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[Flycaster]

Hi all,
Was at the range, shooting my Thompson Center Hawken. 50 cal Green Mountain replacement barrel. Was shooting a mild target load of 40grns. 2f.
After the first couple rounds, the ramrod started pushing back up under pressure. I had to repeatedly push the ball back down, until it would set on the powder. The ball and ramrod were under quite a bit of pressure coming back up.
I've fired several hundred rounds out of this barrel, and never had this happen before. Any ideas on what was going on?
Thanks,
Flycaster

 

[DuncNZ]

Are you loading with the hammer down on the fired cap ? this can trap air below the ball

 

[biliff]

Trapped air. Something is plugging up the nipple orifice.

 

[oldwood]

I've not seen this issue before , but would assume it could be a fouling problem. One thing to try using light loads , would be use a finer powder for less fouling. It's perfectly ok to use FFFG , instead of FFG. 40 gr. of FFG might not be burning clean enough , and causing a slightly plugged breech area. Also , if the rifle is a percussion , remove the spent cap to allow air to exit the nipple when loading.

 

[mushka]

My experience like that was a plugged nipple.

 

[Flycaster]

You guys are probably on the right track. Little more info:
Brandy new, shiney nipple from TOTW. I noticed, when installing it, the orifice looked tiny.
No spent cap. Hammer at half cock.
I was using some old RWS caps I just got from a gun shop up north, had to blow the dust off the tin. That was how old they were, in a tin, not plastic.

 

[Rock Home Isle]

Hi all,
Was at the range, shooting my Thompson Center Hawken. 50 cal Green Mountain replacement barrel. Was shooting a mild target load of 40grns. 2f.
After the first couple rounds, the ramrod started pushing back up under pressure. I had to repeatedly push the ball back down, until it would set on the powder. The ball and ramrod were under quite a bit of pressure coming back up.
I've fired several hundred rounds out of this barrel, and never had this happen before. Any ideas on what was going on?
Thanks,
Flycaster

Something is blocking the air flow out of the barrel through the nipple. But for this to happen, you should be having ignition problems…so for now, color me perpelxed

 

[N.Y. Yankee]

You're just getting some fouling or unburned powder up against the nipple, plugging the hole. If it happens again, just take a nipple pick and work it a bit to help unclog it. If you are using a "bore button" wool felt wad under the ball, that may cause a restriction too. Dont drive it down by itself, just push it into the muzzle and drive the ball down on top of it.

 

[Andrewmtnman]

Did you try firing off just a nipple between loads to clean out the breech? If that solves the problem you then know what the problem is

 

[oldwood]

Some of the caps used to have foil covering the percussion cap explosive. Way back in the fog of my brain , I remember someone having a buildup of the cap foils , causing irregular ignition.

 

[leadhoarder]

I had that happen for the first time a few days ago firing my plains rifle and it was a clogged nipple as indicated above.

 

[Smokey Plainsman]

You guys are probably on the right track. Little more info:
Brandy new, shiney nipple from TOTW. I noticed, when installing it, the orifice looked tiny.
No spent cap. Hammer at half cock.
I was using some old RWS caps I just got from a gun shop up north, had to blow the dust off the tin. That was how old they were, in a tin, not plastic.

Brandy new?

 

[rafterob]

Similar incidence a few years back, the pressure popped the ramrod out of my grip and sent it in to orbit through the rafters of our range cover. No ball, I was swabbing the barrel.

 

[deerstalkert]

Brandy new?

Brandy new..
definition... kinda new, sorta new , almost new, fairly new!

 

[Flycaster]

Brandy new. play on words...brand new.. fresh out of the package...never used before.. direct from the factory.

 

[ord sgt]

The tiny flash hole in the new nipple is part of the problem. Not enough air can flow back through the nipple. As the hole enlarges, the problem will decrease.