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1/25/2018 7:38:29 AM
Posted: 11/26/2002 8:58:02 PM EST
I think I destroyed my A-1 Upper. I was changing barrels and put the upper in one of those Bushmaster plastic vise clamps. As I was torquing the barrel, the receiver clamp kept slipping out of the vise, so I tightened the vise more. After the installation was complete, I tried to assemble the bolt. It stuck midway into the upper. The bolt could be forced into the receiver, but it had a great deal of resistance. I could carefully wedge open the bottom of the receiver with a plastic screw driver handle and the bolt would move freely. When I remove the wedge, the bolt sticks again.

Is there anything I can do to save the receiver.
Could I have a gunsmith to open it up with a vise? If so, would that cause metal fatigue and be dangerous when fired?

Thanks for your help
Link Posted: 11/26/2002 9:18:42 PM EST
That sounded bad. This is what you used? [img]http://bushmaster.com/shopping/gunsmith/Images/om-003_small.jpg[/img] Sorry to hear that...
Link Posted: 11/27/2002 12:12:33 AM EST
It kind of sounds like you killed it. I do not think any gunsmith would attempt to bend it back into shape. Armalite has a special going on flattop uppers (cosmetic flaws) for $56, you might want to just build another one, or pick up a used one if you want to match your old upper. Sorry to hear about it, I would have thought you were safe with the adaptor.
Link Posted: 11/27/2002 3:44:20 AM EST
Yea, that was the tool I used. Unfortunately, replacing this upper isn't as easy. I wanted one with the forward assist, A-1 sights, but without the brass deflector. I want these characteristics to be authentic with the military issue of the early 70's. Most of the ones on the market have the brass deflector. Those without brass deflectors have no forward assist. Do any of you know where I can find the early military uppers with those features just described? Thanks for all the help. You confirmed my fears.
Link Posted: 11/27/2002 4:05:18 AM EST
just one other thought...is the gas tube straight?? could it be binding on that as the bolt/carrier begins to seat??..a long shot but maybe
Link Posted: 11/27/2002 4:22:46 AM EST
Good idea! Sure wished it was binding on the gas tube. Unfortunately, the binding occurs way before the gas tube engages.
Link Posted: 11/27/2002 4:24:07 AM EST
Originally Posted By Stickman: Armalite has a special going on flattop uppers (cosmetic flaws) for $56.
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They are sold out on these anyway. I could have used one. Good luck. MM419
Link Posted: 11/27/2002 5:49:37 AM EST
I'm just curious. Did your action block clamp from Bushmaster come with a solid plastic rod insert that is supposed to be placed inside of the upper when using the clamp? My Peace River Arms block did and I've never had any problem such as what you experienced. I wouldn't reccommend trying to "bend" your upper back into shape, but you might try lapping your bolt carrier to it with some fine lapping compound. If it's just "sticking", this might solve the problem. As a last ditch effort to salvage it, you could try running a 1" reamer through the upper. Either method will remove the anodized skin from the inside of the uppers tube and it will probably wear quicker, but it might get you shooting again. HTH . . . . . . Doug
Link Posted: 11/27/2002 6:05:36 AM EST
Doug, I have one of the bushy calmps, and it didn't come with an insert. I haven't had a problems with it though. I can't imagine how it would do this though.
Link Posted: 11/27/2002 6:26:45 AM EST
That sucks about the upper. Awhile back I rebarelled an A-2 upper using the Bushmaster vise block. Everything went back together fine except that the charging handle had just a tiny bit more drag. As far as a replacement goes, [url=http://www.shooterstore.com/acb/showprod.cfm?&DID=90&CATID=508&ObjectGroup_ID=1252] DPMS [/url] has A-1 uppers listed on their website. Unfortunately it's listed as being out of stock but you might want to contact them and ask when or if they expect more in. No price mentioned but their A-2 uppers are $175.00... adjust accordingly.
Link Posted: 11/27/2002 6:34:09 AM EST
[url=http://www.fulton-armory.com/M16Parts3.htm]Fulton Armory[/url] has USGI M16A1 stripped uppers (no rear sight assy, forward assist assy, dust cover) for around $100. A quick Google search for M16A1 Upper Receiver should pull up more hits as well.
Link Posted: 11/27/2002 7:24:46 AM EST
Just wondering if the bench vice you used is small/cheap. Maybe it let things torque around some. Otherwise I am having trouble visualizing how the action could move around enough to cause any damage.
