am sure about the round count. Edited January 13, 2009 by Shay1911 Link to comment Share on other sites More sharing options...
George Posted January 13, 2009 Share Posted January 13, 2009 Hard to say from the photo angle and the shallow shadows, but it looks to me like copper/powder buildup rather than erosion. Have you tried using a copper/powder solvent and a nylon brush to see if it cleans up. You need to see the bare metal itself to see what's really happening here. Link to comment Share on other sites More sharing options...
ken hebert Posted January 13, 2009 Share Posted January 13, 2009 I have that particular brand of comp, as well as the first generation one, and have expierenced no similar issues after several thousand rounds. Link to comment Share on other sites More sharing options...
warpspeed Posted January 13, 2009 Share Posted January 13, 2009 Hard to say from the photo angle and the shallow shadows, but it looks to me like copper/powder buildup rather than erosion. Have you tried using a copper/powder solvent and a nylon brush to see if it cleans up. You need to see the bare metal itself to see what's really happening here. It looks like build up, not erosion to me too. Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 I have that particular brand of comp, as well as the first generation one, and have expierenced no similar issues after several thousand rounds. I am no saying its the comp at all! What kind of ammo are you using? I have the comp with solvent right now, after brushing it, the metal so far, is shiny silver. Link to comment Share on other sites More sharing options...
George Posted January 13, 2009 Share Posted January 13, 2009 Copper residue and powder buildup are a normal event. If the comp cleans up with solvent leaving clean or slightly burnished metal behind, then you are good to go. No worries here from what I can see :-) Link to comment Share on other sites More sharing options...
warpspeed Posted January 13, 2009 Share Posted January 13, 2009 I have the comp with solvent right now, after brushing it, the metal so far, is shiny silver. Let's see an after picture Link to comment Share on other sites More sharing options...
kurtm Posted January 13, 2009 Share Posted January 13, 2009 Cooked on carbon looks very "shinny" also! I am betting that it is deposites. Solvents wont really clean them up as it is basically "Coked Carbon" or "Boiler Klinker". a gentle scrap maybe in order, I would also bet that you are running a short barrel. KurtM Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 (edited) This is after cleaning... Should I soak it longer? 18" barrel, rock river barrel... Should I try and sand it off? Edited January 13, 2009 by Shay1911 Link to comment Share on other sites More sharing options...
Franklin D Wolverton Posted January 13, 2009 Share Posted January 13, 2009 Try using a dental pick to take some of that off (gently). You'll probably find that it is build-up and not corrosion. As said earlier... it's cooked on (or coked). Soaking and a nylon brush probably won't take it off. You MIGHT try a copper brush after soaking, but I don't think that'll work either. Worst case... play a carmoney and dremel it out with a really fine tube sander. Frank Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 Thanks for the help guys, I will try scraping it off. Link to comment Share on other sites More sharing options...
George Posted January 13, 2009 Share Posted January 13, 2009 Scrape away, that's what I do when I get tired of looking at the buildup. Kroil and elbow grease is what works for me :-) Link to comment Share on other sites More sharing options...
Scout454 Posted January 13, 2009 Share Posted January 13, 2009 Slip 2000 makes something they call "Carbon Killer". Not the end all or the be all but it seems to work better than most other carbon removers. Link to comment Share on other sites More sharing options...
TeamGE Posted January 13, 2009 Share Posted January 13, 2009 From the pictures I see, that doesn't look like build up to me. It looks like erosion. Carbon or copper buildup only sticks to low pressure areas of the port. The area around the clearance hole is a very high pressure area, thus the erosion wear over time. Now why the erosion so quickly? Could be ammo, could be comp material. Link to comment Share on other sites More sharing options...
iainmcphersn Posted January 13, 2009 Share Posted January 13, 2009 Looks a bit like lead from the open base of the FMJ. Link to comment Share on other sites More sharing options...
TRUBL Posted January 13, 2009 Share Posted January 13, 2009 FYI.....if that who's comp I think it is.....it is made out of 416 stainless. Tim Link to comment Share on other sites More sharing options...
Shay1911 Posted January 13, 2009 Author Share Posted January 13, 2009 I tend to believe its deposits and not erosion. I was able to sand off most of it for now. Link to comment Share on other sites More sharing options...
Bronco Posted January 13, 2009 Share Posted January 13, 2009 Looks like build up to me also. If you have an ultrasonic cleaner or access to one that is what I use. Have seen this stuff build up enough to start ticking the bullet. Link to comment Share on other sites More sharing options...
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