Choke in a rifle barrel

[William Worth]

How is that done?

How is choke cut into a rifle barrel?

[smylee grouch]

It can be alot of work but lapping the bore from breech end can put some choke in the bore.   

[490roundball]

Interesting question,  if there is a constriction (normal choke)  wouldn't the ball need to be under sized for the rest of the bore?   A jug choke would avoid that but i am not sure what that would do to accuracy or even pressure at the muzzle.

If it is for a shot load, the spin of rifling may very well negate any attempt at choke.

[Chris Treichel]

About two weeks ago I was at Sully Plantation talking to a rifle builder about straight rifling... Suppose a choke would be possible with that... but how would you get a ball down if you have a choke unless its removable?

[Jerry V Lape]

Reinventing the wheel again?   The taper bored rifle was tried and discarded long ago because the assumed benefit compared to straight bored barrels didn't appear while the extra work to make them was significant. As recall Pope played with this along with progressive rifling but in the end discarded both.   

[flintriflesmith]

Barrels that were reamed with the wood backed square bit in the CWF Gunshop ended up with a slight taper fron breech to muzzle. The  amount of taper could actually be controlled by how hard the barrel was pressed against the bit during the final few shimmings but I found a taper of about .005 made the rifle a dream to load. I don't think you would call that "choke" but I have found the same taper in some original barrels.

Toward the end of this page you can see the square bit rig.
http://www.flintriflesmith.com/ToolsandTechniques/barrel_making.htm

Gary

[B.Habermehl]

I bought a factory "second" barrel from a well known barrel maker who showed me some reamer tracking down twards the breech end. So I cast a lead lap in the barrel and proceded to lap the barrel. When the reamer marks cleaned up I'm sure I had a good .005 or so taper in the bore. The barrel still shoots and loads as nice as can be on my daughter's rifle.  BJH

[William Worth]

Reknowned barrel maker Bill Large was said to have heard a German 88mm fire and declared that it had a choke due to the distinct rifle like crack compared to our artillery's thump.  He seemed to be pretty good at knowing what he was talking about.

[Don Getz]

I can recall making some barrels  for Warren Fitzgerals of Covington, Va.   He was putting choke into the barrels with the
use of a lap, a lot of work.  He did an article for Muzzle Blast on his experiments.  I one time asked Warren if the choking
made them more accurate?   His reply was "not really"  but it did make them easier to load..........Don

[snowdragon]

An actual choke, not a tapered bore, is done by using a lead lap. Basically, lead is poured in the barrel around a rod to make a lead "plug" that exactly fits the lands and grooves. The plug is pulled out, imbedded with abrasive compound, then carefully replaced in a heavily oiled bore. The plug is pulled back and forth through the barrel, but stopping about 1-1/2" from the muzzle (I may not be exact on that measurement). The idea is to open up the bore, except for the very end, without wearing down the rifling. When the plug becomes loose, it is repoured, but this time stopping more than 1-1/2" from the muzzle. With each new plug, the lapping motion stops a little further away from the muzzle, so you end up with about a 3/4" transition from the old measurement at the muzzle to the new opened up bore size. This make a slight constriction at the muzzle, just like a choke in a shotgun barrel.

I have never done this myself, as any proof of whether or not choking adds to the accuracy has yet ot be proven. As for loading, I hear it's tight at first, but gets real easy as the ball passes the choke. Hope this helps. Bill

[Roger Fisher]

Hmm, interesting way to pass the time..   I have had the following thought which could be also a waste.  After shooting and cleaning (the cleaning in particular) for in the area of 70,000 rounds  and since we seldom pull the cleaning patch breech to muzzle every time, I do wonder if that could put such a minor choke in her

It seems that my ol timer is tight at the last 5 in or so at the muzzle. 

[Dave Faletti]

Choke or squeeze bore makes some sense on breech loaders but I don't see the logic for it in a muzzleloader.  Seems the patch ball combo would just be on the loose side for most of the barrel length. The Germans did the squeeze bore on several anti tank guns.  The 88 was a much higher velocity than any howitzer and most other tank guns which would give it a different sound. 

[smylee grouch]

Interesting topic and one that could generate many a varied response. This could be a good before and after test type project something like the coned muzzle debate. Shoot an unchoked gun for groups with best grouping load and then do the same after a choke job to see if any improvment was realized.

[T*O*F]

Choke or squeeze bore makes some sense on breech loaders but I don't see the logic for it in a muzzleloader.