Link Posted: 11/27/2002 8:10:33 AM EST
Just one other thought on how I might tackle this (take with a grain of salt and use every caution). The Accuracy Speaks receiver clamp is a totally different setup. Its a solid rod that is about the size of the bolt carrier and goes in the BC channel. Under this is a solid Tee shaped bar that screws into the rod and puts the BC channel under outward tension. This Tee bar is the part that actually gets clamped by the vice. If you were in the market for a better receiver clamp anyway, this might possibly reform the BC channel without stressing the metal too much. Might work, might not. Anyway, I have had great results with my Accuracy Speaks clamp. Like most of the Accuracy Speaks stuff, its top notch, but not cheap, tho. HTH
Link Posted: 11/27/2002 9:56:46 AM EST
Thanks for your tip!!! I purchased the A-1 Upper from Fulton earlier today. I couldn't tell if it had the brass deflector, as their picture showed the receiver from the other side. I purchased it anyway, hoping that most of the original G.I. A-1 receivers didn't have the brass deflector feature. I am still a little puzzled of how that plastic clamp could cause such damage. The clamp didn't come with any kind of cylinder to fortify the receiver walls. I did use a high quality, heavy duty vise, the largest sold by Home Depot. I've installed barrels before, but this is my first time I had this problem. The barrel was torqued using a torque wrench set to 30 ft. lbs., then I took it a little tighter, not exceeding 80 ft.lbs, to line up the gas tube hole. Anyway, I'll be more careful next time. All of you have been a big help.
Link Posted: 11/27/2002 10:00:12 AM EST
Maybe you bent the upper when the vise was too loose? That's the only thing I can think of.
Link Posted: 11/27/2002 10:13:05 AM EST
Jetlag-- I think you've got something there. I do recall a lot of give when I first began the pressure. Maybe that could put uneven pressure on the slender wall, just under the dust cover. That seems to be where it is binding.
Link Posted: 11/27/2002 7:33:41 PM EST
The Peace River action block works good for me. The Bushmaster action block looks like a copy of the Peace River action block so I would think it would come with an insert. In the below pic the action block is on the left and the insert is right next to it. [img]http://www.nrahq.org/publications/ssusa/graphics/ARtools.gif[/img] BTW, this pic of [b]AR15 TOOLS[/B] is from the NRA website. [:D]
Link Posted: 11/28/2002 1:04:49 PM EST
I think if you had followed the instructions from the US Military tech manual you would of never had a problem. [img]www.vaq34.com/junk/upper1.jpg[/img] [img]www.vaq34.com/junk/upper2.jpg[/img]
Link Posted: 11/28/2002 5:49:09 PM EST
i was gonna say "why the hell didn't you do the barrel clamp method?" but i see you pointed it out
Link Posted: 11/28/2002 6:33:39 PM EST
Originally Posted By Prebandanna: The barrel was torqued using a torque wrench set to 30 ft. lbs., then I took it a little tighter, not exceeding 80 ft.lbs, to line up the gas tube hole.
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How accurate is your torque wrench? Just a thought.
Link Posted: 11/28/2002 9:27:23 PM EST
Link Posted: 11/29/2002 11:03:57 AM EST
[Last Edit: 11/29/2002 11:06:31 AM EST by Prebandanna]
Guys-- Ouch, that hurts! Thanks for the A**-kicking. I can hear my old drill sergeant in your voices. Maybe that will keep me from screwing up next time. I removed the barrel in this way, because it was one of the options mentioned on an AR-15 armory video made by RKI. They said you could take the barrel off both ways, either by clamping the barrel or by clamping the receiver. Guess I chose wrong. Your right! I should have done my research and used the recommended method in the manual. Thanks for posting the pics. The torque wrench I used is made by Husky and has the adjustable dial on the handle. I bought it new, and it was the higher priced one, so hopefully it is accurate. I think I'll hang on to the upper, maybe try some of your suggestions on repairing it.
