OK, I am at my wits end with my P938. I have ~ 1700 rounds through it now and the guide rod keeps loosening despite thorough cleaning and application of Loctite Red. I went to the range today and got 35 rounds off before the guide rod was protuding.

Any other solutions?

I'll show my ignorance and ask, why is the guide rod a two-piece thing? Could it be a single piece?

I ask, not to be a smart-aleck, but because I don't understand.

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Edit: having taken a look at it, I see it's likely an economics thing. That could be machined from a solid, but would be more economical as a two-piece.

Yes, it is a 2 piece due to the economics and manufacturability of making that design as a single piece. I have given some limited thought to a redesign, but have not put it into motion, yet.

I wonder if the "rod" could be serrated and press-fit into the "block," rather than them being threaded together.

quote:

Originally posted by vthoky:
I wonder if the "rod" could be serrated and press-fit into the "block," rather than them being threaded together.

Your idea has merit.

I'm tempted to pull mine apart and start measuring.

We do a lot with serrations at work... it's not that tough to do (given a proper die), and you really have to force things apart if pressed together correctly.

Now I'm wondering if I can get some time with the CMM this week.

ETA: Heck, a new one is just $22. Maybe I should just go ahead and get a spare, and start measuring from it. I'd have a "sample of two" on hand for measurements....

I just cleaned and degreased mine and applied red Loctite again - it started coming apart. I was more fastidious cleaning this time.

If the threads come apart, I wouldn't hold a lot of hope for a spline press fit either. Before that, I'd cross drill and put pin through the threaded area for a SS roll pin.

Heard there is a one piece aftermarket guide rod to be out shortly for around $40 something. No other info though.

 
The P220-10mm also has a two piece guide rod, but the spring is captive on the rod. I noticed mine backing out several months ago, and I did the thorough cleaning, inside and out, with acetone, used red loctite to reassemble, and so far it has held. Perhaps the captive spring helps keep it from unscrewing itself.
 

I disassembled and soaked both pieces again in acetone then thoroughly vcleaned out the threads again. This time I used JB Weld instead of Loktite during assembly. I let it set for 24 hours and then reassembled. Thus far I have put 250 rounds of mixed ammo down range, including 14 rounds of +P 124 gr HST's and no movement.

I got a spare guide rod from Sig just in case anything funky happens, but thus far it looks promising.

BTW, my JB Weld guide Rod fix is still working flawlessly. I do not know the round count since the fix, but it is likely 600×

Are all P938 subject to this, or only ones manufactured at certain times? Does Sig offer a different rod?

quote:

Originally posted by bumper:
I just cleaned and degreased mine and applied red Loctite again

I'm not doubting you a bit, but I'd like to ask: what's the number on the red Loctite you used? We use it at work in a stainless steel application, and we have to torch it to get it to come loose.

quote:

Originally posted by coloradohunter44:
Does Sig offer a different rod?

I'm not sure Sig offers one, but several others do. A quickie search brings me these two:
- Midwest Gun Works
- SSGuiderods.com

Vthoky, thanks for the info. Looks like I should order one of those, even though my P938 has yet to act up.

I'm very glad I could help.
I probably should get hold of one as well, though -- like you -- I've not had an issue with the P938s I've shot.