Extension tubes loosen in use. Solutions?

[314159]

I've removed barrel clamps on any shotguns I expect to use slugs in since they seem to affect accuracy.

At the end of a shooting session I found the extension tube having backed off a few notches from fully tight.

What's ways are there to prevent this? I was thinking some sort of thin tape to increase friction on the screw threads (similar to plumbers tape perhaps). A few dabs of a coarse thread loctite? Ideas welcome.

[RevolverRob]

Leave it dry, install a wave washer, tighten it down. https://sjhardware.us/product/wave-washers-for-12-gauge-mag-extensions-package-of-3/

[314159]

The 1301 has a spring detent that indexes into the cap/tube. I've used wave washers before with success but it didn't enter my mind to try one here. Don't suppose that would interfere here, I'll give it a try.

[Navin Johnson]

What is fully tight?

What is a session?

Does it effect function?

Does it "feel" looser or are there witness marks confirming?

If it is objectively moving try it through 2-3 sessions and see if it moves more with each session as this would be good and interesting data

I have a Nordic, factory 1301 and factory A300 all without clamps and havent had any problems with my guns

At minimum I (check) tighten chokes and check extensions every time I shoot

[TCinVA]

You most definitely do not want to loc-tite your magazine tube extension. Nor do you want to give into temptation and over-torque your extension to try and keep it tight as you run a high risk of damaging the thin, rather delicate magazine tube.

The extension itself is the first place to look. Not all are created equal. In general, I have found that the extensions made by Wilson Combat, Vang Comp, and Nordic all do a good job of staying tight despite being shot. I don't use magazine clamps on my guns due to how often I take them apart as demonstration or for basic cleaning/lubrication. Nevertheless, the aforementioned extensions will still be as tight at the end of a training day as they were before a shot was fired. The factory Remington 870 magazine tube extension...not so much.

This is not an issue confined to magazine extensions. The tube cap on a lot of shotguns will loosen as the gun is fired and needs to be checked from time to time during the day to ensure it's not too loose. When the magazine cap gets loose it allows the barrel to move back and forth and that will cause various issues with different shotguns. The 870, for example, will often end up with a broken ejector housing as the nose of it is smashed by a barrel that can move back and forth.

[314159]

I was pretty vague in my descriptions.

A session was about 30 rounds of various slugs.

I had tightened the Nordic extension all the way without really cranking down on it. At the time I wondered if being a couple of clicks loose from what I perceived as fully tight might actually be a better spot to start from. No witness marks (there are now) but afterwards it was not bottomed out, so to speak.

I should be able to shoot again tomorrow, I will pay close attention. We shall see. I await my wave washers...

[LHS]

Tim's spot-on with this.

Mag tubes just loosen under vibration over time, it's a thing. Witness mark your stuff, check it frequently, and re-tighten when needed.

[gato naranja]

The extension itself is the first place to look. Not all are created equal. In general, I have found that the extensions made by Wilson Combat, Vang Comp, and Nordic all do a good job of staying tight despite being shot. I don't use magazine clamps on my guns due to how often I take them apart as demonstration or for basic cleaning/lubrication. Nevertheless, the aforementioned extensions will still be as tight at the end of a training day as they were before a shot was fired. The factory Remington 870 magazine tube extension...not so much.

This is not an issue confined to magazine extensions. The tube cap on a lot of shotguns will loosen as the gun is fired and needs to be checked from time to time during the day to ensure it's not too loose. When the magazine cap gets loose it allows the barrel to move back and forth and that will cause various issues with different shotguns. The 870, for example, will often end up with a broken ejector housing as the nose of it is smashed by a barrel that can move back and forth.

I still use the Remington factory extension/clamp setup on the pet 870P DESPITE its procedural pain-in-the-assery because if I pay attention to what I am doing (not always a given, though I have become pretty consistent over time), it stays put with the clamp... but not necessarily without it.