Pistol Crown

44Magnum · February 24, 2009, 01:27 AM

Say you have a pistol with a crown that looks a little messy upon close inspection. The gun, however, is extremely accurate. Do you have it fixed or not?

**JohnKSa** · February 24, 2009, 02:06 AM

If the gun is extremely accurate then don't mess with it.

44Magnum · February 24, 2009, 10:28 AM

That's what I was thinking. Wouldn't it be a kick in the teeth if the accuracy got worse after a repair?

I hate to say this, but it really makes me wonder just how important a "perfect" crown is on a handgun.

**JohnKSa** · February 25, 2009, 03:36 AM

Not that important. Here's a test done with rifles. It made a difference, but not that much. Not enough that most pistol shooters would be able to see a change.

In other words, there are other factors in pistol accuracy that will tend to swamp out issues with the crown. If you're shooting around a half-MOA at 50 yards then a damaged crown will show up in your groups. Otherwise it's not likely that it will affect you much.

March 2008 American Hunter

“bullshooters” column

Will Damage to a Rifle’s Crown Hamper Accuracy?

Four barrels were tested before and after intentionally damaging the crowns.

Tested @ 50 yards at an indoor range.

Cleaning rod damage (cleaning from the muzzle with an aluminum rod 100 strokes--slight visible damage) Group went from 0.550” to 0.874” and shifted 0.006 down & 1.059” right.

Gravel damage (dragged muzzle down in gravel and then mashed into the gravel with high force—mild damage) Group went from 0.326” to 0.790” and shifted 0.061” down & 0.151” left.

Cut off with a hacksaw and not recrowned damage (severe damage) Group went from 0.329” to 0.945” and shifted 1.101” down & 0.457” right.

Crown intentionally damaged with a file (severe damage) Group went from 0.506” to 0.848” and shifted 0.020” down & 0.248” right.

Muzzle drilled out to about .45 cal with a drill bit. (severe damage) Group went from 0.506” to 0.697” and shifted 2.206” up & 1.032” right.

44Magnum · February 25, 2009, 01:24 PM

Oh yeah. I suck way too much to notice anything like a few hundredths of an inch.

Thank you for the information.

Harry Bonar · February 27, 2009, 12:03 PM

Sir;
Yes it's important! Get it recrowned on a good lathe by a professional! And, it's not a matter of "hundreds of an inch" it's a matter of ten-thousandths of an inch. Muzzle crown is crucial - I'd get it fixed.
Harry B.

44Magnum · February 27, 2009, 01:03 PM

There is only a little bit of barrel sticking past the slide. How much "excess" barrel would a recrowning job take?

musher · February 27, 2009, 01:38 PM

Well, I'm a big subscriber to the "if it ain't broke" approach. No way would I mess with the muzzle of a firearm I would describe as "extremely accurate"

Just think about it in terms of risk:reward. How much more accurate do you believe the firearm could be? That's your potential reward. How much less accurate do you think it could end up. That's your risk.

JohnKSa, I haven't read that column, so I don't know what the methodology or sample sizes were, and have no way of telling whether the numbers are meaningful or not, the examples in your quote show increases in dispersion on the order of 60-70% of the premutilation figures. Pretty big difference.

Oh, and cleaning up the crown should only take off what's needed to remove the visible damage. How much you lose is directly related to how deep the nicks are. Given your description, I'd guess a few thou is all you'd need to clean it up. Not enough to visibly shorten the barrel.

44Magnum · February 27, 2009, 02:24 PM

Yeah, I honestly don't know how it is possibly as accurate as it is. When you shake the gun you can hear the slide wiggling against the frame and the crown looks like a guy cut it on a lathe with a dull nail. But the groups are impressive.

**JohnKSa** · February 27, 2009, 04:17 PM

Quote:

How much "excess" barrel would a recrowning job take?

It depends on how deep the imperfections in the crown are, but I would be tremendously surprised if it changed the length of the barrel to any significant extent even if everything is recut.

But unless it's pretty badly banged up, you don't even need to have it recut, you can just touch it up yourself if you're so inclined.

http://www.brownells.com/aspx/NS/sto...x?p=855&st=&s=

February 24, 2009, 01:27 AM	#1
44Magnum Senior Member Join Date: September 29, 2008 Posts: 325	Pistol Crown Say you have a pistol with a crown that looks a little messy upon close inspection. The gun, however, is extremely accurate. Do you have it fixed or not? __________________ "It'll all fit in there, it must be a compressed load." I never joined SAMMI.

