Which Crown?

[CentrePunch]

Recessed target or 11° angled?
I am building a 22BR short range varmint rifle which will also be used for occaisional Bench Rest in LV class.
I have a recessed target crown on my current 257 AI varmint rifle and an angled crown on my 22-250 AI which the 22BR is going to replace.
Both of the above carry Pac Nor Supermatch barrels and both were chambered by myself using tried and tested BR techniques.
The 257 shows the edge accuracy wise, with all bullet styles.
The 22Br will also carry a Pac Nor Supermatch tube, what say ye men?
Thanks.

Ian.

 

[butchlambert]

Shape of the crown does not affect accuracy. It just needs to be indicated properly and cut with a very sharp tool.
Butch

 

[CentrePunch]

Shape of the crown does not affect accuracy. It just needs to be indicated properly and cut with a very sharp tool.
Butch

Thanks butch, thats what has been hinted at and is what i have been thinking.
I have also previously finished my crowns by facing from the bore to the outer edge, so as not form a burr in the bore by facing in the the conventional way, what are your thoughts on this, i have claims that both ways are equally correct.
Also what do you think about lapping a small chamfer to groove depth using paste and a suitabley sized ball?
Thanks.

Ian.

Ian.

 

[butchlambert]

Ian,
I cut from the bore out and touch it with a cratex rubber stick.
Butch

 

[CentrePunch]

Ian,
I cut from the bore out and touch it with a cratex rubber stick.
Butch

Hmmmm.........interesting....................never thought of that!

Ian.

 

[kendog]

Also what do you think about lapping a small chamfer to groove depth using paste and a suitabley sized ball?
Thanks.
Ian.

Or set your compound at 45 deg and cut this chamfer with said sharp tool.

 

[Preacher]

I always have cut from the bore out with lots of speed, and oil, and a newly sharpened cutter every time, cut very slow, and never touch it again with anything...

 

[Bob3700]

A lot of ways to skin the cat here. I turn the crown from bore to outside diameter. Take your pic 90 degrees or 11 degrees. When that is done, I use a dedicated, piloted 60 degree countersink to just touch the crown. Usually the cut is about 1/32 to 1/16 inch wide.

The nice thing about this method, you can touch the crown up by hand as the round count builds.

Bob

 

[CentrePunch]

I usually lap the edge of the bore with a spherical brass lap and #360 then #600 grit paste until the slightest witness appears in the groove edge.

Ian.