help with 7mm rem mag

[blade]

My 7mm rem mag has all of a sudden started getting some very wide extreme spreads 100 fps plus. On its worst day it has always held about 30 fps. My velocity seems to be all over the place. My velocity is running around 2760 fps im about middle of the load data on my charge weight. The one thing i have noticed is that when i try to close the bolt here lately it tends to stick a little when it starts to enter the barrel. Any suggestions why all of a sudden it started doing this?

 

[fourpower]

clean your camber but really check your headspace. I had that happen once and found out that my dies had moved!

 

[Sheldon N]

Yes, and check your seating depth and that it is consistent between bullets. You may be jamming the bullet into the rifling for some rounds which can cause increased pressure and velocity swings if you are right at the lands.

 

[ebb]

Check OAL of brass

 

[blade]

Yes, and check your seating depth and that it is consistent between bullets. You may be jamming the bullet into the rifling for some rounds which can cause increased pressure and velocity swings if you are right at the lands.

I use the lee factory crimp die so I really don't think it's got to do with the seating. I use the hot day bullet comparator on every round. Don't think that is either.

 

[blade]

clean your camber but really check your headspace. I had that happen once and found out that my dies had moved! That was my first thought. I check with Hornsby headspace comparator and had .004 difference in and unfired case and a fired case. Is that enough?

 

[blade]

Check OAL of brass

All my brass was trimmed to perfection.

 

[Toolbreaker]

Try a different chronograph. Might not be the load.

 

[blade]

Try a different chronograph. Might not be the load.

I might think that would be the case if all my other guns wasn't doing as they should.

 

[blade]

I'm wondering if it's not the primers causing this? I have all of sudden started getting a lot of misfires. I'm using Winchester wlrm. I'm also getting a few with the wlr in other cal. I have never had a primer fail to fire up until recently.

 

[Chief 101]

I would think you need to check the firing pin/bolt. Could be debris not allowing firing pin to fully extend from the boltface.

 

[blade]

Well gentlemen I think I might have figured it out. Seems as though I misread my data on the seating depth. That explains the lower velocity I had . The spikes I was getting was due to to much crimp. I wasnt crimping in the cannelure. I was using the lee factory crimp die. You are suppose be able to crimp on the bullet shank. I pulled a bullet I had left over from my last trip out and there was a ring around the bullet shank and the bullet was distorted. I loaded some groups today and seated and crimped them in the cannalure. I should be good to go now.