Heavy barrel

[JIMHAY97]

I've been thinking of a scratch built underhammer target rifle for bench shooting. Where can I find a 1 & 3/4" across the flats barrel that has a 1 in 18 twist? 48" long. Percussion. Thanks, Jim in Port Townsend, WA

 

[ohio ramrod]

Sounds like a custom job to me! :idunno:

 

[Rifleman1776]

a 1 in 18 twist

Do you want to build a slug gun?
That rate of twist would be pitiful for a patched round ball.

 

[JIMHAY97]

Yes,it would be a slug gun shooting swaged bullets with paper patch. I've been reading Ned Roberts book on cap lock rifles now for a couple years and would really like to make a target rifle with all the accessories. I'm a retired machinist and have the skills to do it but I need a barrel. I would like a 40 to 45 cal barrel 40" long when I'm done. A 1 in 18 twist with Pope rifling.

 

[Rifleman1776]

Yes,it would be a slug gun shooting swaged bullets with paper patch. I've been reading Ned Roberts book on cap lock rifles now for a couple years and would really like to make a target rifle with all the accessories. I'm a retired machinist and have the skills to do it but I need a barrel. I would like a 40 to 45 cal barrel 40" long when I'm done. A 1 in 18 twist with Pope rifling.

Congratulations on an ambitious project. :hatsoff:
I won't mention a barrel maker, the guys I know/knew are probably all dead. I suggest you attend some big shoots like Friendship and ask around.
Only advice I can give is don't ask questions of the slug shooters while they are loading or in a match. Nice guys off the range but really super serious when competing.
Do keep us informed of your progress.

 

[Walks with fire]

Hello Jim,

I believe Green Mountain will have some barrel blanks that would be in the 1/18 twist rate and .450/.458 caliber. I believe they are for black powder cartridge rifles though; may not be long enough for what you want to do. They won't be 1 3/4" across the flats either.

Here is what I was thinking of ...

GM Sharps barrels

 

Jim,
Contact Ed Rayl in Gasawy, W Va.
Mark

 

[Rifleman1776]

may not be long enough for what you want to do.

They may be 'long enough' for a bench type target slug gun. But he wants a 40" barrel. It is what he wants. Seems overly long for the task however, IMHO. This from one who has never fired a slug gun. :redface:
But, I've watched a few. :wink:

 

[Walks with fire]

These are 32" barrels but I am sure he can find a barrel maker to make something heavier and longer; just thought I would pass the link to GM along if he didn't know about GM.

 

[JIMHAY97]

I just made a startling discovery about my lathe. The through hole in the spindle is only 1.4" dia so the measurement across the flats can only be 1.29". So I guess I'll look for a barrel that is 1.25 wide. The reason I was asking about 40" lengths was so that I could use the excess to turn the false muzzle and bullet starter. I plan on doing as much of the machine work as possible on my lathe and my friends Bridgeport mill. I requested info from Green Mountain, hope to hear from them Monday. Thanks again.

 

[bob308]

the false muzzle has to be made and fitted to the barrel before it is reamed and rifled. then it is clamped and reamed and rifled.

bob hoyt in fairfield pa. can do the job.

 

[JIMHAY97]

I've read where you can do it to a barrel that is already rifled. You have to pour a lead slug in the location where you want to cut the barrel then cut it on a lathe to the depth where it just starts cutting lead all the way around. Twist off the piece that will be your false muzzle and set aside. Leave the slug in the barrel. Face the barrel muzzle square. Now face the false muzzle square. You can now put the false muzzle back on the barrel using the slug as a guide and the rifling should line up. The flats won't line up but they'll be turned off anyway. Drill for the locating pins. I think I could do this using a drill jig or two.

 

[JIMHAY97]

After thinking some more on this I have my doubts if the lead slug would be stiff enough to hold the alignment while parting the false muzzle off. Have to do some more thinking I guess.

 

[Zonie]

A method used when cutting off a length of the rifled barrel to make a false muzzle consists of first drilling two holes parallel with the bore and deeper than the length of the future false muzzle.
These two holes are not equally spaced. In fact, it is better to have one of them significantly off of a equal spaced pattern.

Then, the false muzzle is cut off of the barrel with a very narrow cut off tool in a lathe.

The previously drilled holes are then reamed to fit dowel pins.
The reamer size used in the false muzzle will produce a light to medium press fit to the dowels.
The reamer size used to enlarge the holes in the barrel will be a close "slip fit" to the dowels with approximately .0005 clearance.

When the false muzzle dowels are inserted into the barrels holes the bore and the rifling will be aligned with great precision.

Usually, the false muzzle will have another pin installed that is aligned with the front sight.