Link Posted: 11/29/2002 11:29:08 AM EST
No flame intended, but there are risks associated with using the recommended method in the manual too... ... just so you know that. [;)]
Link Posted: 11/29/2002 11:33:23 AM EST
Hell, there are risks in everything you do, including gong to the porcelain library to take a crap. [:D] -FOTBR
Link Posted: 11/29/2002 5:51:36 PM EST
USNJoe that is outdated .. You can end up misaligning the pin that aligns the barrel in the upper receiver... if the nut siezes to the upper... something has to give...the nut and the upper turn against the barrel ... (instead of with the clamp you had setup if you had the insert then the barrel would not have had any stress...) Ted...
Link Posted: 11/30/2002 8:56:37 AM EST
I highly recommend the Peace River receiver block. I used one in my armory (a 3rd/4th echelon IW shop), and it has been used numerous times with great results. Some of the other designs seem a bit shady, with no internal support for the receiver.
Link Posted: 11/30/2002 9:06:48 PM EST
Could you send me the change to the manuals. I have all of the current dated manuals and updates. I think that part of the problem is that the A1 upper is not as "beefy" as the A2 upper, so there may be a possibility of crushing it. I don't see how you could misalign that pin. On every AR15 upper I have assembled the pin fits snug in the slot, there is no play. That pin is too beefy to be bent IF you use the proper torque values. It seems to me that if you wanted to have zero stress in the barrel and the reciever someone would make a dual mount that clamps both the upper and the barrel in place. I figure it could also have an index mark so you could line it up with the rifeling in the barrel. Big Bear, what are the risks?
Originally Posted By phonegunner: USNJoe that is outdated .. You can end up misaligning the pin that aligns the barrel in the upper receiver... if the nut siezes to the upper... something has to give...the nut and the upper turn against the barrel ... (instead of with the clamp you had setup if you had the insert then the barrel would not have had any stress...) Ted...
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Link Posted: 11/30/2002 9:42:45 PM EST
Besides what phonegunner said, turning the barrel in the barrel vise if it's not clamped tight enough, marring the finish.
Link Posted: 12/1/2002 12:23:54 AM EST
Did you put wheel bearing or moly grease on the threads?
Link Posted: 12/1/2002 4:20:23 AM EST
I used a good dose of gun oil, like LSA.
Link Posted: 12/1/2002 4:22:20 AM EST
The dual mount sounds like an interesting idea, but how would you tighten anything if both sides are clamped in a vise?
Link Posted: 12/1/2002 6:30:07 AM EST
Forget about the action blocks, I use the old barrel blocks & a piece of leather to prevent the blocks from scraping the barrel, Works every time & No damage!
Link Posted: 12/1/2002 12:03:25 PM EST
Originally Posted By Prebandanna: Do any of you know where I can find the early military uppers with those features just described? Thanks for all the help. You confirmed my fears.
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Brownells lists the DPMS A1 upper in their catalogue(#55) on page 156 for $99.95($71.00 dealer cost) The picture shows forward assist but no brass deflector.
Link Posted: 12/2/2002 2:04:09 PM EST
To each his own. I don't like the barrel vise, though many use them. I'll go with Big Bear on the Peace River action block and insert. They are foolproof. I have gone as high as 90# on installing a barrel (and who knows how high on breaking a barrel nut loose) with no ill effects. Sounds like you did (almost) everything right. Could have happened to any of us. It's called experience.
Link Posted: 12/2/2002 3:09:13 PM EST
Question for someone who is in the know! What do military armorers use to mount & remove M16 rifle barrels, Barrel blocks & Vice or Action blocks?
Link Posted: 12/2/2002 3:13:53 PM EST
garr, according to two previous posters in this topic, both.
Link Posted: 12/3/2002 1:22:36 PM EST
Originally Posted By garr: Question for someone who is in the know! What do military armorers use to mount & remove M16 rifle barrels, Barrel blocks & Vice or Action blocks?
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I don't claim to be one who is "in the know", but my Peace River Action Block set bears the inscription "MILITARY PART #ABK 16-1" and the internal reinforcing rod that goes with it bears the inscription "MILITARY PART #ABK 16-2". The set of aluminum barrel vice blocks that I own have no markings of any sort whatsoever on them. The Peace River action block, in addition to having their name and address on it, also bears the inscription,
Read instructions before using.
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HTH . . . . . Doug
Link Posted: 12/3/2002 1:35:39 PM EST
Garr, not to be a smart a** but they use whatever is in the arms room. They are usually supplied with barrel blocks, but the military smiths (small arms repair) I've talked to would love to have the Action Block to use. Many small arms guys really don't have decent tools to work with.
