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Lyman GPR Cleanout screw

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hrchotaw

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The cleanout screw on a new GPR barrel I just purchased has me bumfuzzled! With the nipple removed it appears it can be screwed all the way into the bore. The threads in both the plug and screw are fine. But the only way to tighten it securely is against the bottom of the nipple once the nipple is installed! This can't be right,or I'm missing something. What does anyoine think about threadlocker or a little super glue on the threads. I guess it's there for a machining process,but I've got 3 T/C's that work fine without.I,d appreciate any ideas on this! :hmm:
 
That screw is there to plug the end of the bore made to transmit primer flash to powder chamber in the breech plug. I have an old TC Renegade barrel made the other way around- the passage was drilled from the opposite side, then permanently plugged.

It really isn't necessary to remove the screw to clean the barrel assembly. Just remove the nipple and pump warm water and a few drops of dish soap up and down with range rod. If you really feel a need to brush out the passage, run a bent pipe cleaner down through the nipple seat.

White Fox
 
I might of got too long winded,but my problem is the screw won't stay tightened down. On my other lymans I never take it out to clean! This appears to be a redesigned screw which is more like a set screw. It just doesn't stay tight,thats why I asked about threadlocker(lock-tite)on the threads! :surrender:
 
ky choctaw said:
I might of got too long winded,but my problem is the screw won't stay tightened down. On my other lymans I never take it out to clean! This appears to be a redesigned screw which is more like a set screw. It just doesn't stay tight,thats why I asked about threadlocker(lock-tite)on the threads! :surrender:

Put a drop of blue Locktite on those threads and run the screw in just short of where it would interfere with the nipple. That should take care of things for you.

I've shot a GPR for over 20 years and have NEVER needed to remove the cleanout screw.
 
I appreciate that! I've got a trade rifle and another GPR and they have never gave a problem and never had the screws out. Thanks for your input! I imagine they locked in pretty good on thier own.:thumbsup:
 
Guess I've always had it wrong, then. I always remove the cleanout screw for cleaning and then always tighten it firmly against the bottom threads of the nipple when I put the gun back together. Thought it was a "belt and suspenders" approach to keeping the nipple from backing out.

So far my misguided acts haven't caused any problems. Both screw and nipple stay in place when I need them to and come out readily for cleaning.
Bob
 
I wouldn't say you are wrong, thats why I posted this question! On my older Lymans Its never posed a problem,I just didn't think you aught to use the base of the nipple threads to tighten against. If it hasn't gave anybody else doing this problems,I guess it's a normal thing! But I still may loctite it,as I believe removing the nipple opens a big enough passage to clean it out!Thanks though for the input! :)
 
why call it a "cleanout" screw? I also thought it was to be used as a setscrew against the nipple. Had me concerned about smashing the threads on nipple, then ruining the threads in the barrel itself. I guess I just take it and the nip. out for cleaning.
 
I also remove it when cleaning and use a pipe cleaner to clean the port after running water thru it. I also tighten it against the nipple(lightly).
Stew
 
Just thought of anouther option. A quick wrap of teflon plumbing tape should do the same as thread locker.
Stew
 
newtewsmoke said:
why is it even there?
It's a conversation piece.

Years ago, Thompson Center used a similar screw in their snail breech plugs and then they decided to stop using it.

That's the reason the conversations around the hunters fire used to be lively and could go on far into the night.

Now, with the hunters using the newer Thompson Center Hawkens there is a dreadful silence around the fire. The only comments being made lately are things like, "Was that you?" and the answer being, "Yup" followed by some gagging and choking gasps coming from the others gathered there.

Enter the Lyman GPR and now I'm happy to report that once again great debates about that little screw are once more in vogue, occasionally interrupted by, "Was that you?" and followed by, "Yup" and a few gagging and choking sounds. :grin:

Seriously the screw some folks call a "clean out" screw is there because it plugs one of the drilled holes that connect the nipple to the barrels chamber. It allows the manufacturer to drill straight thru and tap the mouth of the hole.

It is a handy little screw hole for those of us who dry-ball (forget to pour in the powder) sometimes.
Removing that little screw allows the shooter to easily pour in enough fine powder to blow the unpowdered ball out of the barrel.

