Big problem with my brass need help!

[elmerdeer]

I just finished resizing my brass with a lee collet necksizer and found groove marks on my belts on the 7mm mag nosler brass, some of the groove marks are way more evident than others, meaning you can see and feel them with your finger much more. They metal snags on my finger a bit from how rough they are. This was the 4th time they were fired, I annealed them on the 3rd. When I was at the range the temp was 75 degrees. My load is 70grs of RL-25 with a 160 accubond my avg speed is 3077. I have shot this load over 300 times with out a problem like this, but maybe not at 75 degrees, but I have shot it at 70 degrees many times with out a problem.My measurement on the belt is .530" it seems fine compared to my twice and 3 times fired brass. Now has anyone seen these marks before and what caused them I am stumped? That day I fired 30 rnds 6rnds per target on of my targets was a .860" for 6 shots in a gusty day, the rest were average between 1.5-2 inch groups.
Thanks
elmer

 

[MagMan]

By chance was this the first time they were fed from the magazine?

I think a picture would add more insight to your problem.

 

[elmerdeer]

By chance was this the first time they were fed from the magazine?

I think a picture would add more insight to your problem.

I cant get the picture to load. Single fed them.
Elmer

 

[MagMan]

send the pictures to me and I'll post them.

[email protected]

 

[elmerdeer]

send the pictures to me and I'll post them.

[email protected]

Pics sent to your email.
Thanks
Elmer

 

[MagMan]

I'm not sure what that is all about. Surely you wouldn't think the back of your chamber was that rough.

It can take up to 3, 4 or even more firings for brass to fully expand. I'd make sure its clean in there and maybe drag a qtip around to see if it is as rough as it looks then perhaps a plastic pick to get all of the stuck brass shavings out.

 

[Winchester 69]

I just finished resizing my brass with a lee collet necksizer and found groove marks on my belts on the 7mm mag nosler brass....

Did the Lee collet die do the damage? Any chance that it's a 280 die?

 

[KRP]

I think he's saying that the Lee collet die did the damage. Any chance that it's a 280 die?

Shouldn't matter, all the Lee collets are ~.532 inside.

I think the belt is slightly oversized or the die is slightly undersized and causing the problem or maybe the bottom of the collet has some crap/burrs on it. Turn a case around backward and see if the head will slide easily into the collet. If not clean the die well, then maybe hone the bottom inside of the collet a little to clean it up and make it smooth.

 

[kraky2]

belted mag...can't be a 280...no belt on 280.

 

[elmerdeer]

Did the Lee collet die did the damage? Any chance that it's a 280 die?

Its a 7mm rem.