Link Posted: 12/3/2002 2:50:25 PM EST
My Peace River action block, along with the military part #'s, has MAX Torque Load: 200 FT LBS. So, is it possible you over tighten the vise? Just a thought.
Link Posted: 12/3/2002 4:37:09 PM EST
The small arms repair toolbox I was issued was a piece of crap. I ended up buying most of the tools I used on my own. The use of the Peace action block is actually taught in the small arms repair course at Aberdeen Proving Ground. However it is not part of the normal tool kit. It can be ordered through the supply system though (It has an NSN). Using the barrel clamped in a vice is an easy way to tweak the receiver. The indexing pin bears the brunt of 30+ ft. lbs. of torque. I have seen this method result in excessive windage, as the pin actually makes an indentation in the receiver's pin slot. If your not going to do it right, why bother to do it at all?
Link Posted: 12/4/2002 4:05:26 PM EST
I see you've already replaced your upper, but I just thought I'd mention that you can get uppers in just about any imaginable configuration, including Colt AR-15 or GI surplus M16A1 uppers with or without forward assist, and for both spec and "large-hole" lowers on - you guessed it - eBay! I recently picked up a Colt A1 "large-hole" upper with forward assist but no deflector hump (I think these were for the AR-15A2 that used a large-hole M16A1 type upper with SP-1 lower) for about $50 or so, in like-new condition.
Link Posted: 12/4/2002 4:40:50 PM EST
[Last Edit: 12/4/2002 4:41:45 PM EST by Prebandanna]
Booth-- Yea, Ebay seems to be a good source to find the less common configurations. Since I began looking, I also found a lot of variety at our local gun shows. Some tables are completely devoted to uppers. Their prices seem to be a bit high though. Thanks for all your responses about the pros and cons of action blocks vs. barrel vises. I think I have some good information that will help me to install my next receiver safely. Incidentally, M-16 barrel installation sounds like a good question for the TV series, "Mail Call." Some of you who watch that show might want to send it in.
Link Posted: 12/4/2002 5:49:59 PM EST
[Last Edit: 12/4/2002 5:52:57 PM EST by Aces-and-Eights]
Not many of us would have the need or worth while expense too have both types of blocks. Given one or the other, I'd choose a receiver type of block because it has the added advantage for installing certain float tubes... something you can't do with a barrel block.
Link Posted: 12/5/2002 8:29:14 PM EST
Dog-gone-it! Got my upper from Fulton Armory today. As you know, I was looking for the A-1, with forward assist and no brass or casing deflector. Guess what! It had the brass deflector. That was disappointing, especially when they reassured me that it wouldn't have that feature. Just can't trust people over the phone.
Link Posted: 12/6/2002 4:16:19 AM EST
That really sucks. They are mis-advertising the part as "USGI" then, as (to the best of my knowledge) no M16A1 had a brass deflector on the upper receiver. The built-in brass deflector was introduced with the M16A2. I shot an A1 competitively for 10+ years and shoot lefty so I'm pretty damn intimate with that particular piece of eqiupment. Personally, I would take issue with them on this as it is advertised as [b]"Upper Receiver, A1, USGI, Hard Coat Black Anodized Stripped, foward assist and ejection port cover assembly not included"[/b]
Link Posted: 12/6/2002 12:45:03 PM EST
Redleg-- Good point. I don't know if the people who take orders make those kind of statements intentionally, but it sure messes up one's day. I'll write them a letter of concern, when I send the part back.
Link Posted: 12/6/2002 1:19:20 PM EST
Prebandana - I'll try to remember to look through a Shotgun News or two, as I seem to recall somebody actually selling M16A1 complete uppers for a reasonable price. I'll see if I can find the ad.
Link Posted: 12/6/2002 6:31:20 PM EST
When you use an action block, you MUST use an insert inside the upper. Is your upper ruined? No. Ream? Lap? No. Turn it upside down on your work bench, and using something soft, so as not to scratch the aluminum upper, pry gently open about halfway between the front and rear pin lugs, about in the area of the ejection port. Just a little. Now check how the bolt carrier fits. Keep going, just a little more, until you get to a point where the bolt carrier glides easily in and out. If you don't want to do this, I have a used, but very nice, A-1 upper, no brass deflector, and with fwd assist. Email me if interested. In fact, if you want to ship me your upper, I will install the this upper for you.
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