Interesting crown

[clowdis]

If the moderators don't mind. How about this all you crown junkies?
http://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/4741087002

 

[Erik Cortina]

Why are they saying "myth busted" about a bad crown being bad for accuracy. That group is terrible, and it's only 90 yards!

The same thread would get different replies on this forum!

 

[watercam]

Yes but still, imagine what the rest of the bore looked like. And 80 year old, 160 grain round nose ammunition to boot. Can not remember where I read about a crown test where they cut a barrel, filed it flat by eye with no deburring, and shot a group. Then crowned it properly and shot again. The difference in group size was less than 20% I believe.
I am with everyone else on how important well executed crowns are, it is interesting nonetheless.

 

[clowdis]

I'm not condoning bad crowns but it is amazing how well this barrel shot with such a bad crown. I think the article watercam is referring to is one in Prcision Shooting years ago where someone had a .22lr barrel that had a questionable crown but shot "lights out" for several years before he recrowned it and the barrel never shot well again. He tried recrowning several different ways and the group didn't change but did move point of impact. It probably got recrowned at a loose spot or something. Still..interesting about why some barrels shoot regardless and others won't.

 

[akajun]

I think something else to realize is this group was shot with crappy old iron sights, not precision micrometer sights or a scope.

 

[Grimstod]

Yes but still, imagine what the rest of the bore looked like. And 80 year old, 160 grain round nose ammunition to boot. Can not remember where I read about a crown test where they cut a barrel, filed it flat by eye with no deburring, and shot a group. Then crowned it properly and shot again. The difference in group size was less than 20% I believe.
I am with everyone else on how important well executed crowns are, it is interesting nonetheless.

Target Shooter had an article in their very first published magazine on this very topic. They took a rifle with a bad crown and fixed it then lapped the bolt lugs. Results showed.
I am searching for it now but cannot find the things. They have changed their website so much and non of it makes sense.

 

[clowdis]

Would like to read that if you find it.

 

[Grimstod]

I finally found it. It's in the 2011 July issue. Page 22-30