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Posted: 4/22/2007 7:22:48 PM EDT
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I have a RRA lower, Bushy 20" govt' profile A3 upper. I was sighting it in, and loaded 10 rounds from a stripper clip. This was no problem. When I went to a full mag, it wouldn't feed properly; the bolt carrier did not have enough force to strip off a new round. Dropping back to 10 rounds fixes the problem. Pulling back on the charging handle, there is a noted difference in force between this A2 stock and my carbines. The latter have a much stiffer spring. The problem seems to have been exacerbated by the fact that I was using Wolf ammo and Taiwanese steel mags. When I ride the carrier home on a full USGI mag with XM193, the carbines will strip a round off every time; the A2 will need a couple of pushes from the forward assist to work. Going to 10 rounds with the A2 stock will also work reliably. With a full Taiwanese mag and Wolf, even the carbines need a little bit of assist when letting the bolt carrier ride home. Using the same mag/ammo combination, the problem was much worse with the A2 stock due to its weaker spring. Sounds like the buffer spring, no? Edited to add: I checked the bolt carrier key (screws are tight) and the gas rings (they were properly offset) just to be sure. It didn't look like it's short stroking anyway. |
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See if the feed problem is only related to the TW mags. Could be burs on the feed lips, the feed lips not correctly set, and even a bur on the front edge of the mags not allowing the round to feed clean (read break out the USGI mags with the wolf ammo). As for the recoil spring, could be a weak puppy, and if you have another lower to compare it to with a known good spring, could be the problem alone if this is just a first round charging problem. As always, the bench mark to compare it all to is a good working USGI mag, and ammo such as Q-3131 or M-193 if your rifle is chambered for such. |
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Yeah, I usually always have a USGI mag with me, but I just didn't expect there to be any problems. It was a RRA 20" A3, but I recently bought one of the Bushy special uppers that they had on sale and just took it out to the range not thinking that there would be any problems - and there weren't at first when I only had 10 rounds in the mag while sighting it in. I've noted all along that the recoil spring in this A2 stock is significantly weaker than those with the carbine buttstock, but I don't have any basis for comparison to other A2's. It's been a long time since I've shot this rifle (well, the lower I guess), so I'm not sure if this would have been an issue with the original upper. I just remembered too that it always locked the BC back on the last round, so it's definitely short stroking. It just seems that the extra force of a full mag pushing up on the top round is more than the buffer spring can handle reliably. The question is: would I start short-stroking if I went to a Wolff extra power spring when I shoot Wolf ammo. I kind of doubt it; Wolf is able to cycle the carbines with their much stiffer springs correctly so I should be OK. I may order a Wolff spring and a standard one so I can muck with it... |
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New mags + new upper + weak buffer spring = FTF I had the same problem with both my 20" rifles, A-1 stocks. My solution was to use Wolffe XP springs. The xp springs do cause short stroking with wolf and monarch ammo in these rifles. I calibrated the xp springs by clipping 3-4 coils off to avoid short stroking with commercial ammo. They never did short stroke with any other ammo, I just wanted a margin of safety. I've since firerd a few k rnds without any problems though under powered stuff like wolf and monarch still short strokes. The mags I had new and broke in with the rifles were the TW T-65's and D&H teflon coated. Dano may chime back in and issue a word of caution against clipping coils off the spring but I've had no problems, I just make sure to put clipped end against the rear of the tube. The springs are still much stronger through out the full range of travel as compared to supposedly spec springs that came with the stocks. The fact that you are starting with a extra power spring does buy you some working room to clip, but note that this trick is just taking the spring back down to the tension of that of a good working standard spring, and the problem may have been that your stock spring was weak to begin with. Dano523 |
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(New mags + new upper + weak buffer spring = FTF) +1 on that! I had this combo on an LMT carbine. Some polishing and letting it break in (with plenty of clp) has nearly got the problem solved. I got one of the tubb recoil xp springs which works great for the ftf. However, after reading the post about a slam fire with the tubb spring and win primers (All mine are win) I don't know if xp springs are good idea or not! Good luck. |
Well, technically they're not "new" mags. I've used them with my other rifles, but I don't *think* I've used them with this rifle. I've ordered a standard spring and a Wolff spring, and next time I got out, I'll take some M193 and USGI mags to go along with the Taiwanese mags and Wolf... |
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UPDATE: Looks like a bad mag. I took the same mag and Wolf ammo, as well as a USGI and M193. I had ordered a standard and Wolff extra power spring. Strangely enough, the original "weak" spring didn't have any problems this time with a full mag. While I didn't clean the rifle, I disassembled everything and checked for problems and wiped off a little bit of the worst crud. I did notice that the Wolf failed to lock back the BC on the last shot, although there were no other failures. With the USGI mag, the BC reliably locked back; I tried a single round with each mag several times, and it looks like the Taiwanese mag is having some problems. For one thing, they're steel and a little thinner. I replaced the original follower with a USGI green one, and it appears to slightly bind in some spots. The follower doesn't ride down as smoothly as it does on the USGI mag. It's possible that the follower was binding a little when the mag spring was completely compressed, and then the cycling action caused the next round to "pop up" a little too much and not feed properly. Either way, I don't think it's the rifle that's a problem. Some guys take a bunch of loaded mags, while I take ammo on stripper clips and just a single mag. The Taiwanese mag hasn't had any other problems previously; I'll keep shooting it and see if the mag is just going bad. From now on, I'll just stick a USGI mag in the range ammo can and keep that with me as well. I'm going to keep the Wolff extra power spring in the rifle. The recoil is lighter, and the BC locks back even when shooting Wolf ammo. |
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