muzzle choke point, almost too easy to find

[timbertoes]

playing around with my Shilen .22lr barrel.
checking the fit of the bushings on range rod and reamer.

playing with the range rod, from muzzle end, voila, choke point found
stopped a few inches in. that was easy....lol

bushings are a hair too loose otherwise, on chambering end. Hopefully the PTG 9 piece bushing kit will have one that fits well.
be fun to get an idea of that choke point again as well.

 

[sailhertoo]

Question for you.....If the choke point is 2" or more back is it better to cut the barrel there and lose the 2" or would it be better to save the 2" for velocity's sake?

I'm talking about a F-Class open match rifle.

 

[timbertoes]

cut it there, for sure.
of course I am just an internet-warrior, so worth your time to ask around.

 

[BoydAllen]

Barrels can have multiple loose and tight spots. I suggest that you slug the barrel with a lead slug, and survey its full length to see what you have.

 

[timbertoes]

I will, thanks. planning on a lot of slugging.
the point found last night still leaves a good 21" of barrel, and may well find a tighter spot in the 17+ inches length.

Although now I do wonder, since I will be getting a kit of bushings,
thinking of making a rod to hold the bushings, thats long enough to go thru the barrel.

I guess the rod only needs precision where and near , the bushing fits.

also picked up a lead melter and soft lead. Will try a lap if needed.

 

[timbertoes]

was thinking about this, and have this to say;
I slugged it once-thru when I got the barrel, it was tight enough that it was very hard to feel any difference.

 

[BoydAllen]

The bore needs to be lightly oiled, and sometimes you have to run the slug back an forth a few times to get the fit to the place where you can feel small differences.

 

[sailhertoo]

cut it there, for sure.
of course I am just an internet-warrior, so worth your time to ask around.

Whats your thoughts on this Boyd?

Would you cut 2" off the barrel to get to the choke point?

I like the idea of usings the bushings to find the choke spot timbertoes.

 

[BoydAllen]

I have read that Gordy Gritters is putting out a new video on slugging and lapping barrels. I would try to get a hold of a copy. Beyond that, the fellow that has written the most on this is Bill Calfee, and he uses a lead slug. I think that if he tells me that that is the way to do it, I would bow to his experience. I find it pretty common that fellows that lack experience think that something that they have thought of is new. Most of the time it has been tried, and if the best are doing it differently, there is a reason. A friend has done some slugging and lapping of finished barrels, with cast lead laps, both CF and RF. After hearing of his results, If I decide to try to learn how to do this. I would start out with an old factory barrel or two, and once I was confident that I had it down, graduate to a new factory barrel. He has achieved some great results, without belling muzzles or having to recrown. He also has a lifetime of experience in machining, and is an exceptionally good observer. I would say, in the top 5% in that respect.

 

[timbertoes]

when it comes to 22rf, velocity loss is not a factor.
although match ammo is graded by velocity, it really boils down to that bullseye
but thats true always.

again though its just from reading, not measurable actual experience, the ideal situation is the bullet is last-sized at exit, unless of course the barrel was dead nutz perfect.
elimination of the micro-inches of bullet yaw as it exits is the idea, i believe.
seems logical to me at least in thought/paper.

for CF, I just hunt varmints, and do love some velocity. I'd be disapointed if I had to cut back on Velocity, esp with some of the faster rounds like Swift, .257wby, etc.
bt I do want the confidence in a accurate gun that can pop a frontal-looking bobcat at 200 yards. thats a lot for the shooter to accomplish though.

 

[HiredGun]

Let us know what you finally end up with for a bushing that actually fits.

 

[timbertoes]

I'm an idiot. forgot that the dang rod is tapered. I'll just blame it on cheap beer.
slugging that barrel was a chore. tight as heck.
After about 4 slugs, one full through and the rest at different depths, I could not accuratly measure the (any) difference.

anyhow, its now done except for the dang extractor slots

 

[BoydAllen]

Come back and tell us how it shoots. On the slugging, I think that most of what you learn with be after pushing a slug back full length several times, by the feel as it passes through. Tighter spots will take more push than looser ones. Once through will probably be too tight for proper feel. It will need to loosen up a bit.

 

[STS]

I will, thanks. planning on a lot of slugging.
the point found last night still leaves a good 21" of barrel, and may well find a tighter spot in the 17+ inches length.

Although now I do wonder, since I will be getting a kit of bushings,
thinking of making a rod to hold the bushings, thats long enough to go thru the barrel.

I guess the rod only needs precision where and near , the bushing fits.

also picked up a lead melter and soft lead. Will try a lap if needed.

I've seen that tried before and the end result was two nice pistol barrels after getting the bushing stuck in the middle of the blank. This wasn't some $100 junker blank either that you would expect to have quite a bit of variability in the bore size. It was a top end BR barrel. I assume there was enough curvature to the bore to get it stuck. The blank was sawed in half to get the bushing and rod out. Word to the wise.
Edit to say that it wasn't me that was the poor soul that stuck the thing in the barrel....... thankfully. ;D

 

[timbertoes]

I will, thanks. planning on a lot of slugging.
the point found last night still leaves a good 21" of barrel, and may well find a tighter spot in the 17+ inches length.

Although now I do wonder, since I will be getting a kit of bushings,
thinking of making a rod to hold the bushings, thats long enough to go thru the barrel.

I guess the rod only needs precision where and near , the bushing fits.

also picked up a lead melter and soft lead. Will try a lap if needed.

I've seen that tried before and the end result was two nice pistol barrels after getting the bushing stuck in the middle of the blank. This wasn't some $100 junker blank either that you would expect to have quite a bit of variability in the bore size. It was a top end BR barrel. I assume there was enough curvature to the bore to get it stuck. The blank was sawed in half to get the bushing and rod out. Word to the wise.
Edit to say that it wasn't me that was the poor soul that stuck the thing in the barrel....... thankfully. ;D

eeek.