Gunsmithing Brass lap or perhaps a 90 degree cutter and brass pilot to repair crown....any good?

[want2learn]

Need to touch up the crown of my rifle, it's an old savage .222 remington. I just had it bedded and blueprinted now notice a small blemish that i can feel with my fingernail at the exit of the barrel....I can't really afford to mail it back to the smith who worked on the gun...it's too much money and i just don't have it.

I was wondering if anyone has used either one of these to optimize the quality of the crown, it would cost less than shipping the gun if it's a good option. Unfortunately, I do not own a lathe:



080-764-243WB
Non-Handled fits Bore .17-6.5mm Tip Radius 5/32"(3.96mm)


080-947-239WB
90\ Cutter & Brass Pilot fits .22 Centerfire Muzzle



Thank you

 

[DAVETOOLEY]

round head brass screw,lapping compound and a drill
much cheaper

 

[Easy_E]

I hate to be that guy but wouldn't blueprinting include checking the muzzle ? Sorry the brass screw thing works make sure the screw is brass and not steel/brass plated.

 

[want2learn]

i appreciate you're input, don't want to blame anyone. the rifle smith has been good to work with. I just want to figure out how best to proceed, if these modalities are favorable and prudent.

 

[flyer]

I have seen the piloted crown cutters do a good job. Started with the 90° and after it cleaned up, cut a small 11° crown to make it slightly recessed (but not a real recessed crown).

I've heard of the brass screw method but have never seen it done.

 

[NWnewguy]

I would recommend shooting it before doing anything. Ive read some articles about testing the effects of muscle imperfections and they had to be amazingly bad before they effected the group size or anything else accuracy related. If it isn't shooting then the recommendation from Dave Tooley is spot on.

 

[want2learn]

hope perhaps to get out this weekend. should know more then.
glad i've not heard any significant negatives

 

[Jackalope]

I have both the 90* and the 11* cutters. You’d need to purchase the .22 pilot though as I only have a .30.

 

[hermosabeach]

A Manson cutter is great to cut the crown.......

If you have a small ding.... I agree with the folks above... smallest to bigger....

So Shoot it? is it consistent? If not, Polish out the existing crown....

 

[...]

yeah, ive always used a brass screw with valve grinding compound.........gives a nice consistent crown and is pretty hard to screw up.

i use this on all my guns to not only establish crowns on new barrels, but also to touch them up.

 

[want2learn]

thanks...going to give it a try

 

[Decoy]

I would polish it out with some compound.

There was a test on crowns and their effect on accuracy a number of years ago in one of the precision rifle magazines. I have done testing on a 45 acp to confirm their finding.

They took a rifle and shot a series of groups with no crown, a 11 degree crown, cut the barrel off at a 45 degree angle and a couple of other angles (sorry going from memory at this point).

Anyway the accuracy was not affected much at all, point of impact was shifted from each test. I think the 45 degree angle changed the poi but several inches but the groups remained pretty much unaffected.