What to do when the barrel nut is either too loose or too tight?

Wow, great info. Learned something new today.

For future reference Spikes makes barrel nut shims to time a pesky nut. They are really handy for nuts that are proprietary. For standard nuts if I get one that won't time in a decent torque range I use a different nut.
Ray is on the money for wrenches, as long as they are not mis used they keep an accurate torque for a long time.
Always back the wrench off to its lowest possible setting before storing it.

Quote:

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Originally Posted by BPTactical

For future reference Spikes makes barrel nut shims to time a pesky nut. They are really handy for nuts that are proprietary. For standard nuts if I get one that won't time in a decent torque range I use a different nut.
Ray is on the money for wrenches, as long as they are not mis used they keep an accurate torque for a long time.
Always back the wrench off to its lowest possible setting before storing it.

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AND put some lube NOT Loctite on the receiver threads.

Quote:

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Originally Posted by BPTactical

For future reference Spikes makes barrel nut shims to time a pesky nut. They are really handy for nuts that are proprietary. For standard nuts if I get one that won't time in a decent torque range I use a different nut.
Ray is on the money for wrenches, as long as they are not mis used they keep an accurate torque for a long time.
Always back the wrench off to its lowest possible setting before storing it.

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More great advice. Thanks.

The linked tool worked perfectly, and very quickly. I put a little lapping compound on the surface and ran the drill for 5 or 6 seconds at a shot. It took 3 treatments to get it right, but it's perfect. It took far longer to try the fit after each treatment than it did to actually do the work.

Highly recommended.