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Posted: 1/24/2013 2:47:56 PM EDT
| I have an A2 upper that has the handle cut off flush with the receiver top. It would be easy to mount a rail between the stubs of handle bases. Can someone point me to a rail that I could mount (drill and tap) to the upper? |
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Quoted: I have an A2 upper that has the handle cut off flush with the receiver top. It would be easy to mount a rail between the stubs of handle bases. Can someone point me to a rail that I could mount (drill and tap) to the upper? throw it away, buy a flatop. that project will not work for what you want. We have progressed since the 80s |
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I have an A2 upper that has the handle cut off flush with the receiver top. It would be easy to mount a rail between the stubs of handle bases. Can someone point me to a rail that I could mount (drill and tap) to the upper? throw it away, buy a flatop. that project will not work for what you want. We have progressed since the 80s This. |
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How does respond to my query? Throw it away is not an appropriate response. I think people are being helpful, just not in the way you were looking to hear or that gives you a direct answer. I know of people who have tapped and drilled their receivers after some idiot has taken a hacksaw to them, I also know people who have used epoxy putty. I do not know of any of them who have used their uppers after that modification and been happy with them. Typically the cheap parts don't help, but by the time you start paying good money, the flat top upper was cheaper or close to the price of the cobbled together conglomeration. Making it perfectly level seems to be an issue, but not the only issue. If you do it, please make sure you update this post after you have 500 rounds through the upper and let us know how it is doing. It would be great to see someone actually do this, put a decent amount of rounds down range, and give follow up showing it was worth their time. 
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How does respond to my query? Throw it away is not an appropriate response. I think people are being helpful, just not in the way you were looking to hear or that gives you a direct answer. I know of people who have tapped and drilled their receivers after some idiot has taken a hacksaw to them, I also know people who have used epoxy putty. I do not know of any of them who have used their uppers after that modification and been happy with them. Typically the cheap parts don't help, but by the time you start paying good money, the flat top upper was cheaper or close to the price of the cobbled together conglomeration. Making it perfectly level seems to be an issue, but not the only issue. If you do it, please make sure you update this post after you have 500 rounds through the upper and let us know how it is doing. It would be great to see someone actually do this, put a decent amount of rounds down range, and give follow up showing it was worth their time.
@ Stickman, you are the man. Thanks for helping him feels better. I agree by investing a new upper is a much better option!! 
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How does respond to my query? Throw it away is not an appropriate response. Not to sound negative, but you could salvage the A2 upper if money is no issue. Buy a picatinny rail section, some helicoils, a helicoil install kit, take it to a gunsmith, have them put it in a fixture, drill the holes, install the helicoils, fit the rail to the upper, screw it down, and have way more then $75 invested in it. If you want to play and experiment go for it, thats how the first flat tops came about, people mounting weaver rails on a cut off A1/A2 upper just like you describe. But once all these shenanigans calm down parts will be readily available again and you can just buy an A4. |
| You guys might also be forgetting that not every AR lower can take a new flattop receiver. He may have one of the big hole colt lowers. I remember back in the 80s, reading about ranchers out west that would cut down their A1 uppers to mount a scope for hunting coyotes. |
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Quoted: You guys might also be forgetting that not every AR lower can take a new flattop receiver. He may have one of the big hole colt lowers. I remember back in the 80s, reading about ranchers out west that would cut down their A1 uppers to mount a scope for hunting coyotes. Incorrect. We have the technology to mix and match hole sizes. There are adapters to make it work. |
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You guys might also be forgetting that not every AR lower can take a new flattop receiver. He may have one of the big hole colt lowers. I remember back in the 80s, reading about ranchers out west that would cut down their A1 uppers to mount a scope for hunting coyotes. Incorrect. We have the technology to mix and match hole sizes. There are adapters to make it work. I am well acquainted with the adaptor pins. I was making the assumption that the OP is not. That is all. |
| Thanks for all the advice. Perhaps I was too hasty in my comment but it did not answer the question I asked. Money or time is not the issue. I do this stuff for fun. I was looking for methodology. Seeing the picture shows a very neat job and is exactly what I want to do. |
| I agree with the others--if you are doing it for fun, have at it. If you are doing it to get a firearm back use-able ASAP, you could get a new flat top upper for about $50 if you shop (once things go back to November levels). If you do it, good luck and please post some pictures when you are done. |
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Well that was really smart. It's likely if you sold that A2 upper instead of destroying you would have the funds to buy a flat top upper. As smart as assuming the OP was the one who cut off the handle and insulting him when he said nothing of the sort? Posted Via AR15.Com Mobile |
