Crown Importance!

[Keef]

I see the importance of a good crown brought up often when accuracy is mentioned.

My question is, how can the crown matter that much??? *Most* of my guns have muzzle devises on them, when I remove said muzzle device those pretty crowns are always covered in thick, irregular carbon. My groups are the same with a freshly cleaned crown and with a crown that is crusted up with carbon......

Yes I am at work and things are s l o w.

[LR1955]

I see the importance of a good crown brought up often when accuracy is mentioned.

My question is, how can the crown matter that much??? *Most* of my guns have muzzle devises on them, when I remove said muzzle device those pretty crowns are always covered in thick, irregular carbon. My groups are the same with a freshly cleaned crown and with a crown that is crusted up with carbon......

Yes I am at work and things are s l o w.

Keef:

All the crown does is protect the bore from damage. Some believe that certain angles of the crown assist in accuracy but there isn't much evidence to back them.

So, carbon on the crown probably won't do anything. If you decided to take a triangular file and file a notch in the bore, I bet your accuracy would drop.

LR55

[Keef]

I don't have a Grendel to do this with but I do have 7.62x39 barrel that I want to cut shorter. I will do this after hunting season is done.

[1Shot]

The actual crown of a barrel is where the rifling exits the barrel not the face of the muzzle. If the actual crown is unevenly cut or has nicks or worn places caused most often my improper use of a cleaning rod it will cause accuracy problems. This is what happens. When the bullet is being pushed down the bore by the gas if the crown is uneven some of the gas will blow by the bullet base on one side before the base of the bullet leaves the other part of the bore and thus cause the bullet to yaw ever so slightly and cause inaccuracy. The base of the bullet needs to leave the bore squarely. I have fix the crown on a number of old military or abused rifles by simply using a round head brass screw chucked in a drill with some valve grinding compound applied. Run the drill slow and place the round head screw with the compound applied to the muzzle and it will center up over the bore and cut the crown square. This turns pattern shooters into group shooters most of the time.

[Keef]

1shot: I have done many diy cut and crowns at home.(started with SKS's, then AR's) I also did two where I just cut and didn't crown, was planning to crown, but they shot so well I didn't.

[Harpoon1]

I see the importance of a good crown brought up often when accuracy is mentioned.

My question is, how can the crown matter that much??? *Most* of my guns have muzzle devises on them, when I remove said muzzle device those pretty crowns are always covered in thick, irregular carbon. My groups are the same with a freshly cleaned crown and with a crown that is crusted up with carbon......

Yes I am at work and things are s l o w.

I think I remember Frank Galli of Snipers Hide saying the military ran a bunch test and didn’t find the crown to be that important for accuracy. Of course “accuracy” is subjective and the military being the military, maybe there’s more to story than meets the eye.

Having said that, I stumbled across this a while ago.........I might try it one day with a junker and see.

https://youtu.be/7oGtLmzfWos