7.62x39 Barrel Re crown

[Alpha1]

As the title should I go for a 90 or 60 degree crown.
The muzzle on my AIA barrel looks dread full I think its due to the screw on front sight. I have removed it. My thoughts were to face off the front of the barrel then re cut the crown. (On the lathe)

So 90 or 60 or is there a better option.

[Alpha1]

It seems some guys are going with a 11 degree crown.
Im confused yes I know that,s not difficult to do if some one could explain the process to me I would appreciate it.

[Mattnall]

True the barrel in the lathe clocking on the bore and centre the chamber end in a spider or however you do it.

Face the muzzle, then set the compound slide to 11° and cut the crown with a crowning tool. I think Brownells sell one but they aren't too hard to grind. I work from the inside out so I don't have to shoot the burrs off.

[Mattnall]

Finally I use a fine wet-n-dry to polish the face, and if there's no muzzle thread it will take off the sharp edge on the outside of the barrel.

[Alpha1]

Were do you get your indication rods from that you use to clock the barrel.

[Mattnall]

I made them out of brass rod.
You could clock off the bore if you have a lever type DTI, you get to 'see' the rifling too

[Alpha1]

Do you cut a taper on the rods or do you size them to the bore size.

[ovenpaa]

The crown shape is down to application. I put a 90 degree crown on rifles that will be used with sound moderators as they are protected and easier to clean. 11 degree crowns are favoured for target type rifles as are stepped crowns and this is usually chosen after discussing the job with the customer. I have also been experimenting with radiused crowns and latest is a crown with a 100m radius which will be shot in the next few days and the customer will report back. For older rifles I try and replicate the original form as closely as possible.

I only ever crown with a 4 jaw chuck and I use a long arm indicator as I am quicker with it however I also use range rods. Mine are grizzly type so tapered with a reamer bushing on the end. They work well, I just prefer the long arm indicator.

Always cut from the centre out and take care polishing. Finally, use a cotton bud to confirm there are no burrs. Having said that, I am yet to meet a burr that lasted more than one shot....

EDIT - BBT have added range rods to the range of products they produce so they will be very good quality.

[Alpha1]

I have checked out BBT,s web site unfortunately BBT wont sell me any of there products because Im not a registered firearms dealer or gunsmith.
I might have a word with my local friendly registered firearms dealer and see if he will order me a couple of range rods.

[Andy]

Finger clock, ideal for setting small bores.