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Posted: 4/1/2016 11:52:05 PM EDT
| I need an upper bored out to a slightly larger diameter, 1.116". Who would you guys recommend, either machine shop or gunsmith? |
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Walk in the park,
Chuck side gets a piece of round stock bored and ID threaded to 1.25x18 (or just gas tube type barrel nut sitting around), Back of the receiver gets a piece of round stock bored to match the back of the receiver so it can be put in a roller steady rest to hold it solid, and the inside of the bore can be cleanly bored to what every you want on a lathe. If all you have is a mill, then clam shell type upper receiver block can be used to tram the upper in the vise, and a boring bar in boring head used to open the ID of the receiver isntead. The lathe will end up with the ID smoother, but Mill with boring bar will be a lot faster isntead (don't have to make support tooling). |
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Quoted:
Walk in the park, Chuck side gets a piece of round stock bored and ID threaded to 1.25x18 (or just gas tube type barrel nut sitting around), Back of the receiver gets a piece of round stock bored to match the back of the receiver so it can be put in a roller steady rest to hold it solid, and the inside of the bore can be cleanly bored to what every you want on a lathe. If all you have is a mill, then clam shell type upper receiver block can be used to tram the upper in the vise, and a boring bar in boring head used to open the ID of the receiver isntead. The lathe will end up with the ID smoother, but Mill with boring bar will be a lot faster isntead (don't have to make support tooling). This is probably an airsoft mod. The question comes up every now and then. Your walk in the park will probably cost 4 hours of machine shop time. I don't know where you are from, but machine shop time is expensive where I am. You may be able to find a new AR for cheaper than this machine work will cost. |
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Quoted:
Your walk in the park will probably cost 4 hours of machine shop time. I don't know where you are from, but machine shop time is expensive where I am. You may be able to find a new AR for cheaper than this machine work will cost. About 15 mins via mill, including set up time to get the upper trammed correctly so you can run a few passes to bore it out to the intended ID. Hell, tramming in the easy part, since I already have a Mandel that used in the ID of the receiver that I use to face the upper barrel face in a lathe, and can just run a spinal dial indicator down the sides of it front and side on the Z axis to make sure the ID of the receiver it trammed to the spindle before boring. So at most, a smith should only be charging him his minimal milling flat rates to begin with. And hell, since the upper receiver has a front and back pivot lugs, don't really even need a clamp shell upper receiver vise block, since they can use the pivot lub for clamping to just horizontal bore instead. |
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Quoted:  . Why would I bore out a real upper for an airsoft project? I'm just trying to shave some weight  There's a couple of automotive machine shops local to me, I'll check with them and see if they can do it. Quoted: Quoted: This is probably an airsoft mod. . Why would I bore out a real upper for an airsoft project? I'm just trying to shave some weight There's a couple of automotive machine shops local to me, I'll check with them and see if they can do it. |
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