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Posted: 5/4/2009 6:41:51 PM EDT
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I'll try to make a long story short. I've built a good many AR's over the years, no stranger to their operation. I'm in the process of completing a recent build. I've been waiting for a SOG charging handle that has been back ordered for quite some time. I picked up a mil-spec (as advertised by the distributor) CH from a friend who had recently picked up a half dozen of these from a forum vendor (name withheld to protect the innocent, at least until I've figured this out). The rifle was all but complete with the exception of clocking the muzzle brake. I assembled the upper and performed a function test. All appeared to be as expected and felt good, I cycled the bolt a couple of dozen times using dummy test ammo. The cycling became less smooth to the point where it became a bit difficult. It felt gritty. The rifle had been thoroughly cleaned and assembled wet (well lubed). I tore it down and checked everything from the buffer spring to the barrel. Initially I could see no problem. I got a caliper out to compare the measurements with a known good CH in a different rifle. I still could see no glaring problem. I looked at this for a while and then noticed that the end of the charging handle was bending slightly forward and the tip and was just touching the roof of the upper. The barrel was appropriately torqued and the head space properly checked using go/no go gauges. I could see no stress marks on the CH or other problem than it was bent slightly forward at the tip. I spoke to my friend about this problem and we jointly concluded it was likely a defective CH. He let me take a second handle as he had several he hadn't yet installed. I installed it and cycled the rifle 50 times or so. Everything appeared to be GTG. In the meantime he called the distributor and they indicated they had seen no issues with their CH's but that they would stand behind it. I took the rifle apart today after indexing the muzzle brake to give it one final look before going to the range. The second CH is now beginning to bow (pretty much in the center), at this point it feels fairly smooth but it's not right. It's easy to see this problem using a mechanics straight edge. The problem is not identical to the 1st CH. I've given this a good deal of thought and have not been able to determine a cause. Of course it could be a batch of less than stellar CH's. The parts in this rifle are all new, the upper is a DSA and the BCG is a Young's National Match, it has a carbine buffer and buffer spring. Gas tube is sitting pretty (centered) and as I indicated the barrel is torqued and the head space is fine. I've seen a little information on the difference in quality on some CH's (steel vs. aluminum). O.K., I didn't keep this very short, I would welcome comments from any who may have seen a similar situation. Thanks in advance for your time. |
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Your post makes me wonder a little bit about the provenance of a lot of AR parts that are out there now. Im having trouble with gas rings wearing out in less that 200 rounds. I have also had a problem or two with a really gritty feeling phosphate finish in uppers and buffer tubes. (Buffer spring having a tendency to drag for the first several mags of ammo) I have used lots of lube and everything has worked out good so far.
Im at a loss to help you out with the charging handle problem however. I think there could be a possibility that the charging handles are made of a soft aluminum alloy and is not up to the job of pulling the bolt carrier group into the buffer tube without bending near the end where the hole for the gas tube fits when its in battery. |
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while Ive never seen this problem myself but depending on who made it, from what and what processes there are you could easily see a problem
If they are cast and machined its a problem. If they are billet and havent gotten the proper heat treatment *not likely* it could be a problem I would take a charging handle from a known good gun and run its ass off, see what gives and report. I for one suspect a lot of shady stuff these days in efforts to capitalize on our overall desperation |
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Have you tried one of the CH's without a dummy round to see if the issue could be that?
Reason I ask is I had some reloads that got stuck in the chamber once causing a charging handle to get broke trying to extract them. Also have you tried putting some marking on the BCG to verify it isn't dragging anywhere is shouldn't? Try one of the Ch's in a known good rifle? |
| Yes, I've tried both with and without. These particular dummy rounds are commercial ones that I've had for a long time. I've also loaded up a dozen or so of my own, minus powder and primer. I'm not really sure why I used these this time. They are painted or varnished and not a good choice. I removed these, cycled it empty and then with the brass dummies I had made. After putting the 3rd CH in I've cycled around 100 times or so allowing full bolt drops multiple times. My gut tells me that this is harder on the CH than having a round in there. I haven't marked the bolt specifically but it slides in and out of the upper very nicely no sign (feel) of binding. I'm going to pull it out in a while and cycle it some more. I'll try to get it out and shoot it this week end.Thanks guys, I appreciate you spending a few brain cycles on my problem. Maybe I don't really have one, fingers crossed. |
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