Home Forums Hunting & Shooting Gunsmithing Muzzle crowning tips...

So, I have a CZ 455 HB with a slightly uneven crown.
I may decide to true it and recrown it.

So I have two questions -

1. Is there a consensus "best target crown" style? I have always assumed that the famous 11° crown was famous for a reason, and that it would be best without any chamfer at the transition from lands/grooves to the perpendicular muzzle face. Just a hunch though.

2. Once the muzzle face is in the white, is there a legitimate way to protect it from rusting short of a full reblue?
Because I'm thinking that I would probably end up using Eezox on it regularly (I've never had any luck with cold blue) but I'd love to have a better option.

Thanks all

I have used the 11 degree chamfer on several of my rifles. They all shoot just fine. I did buy the tool and the right pilots from Brownells and everything gets re-chamfered now. I did have to fix a muzzle on a rifle that required a 45 degree chamfer. It shoots as good as any of the 11 degree chamfers. I think the big issue is the muzzle has to be on the same plain around the complete diameter of the hole. It's just that if you only need a touch of correction, the 11 degree cutter works great since it removes a minimum amount of metal. I use Brownells 44-40 bluing and their Oxfo bluing to do touchups. The Oxfo takes longer to get the metal dark blue but it seems to stay better.

kwg

Time for a little heresy. Touched up a couple muzzles with nicks in the crown. In one case recut with a round ball Dremel stone in a variable speed drill followed by the classic round head brass screw and grinding compound. Otherwise just the brass screw treatment. Accuracy improved substantially if not dramatically and was totally acceptable considering the rifles. So I'm not convinced the shape of the crown makes much difference. The target crowns look cool though.

All cold blues are chemically variations on a theme. 44/40 is aggressive but the only cold blue to give me after rust problems. If I use it I neutralize with baking soda in water.

Never tried that... May be just the tip I'm looking for.

What mix, how long, etc....

Most benchrest barrels have a flat crown. I don't think anybody has proven the "best" way.

A component of any cold blue is an acid to passivate the steel so it will accept the selenium compound and different cold blues use different acids in different proportions. I'm not a big fan of 44/40 preferring Brownell' products like T-4. But 44/40 has more "bite" which makes it easier to use. All trade secrets but I suspect more acid which, after bluing, remains on the steel and promotes rusting. However it happens I've had red rust show up. So after bluing. I swab the area with baking soda in water to neutralize any remaining acid. Proportions not important, there's not that much acid to neutralize. Anyway no red rust when I do that.

Works on stomach acid too. The old remedy for heartburn was to take a bicarb, maybet a teaspoon in a glass of water. Made for lovely belches. Not recommended today because it's sodium bicarbonate and people worry about sodium intake these days. But it still works in a pinch.

Butch,

I crown the AR barrels that were done in the garage with a flat 90 degree crown, like a bench gun, like you showed me when I started on my brother's 30 BR. Works so far.

Nez

Crowns don't matter nearly as much as most think they do.

As long as there are no really bad burrs and imperfections it doesn't matter what type of crown is used.

http://www.accuratereloading.com/crownr.html

Brownell's offers a real nice crowning tool set

As long as the crowning is even around the bore then it doesn't seem to make too much difference what type it is. Crowning recesses the end of the barrel/bore from potential damage from impact. I hacksawed and filed flat the end on an old Mauser barrel because there was muzzle damage - oval from excessive and poor pull-through technique, so I've been told (I guess a rope pull through with grit on it might wear it away if you tried hard enough). Not a good high accuracy example but it went from sideways bullet holes at 50yards (at least those that hit the target) to equalling the accuracy of my other Mausers with open sights.

Personally I like a recess crown

That's why I went to a round ball grindstone in a drill on one crown job. My cousin was taught to ride with the muzzle down on the floorboard. Knew I'd be doing it all again if I didn't give it an extra deep recess.