Marvel guide rod loosening up

Hi Smart People, 

I have an original non-lockback Marvel Unit 1.  Lately I have been shooting it a lot and noticed that the guide rod is routinely loosening after maybe 50 rounds, sometimes less it seems.

I keep the wrench in my kit and tighten the rod periodically but it's becoming annoying.  I had noticed this behavior in the past only after many rounds.  Like hundreds.

Has anyone come up with a way to address this or slow it down?

Many thanks in advance and a tip of the hat to everyone.

Rod

Check the condition of the threads, they could be worn.

Try something like this, and then TIGHTEN it.

Amazon.com: Westward 10J365 Precision Nut Driver, 5/32 In, 6-1/8 In : Tools & Home Improvement

Mine have never come loose.

FCW (Travis) sells a torque wrench (pre-set) just for that rod
Every 3 or 4 matches I give it a twist

Yeah i added a nut driver to my range case because it's easier to find and use than the little wrench. Getting it good and snug as I dare without stripping the threads. Maybe I underestimate the quality of the steel but it's not a 1/2" lag bolt.

Appreciate everyone's thoughts. Hoping the threads aren't getting tired like chiz offered. This thing eats anything i stuff in thr magazine.

If hand tightening doesn't get it to hold, I would try a new rod.  FWIW, my marvels have 1000s of rounds through them and that rod never loosens up on either of mine.  I would suspect something is going on with the threads and a new rod is the cheapest first step.

Good luck.
John

Just don’t over tighten it, you can break the block.

My favorite starting point for loose threads of any sort is this stuff:

https://www.zoro.com/vibra-tite-reusable-threadlocker-vibra-tite-vc-3-red-high-strength-liquid-1-ml-capsule-21302/i/G6282109/

I discovered it when I bought a scope mount for my AR-15 and it came with one of these little pouches.  It is specifically designed for things you may need to adjust or remove, so you don't have to worry about gluing a screw in too permanently.  The little pouches keep forever, and you can actually use the same packet for a lot of applications if you fold over the corner you cut and put a binder clip on it.

Sometimes it's not enough and I have to step up to blue LocTite, but it's a very safe place to start.  You can even apply it to screws in advance, and keep pre-treated ones around indefinitely.

A good cleaning helped, I think, getting rid of oil that worked it's way into the threads.   The vibra tite stuff is on the way - sounds ideal for a lot of uses.  And it's probably time for a spring refresh including magazines.  I love my Marvel!

Thanks everyone.

PS not ignoring the new guide rod idea, but hopefully dont have to go there and worry about the female threads as well.

John Dervis wrote:If hand tightening doesn't get it to hold, I would try a new rod.  FWIW, my marvels have 1000s of rounds through them and that rod never loosens up on either of mine.  I would suspect something is going on with the threads and a new rod is the cheapest first step.

Good luck.
John

Well John Dervis wins the prize.  I failed to closely inspect the guide rod threads until last night when i applied vibratite.  Threads are clearly worn and unfortunately my FCW order shipped already without a new guide rod.

So the vibratite.  Great stuff!   The tape wont work in this application became the recoil spring tears it off as i try to get the spring squished during installation.  At least I couldn't get it to work.  The liquid by contrast was able to get in there and stay sufficiently to tighten things up.

GWhite, this is a great product, thanks for suggesting it.  I bought both tape and liquid. 

Thanks again everyone.  I love the camaraderie and endless offers of help and information.

I live in Massachusetts, and I tried to buy some of the little Vibratite packs from an industrial supplier.  They wouldn't ship them to me due to some State environmental regulation.  It does contain a pretty nasty solvent, but the packs are tiny.  I think I ended up getting some from an eBay seller who either didn't know, or didn't care.  

For the small stuff I usually have to deal with, I clip off a tiny corner of one of the packets.  I squeeze a small amount on the end of a toothpick, and apply it to the (degreased) male threads.  Take a half hour break to let it cure, and assemble.  I fold over the clipped corner, and clamp it with a small binder clip.  I've used the same packet a dozen times or more before enough of the solvent has escaped that it won't flow well any more.

I use it on all the sight mount screws I encounter, and I've also used it to keep the Picatinny rail on a High Standard Victor from loosening up.  I tried it on the muzzle weights on my MatchGun MG2, and that's one place where I had to go to blue Loctite.