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Posted: 11/2/2004 8:14:00 PM EDT
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I have a bushmaster flattop. What modifications are recommended to enhance the reliability? It works great as-is, but I wonder if there is really something that could be improved. |
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1. Good Magazines - it all starts there, not to mention good ammo to run in them 2. A heavy duty / Wolff Xtra force extractor spring if there wasn't one already in the bolt 3. "H" type heavy buffer if it's a carbine 4. M16 carrier or other heavy weight carrier like the LBC ETA: If you start with a rifle length gas and buffer system that's more reliable to begin with. It's when you start shortening the barrel, opening the gas port, shortening the system length, and of course shorter buffer and spring for telestocks - that you start running in to trouble. The shorter you go, the more finicky it can get. One last cool thing to have - On all (or is it some?) Colt M16 chambers(and I suppose others) are cut to a wider tolerance to aid in reliability but I suppose you lose some accuracy potential. |
Listen to this man! This is something that everyone should do to their carbines..... |
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Good ammo and more good mags? Good cleaning supplies and if necessary, a book to tell you how to clean it propperly... A lot of truth here. Good USGI mags. Good ammo does not have to be expensive. Most of all, KISS. 1. Good Magazines - it all starts there, not to mention good ammo to run in them 2. A heavy duty / Wolff Xtra force extractor spring if there wasn't one already in the bolt 3. "H" type heavy buffer if it's a carbine 4. M16 carrier or other heavy weight carrier like the LBC And yes, these suggestions by AK Mike are good, too. Some Breakfree CLP, and cleaning kit, I use the regular GI cleaning kit, will keep you running fine. Pay special attention to cleaning the chamber, moreso than the bore. Get some spare chamber brushes. If short of time, pull the carrier, clean the chamber well, run a dry patch to dry it, run dry down the bore to get excess clp from cleaning the chamber. Lube the bolt, reassemble, the rifle will run. |
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red65, while all of the suggestions above are excellent ones, dont let yourself get caught up in the "GOT TO HAVES" that some do. You already own one of the best rifles out there for reliability and durability. Would the items described above help your Bushy become more reliable? May or may not. Just remember this, these rifles go through extreme durability test to make them reliable. Any new or "more durable" parts are subject to break or fail like all others do. Plus it wont cost you a dime to keep what you have. I have owned many over the years and have never had a "reliability" problem with any, outside of wear and tear, due to the fact that I bought a good rifle to begin with. IMO henew-arguy above, thats the best way to ensure reliability. |
Yep |
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Carbines have the gas port closer to the chamber, and the gas pressure is double that of the rifle. A short very violent gas pulse rather than a longer smoother lower pressure gas pulse. Plus it happens a little sooner in the cycle. The bolt tends to want to open before the brass has shrunk away from the walls of the chamber as much as with a rifle, so the case is still grabbing the chamber somewhat. Also the bolt carrier's rearward velocity is faster. These two factors combine to make a carbine more likely to rip rims, or otherwise have extraction problems. This is the reason for using better extractors and stronger extractor springs on the carbines. Since the carrier moved back faster and sooner, it is also going to slam back closed on the next round faster. This can interfere with smooth ejection of the extracted case, spin back, etc. Cyclic rate in full auto is faster than for the AR rifle. The CAR buffer is 2.9 oz, almost half of the wt of the rifle buffer. Using the heavier "H" buffer slows the movement both ways. It will never be a smooth as the operation of the rifle, but can help. All of the above is also why many are going to the "mid length" handguards on the carbines. Not so much because they need a longer handguard, but because the gas port is farther out on the barrel, reducing the problems described above. When one considers how carefully balanced and timed the AR-15/M16 rifle's cycle of operation, it is amazing that the carbines work as reliably as they do, but today's carbines work as well as 20" rifles. |
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A_Free_Man That has to be one of the best answers to this question I have heard in a while. Well said. As you said, there is something to be said for a mid length gas system. If you are going to be stuck with a 16 inch barrel, then you might as well go for a midlength gas system. I also find the look more balanced and you get the benefits of 2 more inches of sight radius. Also don't forget you can mount a bayonet on a midlength without any problems. Jeff |
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Thank you, when I am not being a wiseguy, I am a technical writer and a columnist on a website, edit 4 other columns as well as my own, and moderate 4 websites. When I have time, I play with AR-15's and maintain my own, as well as those of friends' (some of whom are LEO's) AR's. I have had opportunity to shoot and work on a wide variety of AR's for quite a long time. Back in the 80's when I first began playing with AR's most carbines were built with milsurp 11.5" barrels with permanently welded on flash hiders to make them legal 16". These barrels were available new and used quite cheaply. There was little reason to buy true 16" barrels, which were quite a bit more expensive. (Edited to add: The reason I was interested in true 16" barrels, as compared to a 20" barrel, an 11.5" loses 600 fps muzzle velocity, but a 16" loses only 200 fps) The true 16" barrels were relatively new, and some early mfg's did not know how to make them. They drilled them with the same port diameter as 20" barrels, or drilled them same as 11.5". Many 16"'s were drilled too big or too small. So, you had short stroking with some, and the cure was to pull the FSB and drill larger. This was hit or miss, and there were problems. Others that were drilled too large worked too violently, and also caused problems. My first 16" barrel was like this. I would often, once or twice per mag, have a stovepipe, with a fresh round halfway up into the chamber. Also, shooting that rifle would quite literally bruise my shoulder. Now, I am a big guy, lots of meat on my bones, but I would be bruised like a 12 yr old with his first 12 ga. What happens in that case, the bolt carrier travels back too fast, bounces off the back of the buffer tube, and starts forward too soon, too fast for the extracted brass to be ejected. Thus, the stovepipe. Now, Tweak would tap the hole, thread in a setscrew, and drill that to the proper size. Well, I could not do that then. I did cure the problem by using a Wolff Extra Power Action Spring. This slowed rearward movement of the carrier so that extracted brass could eject properly, and the rifle no longer battered against the back of the buffer tube. So, this adventure, and working with other carbines, gave me lots of hands on with carbine timing, tuning, troubleshooting. At that time (80's) it was common wisdom that carbines were trouble, but 20" rifles were pretty much trouble free. Well, those days are long gone. We know how to make 16" (and 14.5") barrels run well. And they do. |
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Start with a chrome lined bore - which you did. GI mags with good springs and followers (think green or Magpul) A Wolff extractor spring. Regular maintenance, proper lubrication (relube if its sat in storage for a while - mine dont run well dry). Springs dont last forever. Replace as needed. Quality ammo. #1 factor Ive discovered over the years? QUALITY AR15 There are only a few brands Id trust. I technically have frankenguns, but I know the source of every part in them. |
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How unreliable are AR's if you go to the range and plink with wolf ammo? I have no experience with AR15's but I am building one. I have had a couple AK's and it doesn't matter what you run through them. They will shoot all day on wolf or other crappy ammo. And mag quality really isn't an issue. I am just paranoid. I hope my RRA/MEGA combo isn't an unreliable one. |
A reliable weapon and magazine should have no problems firing Wolf ammunition. If one of my weapons wouldn't fire it after being broken in, I would be concerned... |
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