A choke serves no useful purpose on a round ball gun.  Choked or tapered bores are used on bullet guns because the bullet bumps up on ignition.  Most long range muzzleloaders have choked or tapered bores.

[Dphariss]

Reknowned barrel maker Bill Large was said to have heard a German 88mm fire and declared that it had a choke due to the distinct rifle like crack compared to our artillery's thump.  He seemed to be pretty good at knowing what he was talking about.

Maybe it was the gain twist. The 88 was a gain twist from my reading.

Most likely it was the velocity. About 2690 fps and the bore size and pressure at the muzzle.
The 88 was actually lower velocity than the 155mm Long Tom of WW-II
But these large bore guns have no crack to the report like a small bore ML does, at least this is my experience from serving where HV   heavy artillery (3000 fps with 174 pound shell according the WWW) was routinely fired.

Even a rifle like a 54 caliber  does not have the sharp crack of the small bore ML like a 32-36 cal. These need not have a choke to "crack". Just the right powder charge.

Dan

[B Shipman]

GRRW purportedly had a slight constiction at the muzzle. I stress slight. Pop the the short starter and they went down easily. My choice over any other at the time for accuracy. Rumor had it that they got the idea from Bill Large. How is it bad if the barrel is easy to load and the patch ball combo tightens up as it leaves the muzzle.

[willyr]

I have a Rifle with one of those GRRW barrels in .54 caliber. I don't know when it was made but I bought the barrel from Track Of The Wolf in 1978. It has been my "go to" hunting rifle since 1980. You can feel the choke when loading the rifle and when cleaning. It is also very accurate with any powder charge from 70 grains ffg to 140 grains ffg.
Bill

[Bob Roller]

Bill Large trained a GRRW employee in barrel making and sold them
a rifling machine and maybe a deep hole drill. This was in the early 1970's.
By 1980,the company was going under.

Bob Roller

[Fred]

I have a Bill Large barrel that is choked, not a lot but you can feel it when loading. I don't know if it made it more accurate but it sure didn't hurt it any. I have shot it a lot and it still does a good job. What I would really like to find is another Chet Shoults lock

[Bob Roller]

I can make the Chet Shoults lock if you want one. Is it a flint or percussion?
Parts are still available from Jerry Devaudreuil in Wooster,Ohio.

Bob Roller

[Bob Roller]

According to a German tanker there were two types of 8.8cm (88MM)
shells. One was lower veloctity and the other was hot.I can't recall this
man's name but he was in Canada when I was there in 1987 for an
International ML match.
A choke or taper bore in a round ball gun is beneficial and Bill Large
stressed that often.

Bob Roller

[Dphariss]

According to a German tanker there were two types of 8.8cm (88MM)
shells. One was lower veloctity and the other was hot.I can't recall this
man's name but he was in Canada when I was there in 1987 for an
International ML match.
A choke or taper bore in a round ball gun is beneficial and Bill Large
stressed that often.

Bob Roller

There was a higher vel. 88 (3000 fps) but it was not used outside Germany, it was not as reliable as the earlier versions and needed more maintenance so it was kept close to home in its AA role.

Dan

[pathfinder]

I have a Bill Large .40 smoothbore barrel,13/16th,41",and it tapers down from .420 to .408, from the breech to @ 8" from the muzzle,then open back to .413 at the muzzle. Absolute tack driver. To 75 yds,she'll hold a 3/4" group with a .400 ball,.018 pillow tick patch,and 65grs of 3f. She was built by Anson Morgan in Avoca,Mi.

[Mike R]

GRRW purportedly had a slight constiction at the muzzle. I stress slight. Pop the the short starter and they went down easily. My choice over any other at the time for accuracy. Rumor had it that they got the idea from Bill Large. How is it bad if the barrel is easy to load and the patch ball combo tightens up as it leaves the muzzle.

When I made my first MLing rifle [1978] I used a .45 GRRW barrel--it was sold to me as a "choked bore" barrel--and it seemed to be so.  It was and still is the most accurate ML rifle I have shot.  All I can say, as I never measured it, is that the ball loads very tight for the first few inches, then slides down more easily. 

[tyro]

U guys just gave me an answere to a question Ive been kicking around. want to build a 22 cal cap and ball, was thinking of tapering the forcing cone to swage down #4 buckshot. By lapping the cone and continuing up the bore a bit it may just work..thnx ty