Marks on bullet vs jam ?

[1shot]

+1 to both Boyd and catshooter. Reading your posts made me remember something everyone should do when the get a new barrel. That inch or two that comes off the muzzle has a very good use. Have your gun plumber or if you do your own and square it off then run your finish reamer in to the depth of the shoulder/body junction of the reamer. Put a fired case in the "stub" and measure it from the end of the "stub" to the base of the case. If you de-prime first before sizing, it will be even a little more true and consistent. That way you are measuring to the center of the shoulder from the same reamer that cut your chamber. Record that number and when you re-size your brass you have an accurate measurement as to how much you bump your shoulder. I have one of these for every reamer I own and the results compare favorably with the bolt body method, without the hassle and is much faster. BTW, you do need to be able to read a micrometer.
I hope this helps,
Lloyd

 

[Link]

I wonder how you guys measure "jam" when the bullet is pushed as far as it will go into the lands with a certain neck tension. When I chamber a round the bullet sticks in the lands and I have to push it out with a cleaning rod and my measureable distance is gone.

A lot of great info is shared on this site.

 

[Tim Singleton]

I wonder how you guys measure "jam" when the bullet is pushed as far as it will go into the lands with a certain neck tension. When I chamber a round the bullet sticks in the lands and I have to push it out with a cleaning rod and my measureable distance is gone.

A lot of great info is shared on this site.

Great question it happens
Just seat the bullet slightly deeper re measure before you chamber again. Repeat until it pushes back but does not stick. Do this a couple times to confirm measurement

 

[C Valentine]

I seat it long, then keep gently chambering it and measuring until it is no longer moves when I chamber it three or four times. I do this several times. Right or wrong, that is my reference point for testing seating depths...longer it's "my" Jam and shorter its "my" Jump. I will re-measure after so many fired rounds (depending on the rifle) and when I open a new lot of bullets, I also measure using one of those bullets that is an average of the lot.

 

[Dusty Stevens]

I use enough neck tension and angles on my reamers i dont stick em anymore