Questions about Jug Chokes

[Mad Professor]

Hi Everybody, I've a 62 cal smooth bore barrel that I'd like to improve the patterns for using shot so am thinking about jug choke.

How is the choke cavity enlarged into the barrel? machined or honed?

What type of lenght and taper(s) is used for various chokes (full, modified....)?

How far from muzzle is the choke?

Can your average gunsmith do this and what have you paid for the service?

Anyone do this themselves using something like a brake cylinder hone and micrometer/snap guages to see how the taper is progressing?

Thanks in advance for sharing your knowledge and advice,

Mad Professor

 

[MRW]

Metalshaper and I have done a couple of our seamless 4130 aircraft tube barrels with a jug choke of sorts. What we did was chuck them in a lathe and used a regular boring bar to remove about 20-25 thousands from the inside for about 21/2-3 inches , when we did the last pass we slowly back the bar out of the cut to extend the taper toward the muzzle so it was a more gradual transition back to bore size. We felt we went from cylinder bore patterns to a loose modified pattern with what we did , bottom line was it definitly tightened up our patterns . We also found patterns were helped by just using two hard cards and light over shot card and forget the cushion wad. for whatever reason patterns were not worth a hoot out of my gun with a cushion wad, I don't understand all the physics of this but i know I had a very dead turkey at 30 yards last year with a load of #5's so all of the speculating aside what I was after was improved pattern for turkeys/ end result dead turkey

 

[Eric Krewson]

I have a friend that has done several barrels with a brake hone. Vastly improved long range patterns. He didn't measure anything but did it by feel.

He said he read instructions on the net somewhere but didn't remember where.

 

[MRW]

Well that is about how we did it sort of "Well metalshaper does that look about like enough"? and his reply is yeah I think that will work go shoot and see what happens, I will probably get blasted for this comment but I think many times on some of this gun building people tend to overengineer some things and make it too complicated I am sure some of the old timers had to figure out things by trial and error as well, this statement doens't mean compromise safety but I am sure somewhere people will argue and analize how much material ro remove and what all specialized equipment one should have instead of like your friend just go get a brake hone hone a bit out nd see what happens

 

[CoyoteJoe]

I've jug choked a couple of barrels with a wheel cylinder hone. Brownells sells an identical tool as a shotgun bore hone but I got mine from Checker Auto.
Leave 1/2" untouched at the muzzle and run the hone in and out for the next four inches, spending most of the time in the middle. That produces a gentle taper at both ends. Be careful not to remove the hone while still spinning, it will fly to bits like shrapnel!
I ran it at 2400 RPM for about an hour, stopping often to brush the stones clean and spraying WD-40 down the bore to keep it cutting. That nearly but not quite wore out a set of stones, you may want to get replacement stones when you buy the hone since different makes may not interchange.
I don't know the exact depth of the jug but it brought my patterns up to 50% in a 30" circle at forty yards, with considerable central thickening. If I had wanted a full choke, 70% pattern, I guess a couple more hours and a couple more sets of stones would have done it but I consider full choke to be a very specialized tool and I'm happy with improved cylinder for general use. :grin: