Distance off lands
- Thread starter DarkSith
- Start date
You can make a jam cartridge by FL resizing a case .cut the neck with a dremel tool to the bottom of the neck down the side.place a bullet into the neck and put it into the rifle close the bolt .open the bolt and carefully remove the cartridge and measure it with you calibers.check out ammosmith .com he will show you another way of making a col cartridge.
There are several ways. You can buy a tool to do this ( most accurate way) , You can smoke the bullets in an unloaded, unprimed case and chamber the round moving out the bullet till you just see the lands on the bullet. You can use a wooden dowel and insert into the barrel with the action cocked and mark the location at the muzzle with a very fine pencil or a razor blade then insert a bullet through the chamber till it touches the lands and hold it there lightly with a dowel and a weak elastic band , measure and mark this location on the above dowel and measure the distance between the marks. Most often I keep hunting ammo about .020" off the lands.
There are several tools available for doing this. One quick way of determining that your bullet is not in contact with the rifling is simply to take a fired case from the rifle,roll in the case mouth to provide enough tension to hold a bullet, coat a bullet with magic marker and then chamber the dummy round. Extract the round and look for rifling imprints/bright spots where the rifling has made contact with the bullet.
You can do this a number of times seating the bullet deeper each time to a point where the rifling marks are no longer evident. At this point measure the COL with a caliper.
It is not a good idea to seat bullets so that they jam in the rifling. In the first case this will elevate pressure,and secondly,the rifling may engage the bullet with enough pressure that the bullet will pull out of the case when an unfired round is extracted. The length of the magazine and functionality through the feeding and extraction of an unfired round will also have a bearing on this.
You can do this a number of times seating the bullet deeper each time to a point where the rifling marks are no longer evident. At this point measure the COL with a caliper.
It is not a good idea to seat bullets so that they jam in the rifling. In the first case this will elevate pressure,and secondly,the rifling may engage the bullet with enough pressure that the bullet will pull out of the case when an unfired round is extracted. The length of the magazine and functionality through the feeding and extraction of an unfired round will also have a bearing on this.
a partial collet neck sizing works great for me. size it so you can seat the bullet by hand with relative ease and then chamber in the gun. the lands will seat the bullet, at which point i extract and measure the oal, remove that bullet and seat that very same bullet (to eliminate the chance of bullet length difference) into a charged case at .010 back from the recorded length. at that point you are very close but you can creep it up even closer if you use the marker trick described above to ensure you aren't too jammed in there.
