Crowns

My own approach for my own competitive cast bullet rifles. Flat with a 30 degee bevel cut to just beyond the bottom of the grooves and then polished. Having tried several others this has worked the best. When cleaning with a wrapped patch it just peaks through the muzzles and I never push it all the way out. The fouling including the primers is actually quite abrasive and if pushed all the way it can start to bell the muzzle. We also have to clean quite allot and one of my barrels and still very competitive now has over 140,000 bullets down the bore and I have only had to re-crown it but once. And right before I retired it, it set a new national record and it has also never been setback but now needs it.

 
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There was an article

In PS magazine years ago about crowns where someone did a number of different crowns on the same barrel and if my memory serves, the crowns made no difference in accuracy, even the one hacksaw cut. Suppose it could just have been a great barrel ?

Pete
 
my limited knowledge opinion is 1000 yards does not matter.
do the test at longer range,,,say 300/500 yards.
me thinks those 100 groups will open up...big time
 
rsmithsr said:
(yes i have a 3 phase motor on my lathe at my house!)
Click to expand...

I had 3-phase with idlers for years.
Had a neat little starter system to spin up the 3-phase idler.
Used a rubber tire rubbing on a pulley sheave to spin up the idler.
Pull lever, enough frictions to get idler spinning.
Had and indicating system that came on when it was close enough
in speed to generate decent quality waveforms.

It is not perfect 3-phase though.
More like 2-1/2 phase.Two phases at 180 degrees and the middle one between them.

Switched all but one over to a VFD with 240 V single phase inputs and 3-phase outputs.
The last one is large enough even a VFD is going to be pricey.

And I usually only use it for hogging with carbide tooling, then switch to a 3-phase for finish work.

Doing this saves a decent amount of time on larger items.
I even did a 3-phase industrial sewing machine for one of the ladies I worked with.
Linda saw it at auction, called me and asked "Can you make it work?"
I told her "Not all that hard."
She bought it at auction.
Non one else wanted it since they did not know how easy it is to make an idler system.
 
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i think a lot would depend on the cartridge.
imho...if the powder burn is complete behind the crown, it will wear less than something that is still burning at the crown
velocity
bullet
powder

ArtinNC said:
Now how much do you take off of the barrel on a re-crown ? .100 ?
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I suspect that more crowns are damaged through poor cleaning techniques (and physical abuse) than by actual shooting.

The most difficult barrels to clean imho are a lever action and my black powder muzzle loader, no choice but to put the rod in from the front but it can be accomplished with a bit of care and a rod guide can be made from Delrin to slip over the end of the barrel to keep things centered.

As Pete Wass pointed out, don't let the patch completely leave the muzzle. (Although I must admit that I usually just let it protrude enough to drop off the jag so not to drag the fouling back into the bore)

Keep safe * doggie *
 
(((Although I must admit that I usually just let it protrude enough to drop off the jag so not to drag the fouling back into the bore)))

this is what I do , if you pull the patch back through you are pulling carbon back through the bore , I don't think that is good .
 
As mentioned in an earlier post I don't let the patch go beyond the muzzle and I do bring the fouling back. If you were to look down the barrel it looks like a Parabolic Mirror from cleaning this way will also using JB. Not sure if a highly polished is good for Jacked bullets but does very will with cast lead and tin bullets for serious competition. Also forgot to mention in my earlier post why I polish the face of the crown it is to be able see the lube star that will be left on its face. If the lube star is not per-say perfectly even for my use it is simply not crowned right and it gives one a visual reference and is also quite common to see a polished face in our competitive sport for that sole purpose. All though the fouling being drawn back by the way that I clean and my barrel now having more than a 140,000 bullets down the bore I have not seen any ill effects being done and as stated earlier I did set a national record with this many bullets down the bore so I am not sure if it was anymore abrasive than the JB its self. Rifle is also chambered in 32-40 and I hope some of this might be helpful to somebody else.
 
I just re-crowned it and only took off .020 . Checked with a Q-tip now burs and it looks good . Now work up some new brass .
 
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