Green Mountain 50 Caliber Barrel Pointers?

[rr2241tx]

Several years ago I happened upon a T/C 50 caliber Hawken percussion rifle and fairly quickly discovered that it had a 1:24 twist barrel that shot REAL bullets and Maxi-Balls quite well but was hopeless with roundballs. My main interest in it was as a silhouette gun, so I ordered a Green Mountain drop-in replacement barrel with a 1:70 twist. A Lee .500 roundball mold sorted out the problem of undersized balls and it is probably more accurate than my shooting suggests. But, there is a fly in the ointment: I shoot 2F Goex and have an awful time keeping the flashhole open inside the breechblock with this new barrel. Never a problem with the original barrel and no problems with a 54 caliber Renegade that also shoots 2F and roundballs. I have verified that the flashhole is the same diameter as the original barrel and there is no observable roughness. I'm stumped. Now what?

[Tatume]

I'm not certain what you mean by "flashhole" (or touchhole, a flintlock term). In a percussion gun, pressure is contained by the orifice in the nipple. If you remove the nipple you will find that the proportions of the fire channel are quite generous all the way into the powder chamber. If the fire channel is clogging, I suggest a good cleaning. However, if you're talking about the orifice in the nipple (as I think you are), then a new nipple is indicated. Get a good one; the best are still not very expensive.

Take care, Tom

[fouronesix]

Sounds like either the patent breech and/or flash channel is different between the T/C and the GM or something is different between how you are managing the loading/lubing/swabbing/cleaning. Having owned and shot both types, I have not noticed much difference of the bolster design between a T/C and a GM. I suppose there could be a small difference causing more fouling of the patent breech recess/flash channel in the GM- but am at a loss as to any specifics to look at.

You may have to take extra care in cleaning/swabbing between shots.

[koger]

Clean the barrel and breech out good with a degreaser, brake cleaner etc before youi start shooting, will cut down on the crud. When I shot ML competition all the time, I damp swabbed between every shot, and after a 5 shot for score, I wiped with 2 or 3 wet patches, and one dry, then went to the line and busted 1-2 caps with the barrel held down, sometimes you wont believe what comes out, especially on humid days!

[johnson1942]

put a mag spark nipple on it and it will never ever misfire again. i have found that sometimes these breech plugs that fit the thompsons let the nipple screw in so far that the end of the nipple almost touches the the bottom of the flash hole. no room for the fire to go anywheres. shorten the bottom of the nipple so it is screwed in the nipple hole good but still plenty of room for the fire to go to the powder or get a mag spark nipple and the fire will find the way from that 209 shotgun primer with out any diff to the powder.

[JeffG]

I have this identical combo and also use the .500 RB. I've never had any issues what the channel through the breech block. A couple things, I swap between shots with either soapy water or a equal parts mix of sudsy ammonia, isopropyl alcohol and murphy's oil soap. After shooting I flush it out with hot soapy water, removing the clean out plug and nipple then drying the channel with a pipe cleaner. I dry the barrel and run a damp patch with birchwood casey sheath, making sure there is not enough to bleed into the flash channel. When it's time to shoot I pop a cap on it first then dry wipe the bore. Sometimes I'll go as far as using the cleaning solution to clean it as well but usually don't since I'm swapping between shots anyhow. Never any issues.

All that said, I DO take a welding tip cleaner the correct size and pass through the nipple between shots to make sure the hole size stays clean and consistent.


Several years ago I happened upon a T/C 50 caliber Hawken percussion rifle and fairly quickly discovered that it had a 1:24 twist barrel that shot REAL bullets and Maxi-Balls quite well but was hopeless with roundballs. My main interest in it was as a silhouette gun, so I ordered a Green Mountain drop-in replacement barrel with a 1:70 twist. A Lee .500 roundball mold sorted out the problem of undersized balls and it is probably more accurate than my shooting suggests. But, there is a fly in the ointment: I shoot 2F Goex and have an awful time keeping the flashhole open inside the breechblock with this new barrel. Never a problem with the original barrel and no problems with a 54 caliber Renegade that also shoots 2F and roundballs. I have verified that the flashhole is the same diameter as the original barrel and there is no observable roughness. I'm stumped. Now what?

[rr2241tx]

Flash channel is where the fouling is getting me. CRS interfering with my vocabulary. High humidity is definitely a factor I had not considered, the matches since I changed barrels all managed to fall on rainy days. Don't recall it raining on previous match days. Will definitely try some brake cleaner. Could be the flash hole in the nipple is too near the bottom of the channel too, will shim it up and see if that helps anything.

[fouronesix]

Denatured alcohol also works well as a final flush solvent for clearing traces of fouling, oil, etc. from flash channels. It too evaporates very rapidly.

If the flat bottom of the nipple is contacting a flat bottom nipple D&Td hole then yes it can interfere with flash into the powder. You can take a diamond bur on a rotary tool and wallow a groove from the center of the D&Td hole into the flash channel. Many guns already have that groove or trough.

[Boogieman]

Try an Uncle Mikes Hot Shot nipple .make sure you get all the oil out of the flash channel & bore before loading. Do not shim the nipple they can blow out, they need all the threads holding.