Target crown?

Biggjimm · Post by **Biggjimm** » Mon Sep 03, 2012 9:52 pm

I was cleaning my mark lll's tonight after a trip to the range & I noticed that the crown on my 5.5" bull barrel target 22-45 was different than my 4.5" threaded bull barrel 22-45. On the later, there's a nice beveled crown on the muzzle & the 5.5" is just a sharp 90 degree at the crown. The crown area is recessed to protect it but there's no bevel to it. Is this how they are supposed to be or did mine skip a step at the factory? I guess I thought all barrels had some sort of beveled crown on them???[/i][/u]

Post by **Bullseye** » Tue Sep 04, 2012 6:43 am

The recessed, step type, target crown usually only gets a slight taper at the bore edges. This cut is very small, only a few hundredths, and may go unnoticed without looking very closely. It is not going to look the same as the larger, non-target bevel crown.

R,
Bullseye

Biggjimm · Post by **Biggjimm** » Tue Sep 04, 2012 10:02 am

Well that makes me feel better & after noticing that difference in them I started looking at other guns & a couple of my Encore barrels have that same type of crown & now that I think about it one of them I know is a target/match grade barrel. Thanks Bullseye.

Post by **Bullseye** » Wed Sep 05, 2012 6:54 am

That little chamfer is there just to reduce inconsistent erosion as the barrel wears. The target crowning tool actually smooths out the end of the rifling, as long as there's no cutting tool chatter marks left behind.

R,
Bullseye

Biggjimm · Post by **Biggjimm** » Wed Sep 05, 2012 9:12 am

Oh I see. I always thought the chamfer itself was the "crown" I didn't realize that was only part of the equation. Thanks.

Post by **Bullseye** » Wed Sep 05, 2012 6:31 pm

It is on a non-target barrel, which is why the bevel is so wide. But on a target barrel the recessed surface is the blast wave reflective surface and the slight chamfer around the edges is there just to keep the erosion wear of hot gasses consistent. Any pitting or erratic wear at the edges will impact the trajectory of the bullet as it leave the lands of the barrel.

R,
Bullseye