GPR Nipple hard to remove after Firing

Went to range today and .50-cal GPR nipple was hard to get off again, but far from frozen. I have noticed considerably more fouling on this nipple than on my other two BP rifles, even after just the first two PRBs. And I'm only shooting target loads of 50 grains Olde Eynsford ff. Still, rifle is shooting great so I hardly can complain. This is a darned accurate rifle!! I'm going to try Teflon tape on it next time out just to experiment.

FWIW I always lube both the nipple threads and the clean-out screw with Choke Tube grease for shotguns. When I forget, I regret it. When I do it, unless I over tightened it it comes right out.

:thumbsup: I do too. It's really not that big a deal. They come out, it just requires a little more torque than when everything is clean. I just make sure I clean out EVERYTHING when I'm done shooting.

Shooting PRBs lately has become an addiction. I've always enjoyed shooting BP for years, but in the past year I can't seem to wait until I can get back out and burn powder. Better than shooting off cherry bombs when I was in high school (before they got banned). I seem to be regressing to my teen years as I get closer to 70 :rotf: :rotf: :rotf:

I'll add one more speculation on a possible reason for difficult to remove nipples. The threads on the nipple may extend down into the drum or breech and become fouled when the gun is fired. That might make a nipple that goes in easily more difficult to remove. I too use a bit or oil or anti seize on nipples and remove the nipple very time I clean the firearm. I always tighten them just to a light snug fit. Not much more than finger tight.

I think that is a definite possibility.

Another thing is the fit of the threads. Maybe it's not as closely fit as others. Or, maybe it's that metric thing.

My 2 cents worth. I have a GPR and have never noticed the nipple being hard to remove. I lube the threads of the nipple well/pack the threads, I run it in then take it out, relube put it back in, and repeat for the third time, That way I make sure I am getting the lube all the way down the recieveing threads, the nipple threads into, I use Borebutter. I bilge clean my barrel and leave the nipple on for the first few strokes 5-6, before removing it, cleans the nipple really well. Nipple comes out with no problem, threads are still greasy from the Borebutter. Do the same with my TC Renegades. I also use the nipple wrench that has the hammer, wedge pin puller, and nipple wrench and only finger tighten the nipple in snug using it. If you don't lube the thread well "I think" what is happening they nipple is getting galled in the recieveing threads making it more difficult to remove. Also (my opinion) I think the Borebutter I use keeps any fouling blown up into the threads from firing soft, making the nipple easier to remove. DANNY

SgtMaj said:

I use Gorilla grease too. May try some bore butter ... got a lot of that somewhere in my stuff.

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:metoo:

bore butter also good for range and clean same day :thumbsup:

After terrorizing a few targets today,I came home to clean, Nipple was really stuck.
Put it in some soapy water and ran a patch a few times. At that point I could have removed it with fingers.
Thanks all who helped on this.........
So much to know and learn.

:hatsoff:

A nipple is designed so that the shoulder or face just above the threads will seat tightly against the face of the bolster or drum to make a gas tight seal when the nipple is tightened.

Your experience with the nipple becoming very difficult to remove without soaking the area with water tells me the nipple face is not sealing like it should.

Without a good seal at that location, every time the gun is fired, fouling gets blown up thru the threads where it will remain until it is cleaned out.
This fouling will replace the clearance built into the threads and if it is bad enough it will create a solid condition that makes the nipple almost impossible to turn.
In your case, the water penetrated the fouling and softened it to the point that the nipple easily unscrewed.

A poor seal of the nipple can be caused by several different things.

If the nipple is too long for the threaded hole, it can tighten up at the bottom of the threads, giving the appearance that it is tight and sealed.

The "clean out screw" if it exists can be screwed in too far and the lower end of the nipple can be hitting it. This would result in the same result as the nipple being too long.

With guns that have the nipple screwing into a round drum, if the drum does not have a flat face around the nipple hole, the nipple face cannot seal the joint. Sealing against a round cylindrical surface does not work because the area on both sides of the nipple next to the point where it is making contact is open.

If the flat face around the nipple hole is not perpendicular to the threads or it is damaged, the nipple cannot seal against it.

Give your gun a good looking at to see if any of these conditions exist.
If they do, your problem will continue to exist until you fix it.

