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On Friday, I cut a Savage factory 22" barrel down to 20" for the third time. Two of those were .308 barrels and this one was a 6.5 CM - all sporter profiles.
I am cutting and crowning these barrels with common hand tools. Hacksaw - Dremel rotary stone - File - Sandpaper - Large brass screw chucked in hand drill - Birchwood Casey cold blue pen.
In all three cases, the "garage" crown job produced better groups than the factory crown.
Has anyone else had this experience?
A proper crowning tool is not that expensive and saves a lot of time
I have cut several barrels down and crowned with a shell deburring tool. They all shoot 1/2 moa. I read an article once where they tried to mangle a crown and could not get the groups to open up. A couple of shots smoothed out any damage they did.
Maybe so, but what I have in my garage has, so far, been better than whatever they are using at the Savage factory. Which is the point of this post.Quote:
Originally Posted by grouse
I'm inclined to believe this after my experience. I think so long as you can cut the barrel reasonably square, you're probably good to go.Quote:
Originally Posted by celltech
It’s probably a shorter stiffer barrel resulting in better accuracy. Not likely the crown.
Hmm, You mean my iscar and the 11 degree crown I have been doing is a waste? :(
I figure that has something to do with it.Quote:
Originally Posted by grouse
Not if it gives you confidence. ;)Quote:
Originally Posted by Robinhood
If you read Pope's work you will find one part where he sliced the muzzle at something like 20 deg and it only changed poi slightly, no group change. And that was with cast bullets.
It would be interesting to see what those same experiments would do at longer ranges.
I hacksawed a barrel once then faced it off with a flat file and lightly touched the bore with a coned shape dremmel. It shot as good or better than the factory crown job.
Likely so, harmonics are changed when a barrel's length is altered. It is unlikely the factory crowns were actually detrimental to accuracy- which one would have to believe to attribute the gain in accuracy to the re-crown.Quote:
Originally Posted by grouse
Yup.Quote:
Originally Posted by 6.5savageguy
This is all the barrel did today...
Keep in mind, this is a 7 lb. rifle with a 2-7x scope on it.
Attachment 5915
So 3 for 3 could be a coincidence. Or not.Quote:
Originally Posted by tobnpr
I remember reading an overview of the experiences gained in "The Secrets of the Houston Warehouse" by David Scott
https://precisionrifleblog.com/2013/...ifle-accuracy/
where Virgil King stated that for a 6ppc, the barrel "must be 21 3/4 inches long for maximum accuracy".
Since barrel length has everything to do with harmonics, and some of us use harmonic tuners just for that reason, it's not inconceivable that you hit upon a better harmonic than the factory length barrel by cutting and crowning your barrels. In the end, I am a firm believer that anything you do to improve your confidence in yourself or equipment is probably well worth the effort expended and will benefit and add to your shooting skills.
For entire article go here: http://www.angelfire.com/ma3/max357/houston.html
Edit: I just re-read the above full article and would like to correct the 21 3/4" reference. That length of barrel did not apply just to the 22PPC, it applied to all the calibers he tested, .22, 6mm, and 30 cal.
Every barrel he had made was cut to 21 3/4 inch and target crowned. Didn't matter what contour, it had to be 21 3/4 inch, and setting back a barrel to gain some life ruined the length requirement and would never shoot as well.
This^Quote:
Originally Posted by grouse
And even though 3/3 have improved, statistically speaking, it’s not enough to categorically claim it’s the road to a more accurate firearm. I’m using that term “accurate” in a very generic definition. With precision vs accuracy being two independent characteristicss.
But if it works, I would keep on keeping on.
Don't think I ever did make that claim. Just seeing a trend. In two of the three cases, I figured I screwed up the crown so bad there is no way it could shoot better. But it did.Quote:
Originally Posted by RustyShackle
Quote:
Originally Posted by Newtosavage
Possibly that’s just how I read those statements. I’m glad things are working out well for you in the accuracy department.Quote:
Originally Posted by Newtosavage
Thanks. I was never claiming that hand crowning was the answer. Only sharing my experience. I would say however that anyone considering chopping their own factory Savage barrel, shouldn't be afraid to give it a go.Quote:
Originally Posted by RustyShackle
Hmmmm? Where do I start? I’ll keep this short.
