11° target crown or barrel tuner ?

D

deffie

Guest
I'm going ahead making experience and reading around (http://riflestocks.tripod.com/targetcrown.html) i've found that many consider 11° to be the optimal angle for muzzle crown for optimal gases dispersion.

And now the questions:

Is this tuning effective also on 22lr rimfire ? (ie. does it have enough gases/gas-speed to influence the bullet ?)

And if yes, will the over-muzzle barrel tuner influence this ?

Regards,
Giacomo.
 
deffie,

An 11 degree crown is popular, looks cool, serves to offer some protection to the edge of the crown by recessing it behind the protective rim formed by the OD of the barrel and it is visual evidence that some care and thought was applied to the machining of the barrel. Evidence doesn't support any greater accuracy from an angled crown than a flat one. This would be equally true for centerfire and rimfire. Your smith will be happy to provide you with either crown at your option.

Greg
 
Looking at the site linked above, I sure wouldn't let anyone crown a benchrest barrel for me by any of those instructions. OK for a hunting rifle but not for benchrest!!

Hand held crowning tools, steel wool on a stainless barrel, etc. YUKK!!
 
I agree with both of you, after more reading i found only a few are saying that the crown angle can influence the accuracy, most are saying it does not, once it is perfectly concentric.

And yes, the procedure described on that website scares me, i find more appropriate using a taster inside the bore to find the center and mill accordingly.

Thank you once again !

Giacomo.
 
I put 11 degree crowns on all my rimfire BR rifles and it works quite well. They win. However, a 90 degree crown works just as well. Either needs to be cut parrallel to the bore. If done correctly, I don't think there's a difference in 11 degree and 90 degree crowns, and accuracy in rimfire rifles, and if there is one, it's a perceived difference. I've seen super shooting rifles, with both types of crowns.
 
I have put a 11 degree crown on some of my Rifles, cannot say its any better than other crowns done right, George.
 
Crude

Get out the old hammer and chisel.:D

I disagree with the first statement in that link. The primary purpose of a crown is to furnish a burr free exit that is truly square with the bore. ........jackie
 
If you're going to cut a eleven degree crown, I'd cut it in the lathe setting the compound to 11 degrees. I haven't seen a difference in any crown that is cut with the bore centered in the lathe and that is burr free. I've been using 30 degree crowns in my hunting rifles with a 60 degree bevel on the bore. It works well and puts the bore back inside the barrel quite aways to protect the crown. A flat crown seems to be the preferred benchrest crown anymore. It's simple to cut and works.
 
FWIW.

I was once told by an old salt that the US Army did all sorts of fancy tests back in the 50's.

They essentially started with a barrel that was cut off with a hacksaw and then machined in one degree increments. They determined that 11* was the optimal relief angle.

That's what I was told, take it for what its worth, I neither confirm nor deny.

There ya' go.
 
target crown

I just did my first crown on a lathe today. What I did was to dial in the bore and then I cut a step type crown, but I didn't cut the 60 degree I left that square. Is this ok or do I need to cut this or lap this?
any advise welcome
thanks
Jonathan
 
buena vida said:
I just did my first crown on a lathe today. What I did was to dial in the bore and then I cut a step type crown, but I didn't cut the 60 degree I left that square. Is this ok or do I need to cut this or lap this?
any advise welcome
thanks
Jonathan
Click to expand...

Disclaimer - I've never even been accused of being a gunsmith.

A cleanly cut and square to the bore crown is OK in any configuration. Fuzz up a Q-tip and pass it back and forth across the crown to check for burrs. Don't know what to do if you find a burr but I think you sharpen your tool and make another pass.

Mike - when you say "flat" do you mean the end of the bore is flush with the end of the barrel with no "bevel"?
 
thank you. No there is no bur. so I guess I'll run with it
thanks again
Jonathan
 
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