February 24, 2009, 02:06 AM	#2
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 24,985	If the gun is extremely accurate then don't mess with it. __________________ Do you know about the TEXAS State Rifle Association?

February 24, 2009, 10:28 AM	#3
44Magnum Senior Member Join Date: September 29, 2008 Posts: 325	That's what I was thinking. Wouldn't it be a kick in the teeth if the accuracy got worse after a repair? I hate to say this, but it really makes me wonder just how important a "perfect" crown is on a handgun. __________________ "It'll all fit in there, it must be a compressed load." I never joined SAMMI.

February 25, 2009, 03:36 AM	#4
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 24,985	Not that important. Here's a test done with rifles. It made a difference, but not that much. Not enough that most pistol shooters would be able to see a change. In other words, there are other factors in pistol accuracy that will tend to swamp out issues with the crown. If you're shooting around a half-MOA at 50 yards then a damaged crown will show up in your groups. Otherwise it's not likely that it will affect you much. March 2008 American Hunter “bullshooters” column Will Damage to a Rifle’s Crown Hamper Accuracy? Four barrels were tested before and after intentionally damaging the crowns. Tested @ 50 yards at an indoor range. Cleaning rod damage (cleaning from the muzzle with an aluminum rod 100 strokes--slight visible damage) Group went from 0.550” to 0.874” and shifted 0.006 down & 1.059” right. Gravel damage (dragged muzzle down in gravel and then mashed into the gravel with high force—mild damage) Group went from 0.326” to 0.790” and shifted 0.061” down & 0.151” left. Cut off with a hacksaw and not recrowned damage (severe damage) Group went from 0.329” to 0.945” and shifted 1.101” down & 0.457” right. Crown intentionally damaged with a file (severe damage) Group went from 0.506” to 0.848” and shifted 0.020” down & 0.248” right. Muzzle drilled out to about .45 cal with a drill bit. (severe damage) Group went from 0.506” to 0.697” and shifted 2.206” up & 1.032” right. __________________ Do you know about the TEXAS State Rifle Association?

February 25, 2009, 01:24 PM	#5
44Magnum Senior Member Join Date: September 29, 2008 Posts: 325	Oh yeah. I suck way too much to notice anything like a few hundredths of an inch. Thank you for the information. __________________ "It'll all fit in there, it must be a compressed load." I never joined SAMMI.

February 27, 2009, 12:03 PM	#6
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	crown Sir; Yes it's important! Get it recrowned on a good lathe by a professional! And, it's not a matter of "hundreds of an inch" it's a matter of ten-thousandths of an inch. Muzzle crown is crucial - I'd get it fixed. Harry B.

February 27, 2009, 01:03 PM	#7
44Magnum Senior Member Join Date: September 29, 2008 Posts: 325	There is only a little bit of barrel sticking past the slide. How much "excess" barrel would a recrowning job take? __________________ "It'll all fit in there, it must be a compressed load." I never joined SAMMI.

February 27, 2009, 01:38 PM	#8
musher Senior Member Join Date: April 23, 2005 Posts: 462	Well, I'm a big subscriber to the "if it ain't broke" approach. No way would I mess with the muzzle of a firearm I would describe as "extremely accurate" Just think about it in terms of risk:reward. How much more accurate do you believe the firearm could be? That's your potential reward. How much less accurate do you think it could end up. That's your risk. JohnKSa, I haven't read that column, so I don't know what the methodology or sample sizes were, and have no way of telling whether the numbers are meaningful or not, the examples in your quote show increases in dispersion on the order of 60-70% of the premutilation figures. Pretty big difference. Oh, and cleaning up the crown should only take off what's needed to remove the visible damage. How much you lose is directly related to how deep the nicks are. Given your description, I'd guess a few thou is all you'd need to clean it up. Not enough to visibly shorten the barrel.

February 27, 2009, 02:24 PM	#9
44Magnum Senior Member Join Date: September 29, 2008 Posts: 325	Yeah, I honestly don't know how it is possibly as accurate as it is. When you shake the gun you can hear the slide wiggling against the frame and the crown looks like a guy cut it on a lathe with a dull nail. But the groups are impressive. __________________ "It'll all fit in there, it must be a compressed load." I never joined SAMMI.