Regardless of brand of barrel. Factory or custom.
I’ve seen crowns that where poorly done and actually shoot pretty good. I’ll say this is more luck than anything else. Also damage to the muzzles crown from improper cleaning. Some seem to effect accuracy and some not as much.
I’ve seen crowns and have fixed muzzle crowns where you couldn’t even see the damage with the naked eye where the edge of the crown on one land and one groove had a nick to it and the rifle wouldn’t shoot any better than 1 1/4” groups at a 100 yards. Properly recrown the barrel and the gun would go to shooting 1/3moa groups or less.
Last comment....the muzzle crown is the last thing the bullet sees/touches when leaving the barrel. Any damage to the crown can and usually does have a negative impact on accuracy.
First question you need to ask yourself is....”What is my accuracy requirement?”
Later, Frank
Bartlein Barrels
Good to know that somehow, with absolutely no training, I can't damage a crown any worse than the factory has. ;)Quote:
ast comment....the muzzle crown is the last thing the bullet sees/touches when leaving the barrel. Any damage to the crown can and usually does have a negative impact on accuracy.
I have really only damaged one barrel crown- bad enough that it could be easily seen. I cleaned it up the best i could and went and shot it. I was expecting it to not shoot as good but it didn't have any measurable effect on groups. I figured I had gotten lucky and kind of forgot about it. The next time I shot the rifle I used my other load (one was for varmint hunting and the other was a heavier target bullet) and my groups were pretty poor. The rifle had shot both groups very good before- so the damaged crown bothered one bullet but not the other. I had the crown re-cut and it went back to normal- so it definitely can be a issue. I'm still not to the point that i worry about a brush getting pulled back into the barrel every so often....
In my case the barrel still shot flat base bullets excellent but the boat-tailed bullets shot poor. I don't know if it was the gas escaping around them that did it- or the way the bullet shape had it last contacting the barrel. Have you shot different bullet shapes through yours after you re-crowned it?
No, I can't say I've tried that.Quote:
Originally Posted by Whynot
It’s not just the brush but the hard carbon particles that can lay in the bristles of the brush. The hard carbon particles will scratch the bore more so than the brush. That being said if I use a brush I never pull it back over the crown.Quote:
Originally Posted by Whynot
Also you get a gas cutting effect when the bullet leaves the barrel. This alone after X amount of rounds can wear the crown. This is why I don’t like a flat/sharp crown edge. We cut a 60 degree chamfer on the edge of the bore. Feel this helps the crown hold up better overall. Ever look at a M1 Garand barrel? 1903? M14 and even on the Gov’t test barrel drawings they all call out a chamfer on the edge of the bore. Some where at some point in time someone figured out something here years ago!
Flat base bullets I’ll say are more forgiving then boat tails are but boat tail helps b.c.
Most factory type rifles/guns as a good ball park number.....the cost for them to make the barrel and this includes the cost of the steel, contouring, chamber, threading, crowning etc...I’ll throw a number of $60-$100. Some makers do put a little more time and effort into the barrels and will have more cost into them.Quote:
Originally Posted by Newtosavage
I don’t know how to post pictures here (think I have to pay a fee) but I have pictures of factory barrels where the centerline of the bore of the barrel isn’t even in the center of the barrel blank. It’s not a Savage either but is a factory barrel.
tex10.....reckon the 21.75 length was the overall length including the crown, or was it just the bore length not including the 11* crown. i kno this isnt much difference, only .075" on a 1" barrel, but it is a difference that matters?
i hav read the article several times and pick up on sonthing new each time
Quote:
Originally Posted by Texas10
Agree. Plus, it takes literally seconds when that piloted 60 degree center tool goes in and the setup is a snap.Quote:
Originally Posted by Shortbox4x4
If you want to know if it is your crown job or the shortening of the barrel that is making the accuracy improvements, take a factory barrel and only trim off like 1/4 inch or so then recrown like you have been.
If accuracy improves, then you might be on to something. If nothing changes, then it is the barrel being shorter and stiffer that helped them.