Increasing the thickness of a loose Radian barrel nut?

[Leicafan1990]

I recently purchased a Model 1 build kit and I’m really impressed with the quality of the parts. I do have an issue with the rail and barrel nut though.

In the build instructions, it says: “The rail is designed to have a tight fight with the barrel nut. Moderate force might be needed to slide the rail over the barrel nut.” Unfortunately, the fit between my barrel nut and rail is very loose. The barrel nut slides easily in an out of the rail with little to no resistance.

Here is a video of the loose fit: https://imgur.com/a/4K7PD24

I contacted Radian about this and the rep I spoke with was nice enough but he didn’t really seem to be concerned about my problem and told me the rail will lock up just fine. I want to trust him but everything I could find online about this says that there should be a very tight fit between the rail and the barrel nut.

This Reddit thread shows how tight the fit should be: https://www.reddit.com/r/RadianWeapons/comments/y8jlot/how_in_gods_name_do_i_remove_the_handguard_on_a/?utm_source=share&utm_medium=ios_app&utm_name=iossmf

Since Radian didn’t really seem concerned with my issue, I either have to ignore it and hope for the best or I need to find some way to tighten up the fit between the barrel nut and the rail.

My best idea at the moment is the spray the outside of the barrel nut with a few coats of Alumahyde II. This should add a little bit of thickness to tighten up the fit between the rail and barrel nut.

Any thoughts? Am I just being an OCD nutcase?

[georgeib]

Why do you feel it necessary for the barrel nut to be a press fit into the handguard? I see that it slides on easily, but is there wobble?

[Leicafan1990]

Why do you feel it necessary for the barrel nut to be a press fit into the handguard? I see that it slides on easily, but is there wobble?

Yes, the barrel nut has is a small amount of wobble once it’s slid all the way in to the rail.

[markm]

I'm not familiar with radian. Is there some kind of fastener that will tighten up the handguard and remove the play??

[TMS951]

I’d get back on the phone with radian and ask if you can buy a larger barrel nut or even batter exchange it.

Everything machined has a tolerance range. Probably +/- .005 that means through stacking tolerances your barrel nut and rail could have a difference in size of .019” and still be “in spec”. Ideally I think you want a rail about .001 larger than the nut.

I recently bought a Geissele ‘blem’ upper and rail with the tab. They state everything is “in spec” and only cosmetic blem. We’ll I’ll tell you what, if it’s “inspec” it’s at the absolute outer limits of that spec. The upper rattles around when put on lowers and the rail to barrel nut is also super loose. I have other Geissele rails and the rail to but meet up is not more than a .001 gap.

[themonk]

I think press fits are a PIA. I would mock it up on a upper reciver and tighten down the rail to the barrel nut and evaluate from there.

[GH41]

What ^^ He ^^ said

[markm]

Everything machined has a tolerance range. Probably +/- .005 that means through stacking tolerances your barrel nut and rail could have a difference in size of .019” and still be “in spec”

hash tag AMERICAN MEDIOCRITY!

[TMS951]

I think press fits are a PIA. I would mock it up on a upper reciver and tighten down the rail to the barrel nut and evaluate from there.

Press fits are a pain in the ass. But they are not what we are talking about here. They are just another way of selling parts of loose tolerances. Everything is just sized tight.

We’re talking about matching the over diameter of the barrel but to the inside diameter of the rail. We’re taking about a what should be .001” size difference with a +/- .001” tolerance. This is easily achievable by high quality American manufacturing. You need sharp tooling and the right machine speed. That’s it.

There is an alternative if you want to run production faster and sloppier at the mediocre standard of +/- .005” and thats to hand match nuts to rails. You can honestly send out a perfect match this way, but you lose interchangeability.

Sounds like the op just got a sloppy fit from a loose tolerance call out. MarkM was correct to call it American mediocrity.

[themonk]

Press fits are a pain in the ass. But they are not what we are talking about here. They are just another way of selling parts of loose tolerances. Everything is just sized tight.

We’re talking about matching the over diameter of the barrel but to the inside diameter of the rail. We’re taking about a what should be .001” size difference with a +/- .001” tolerance. This is easily achievable by high quality American manufacturing. You need sharp tooling and the right machine speed. That’s it.

There is an alternative if you want to run production faster and sloppier at the mediocre standard of +/- .005” and thats to hand match nuts to rails. You can honestly send out a perfect match this way, but you lose interchangeability.

Sounds like the op just got a sloppy fit from a loose tolerance call out. MarkM was correct to call it American mediocrity.

I understand exactly what we are talking about. Thanks for the clarification