Gas escaping around nipple

[Goldhunter]

I searched and didn't find much on the subject.

I was cleaning my GPR last night and noticed a mist coming out from under my nipple. Once I removed the nipple I noticed that one side of the threads was scorched and the thread hole in the BP was slightly oval shaped. The underside of the nipple (the shoulder that sits on the BP) has a dished out area where the hot gasses have been hitting it.

The nipple is correctly threaded for the GPR and is one I've been using for a few years now. Not sure how long it's been happening or what caused it to happen. I pull clean and replace the nipple every time I shoot and could see a discoloration on the nipple but hadn't noticed the hole shape or the hole under the nipple.

So my question is; Is the barrel shot? I don't see being able to drill out and re thread for a bigger nipple. I can see this getting worse until the nipple blows.

 

[longcruise]

Is the barrel shot?

No! This is purely a problem with the breech plug.

I don't see being able to drill out and re thread for a bigger nipple.

This would be the easy fix. I have done this with badly worn threads in the past. Now, I was going up from a .250X28 to a .255X28 so, the next size up was perfectly obvious. I'm just metrically challenged enough to not know what the next up nipple would be from your metric GPR nipple. But, we have geniuses here on this board who can pull that right out of their hats.

I'd say if there is no next up metric, then figure out which oversize ASA thread would be a slight oversize and use that one. ASA oversizes come as large as .260X28 and maybe larger.

I can see this getting worse until the nipple blows.

That's a good possibility :shocked2:

The worst case scenario is that you might have to replace the breech plug.

Maybe Lyman would replace the barrel if it is an obvious factory defect.

There will be other suggestions for you so hopefully you will get this taken care of.

 

[Pete Gaimari]

Is it the stock nipple?

How about trying a Treso nipple? They fit a little tighter.

 

[Goldhunter]

No, it's one I replaced the stock with a few years ago. Hot Shot maybe? can't remember.

 

[Dave Rosenthal]

I searched and didn't find much on the subject.

I was cleaning my GPR last night and noticed a mist coming out from under my nipple. Once I removed the nipple I noticed that one side of the threads was scorched and the thread hole in the BP was slightly oval shaped. The underside of the nipple (the shoulder that sits on the BP) has a dished out area where the hot gasses have been hitting it.

The nipple is correctly threaded for the GPR and is one I've been using for a few years now. Not sure how long it's been happening or what caused it to happen. I pull clean and replace the nipple every time I shoot and could see a discoloration on the nipple but hadn't noticed the hole shape or the hole under the nipple.

So my question is; Is the barrel shot? I don't see being able to drill out and re thread for a bigger nipple. I can see this getting worse until the nipple blows.

Sounds to me like all you have to do is to replace the several years old nipple with a brand-new one! If it's an original Lyman nipple, it's a sheer wonder how you've used the same nipple for so many years! At $7.95 for a package of (3)nipples, I change mine at the first sight of orifice erosion (the underside hole becomes larger & ovaled).

The mist you write about is normal, especially with heavier loads used with heavy conicals. My rifle sprays this "mist" several inches up towards the rear sight. I just use hot water and BP cleaner (Butch's Black Powder Bore Shine) to wipe it off.

On the other hand, if the threaded area in the breech plug (where the nipple gets screwed-into) shows signs of excessive wear, I'd have a Smith who KNOWS muzzleloaders take a good look at your rifle to determine the exact cause & remedy for the situation. Armchair gunsmithing isn't all it's cracked-up to be, and it's always better to err on the side of caution!

I've had my Lyman Trade Rifle for several years, and do quite a lot of shooting with it (several pounds of powder in a year)! Never had an issue with the threads in the breech plug. Some matches require over (50) 72-grain charges be fired in a single day, and I've done Scout Days where I (the Scouts) shot the rifle over 100 times.

In any case, have it looked at for safety's sake. And have fun when you make smoke!

Dave

 

[rafterob]

For now, I would just get a new nipple (or 2-3) and use some thread compound, anti seize etc.. to fill any imperfections in the BP threading. That will help prevent further gas cutting in that area. As you are already used to removing the nipple for cleaning, you can reapply the compound for each shooting session.

 

[Goldhunter]

I searched and didn't find much on the subject.

I was cleaning my GPR last night and noticed a mist coming out from under my nipple. Once I removed the nipple I noticed that one side of the threads was scorched and the thread hole in the BP was slightly oval shaped. The underside of the nipple (the shoulder that sits on the BP) has a dished out area where the hot gasses have been hitting it.

The nipple is correctly threaded for the GPR and is one I've been using for a few years now. Not sure how long it's been happening or what caused it to happen. I pull clean and replace the nipple every time I shoot and could see a discoloration on the nipple but hadn't noticed the hole shape or the hole under the nipple.

So my question is; Is the barrel shot? I don't see being able to drill out and re thread for a bigger nipple. I can see this getting worse until the nipple blows.

Sounds to me like all you have to do is to replace the several years old nipple with a brand-new one! If it's an original Lyman nipple, it's a sheer wonder how you've used the same nipple for so many years! At $7.95 for a package of (3)nipples, I change mine at the first sight of orifice erosion (the underside hole becomes larger & ovaled).

The mist you write about is normal, especially with heavier loads used with heavy conicals. My rifle sprays this "mist" several inches up towards the rear sight. I just use hot water and BP cleaner (Butch's Black Powder Bore Shine) to wipe it off.

On the other hand, if the threaded area in the breech plug (where the nipple gets screwed-into) shows signs of excessive wear, I'd have a Smith who KNOWS muzzleloaders take a good look at your rifle to determine the exact cause & remedy for the situation. Armchair gunsmithing isn't all it's cracked-up to be, and it's always better to err on the side of caution!

I've had my Lyman Trade Rifle for several years, and do quite a lot of shooting with it (several pounds of powder in a year)! Never had an issue with the threads in the breech plug. Some matches require over (50) 72-grain charges be fired in a single day, and I've done Scout Days where I (the Scouts) shot the rifle over 100 times.

In any case, have it looked at for safety's sake. And have fun when you make smoke!

Dave

Dave, no it's not the original nipple. That was filed in the circular filing cabinate years ago. The mist I was refering to is coming from between the nipple and the breach, when I push the rod down the barrel while cleaning. This is not normal. I only noticed it when I pulled the barrel out of the water bucket and was flushing the water in the barrel out the nipple (I typically do this a couple times when I first start cleaning to clean the nipple then take it out and finish the flushing without it in place.)

The thread hole is definately egg shaped now, not round. I'll try a new nipple but that won't help the enlarged hole and burnt threads.

 

[Goldhunter]

Thanks for all the replies. I'll try the new nipple and thread compound.