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I have an A2 upper that has the handle cut off flush with the receiver top. It would be easy to mount a rail between the stubs of handle bases. Can someone point me to a rail that I could mount (drill and tap) to the upper? Back in 1981 before the Picatinny Rail was born, I had, or personally cut the handle off A1 uppers and mounted a long weaver shotgun bases to them. The base had slots at both ends which allowed spacing the rings (Weaver See-Thru’s with rail-grabbing cross-bolts) that also helped position the scope at a correct height above the centerline. Such rings are still listed in the Brownells catalog, but I am not sure of the base number. The base had a smaller under side radius, than did the upper’s new top surface, which helped establish alignment between the two. The base’s underside radius thankfully allowed proper front to rear alignment via the carefully filed carrying handle stubs that were filed as far down as possible and rounded over only slightly. The rail was then clamped to the upper on both ends as plumb as possible. Then the rail’s mid-section and upper were drilled simultaneously with a tap size drill. The rail was then removed and its newly drilled hole was enlarged with a screw passage size drill and a counter-bore for the screw head. The hole in the upper was tapped. This single hole was used to secure the rail to the upper during the epoxy step. The “having all the subsequent holes line up” trick was using Brownells (carbon-black colored) glass bedding compound along the underside of a deeply (Dremel and cut-off wheel) scored rail, and release compound on the corresponding upper. Then drilling the other tap and dowel pin size holes about mid-way through the bedding set-up time and then knocking it off before it completely set-up. That (using temporary epoxy adhesive and the one screw at the mid-section) was the only way I found (at home with a drill press and drill press vise) to perfectly align the necessary series of holes for later thread tapping in the upper, and the rail’s screw passage holes and counter-bores. After drilling all the holes, the rail was knocked off with a plastic mallet and all but two of the holes in the upper were tapped. The other two were reserved for dowel pins to be inserted after final mounting of the rail. I used two dowel pins (along with the screws) based on the advice of a good machinist at Picatinny Arsenal because the upper was thin in this area and he had no faith in the little screws to prevent shearing from recoil. (He actually built the first of these A1 upper for me while I was stationed there (1980-1983). That prototype was used in military briefings there for several years until the Mil-Std 1913 Rail and upper was later standardized.) When separately drilling the rail, I’d use the original tap drill to help line up the new rail holes under the drill chuck. Then change the tap drill out for a proper screw passage drill and then the counter-bore cutter to a depth so the screw heads would be flush with the top of the rail. The counter-bore cutter thankfully had a pilot that fit the clearance hole diameters, as you would not be able to cut proper counter-bores without such a pilot, even in the soft Weaver Rail aluminum. I used this rail for years without issue. Certainly if Picatinny Rail uppers were available way back then, that would be my first course of action, but they were not. And since the handle has already been removed from this upper, I think it best to put it to use if he wants a sighting system on it. Another alternative (and a lot less work) is to assemble the handle minus upper with a rigid free-floating rail forend and scout mount a reflex optic out on the forend’s top rail. |
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I did not mean to sandbag but perhaps I should have given more background. I had a machine shop and did gunsmithing in the late 80's to the early 90's, that is until my day job consumed all my time.
I have added rails to uppers before. In those days, flat tops were scarce. In fact, I don't ever remember working on one. My question to this forum would have better been stated, "Is there anything new in the last 25 years that would help me mount a rail on a cut down A2 upper?" I should post a pic but this is a ratty looking upper. It has been cut down with a mill. I think I got it in some trading I did then. This is a project where time is inconsequential. I have been retired for some time. I have a cabinet full of pieces and parts but very little AR parts. I have a great deal of mil spec 1911 parts. The process mentioned earlier is essentially what I have done. Although I have never epoxied as part of the process. I just drilled and tapped into the stubs of the handle. Never had one come back but they were never meant to be combat arms either. I will still take any ideas you'll might have. Also I want to thank ColdBlue for taking the time to outline his process. Col R |
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Quoted: I did not mean to sandbag but perhaps I should have given more background. I had a machine shop and did gunsmithing in the late 80's to the early 90's, that is until my day job consumed all my time. I have added rails to uppers before. In those days, flat tops were scarce. In fact, I don't ever remember working on one. My question to this forum would have better been stated, "Is there anything new in the last 25 years that would help me mount a rail on a cut down A2 upper?" I should post a pic but this is a ratty looking upper. It has been cut down with a mill. I think I got it in some trading I did then. This is a project where time is inconsequential. I have been retired for some time. I have a cabinet full of pieces and parts but very little AR parts. I have a great deal of mil spec 1911 parts. The process mentioned earlier is essentially what I have done. Although I have never epoxied as part of the process. I just drilled and tapped into the stubs of the handle. Never had one come back but they were never meant to be combat arms either. I will still take any ideas you'll might have. Also I want to thank ColdBlue for taking the time to outline his process. Col R Listen to ColdBlue. He knows about this stuff. |
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