Tapered Barrel

[lreed]

In an armload of flea-market gun stuff I recently acquired was a muzzle loader barrel that was someones never finished project, a .45cal 60 twistX15/16 flats 44 in long,a high quality looking barrel.The fly in the ointment is that a straight taper has been started a couple of inches from the breach end and terminates 36 in down the barrel,except for two short sections the flats are finished. The muzzle will finish at around 1/8 in per flat wall thickness,is this too thin to be considered for use in using for a rifle build? I am thinking of building a underhammer and maybe using this barrel.I sure would appreciate advice on the thin muzzle barrel such as this. Thanks lreed

[fouronesix]

Kind of hard visualizing the exact profile, but if the basic breech half or so of the barrel is close to 15/16, then that is more than plenty. With modern steel, even 13/16 is enough. The bore pressure at the muzzle end of a long barrel, burning BP, has dropped to the point of not being of much consequence. Many of the old muskets made of lesser steels have a muzzle wall thickness less than 1/8.

[johnson1942]

this may be out of place but 36 inches is my favorite length for a muzzle loader barrel, why dont you cut it off square and crown it and use the barrel as 36 inches long. a nice under hammer with a 36 inch barrel would be pleasant to carry and shoot.

[fouronesix]

Good point about the length. 44" seems like it was the "stock" length for that blank with something on the order of 40-42" being normal for a finished regular long rifle. I know that 45 cal in 15/16" across the flats is going to be a tad heavy for off hand hold- even with the taper. A 45 cal 15/16" 28" barrel is heavy and a 15/16" 45 at 32" is too heavy (for me anyway). If the bore is good- that blank should make for a nice round ball rifle no matter the type you choose. I don't know if it has a breech plug or tang already fitted but one other thing to check before assuming which end is muzzle and which is breech. You can take a tight, oiled patch on a jag and run it in carefully to feel if there is a tight or loose end. That may determine which end is which and which end to cut off. Another possibility and one I'd consider if starting with that barrel, would be to draw file it down to a more non-tapered profile and closer to 13/16" across the flats. Then cut the muzzle end off to your preferred length.

[johnson1942]

i forgot to mention i had a 34 inch .45 cal 1/60 twist barrel sitting around for years and last winter i put a nice half stock side lock together with it. that cal and twist is very easy to work up a load for and it is pinpoint accurate. i dont try to make a magnum out of that as i have enough muzzle loaders that can take anything so i use 60 grains of 2f black behind the patched ball and it is every thing that kind of gun should be. make your self a good gun with your find. it will shoot like you want and be a lot of fun. the only thing i do different than others is i relube the over the counter precut prelubed round patches each with rooser paper patch lube and let dry well. it tightened up my 100 yard groups even more. have fun

[Zymurgy50]

That type of barrel was called a "swamped" taper, was used mainly to reduce weight on full stocked muzzleloaders.

[fouronesix]

Thought of some kind of swamped profile also. But a 1/8" wall thickness at muzzle on a basic 15/16" ATF barrel sure doesn't sound like a "swamped" profile.

[lreed]

I am unsure of the mindset of the original owner of this barrel-the gentleman that I purchased it from had a pickup bed full of gun stuff-said he bought it all from a gunsmith's estate sale.I purchased four muzzle loading barrels,two lee style case trimmers,some old unknown military sights,one of which was identified as a 1901 Krag all for the sum of ten dollars.The prices were low and the action was grab and snatch.
Back to the tapered barrel question,the bore is pristine,the breech threaded,a expensive barrel to buy for someone of my financial condition. If to guess the maker-at least the quality of Green Mt, I agree, the barrel would finish too thin for a under rib to be attached other than soldering.As to the milling being done for the start of making a "swamped" barrel it would seem to me that taper was too severe and continues too far.
I too like 36 in barrels and will probably finish it as such.My concern was with the thin muzzle as I have never worked with rifle barrels as thin as this will be,unknowns,but I'll give it a try. Thanks lreed

[fouronesix]

Hey for a good "lot" price and good quality barrel with good bore... I'd sure give it a try. Kind of hard to tell how it will "hold" off hand without a stock fitted though. But as to the "thin" muzzle--- still sounds like no strength problem as far as pressure goes. Really, no issue it if starts out at 15/16" at the breech and tapers down to something like 13/16" at the muzzle. Modern steel ML 45 cal barrels of even 13/16" ATF can handle fairly stiff charges under conicals. I think T/C lists a max charge of 80 gr FF under their 220 gr Maxi in the 45 Seneca which is a 13/16" and that recommendation would have some margin built in. From a maximum pressure just after ignition/and a few inches down the bore- pressure begins to drop rapidly as the ball proceeds farther down the barrel.