243 Win Backing Out Primers

[turkeyfever]

I have a Rem 700 Sendero that I have been shooting off and on this summer. I bought this rifle to get trigger time at the range. I have used 3 manufacturers types of brass Nosler, Remington and Lapua. All brass is new. Have used Federal primers 210m, 215m and a standard mag primer. The CCI primers have been the benchrest. I have used mutiple powders from IMR 4831,7828, H4895, H4831SC, H4831, H4350 and H1000. The only bullet that I have used is Nosler 95 gr BT. Have only worked up to a mid load for a average thru 3 reloading manual. There are no other signs of excessive pressure but the primers. Any idea of what my issues may be.
Thanks
Rusty

 

[cahunter805]

Could be your load is to mild or a headspace issue.

 

[Dosh]

Check the bolt, headspace.

 

[243winxb]

"mid load" may not expand the brass enough to reseat the primer on firing. Remington did make a few bolts that let the primer flow. Bevel around the firing pin/

hole. Does factory ammo do it ??

 

[okie man]

Could be your sizing die is setting the shoulder back too far! Leave gap between your die and she'll holder and size 3 new cases, load them and shoot them. See if that helps! You could have a shell holder that's a little short

 

[CliffM]

Could be your load is to mild or a headspace issue.

Or both.

 

[Grumulkin]

Have only worked up to a mid load for a average thru 3 reloading manual. There are no other signs of excessive pressure but the primers. Any idea of what my issues may be.

Backed out primers are not caused by high pressure. With high pressure you can get a blown primer, primer cratering and pierced primers but not backed out primers. I also think it's pretty unlikely that excess head space would cause backed out primers but if your gun does that with factory ammo I might believe it.

You mention that you have "worked up to a mild load" and I think that is your problem. Try increasing the load a bit.

 

[AZShooter]

You say you are using mild loads. IMO the primers LOOK like you have excessive pressure because their shape has been altered by the primer backing out of the primer pocket during combustion. A bit later the pressure causes the case to move rearward against the bolt face flattening the primer which is sticking out of the case head. The case head is not held against the bolt face due to forward movement of the case by the firing pin. As others have mentioned this is excessive headspace.

Have you shot any once fired brass? If the brass is sized with minimal setback of shoulder the case should maintain contact with the bolt face preventing the flattening of the primer. If issue disappears it is excessive headspace.

Have you tried seating a bullet to engage the rifling? That would eliminate the headspace issue keeping the case head against the bolt face.

Try some changes and let us know. This is what this forum is all about, sharing information.

 

[turkeyfever]

I went back and checked some factory Ammo brass that I was shooting earlier in the life of this rifle. No primer back out at all. I have shot once fired brass and have the same issues. I have not tried the bullet in the lands will try that today to see if that helps any at all. Have pictures of bolt and last brass that I have shot.

 

[turkeyfever]

Picture

 

[AZShooter]

Describe how you are sizing your brass? Are you partial full length sizing to move shoulder and body taper just enough for easy bolt closure or are you placing the sizer die against the shell holder?

The bolt face has that shiny center, is it slightly lower than the rest of the bolt face?

 

[turkeyfever]

I have the Redding 3 die set. The sizer die is barely touching the shell holder when the ram is up. Then I use the bump die to push the shoulders back .0002. Then I load the rounds. I have checked brass when I run it thru the sizer and I am not pushing the shoulders back any just sizing the neck with the bushing.

 

[Mikecr]

Are you bumping the shoulder back w/resp to new brass or fired brass?
The brass should be allowed to fire form to snug fit before any shoulder bumping should be applied.

What you have is primers backing to the bolt face on their firing (normal), but your case heads are not reaching back to the bolt face on that firing -to reseat the primers. With high enough pressure reseating will occur no matter what, but mid/low pressures should not be a problem with fire formed cases that are well head spaced.

 

[turkeyfever]

New brass just run it over the expander to make sure necks are the correct size. Once fired brass i do the procedure list before.