Barrel nut help

[SINNER]

I bet $100 when I'm done with the mill it's more true and square to the carrier bore than 90% of the ones sold.

The biggest issue is when people go too far it will cause FTF's due to the barrel extension protrusion. M4 feed ramps are even more prone to issues.

[rxer311]

What? I was not even thinking about sanding.

[alamo5000]

Really though for the forum purposes... if you're going to take it to a gunsmith then that's up to you. Nobody is trying to persuade you otherwise. But from previous experience (here on WEVO) if you take a few photos and put them up we might be able to save you a lot or a little bit of time and money.

There are a lot of people here that have a lot of experience.

[Joelski]

Really though for the forum purposes... if you're going to take it to a gunsmith then that's up to you. Nobody is trying to persuade you otherwise. But from previous experience (here on WEVO) if you take a few photos and put them up we might be able to save you a lot or a little bit of time and money.

There are a lot of people here that have a lot of experience.

That, or you're going to get a bunch of contradicting information and nobody agreeing on how to fix the damn thing. I've personally never heard of "Thermal fitting" a barrell extension to a receiver unless it's to mate out-of-spec parts together. Properly spec'd parts should fit together with a minimum of nev r sieze moly grease and very little pressure. Sinner is correct that lapping the receiver face is the best solution to avoid adapting (Read: Making it fit) with shims. The shims are an accepted intervention among armorers, however.

Your choice: non-destructive lapping to square up the receiver face and remove several thousandths of material that shims would add, or simple add shims. Either will work. Either are accepted as primary remedies. The benefits of "Accurizing" are minimal to a less seasoned shooter and incorporate other expensive, esoteric measures that add to the cost, but not the gross performance return on investment.

[UWone77]

Shims or just ask for another barrel nut and swap it out.

Ridiculous advice given on this thread is rather embarrassing. The guy just needs to get his barrel nut timed...

[Mecha_Arms]

Seems like shims are the solution. I don't know what the barrel nut is on that rail, but any other time I've run into that problem, shims have been the answer.

[JGifford]

That, or you're going to get a bunch of contradicting information and nobody agreeing on how to fix the damn thing. I've personally never heard of "Thermal fitting" a barrell extension to a receiver unless it's to mate out-of-spec parts together. Properly spec'd parts should fit together with a minimum of nev r sieze moly grease and very little pressure. Sinner is correct that lapping the receiver face is the best solution to avoid adapting (Read: Making it fit) with shims. The shims are an accepted intervention among armorers, however.

Your choice: non-destructive lapping to square up the receiver face and remove several thousandths of material that shims would add, or simple add shims. Either will work. Either are accepted as primary remedies. The benefits of "Accurizing" are minimal to a less seasoned shooter and incorporate other expensive, esoteric measures that add to the cost, but not the gross performance return on investment.

Thermal fitting is what is spec'ed by some manufacturers. It just depends on how close you hold your tolerances and what you set the ID of the uppers spec to. I personally like it, although I have also heard that accuracy testing has not demonstrated quantifiable superiority over a simple slip fit.

[JGifford]

I still say OP needs to buy a torque wrench and try to properly install it first instead of just guessing like OP has been doing...

[rxer311]

I stopped by my gun Smith today and he got my barrel nut torqued and timed. He did need to use a shim. Best $10 I could spend to get it done right.

[SINNER]

Shims are a band aid for lack of equipment or ability IMO. Then again everyone with a set of punches and a torque wench is a gunsmith now a days.

[JGifford]

I stopped by my gun Smith today and he got my barrel nut torqued and timed. He did need to use a shim. Best $10 I could spend to get it done right.

I'm guessing he just lubed the threads and torqued it properly with the correct wrench vs. guessing?

[rxer311]

You missed the part where I said he had to use a shim.

[JGifford]

You missed the part where I said he had to use a shim.

I read it wrong, my fault.

[The Truth]

I just saw this but, if you are still having issues please call. We will do whatever we can to help.

[rxer311]

I just saw this but, if you are still having issues please call. We will do whatever we can to help.

No problem. Took it to my gunsmith and he was able to get it installed with a shim.