The purpose of this pin is to block the view of the target should the shooter forget to remove the false muzzle.

 

Zonie,
In reading your post; no matter how thin your cut off tool is,won't the rifling be off by that same dimension? It seems to me that the correct way is, as stated, cut off the false muzzle piece prior to rifling and then clamp the parts together to cut the rifling and keep everything in alignment.
Mark :idunno:

 

[JIMHAY97]

Yes, it will be off. Depending on the rate of twist will tell you how much. Example: a .5" dia bore has a circumference of 1.570". A 1 in 18 twist means that for every inch you go along the bore the rifling twists .087, (1.570/18). If you have a 1/8" wide part off tool you will lose 1/8 of .087 or .0109. A 1 in 60 twist will only lose .003. I don't know how much misalignment can be tolerated but .0109 seems like it would tear the paper patch. A smaller dia bore also gives smaller mismatch.

 

[zimmerstutzen]

Just because the barrel is octagon doesn't mean the false muzzle must be. I have seen lots of round false muzzles. The trick is to line up the rifling, drill the pins and not worry about the exterior flats lining up. turn it round. It is still not the proper way, which is to machine the false muzzle before reaming and rifling.

 

[paulvallandigham]

Most false muzzles are rifled along with the barrel at the same time, for a perfect fit. That means that you cut off a piece of the barrel BEFORE the grooves are cut, drill the short false muzzle for pins, and drill through the new muzzle so that pins will hold the false muzzle Exactly in place when the rifling is done.

After the rifling is cut, the false muzzle is CONED- a taper is cut into the front of the false muzzle, to make it easier to begin loading the bullet that will be seated in the barrel. If paper patching is used( almost always), cross grooves are milled into the face of the false muzzle, that are the exact width of the strips to be used. They serve as a guide for the strips, both placing them at right angles, and insuring that the strips butt their edges against each other as the bullet is pushed into the false muzzle, for a Perfect GAS SEAL. Also, typically, a round groove is cut in the face to hold a WASHER. The washer is placed on top of the two strips of onion skin, or other paper in those grooves. The washer holds the two strips down, while the bullet is pushed through the hole in the washer and slowly pushed on the two strips of paper so that they are drawn down into the tapered bore of the false muzzle. The paper strips are typically lubed with a fine oil, and that oil helps the strips slip down into the bore around the bullet. When the bullet exits the back, or bottom side of the false muzzle, its completely surrounded by the paper patches, butted exactly against each other's edges, so that no seam can be noticed without a very close look for them. The False muzzle also serves as a "sizing " die, particularly for the paper, smoothing down folds at the corners. This sizing helps the PP bullet move down the bore of the rifle easily, with the grooves in the false muzzle guiding the bullet into the grooves in the barrel.

If you don't cut the grooves in both the barrel and the false muzzle at the same time, the little bit that the grooves of the barrel don't line up with those in the false muzzle will tear the paper patching. You would be better off using a false muzzle with NO rifling in it, and a coned barrel muzzle, but that would defeat the purpose of using a false muzzle in the first place. :hmm: :shocked2:

 

[Zonie]

Yes, it will be off. Depending on the rate of twist will tell you how much. Example: a .5" dia bore has a circumference of 1.570". A 1 in 18 twist means that for every inch you go along the bore the rifling twists .087, (1.570/18). If you have a 1/8" wide part off tool you will lose 1/8 of .087 or .0109. A 1 in 60 twist will only lose .003. I don't know how much misalignment can be tolerated but .0109 seems like it would tear the paper patch. A smaller dia bore also gives smaller mismatch.

I mentioned a "very narrow" cutoff tool.
To my thinking a 1/8" cutoff tool is a standard off the shelf tool, not something a craftsman would be using for this sort of operation.

Using your figures, if a .032 wide tool were to be used the calculated .0109 mismatch becomes .0028 and the .003 mismatch becomes .0008.

 

[JIMHAY97]

Thanks to all who have replied to my question about false muzzles. You have all made very valid points about how this should be done. I went back into the forum posts to 2006 and found the idea of using a spacer the same width as the part off tool which would put the rifling back in the same relationship as it was prior to being cut off. This assumes that you have already drilled the locating pin holes.
There are a couple reasons I would like to do this myself. One of them is that it would be a lot cheaper then buying a premade barrel with false muzzle. Another is that I'm a retired machinist with 40+ years experience and I would like to be able to say I did it when showing off the rifle and explaining the use of the false muzzle.
There sure is a lot of very useful info in this forum if you can dig it out. I've been involved with black powder for a long time. Bought my first pile of parts for a rifle from Ted Fellowes back in 77. I'm still working on it but it shoots great.
Now if I can find the right barrel to start this next project......