As for keeping a loose set screw in place some have recommended using a thread locking compound and although this will work some of these compounds are very difficult to break loose after they have hardened.
A inexpensive locking compound can easily be bought at your local drug store. It's called Clear Finger Nail Polish.
Applying a small amount to the screw and then screwing the screw in place will keep it from loosening but it is very easy to break loose if you ever want to remove the screw.
 
short_start said:
Guess I've always had it wrong, then. I always remove the cleanout screw for cleaning and then always tighten it firmly against the bottom threads of the nipple when I put the gun back together. Thought it was a "belt and suspenders" approach to keeping the nipple from backing out.

So far my misguided acts haven't caused any problems. Both screw and nipple stay in place when I need them to and come out readily for cleaning.
Bob


Same here. Never a problem. I always take it out for cleaning, lube it, and put back in after the nipple. Wrong? Maybe on another gun, but not on the 3 Lymans in our house.
 
newtewsmoke said:
why is it even there?

When they make the breech plug, it's solid cast, They have to make the "fire channel" to go from the nipple to the main charge.
They drill a hole from the face of the plug down a bit, then they take a smaller bit and drill into that hole at a bit of an angle, then a third at more of an angle. The final drilling to connect the nipple and the "channel" is made by drilling from the outside of the breech to that first set of holes inside it.
Now they have an extra hole in the side of the breech that doesn't need to be there for anything besides connecting the port/fire channel. So they tap it and stick a screw init. They used to use a flat top screw that was cut to fit shallow enough to not interfear with the nipp. But guy's kept stripping the head on the screw and sending the barrel back for repair. The allen head get's a better grip, but now guy's screw it too deep and bugger the nipp threads. They can't weld it shut because that would change the temper of the steel.

I used to worry about it too, locktite it in just deep enough so it doesn't hit the nipple threads and forget about it. Usually after a 1000 rounds and a couple of years the "clean out screw" starts getting worn and harder to git in and out and get's stuck anyways,,it's best to locktite a clean freash screw in the hole at a proper depth and not have another worry :thumbsup:

Older T'C's have one, but as someone else said, they now drill from the opposite side and press a piece of rod in there,,I'm guessing that rod is some kind of composite metal designed to expand to fit tight when pressed

p.s. if ya use the blue stuff, you can always heat it a bit with a tourch and take it out if ya feel the need
 
Stewswanson said:
Just thought of anouther option. A quick wrap of teflon plumbing tape should do the same as thread locker.
Stew

The teflon tape will essentially provide lubrication, not adhesion between the setscrew and the threaded hole. Also remember that the threads are straight, not tapered, which will still allow you to bottom-out the setscrew against the nipple threads and possibly damage them.
 
Acorn Mush said:
which will still allow you to bottom-out the setscrew against the nipple threads and possibly damage them.

Unless a guy really reefs on that little set screw, it just isn't going to happen. At least it's never happened in hundreds of cleanings with our three Lymans. And I'm no mechanical wizard. Just a firm stop, and it's not going to back out, and I've never damaged a nipple or the set screw. Based on lots of first hand experience, the whole question is a pure and simple mole hill to me.
 
Same here. I remove it to clean and oil, then lightly screw it back in against the nipple threads. I actually prefer this because before hunting, I can run a pipe cleaner through the flash channel to get out all of the oil which might cause a misfire.
 
Even a dab of anti-seize will keep the screw from moving, yet allow it to be unscrewed for cleaning. I have not used the Blue Lock-tite, but I understands its made specifically so that you can remove the screw. It would be cheaper to buy a cheap bottle of clear finger nail polish( lacquer), IMHO. If you already have some lacquer at home, don't spend more money on that finger nail polish.

Paul
 
I appreciate all the good info,I just had never had one that wouldnt stay put. The "boss" has some clear nail polish I can pilfer! Thanks! :thumbsup:
 
I've had my .54 GPR percussion fo 30 years and never removed that "clean out" screw. If you remove the nipple while cleaning and use soap and water, everything in that flash channel will be flushed out. Like Zonie said, it is there for a manufacturing process until someone had a brain storm and started calling it a "clean out" screw. Zonie also mentioned how to fix it. Anyway, if you take it out every time you clean, it's that many more chances for you to loose that tiny screw. You'll be alright :thumbsup:
 
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