Oh, putting grease into the threads might help but usually it gets blown out of the area with the first few shots.
Likewise a anti-seize thread lube can help but if the threads are firmly packed with fouling it won't do much good.

Zonie
Good points to consider, I will look at it to see if they are the problem.
I made a trip to Buffalo Arms awile back to load up on supplies.
The Ampco Nipples were highly recommended by people in the shop.
This was a like new GPR I got at a show and have
not used anything but the Ampco's in it.
I will try a new Nipple to see if it helps.
Yesterday's Range work was very rewarding and I really enjoy the longer sight radius of the GPR over the T.C. Hawken.
I will be going to my first Shoot later this month and am looking forward to meeting other B.P. People.......

When you say the nipple is easy to install with finger pressure only, just how easy is it? With it threaded in about half way, is there any slop in the fit if you try to wiggle it? As others have alluded to, this sounds like it might be a case of the nipple threads being cut undersized. If the thread journal is too short and it is not sealing, loose tolerances on the thread dimensions will exacerbate the problem.

If you have a machinist friend he could measure the pitch diameter of the 6mm-.75 thread to see if it is within tolerance.

Even if the face of the nipple doesn't seal, it shouldn't be this much of a problem if the threads are made correctly.

Forrest,
No real wiggle at all, but that was a good point.
Will be shooting tomorrow and will try a few things suggested here.
Thanks All..........

Something not mentioned.
Perhaps the original owner of the rifle failed to properly clean the packing grease.
We all know some major fouling can happen when any of that stuff is accidentally left in the bore,fire channel or threads. Well the same thing can happen if a new nipple isn't cleaned. Nipples are machined with machine lubrication. Well at least I haven't seen a nipple hammered out on a forge.
Did anyone mention running a tap to chase/clean the breech threads?

You didn't partially cross thread the nipple at some point did you? I've seen that done and it will inhibit proper seating until cleaned up with a tap.

Forrest said:

When you say the nipple is easy to install with finger pressure only, just how easy is it? With it threaded in about half way, is there any slop in the fit if you try to wiggle it? As others have alluded to, this sounds like it might be a case of the nipple threads being cut undersized. If the thread journal is too short and it is not sealing, loose tolerances on the thread dimensions will exacerbate the problem.

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Interesting point ... I checked the nipple on my new GPR, gave it a full turn outward, and it wiggled significantly. I have an extra nipple I purchased from TOW, so I put it on, and it fits tight with no wiggle. I have been experiencing the same problem OP had with his GPR nipple. I'll put on some Teflon tape the next time out to the range and see how it works out on the nipple that came with the rifle.

M.D. said:

You didn't partially cross thread the nipple at some point did you? I've seen that done and it will inhibit proper seating until cleaned up with a tap.

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I have to agree with this statement.
Bet you run a tap down the threads and problem will go away.

IMO, while running a tap down into the threads can clean them up, it can also frinkle them up.

It is all too easy to start a tap slightly cocked without knowing it until you start to screw it in.

I say it is all too easy because the tap is missing large amounts of thread where the 3 or 4 flutes are. Those missing areas will often fail to guide the cutting threads on the tap evenly into the tapped hole.

If the tap is cocked even one thread worth when its being started, screwing it in will totally ruin the existing threads.

Another thing that should be mentioned.

Normal taps have long, tapered "lead in's" to help the tap align with a unthreaded hole.

The tapered portion of the tap's threads won't be able to do much to clean up the existing threads.
The only way to make the tap cut full threads from the get go is to grind off all of the tapered area. That, in a sense, turns the tapered tap into a bottoming tap.

If the existing threads are worn, crossthreaded or have missing material, running a tap into the hole will do nothing to repair it.
I would advise leaving the tap alone. There's little that it can fix and a lot it can frinkle up.

For nipples in a patent breech or drum start with a partially shortened taper tap, to get the threads lined up again and complete with a plug or bottoming tap.
It is done by feel and how well the T-handle lines up with the hole thread. I've cleaned up bugger threads may times as described and it is almost fool proof with any kind of dexterity at all.
Cylinder nipples are almost always at an angle to the chamber axis so these need to be felt through very carefully but the tap will tell you if it's tracking the thread and not the bugger by how it feels.