Recrown muzzle...what is benefit?

[elijdub]

I've been reading more and more, specifically in the Custom "arena", about the additional service of recrowning the muzzle. I'm curious to know what exactly it is, AND what the benefits of this modification are?
Thanks!

[Dave Berryhill]

The crown is the portion of the muzzle where the bore intersects with the front of the barrel. This is the last portion of the rifled bore that the bullet touches as it leaves the barrel so it is very important for accuracy. It needs to be uniform all the way around and free from burrs, dings or other imperfections. Usually it is cut in a manner so that the end of the bore is recessed slightly. That way, if the the muzzle is dinged or dented then the end of the barrel takes the damage while protecting the rifling.

Factory pistols are made on high speed machines and the quality of the crown can range from good to horrible. Many gunsmiths will routinely recut the factory crown using a lathe. For $20 - $25 it's a cheap insurance policy. If done correctly it will only help accuracy and won't hurt it. A crown can also be cut for cosmetic reasons and there are lots of ways it can be done but the looks are secondary to its function.

[Colt45guy]

recrowning the muzzle is simply ensuring that the bullet leaves the barrel the same way, every time....it makes the rifling uniform--exactly the same lenght--and ensures that the muzzle is at a true 90 degrees to the barrel.



I 'crowned' a rifle awhile back with a marble and some lapping compound. The previous owner had a habit of leaning it muzzle down, and had damaged the crown. (small rock ding) That rifle was at best a 4 MOA rifle at 100 yds....after cleaning up the crown, it shoots inside 2 MOA with the same ammo.


I've used the same trick on several FALs that had the last few inches of barrel cut off, and as long as the muzzle gets cut 90 degrees to the barrel, it's worked every time.





edit to add: As usual, Dave has a better description/reason than I have. :o

[elijdub]

Thanks Dave, and Colt45guy,

That makes perfect sense. Uniform rifling, AND the "recess" to prevent damage. I noticed this recently on the Nighthawk T3.
http://www.nighthawkcustom.com/NPDPopImage.aspx?pi=http://www.nighthawkcustom.com/images/T3-UCP_6.jpg
Their "match grade stainless steel barrel is crowned flush with the bushing...." I suppose that by taking "crowning" a step further, and cutting the barrel flush with the bushing, you'd have the additional protection in the even of an impact....?

Thanks again..!

[tightgroups]

There is a specific crown called a target crown and is cut at 11* for accuracy. The reason is the same as Dave and others mentioned, though the crown and the way it is cut also effects the gases as they leave the bore which effects bullet trajectory.

[emilio]

clearly y'all are forgetting the critical reason pistols need crowned barrels, as evidenced in the Nighthawk photo: it makes them look badass!

- emilio