Once we reach a depth of .080", we take lighter passes until the final depth of .090" is reached.
Good crowns are essential to accuracy. Recessing a crown provides added protection for working rifles, preventing damage from damage caused by dropping or bumping the muzzle into something.
We are going to cut a recessed crown on our
custom built 223 bolt action rifle using a lathe. If you don’t have access to a lathe, this article shows an alternative method using a hand tool which produces excellent results.
While the photos don’t show lubricant, we used
Viper’s Venom cutting oil. We find it works well with the high-speed steel on stainless steel barrels.
The recessed crown we are cutting here has a .090″ depth with a 45 degree pull back made famous in the Marine Corps M40A3 and M40A5. Its worth noting that we’ve tried straight and 30 degree pull backs in the past and they didn’t look right.
We ordered the following from
All lathe work is conducted on a
Grizzly 4003G lathe with a Bald Eagle spider attached to the faceplate.
The following documents the process we used to cut a recessed crown and should not be considered instructional advice. We disassembled the safe and empty rifle prior to working on the barrel.
The barrel is removed and cut to length. In this case we want the barrel to be 24″ long. The 28″ was too long for us- it didn’t fit well in our safe and the barrel was too hard to maneuver.
The barrel is then secured in our front and rear spider. Here is the front, Bald Eagle, spider.
The back of the head stock has four holes drilled and tapped, this serves as our rear spider.
Initially, we dial in on the outside of the barrel using a .001″ dial indicator.
An initial squaring cut is made.
With the face trued up, we can now dial in off the bore.
A Pacific Tool and Gauge (PTG) grizzly rod, with the appropriate bushing is used in conjunction with a .001″ dial indicator and the front and rear spiders to dial the bore of the rifle in. Next, a .0001″ dial indicator is used to ensure the bore is true within .0001″. More information on dialing in a bore can be found in our “Chambering a rifle barrel” article.
Another, light facing cut is made. The face of the muzzle is now perpendicular to the bore axis,
Our compound is set to 45 degrees, since we will have a 45 degree pull back on our recess. The dial is set to zero.
We use a boring bar to cut the flat part of the recess. The final depth will be .090″. We zero the digital readout once we reach the point where the flat part of the crown will end…
the tool is then retracted with the compound knob, which cuts the 45 degree pull back needed.
Once we reach a depth of .080″, we take lighter passes of only a few thousandths until the final depth of .090″ is reached.
220 grit abrasive cloth lubricated with oil is used to break the outside edge
To remove any burrs, we chuck a crown lapping tool in a cordless drill and lightly lap the muzzle with silicone carbide abrasive to remove any burrs.
With the crown completed, we reassemble the rifle and head to the range.
Federal Gold Medal 69 OTM. .451″ at 100 yards. Average accuracy with our new crown has been .453″.