Curious bout jug choking

[GreyWhiskers]

Can a double barreled gun be jug choked? Not sure of the process. Wondered if the barrel needed to be chucked up in a lathe. Also, is barrel thickness a concern? GW

 

[bart_anastasi]

What is jug choaking?

 

[Roy]

heres some info
[url] http://www.muzzleloadingforum...9883/hl/"jug+choKe"/fromsearch/1/#409883[/url]

 

[paulvallandigham]

Jug choking is putting an expansion chamber inside the barrel. Barrel thickness is important. However, we are talking about .005-.015" in depth, so only those very thin old barrels are likely to be rejected for such a procedure. DB guns can be jug choke, if the barrels are thick enough. However, since most people who do the jug choking today do use some kind of lathe setup, its pretty hard to find someone to do a DB. I have not heard of anyone recently set up to do DB shotguns. Perhaps in Europe, but I have my doubts. Jug choke consists of a gentle throat into a wider than bore diameter chamber, the width determining the degree of choke being put in the barrel, followed by the chamber, and then a shorter bottle neck leading to the muzzle. Usually, there will be an inch or bore left before the muzzle to allow the shot charge to straighten out, before leaving the muzzle.

Roundball had his single barrel 20 gauge barrel for his T/C renegade, jug choked prior to last year's turkey season, and cleanly took a turkey at 40 yards, and then a second at 30 yards.

 

[No Deer]

I had a double 12 ga. converted to flintlock, and then had the barrels jug choked. The right one is improved cylinder, and the left one is improved modified. It did not have to be done in a lathe, he has an attachment he puts on a drill. Have not had a chance to pattern it yet, but I have shot some trap with it and did ok. Looking forward to working up a load and then see what it can really do.

 

[GreyWhiskers]

Thanks fer the replies guys. :thumbsup: Not sure what I'm going to do with this 10 ga double but will try some more tricks to tighten patterns up. GW

 

[CoyoteJoe]

There is no problem in jug choking a double except that many of the modern repo doubles have chrome lined bores and that will ruin a reamer in short order. It also presents a problem for installing choke tubes which would be the other option. Other than that, chrome is fine.

 

[rayb]

You can do it yourself.

Basic approach is using a brake cylinder hone, slowly and with test firing in between cutting sessions.

Search around some, I've seen instructions on how to do it posted before. ?? Maybe Muzzle Blasts,?? and maybe on this forum. Also try V M Starr search, there may be some info in his writings.

My jug chocked 12 gauge does very well, a recommended procedure if you don't care for cylinder bore.

Your results may vary.

rayb

 

[tab75336]

Slightly off topic of the DB jug choke. Does jug choking a smoothbore prevent it from further use of roundball?

 

[paulvallandigham]

It depends on who does the jug choking, how much choke you put in it, and what kind of wads you use to help the ball skip through the expansion chamber, while not letting gas blow by and cut your patch and ball.

 

[Capt. Jas.]

Paul, Please detail the wads you use to help the ball skip through the expansion chamber, while not letting gas blow by and cut your patch and ball.
Thanks

 

[paulvallandigham]

I got the idea from looking at all the cushion wads that are used to fill up brass casings for those old nitro cartridges, so that smokeless powders made today can be used in the old guns.And, if you have ever cut open a commercially made shotgun slug, you will find losts of wads behind the slug. The Brenneke even uses a screw to hold the wads to the base of the slug, so that the slug and the wads travel down range to the target.

A ML shotgun, or fowler, because the chamber is not a separate part of the gun in these large gauge barrels, is not like the cartridge rifle or shotgun. There is no need for a tapered throat in front of the chamber to ease the slug and wads into the bore.

But, when an expansion chamber is ground or cut into the barrel to provide choke, you have a " Chamber " . Now, that chamber needs a throat, and because you are shooting a PRB, you need some way for the PRB to get through the chamber area without losing the patch, or subjecting the ball to gas cutting.

Basically, the idea is to use several cushion wads- the fat ones that are about 1/2" thick, made of celotex-- to bridge the expansion chamber, so that by the time that gas is able to enter the slope into the expansion chamber, the ball or slug is already past the chamber and into the last remaining portion of the barrel just before the muzzle. What gases do get into the chamber burn or affect only some of the cushion wads BEHIND the ball, or bullet, and do not cut the Patch or ball, or bullet in front of the cushion wads.

The cushion wads would add to the total mass being pushed by the powder, and contribute half their weight to the felt recoil, but I would not expect that small increase to make the recoil intolerable.

Again, depending on the amount of choke( the diameter of the expansion chamber) the length of the chamber, and the total length of the bevel into the chamber and the throat out of it, will determine how much and what kind of wads you will need to bridge the chamber as described.

There is also the problem of barrel harmonica being altered by jug choking, and you may have to work up an entirely new load for a PRB, to get the same kind of accuracy you had before the jug choking.

Frankly, I prefer what ROUNDBALL did last year. He ordered both a barrel that he jug choked, and then a second barrel that is rifled to fire PRB. He is not trying to do all things with the same barrel.


Of the problems I have mentioned, the bridging is the easiest to solve. The Barrel harmonics is the one that will give anyone real headaches,IMHO. A barrel that shot very good groups before it was jug choked, may never fire comparable groups again, simply because the barrel harmonics are dramatically change, particularly in that last inch before the muzzle.

Paul

 

[roundball]

Slightly off topic of the DB jug choke. Does jug choking a smoothbore prevent it from further use of roundball?

The day I pattern tested my 'Full' Jug Choked .62cal GM Flint smoothbore barrel at the range I also took a half dozen PRBs just to get an initial idea of what they would do...and while not even close to being a thorough bench test at all, it shot cloverleafs at 25yds just sitting in a chair so it would have been even tighter from a bench, and the patches were fine.

I just used the same 80grn charges I had with me for shot load patterning and added an Oxyoke .018" pillow ticking patch with a .600 ball. So from my 'hunter' point of view, I don't expect there's any difference to speak of unless longer range testing sessions might reveal something like a trend of an occasional flyer or something

 

[brobb]

some more good info on jug chokes at
[url] http://www.muzzleloadingforum...072/post/339322/hl//fromsearch/1/#339322[/url]