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Posted: 10/10/2005 2:05:23 PM EDT
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As I mentioned elsewhere I picked up a 6 position telestock over the weekend and made it to the range today. The stock is a standard carbine, no "H" marked buffer. Rifle is a Bushy A3 20" HBAR. Ammo was Fed XM193. Every time I reached the end of a mag the bolt failed to hold open on the empty mag. I tried my Colt, BM, and Okay 30 round mags. Tried mags loaded full, mags loaded with one, same result. The bolt would hold open on an empty mag (any empty mag) by pulling the charging handle all the way to the rear. In all cases the gun functioned fine, no FTEject, FTFeed, etc. I have had no previous problems with the standard A2 stock/buffer system. It looks to me like it's got to be due to either the buffer spring or the buffer itself (or maybe the tube itself). It's like the spring/buffer combination lets the BCG go back far enough to feed and eject the rifle but not quite far enough to let the bolt release mechanism be engaged. Based on my fiddling at the range it looks like it's coming up short by mere millimeters, if that. So, could the spring be too strong? The buffer too light? Too much friction in the receiver extension? Anyone else had this problem? Thanks! (edit: Someone IM'd me about how the telestock worked on the rifle and I said I'd let 'em know and I forget who; the fit and feel is great, much better than the A2, but then there's this...) |
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on the barrel. Tap out the front sight pins, slide front sight off, there's the hole. Bust out a drill, bell the port just a little bit, put everything back on, go shoot. Do the one round challenge and see if it locks the bolt back. If ti does, you're good to go! |
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When you retract the bolt with the charging handle, can you lock it open with the bolt catch? I could not when I used an A2 screw to attach a Vltor. I switched to the correct screw and it worked fine. I suggest your buffer or spring need to be compared to an operating carbine buffer/spring to make sure you have the right parts as a start. G |
Yeah, I'm not real keen on removing metal unelss and until. I am using the spring/buffer that came with the tele. I can lock the bolt back with the bolt catch. I can lock the bolt back with an empty mag and the charging handle by pulling the charging handle all the way to the rear. Again, the rifle feeds and ejects perfectly, it just seems the BC is just coming up short to allow the magazine follwer to engage bolt catch when empty. Gnat hairs width, like. I'm not going to do anything to it except leave the bolt locked back in storage for a while and see if it "loosens up" the spring. Also going to put a goodly amount of CLP in the buffer tube. I'll go shoot again late this week or over the weekend and report back. Thanks for all your help! |
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I've been thinking about the depth the buffer tube is seated in the lower receiver. Note that either way I have it set the bolt latch works as advertised while manually operating the action. This picture is of the buffer tube screwed "all the way" in. Note position of buffer retaining pin:  This picture is of the buffer tube backed out one revolution. NOte that the tube still holds the retainer in place, but with a lot less "coverage"  I was shooting with it in the "in" position and had the hold-open failure; I haven't shot it in the "out" position for two reasons: 1. Haven't made it back to the range! 2. I've got some concerns about the "stability" with so little buffer tube holding the pin in. Should I be concerned? The "out" position looks, to my eye, to be just about the exact distance extra the BCG needs to move back on firing to engage the bolt catch. Of course, that doesn't really make a lot of sense because it's not like the buffer is bottoming out in the tube in the "in" position. What do you guys think? The only way I know for sure will be to go shoot the dang thing; has anyone else run into this situation? Thanks!! |
WTF!  why does the buffer tube/receiver extension have that semi circle cut out for the buffer retainer detente!? I have played with M16s and AR15s most of my life and haven't seen that before. I'm not sure that is a good thing at all. Please tell me that is a custom thing and not some new thing Bushmaster is doing. |
That's the way it came. I've seen 'em 3 ways: Pin cutout, no pin cutout, and "untimed" tube end. |
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The buffer locates on the retaining pin , spring pressure ensures this. A 1/8 " difference in how far the tube is screwed in does not matter. If it worked with the full stock , and doesn't now using a carbine buffer and spring of the correct length , it's not a gas problem. More than likely you bolt is hanging up somehow inside the tube. |
My LMT SOPMOD stock has the timing notch as well. It helps you plum the stock. |
I see. |
As it turns out, it does appear to matter. With the buffer tube like this: the bolt does NOT hold open. Unscrew the tube one revolution, so it looks like this: and it functions perfectly. I'm just happy I solved my problem! Go figure... |
I'm glad your rifle works now  But I stand by my previous post. The buffer spring is never fully compressed , so moving the tube out one thread did NOT change that unless your tube is Drastically too short. And the bolt can physically travel only a certain maximum distance. Maybe you had a dent in your tube and it worked out , maybe something else  If it happens again let us know. |
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