Muzzle crowning
I saw the discussion on muzzle crowning tools back on 2/6/12. I read on another forum that just using the crowing tool in a handheld drill could cut a good crown if you just kept the angle constantly changing. Another contributor said that he had obtained good results just using a round head brass screw chucked in a hand held drill with constant motion. This last contributor said that you could tell whether you had a good crown by looking at the brass ring left on the muzzle. As soon as you get a thin line all the way around you are there. It sounds to me as if this could work if you start with a crown that is good except for a minor nick and you would be able to tell quite quickly by observing the brass ring left. I think their recommendations on grit were about the same as the ones that come with the tools: first 320 silicon carbide finishing with 600. Could you please comment? I would appreciate any opinions from the standpoint of older gunsmiths working with limited tools
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johnler,
Hello, and welcome to the forums here on Gunbroker.com.
There is only one way to properly crown a barrel. That is chuck it up in a lathe, and center it, then cut your perfectly concentric crown. Any other method, is shooting in the dark, hoping in one hand, and getting the other hand full of poo. Unfortunately, as Larry Potterfield says...."That's the way it is".
Best
EDIT 1
quote:Originally posted by johnler
Please do not take this wrong, I am unlearned in this area and just seeking information (besides liking to work on the guns).
This would assume the bore concentric. Do not like assumptions. It would seem a close fitting pilot is more likely to give you the concentric crown you are looking for. This is a factory rifle. Understand that custom rifles would necessarily have concentric bore because gunsmith would not turn loose of anything else.
I have been gunsmithing for 30 years, and know several other's on here who do it to make a living. I stand by my statement in the first post. The majority of the big name brands have kept up with technology, and their bores are very concentric, to the smallest 0.0001", in most cases. I am not saying that hobbyist type gunsmiths do not use a bore pilot, and have decent success, but the folks who do use them, are just that...HOBBYIST, or a partially skilled gunsmith....take your pick.
I am sure there will be some other's chime in on this, too. If you will, look up the term crown in the search engine here on the forums. This has been up before.
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One way to check for a good crown - at least on a 22 rifle with a thicker barrel - is to look for the snowflake pattern from the escaping gas/powder debris. 
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tsr1965 is right on the money! (Ideally you have to indicate BOTH ends of the bore) Most match shooters I know would opt for the 11 degree crown. 0 -
Please do not take this wrong, I am unlearned in this area and just seeking information (besides liking to work on the guns).
This would assume the bore concentric. Do not like assumptions. It would seem a close fitting pilot is more likely to give you the concentric crown you are looking for. This is a factory rifle. Understand that custom rifles would necessarily have concentric bore because gunsmith would not turn loose of anything else.0 -
quote:Originally posted by johnler
Please do not take this wrong, I am unlearned in this area and just seeking information (besides liking to work on the guns).
This would assume the bore concentric. Do not like assumptions. It would seem a close fitting pilot is more likely to give you the concentric crown you are looking for. This is a factory rifle. Understand that custom rifles would necessarily have concentric bore because gunsmith would not turn loose of anything else.
You are right on the money here. We have a crowning tool with pilots that works fine. They are not cheap, but you can make your money back doing a few. We do rifle barrels when building them on a lathe for custom builds.
For touch up,s on stock barrels the brass screw with compound works if the muzzle is square. That,s an old time fix [;)]0 -
johnler,
You can most assuredly use any technique you desire for a DIY project and you might even manage some semblance of reasonable results depending on your personal view of the term 'reasonable'.
However, if you're looking for exceptional accuracy or even consistent, improved accuracy from a bad or damaged crown, I suggest getting it done properly in the first place. That will involve having the crown cut in a lathe using a single point tool. I'm sorry if this disappoints you but that is a fact. All of the other methods are simply that, other methods which don't measure up to the quality of a professional cut crown on a lathe. The exception will be what your expectations are for the rifle and how accurate the rifle is in it's current form. If it hasn't show decent accuracy previously with good reloading techniques and load development, a new crown might be just the right answer. Or the whole rifle needs to gone through thoroughly.
Here is a correct 'tactical' crown:
You can choose any shape for a crown which pleases your sensitivities. There is no magic in the shape or the number of degrees associated with the accuracy of a crown. If 11-degrees gets your attention, have at it. If a flat crown or recessed step crown is favored, great! The only things to pay attention to are the concentricity and perpendicularity of the crown surfaces. If the crown is not perpendicular around the circumference of the bore/groove then you're going to lose accuracy.
Here is a muzzle crowning tool as discussed:
Here is the result of using that tool:
The 'gunsmith' using that tool thought this was a good effort...
Sure, dozens of other gunsmiths can post images of crowns cut with a tool such as the one above which demonstrate good technique. But the probability of chatter will remain high due to the process and tool.
As much as I despise 'UTube' (yes I misspelled it on purpose), here is a demonstration performed by Dave Manson, using his tools:
http://www.youtube.com/watch?v=-Xpzv1Spsnk&feature=player_embedded
Any way, it's your choice and your rifle. Maybe it isn't worth the cost of a lathe turned crown but it simply needs a little tender care. Only you can decide the value and technique required.
Best.0 -
Thank you all so very much. The video shows a master craftsman using hand tools with a touch developed with years of experience. I would dare say that he could probably cut something closer by hand than I could with a machine and micrometer gauge. I did not mean to argue but really did not understand fully crown. I thought crown only referred to to angle cut that actually terminated the lands and grooves. Right now I am confining my hobby work to older .22LRs just to see how things work. I use the CZ452 I bought for my son as a target. That particular rifle and scope combination is so accurate it is boring to shoot out to 100 yards, it puts the bullet where the crosshairs were. I am trying to see how good I can get a 10/22 to shoot. I am mid seventies and have a good collection of guns (old to new, but all shooters, nothing we hang up to look at). I have the Remington bolt action I bought with dimes at a Western Auto when I was 12 years old that will get some attention later. I haven't retired yet so am still juggling things for time. This forum is a real jewel for information. Again thanks to all.
John0
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