Want to make sure I have this right.

[Firearrow]

New to the game, so bare with me. For measureing the most accureate OAL on a non custom (hope to be soon) long range hunting rifle.

1. Take fire formed case and cut slits in the neck with drimel.
2. Seat the round I want to use (Berger 190gr for a 300 mag), in the case with slit and leave it long.
3. Carefully chamber round, and carefully extract the round.
4. Look for the marks left by the lands, and mesure them.
5. Then take the measurement from 4 and subtract what ever distance off of the lands you would like be.
6. Adjust the seating die to make said round
7. Then for record keeping purposes, us a bullet comparitor to meassure OAL of round from 6.

Does this sound right, assuming it will fit into my magazine?

 

[jimbires]

I don't cut slits . on a fire formed case the bullet will be to loose already , so I pinch the mouth very little on a fire formed brass case and sharpie color the bullet . the case mouth will scratch the sharpie off when you chamber the round . when you remove the round put the bullet into the case to the scratch mark left in the sharpie . if the bullet gets stuck in the bbl , push it out with a cleaning rod . I do this 4 or 5 times to be sure I get a good repeatable measurement . I use a Hornady OAL tool that measures off the ogive .
I'd say you have the right idea . on your other steps . Jim

 

[boomtube]

"5. Then take the measurement from 4 and subtract what ever distance off of the lands you would like be."

And therein lies the rub; finding the distance the rifle likes the bullets off the lands is much more significant than whatever I might like/hope it should be.

 

[Johnboy]

or you can just neck size a fired case from that one rifel.then seat a bullet of choice long.then chamber it with care,and if it does not chamber.seat the bullet just a little trying it again.but keep doing this till you get to the point to where it almost fully chambers with the bolt not locked yet.now at this point you can close the bolt the rest of the way and remove with care.now measure it.and keep it for resetting the die for future use of the same bullet.after all said and done you can then play with the setting depth to see if it will improve the load.and if it does reset the dummy to that spec and keep for a future use.

this is what I do and it works for me.might be a little more work but works.been doing it this way for 15 years.and I do not on a guage.but alot of dummy bullets for about 5 rifels.

or you can do the cleaning rod test.
first run the rod in on a closed bolt from the muzzel end.now with the rod in place put a pice of tape right at the muzzel.make sure it is touching the end of the bolt.

now remove the bolt and with a dowl rod or pencil hold the bullet of choice in the chamber in the lands.then run the rod back in to just touch the tip of the bullet.now put another pice of tape at the muzzel.

now you can measure distance between the tape at the points where the tape was at the end of the muzzel.and this should give you a C.O.A.L. with that bullet.

both work but the fired case woks better and you get a dummy this way.

 

[Firearrow]

Thanks for the advice guys. I appreciate you taking the time to help a new guy.

Garett

 

[BountyHunter]

=Johnboy;377418]or you can just neck size a fired case from that one rifel.then seat a bullet of choice long.then chamber it with care,and if it does not chamber.seat the bullet just a little trying it again.but keep doing this till you get to the point to where it almost fully chambers with the bolt not locked yet.now at this point you can close the bolt the rest of the way and remove with care.now measure it.and keep it for resetting the die for future use of the same bullet.after all said and done you can then play with the setting depth to see if it will improve the load.and if it does reset the dummy to that spec and keep for a future use.

this method will tell you where the "jam", not the start of the lands. Jam is anywhere from .030-.070 IN THE LANDS. It can vary a good bit from test to test also.

You can try and measure the marks with a caliper but as recommended, use a marking method to leave some color on the bullet. Some others use steel wool to burnish the bullet and the marks show pretty clear in that method also. I have used the latter method succesfully.

BH