AR Sponsor
Posted: 5/28/2010 12:14:12 PM EDT
|
I was cleaning my AR today and when I got to the bolt I noticed that on the bolt face at about 11 o'clock, if you are looking at the face of the bolt with the extractor at 12 o'clock position, there is a piece of metal missing. You can see the ring where the primers contact the bolt face. It kind of follows that contour. I would say that it is more of a gouge, but there is definitely metal missing not just displaced. I am wondering if anyone has seen this before? I seized the opportunity to buy a new bolt carrier group from bravo company (they are on sale). I am not sure I should be shooting with it anyway if it is showing signs of failing. What do you guys think?
Oh yeah the bolt is a Rock River bolt assembly. |
It is easiest explained as a gouge but there is metal missing, not piled up like if it were a gouge or scratch. I am wondering if somehow the metal didn't get tempered right or something like that. I would hate for that thing to fail. I got the wife's camera out and the pictures were much more productive..........
|
|
Plasma cut, hence you had a primer leak at ignition/full burn, and the hot gas pressure blow-by past the primer cup/primer pocket flowed to the bolt face, which was was both hot enough and pressurized enough (50K psi) to melt the metal way from the bolt face.
Bolt is fine for now, and such is just normal wear and tear to the bolt over the life span of it. http://www.ar15.com/content/manuals/TM9-1005-319-23.pdf Page 3-22 But, if you are reloading, limiting/counting the number of times that the brass is used and then thrown away, would be a better indicator of the validity of such still in good life, than just reloading brass until the primer pocket will not longer hold the primers before they are deemed trash. |
|
Quoted:
I would be more concerned about the two lugs that are cracked....or maybe its just an illusion in the pics Whoooo my heart stopped for a second there. Alas it is only an illusion in the pictures. So one leaking primer is enough to do that? I guess if i were to think about all the force/pressure involved with firing a cartridge then it makes sense. A plasma torch indeed. Thanks for the input everybody. I appreciate it. 
|
|
Quoted:
Plasma cut, hence you had a primer leak at ignition/full burn, and the hot gas pressure blow-by past the primer cup/primer pocket flowed to the bolt face, which was was both hot enough and pressurized enough (50K psi) to melt the metal way from the bolt face. Bolt is fine for now, and such is just normal wear and tear to the bolt over the life span of it. http://www.ar15.com/content/manuals/TM9-1005-319-23.pdf Page 3-22 But, if you are reloading, limiting/counting the number of times that the brass is used and then thrown away, would be a better indicator of the validity of such still in good life, than just reloading brass until the primer pocket will not longer hold the primers before they are deemed trash. So if I am reading the Army TM correctly this "gouge" puts the bolt out of limits since it is approximately .10" long and mabye .032" (plus or minus a little bit) wide? |
|
Think .010 deep, and with such, the bolt still has life in it.
Plasma cutting is pretty clean in itself, and if such turns into chipping, then it's time to change out the bolt. Right now, the cutting is only at the edge of the primer cup to brass primer cup area, and really not a bearing area so much. If it does start to chip out/spreed, then your going to have brass and primer cup bonding, and can lead to problems. Bottom line here, such is not going to be covered under any warranty, so you may as get the most life out of the bolt before it is replaced. |
AR Sponsor