Redleg
08-20-2009, 05:23 AM
Though my M4 seemed to function allright with the first magazine through it, I did find quite a few teeney brass flakes when I took the bolt out to clean it. A lot of my brass also had a slight pinch half way between the shoulder and rim. I found out later that the pinch was actually coming from the HK magazine. As the round is forced forward and up, the steel magazine corners were binding into the brass. I compared to one of my old GI mags, and those were slightly beveled up to allow the brass up and out. I need to pick up another HK to compare and see if mine just got pushed in or not, I think I straightened that part out with needle-nose though. T suspect the tiney, squarish, brass flakes were from the front edg of the brass catching on the front edge of the steel magazine, after the bullett cleared it. I checked this on the other magazine as well, it also hit, though not quite as abruptly. This happened with federal and remington .223. I need to pick up some real 5.56 to see if it acts the same way with a heavier slug and shoulder area.
When checking out my magazine situation, I was cycling a few rounds and discovered the brass jacket on my bullets were being cut into by a feedramp. This was almost an S-shaped cut, raising a little edge on the brass. I checked the reciver and found a burr-like high spot along the back edge of the left feed ramp. I know this was not there prior to firing, I think it was just distinct enouph I would have spotted it. It may have gotten pushed over after firing. It was on the right side of the left ramp, as if a bolt lug forced it back as the bolt was rotating back open on the return cycle. I took a small, steel rod and ran across this edge a few times to force it down. I cycled a few more rounds through this and this time the mark was still there, but only a scratch, no raised brass. Now I intend on touching up these edges slightly with a tiny round file. The raised cut was definitely significant enouph to effect accuracy. I'm not blaiming the manufacturer so much as chalking it up to "getting to know your new weapon". Also, I am currently set up with a semi-auto carrier with commercial buffer. Maybe a more violent extraction raised the metal if the manufacturer did their test fire with a heavier BC and Buffer? I DO intend on an FA bolt and maybe H-buffer to try soon.
**** Be careful and know where the gun is pointed if you cycle rounds through. The firing pin free floats in the bolt and could contact the primer when doing your function check. I have some prior experience, but am not a pro.****
Also, if anybody was wondering, the .223 brass has a (slightly detectable to the eye) swollen/steeper shoulder after being fired through the 5.56 than the the unfired rounds.
When checking out my magazine situation, I was cycling a few rounds and discovered the brass jacket on my bullets were being cut into by a feedramp. This was almost an S-shaped cut, raising a little edge on the brass. I checked the reciver and found a burr-like high spot along the back edge of the left feed ramp. I know this was not there prior to firing, I think it was just distinct enouph I would have spotted it. It may have gotten pushed over after firing. It was on the right side of the left ramp, as if a bolt lug forced it back as the bolt was rotating back open on the return cycle. I took a small, steel rod and ran across this edge a few times to force it down. I cycled a few more rounds through this and this time the mark was still there, but only a scratch, no raised brass. Now I intend on touching up these edges slightly with a tiny round file. The raised cut was definitely significant enouph to effect accuracy. I'm not blaiming the manufacturer so much as chalking it up to "getting to know your new weapon". Also, I am currently set up with a semi-auto carrier with commercial buffer. Maybe a more violent extraction raised the metal if the manufacturer did their test fire with a heavier BC and Buffer? I DO intend on an FA bolt and maybe H-buffer to try soon.
**** Be careful and know where the gun is pointed if you cycle rounds through. The firing pin free floats in the bolt and could contact the primer when doing your function check. I have some prior experience, but am not a pro.****
Also, if anybody was wondering, the .223 brass has a (slightly detectable to the eye) swollen/steeper shoulder after being fired through the 5.56 than the the unfired rounds.