jug choke tooling

[CoyoteJoe]

Lot's of people ask how I jug choke a barrel. I won't try to do a how-to "tutorial" here because lots of the actual work is by "feel". One can feel how the tool is cutting and by experience learn to recognize the right feeling and what to do if it is not right. But anyhow, this is what I use to cut jug chokes. The tool is guided by the bore itself and thus is always straight and centered to the bore. Don't even try to cut a chrome plated bore.
This is the tool in working position in the bore.

This is the tool just removed and heavily loaded with cuttings from a "roughing cut".

This shows the tool disassembled for cleaning, note the coarse cuttings.

This shows the tool completely disassembled with micrometer and telescoping gage for measuring the depth of the recess.

This shows the fine powder cuttings typical of a light finishing cut.

The tool shown is for 16 and 20 gauge guns. The wooden backer is reinforced with AccraGlass bedding compound. I use the same cutter with a different backing for 10, 12 and 14 gauge and for that I milled the backer out of Derlin plastic. It is important that the cutter fit very tightly into the slot in the backing, any "wiggle room" will lead to chattering.
Keep the cutting edge sharp, use lots of cutting oil, take it slowly, remove and clean the cutter very frequently, go easy on the finish cuts and it's a snap.

 

[Robby]

Joe, That is pretty neat. I have been pondering on several ideas for a jug choking tool, many learned here. This one seems to be very simple and straight forward. Thank you very much for posting this!
Robby

 

[paulvallandigham]

Joe: Great Set up, and fine photos. Thank you so much for sharing this information. I doubt you are going to see a lot of competitors, but its nice to know how this is done. Your set-up tool seems to be designed so it can even be used to choke DB shotguns, NO?

Q. Is it only friction that keeps that forward wedge from backing out as you turn the cutter in the barrel? ( I am Not suggestion that the friction isn't good enough- just curious.)

 

[CoyoteJoe]

Correct Paul, it does work as well for doubles as singles. As to what keeps the tool from backing out, it is the operator. While turning the cutter I apply slight pressure to keep the tool in against the stop. On the finishing cuts however I like to let it wonder a bit, maybe 1/8 to 3/16 inch in and out. That seems to create a smoother recess without any deep scratches. The finish cuts take longer than the roughing cuts but remove very little material, maybe a couple of thousandths, just enough to get to the bottom of any deep scratches and if the tool is kept sharp, well oiled and frequently cleaned of cuttings there just won't be any really deep scratches. I used to use a Brownells barrel hone for final finishing but have learned that a sharp, well oiled and lightly handled cutter will leave a surface smoother than the Brownells hone. It's all in the touch.

 

[paulvallandigham]

Thanks for the information, Joe. Great Tool. Well designed, and meet that KISS principle very well! The secret to the smooth cut is in the magic needed to hone a sharp edge. I have used the Brownell's hones on barrels, and I am aware of what you mean. Now, if the hones were offered with stones of a much finer grit, that might be something different all together.

Thanks, again, All things being equal, I think I would prefer to send my barrel to you to jug choke, than to spend the time you have mastering the skills needed to make a good tool that works. :thumbsup: :hatsoff:

 

[gonzomann]

Very Informative Joe! Thanks for sharing, great information for us folks out here!

 

[Robby]

Joe, How much over the existing bore diameter do you go to achieve full choke, modified? Is it different for different bore diameters? I'll be doing 16's and 12's, Thanks again.
Robby

 

[Ken Morrison]

What kind of steel is the cutter made from? Looks like a very simple but effective tool.
Thanks.

 

[BS]

CoyoteJoe,

Thanks, for showing us your tool.....it looks like a simple design, that works. :thumbsup: :thumbsup: :thumbsup:

No-BS

 

[CoyoteJoe]

Joe, How much over the existing bore diameter do you go to achieve full choke, modified? Is it different for different bore diameters? I'll be doing 16's and 12's, Thanks again.
Robby

Yes, it is different for different bore sizes. The old standard for 12 gauge full choke was .040" constriction. Modern guns with modern loads really don't need that much constriction but with muzzleloaders we still are duplicating the old loadings. So the recess for a full choke 12 is .020" deep, which of course enlarges the bore diameter by the required .040". That should work just as well for a 16 gauge although you can probably get there with .035" constriction. The only way to know for sure is by shooting test patterns but about any constriction will give a better pattern than a cylinder bore. And the beauty of a jug choke is that they still load just as easily as a cylinder bore.

 

[CoyoteJoe]

What kind of steel is the cutter made from? Looks like a very simple but effective tool.
Thanks.

Oil hardening tool steel. It is purchased in a soft condition to be easily cut with a hacksaw and filed to shape. It is then heated to a uniform bright red and quickly quenched to be glass hard. Then stoned to a very smooth and sharp cutting edge with just a bit of draft to put the pressure on the leading edge. The greatest problem I encountered was that the cutter would tend to warp when heated and quenched. It can be done with a torch but a small forge would be much easier to heat the full length of the blade without warping. The cutter must be very sharp, very hard so as to remain sharp and must fit into the backer very tightly and set on the center line of the bore.
It doesn't show too well in the photos but when your tool is working properly the cuttings from the roughing cuts will resemble what you see when scraping a piece of wood with a sharp scraper. Not surprising since it really is a scraping action more than cutting like a lathe tool or drill bit which produces those long curly cuttings.

 

[Roy]

Nice :thumbsup:

Not to worry though, I will continue to send people your way when they ask me if I will jug choke a barrel :thumbsup: :haha:

 

[CoyoteJoe]

Thanks Roy, the way ammo prices are going I need to work more and shoot less! :cursing:

 

[rkmeyer]

Thanks CJ that is very interesting. Your talent is very special. :hatsoff:
Dusty :wink:

 

[Twice boom]

All very nice. :thumbsup: How thick does the barrel wall needs to be before you can jug choke.
Twice....

 

[CoyoteJoe]

That depends on the degree of choke you want. I personally consider improved cylinder to be the most useful all round choke. Just a slight choke effect will make patterns more round and uniform and more dense in the center while still giving a rather wide spread which is easy to hit with. That only requires about .010" constriction so it actually cuts only .005" deep. Even the thinnest barrel wall can stand that. Full choke requires .040" constriction so the recess is .020" deep and I'd not care to try that if barrel walls are thinner than .050", but few are.

 

[Bretwalda]

:shocked2: Wow...that is amazing!!! Does a damascus barrel present any different problems that a all steel/iron barrel?

 

[Bretwalda]

What is the length of the cut that is made by this tool?

 

[Tinker2]

Joe

Good post, thanks. I do so appreciate your posts.

What determines the depth of cut? Paper shims?



Tinker2

 

[CoyoteJoe]

:shocked2: Wow...that is amazing!!! Does a damascus barrel present any different problems that a all steel/iron barrel?

I've never done any work on damascus so I can't answer that.