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Posted: 8/5/2008 7:46:18 AM EDT
| Can anyone here recommend a 'smith who could thread the end of a barrel for the ar-15 barrel extension? If not, does anyone know the thread specs so I could take it to the local machine shop? I have the tools for profiling but don't yet have the lathe tools for threading. thanks. |
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Actually, 0.8125 x 18(?) or 16 pitch. I forgot. Cut the thread releif to the nominal bottom of the threads (0.750" IIRC). I would be very careful if your machine shops are similar to the ones I've seen. In any case, I would take the bolt and barrel extension in to the shop along with the barrel along with a sheet of very specific instructions. I would aim for 0.010" of space between the barrel face and the front of the bolt when the barrel extension is torqued. If you have a depth micrometer, measure the depth of the barrel extension, subtract the barrel lug height and that 0.010" clearance to determine the length of the threads. I have made several AR barrels as a garage tinkerer, and have not had any problems with bolt/barrel binding due to that small a clearance. That 0.010 will shrink somewhat as you torque the extension on. I don't know what the real spec is, but it works for me. You will get more informative answers at homegunsmith.com in the AR15 section or the ask a guru section. They are more geared to machinist types than here. |
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