Can a rifle barrel have too much choke?

[rich pierce]

The answer is obviously yes if we take it to extreme- say 10 thousandths of choke. After short starting and forming to the lands and grooves the ball/patch combination would be so loose over the charge that the patch would burn or cut or both. But how much choke is helpful and how much is too much?

I’m not saying Bill Large ever did anything wrong, just that I haven’t figured out one of his barrels yet. It’s a .45 and after short starting I can just about use fingers only on the rod to seat the ball. Every ball/patch combination shows some cutting. I have about 300 rounds through it now. I’ve done the Daryl crown. I’ve seated patched balls and pulled them and the patches do not show cutting from seating. Of course there’s no heat, pressure, or velocity. I’ve got to solve this problem as it’s not as accurate as it should be.

For the record I’ve used .440 to .451 balls and patches 0.017” to 0.022” with each of the .440, .445, and .451 balls. They all load very easily after short starting.

Ideas?

[Daryl]

I'm at a loss, Rich. If showing holes, then likely still the crown.

The Enfield I had, had a PH barrel on it, with .008" deeper rifling at the breech, than at the muzzle.
The bore was a constant .574", with .003" depth of rifling at the muzzle.  The patches were reusable,
which to me, meant that in that almost .58 calibre rifle, the balls (.562" as well as .574") were obturating at the breech before
moving forward. I used 75gr. to 85gr. 2F in this rifle's short 24" bl.
This is that rifle's muzzle, along with the muzzle of a .45 bl. Loading .562" as well as .574" balls with .021" patches in the .574" bore, .580" grooved diameter muzzle.
Once short started, they loaded very easily with only 2 fingers on the steel rod, yet the recovered patches were reusable, no holes.

[Hungry Horse]

 Well, you don’t build a wealth of knowledge like Bill had without doing a few experiments that didn’t quite work out. Now I don’t think Bill would have sold one of those questionable barrels, but who knows, mixups happen. Did you get the barrel new?

  Hungry Horse

[rich pierce]

The barrel came on an as new Hawken rifle made by Andy Fautheree in 1967. I bought it at auction and it looked unfired. The front sight had never been filed down- gun was never sighted in.




The edges of the rifling look quite sharp still. I may have to unbreech it and lap it.

[Daryl]

Nice rifle, Rich.
Rich, in looking closely at the rifling lands, the one at 11:30 and at about 1 o'clock appear both to have burs at the top corners.
This will certainly cut the patch, if not when loading, perhaps upon leaving the muzzle at high speed with slight obturation of the ball.
Or - it could be as you, suspect, sharp land corners. If cutting on leaving, it will likely not effect the accuracy if there is no burning as well.
I had only one Large barrel, an 1 1/8" octagonal, 34" x .58 calibre. It shot well right off the bat, making 1 1/2", 5shot groups at 100 yards.
It however, would not shoot that well with less than 140gr. 2F GOEX. That was back in the late 1970's.
This rifle. I did spend a few days working on loads. This is the rifle I shot the modified minnie balls out of - up to (#57730) 675gr. and with up to 165gr. 2F GOEX.
That charge pushed them out at 1,325fps according to my records and shot into 2" at 100yards.
Remember in those days, Val Forget was shooting 530gr. Minnies with up to 175gr. of 3F in the Navy Arms 1/2 stocked rifle he took to Africa.



edit to correct the velocity recorded - misread it first time.

[rich pierce]

Good eyes Daryl. I worked it under magnification. Hopefully it will start to perform like we’d expect.

[Daryl]

Fingers crossed! I also see longitudinal grooving in the grooves. While they follow the rifling (in the grooves) some smoothing, as with Scotch Bright  oil,  might help.
My GRRW .69 barrel had across the land grooving from the drilling, as well as grooving in the grooves from the rifling cutter, but it shot well right off the bat. Just lucky
 I guess.

[Don Steele]

Rich,
Daryl beat me too it, but I'm also gonna tell you that crown looks like it needs work. I love the idea of stuffing a little cotton in the bore to help "light up" the area you want to examine. What does the other side look like (rotate it 180 degrees) ??
I'm not a big fan of coning, but depending upon how deep the tight part of this barrel is...maybe just taking that out with a coning tool, then using a tighter patch/ball combination that's good and snug all the way down might tighten up your groups. 

[rich pierce]

I worked on it. On closer view with my magnifier I saw a couple little burrs that could snag. I’ll try it at the range again tomorrow. Thankful for the expert advice.

[Hungry Horse]

 It appears you did a fine job on the crown edge of the barrel, but the abrupt edge of the rifling is quite a bit below the crown edge. If the bur removal doesn’t improve the accuracy, you may want to gently ease the edge of the nice deep rifling.

  Hungry Horse

[rich pierce]

I did more polishing and found that going back to .445 balls and 0.018” patches cured the patch cutting issues. I had been using .451 balls and 0.020” patches and think the strain of short starting that tight a load, combined with some crown issues, led to patch cutting and unacceptable accuracy. Now I can start over working up a load. Thanks for the great analysis and advice. 

I had to spread out a tarp at the range to catch my patches. We have done so much shooting this year that the ground is littered with patches.

[Daryl]

Now THAT's what so great about fresh snow between shoots. Easy(ier) to find patches.
Glad you're getting it sorted out, Rich. I would, however be using the .020" patches with the
.445" balls. But, of course, if it works, it works.