Loose primer pockets

[BGD]

I am working up a load for a 243 win with IMR4350. I loaded some with Sierra 100 g SBT and 40 grains IMR4350. They shot ok but the primers seemed to back out slightly. Does this mean there was to much pressure. These are new Remington brass. I have seen no other signs of pressure. Could these just be loose primer pockets?

Thanks

 

[Tolkachi Robotnik]

Could be other the direction.

I shoot 30/40 Krag loads of a mild nature. They too back out the primer ever so slightly. This is often a sign of very mild pressures, when the cartridge does not get pushed from it's position and this results in the primer pushing out slightly on firing. It is not pushing back against your extractor. This is more common in rimmed cartridges that have wiggle room in the neck and throat area. A .243 should be just so in size, but it still could exhibit the same slight push back on primers if a mild load. If primer also still rounded and doesn't have the rim lip where the firing pin hit, it is sign of mild pressures.

 

[witchhunter]

It could be that you are sizing too much, creating headspace. Check your sized rounds with a gauge, like a Wilson. You can use your chamber to adjust the sizer die, take a fired case, bump it down only until the bolt just closes without pressure.

 

[James2]

The two previous posters covered the two reasons you may have primers backing out. I have seen this in a couple of old rifles that had excessive head space. Your load seems to be high enough, I would size for minimum head space as witchhunter suggests.

 

[hdbiker]

if primers are backing out, not just flattening out, have the headspace ck'd

 

[steve4102]

I am working up a load for a 243 win with IMR4350. I loaded some with Sierra 100 g SBT and 40 grains IMR4350. They shot ok but the primers seemed to back out slightly. Does this mean there was to much pressure. These are new Remington brass. I have seen no other signs of pressure. Could these just be loose primer pockets?

No, backed out primers is usually a sign of Low pressure.

Are you sure of the powder charge? Did you zero the scale and verify it's accuracy?

If so, carry on, shoot this new brass and then size accordingly.

 

[4895]

Bite the bullet and shoot a box of factory ammo and check for the same problem.

 

[gamestalker]

What your describing is consistent with either low or high pressures. The first thing I would do is, if you have any of those cartridges left, pull some bullets and double check the charges. Things can happen, maybe the scale wan't zeroed correctly, who knows, but check those charges.

I really doubt it has anything to do with excessive head space. This will produce head separations, or incipient HS, but I've never seen backed out primers from setting the shoulders back too far.

GS

 

[rcmodel]

If you have excess headspace for whatever reason?
Actual excess in the rifle, or artificially created by sizing the shoulder too far back.

And the case doesn't stretch to make it up?

The primers will back out and stay backed out.

It simply does not happen with excess pressure.
Because the case will always stretch to fill the available headspace and re-seat the fired.
primer flush with the case head.

rc

 

[243winxb]

Do your primers look like this?? Are you shooting a Rem. 700? Or has the whole primer backed out?

 

[BGD]

The primers are not cratered. They look ok, just backed out ever so slightly. I will pull a couple of bullets and check some of the loads. I weigh the charges on an RCBS electronic scale and then verify them on a RCBS 10 10 scale. I am kinda anal on the charge weights. I have some factory loads I will try in the rifle.

It is a Remington model 7 that I bought in 84. Used it to shoot my first deer. I haven't shot it in many years and decided to work up a load for my kids to hunt with. I never noticed the primers backing out before. Could be I am just paying closer attention to them.

 

[Tolkachi Robotnik]

WinEXB has good photo there!

Note the ring where the firing pin struck in 243winexb photo. This indicates high pressure. If yours just have the firing pin dent and no ring or lift around that area, like RCmodel above states it indicates low pressure not high.

The edges of the primer also say a story, unless you use Sellier and Beloit primers, that edge up flat when installed. Rounded edges there also indicate lower pressure, whether lifted out back of the cartridge or still seated flush. The primer is never as tough as the brass for holding back pressure.

Usually if you get that ring around the firing pin strike, you also get a noticeable jolt to the shoulder, although you might not be sensitive to the change if you shoot larger bores than .243 much.

 

[edfardos]

What rcmodel said... I'd first try to back off the sizing die a few thousandths.

 

[rcmodel]

Note the ring where the firing pin struck in 243winexb photo. This indicates high pressure.

More likely, that indicates how sloppy Remington has gotten in insuring the hole in the bolt is the same size as the firing pin.

When the firing pin fits the bolt face right, you will not see that cratering around the hole until about the time the gun blows up!

rc

 

[brickeyee]

Note the ring where the firing pin struck in 243winexb photo. This indicates high pressure.

Not at all.

The edgers of the primer cup are still perfectly rounded.

That is a sign of an oversize firing pin hole in a breech face.

 

[BGD]

Here is a picture of the primers. These were new cases fired once with a starting load and then neck sized and fired in the same rifle. I checked them in a Wilson case gauge and they appear to be at the minimum speck or close to it. This rifle must have a tight chamber. There is some recoil, but nothing like my 270 WSM.

 

[steve4102]

What rcmodel said... I'd first try to back off the sizing die a few thousandths.

Sorry, not going to help. He is using new unfired brass. Backing the sizing die out will do nothing as most factory brass is short right from the get go. Short as in case head to datum line.

 

[243winxb]

Primers look fine to me.

 

[rcmodel]

Look fine to me too!

If they are backed out?
I sure can't see it in your photo.

rc

 

[BGD]

I set a case down on the table and took a picture. I hope you can see how the case is resting on the primer? Maybe I am concerned about nothing.

 

[Blue68f100]

If that's the case you need to back your sizing die off. Your moving your shoulder too far back. That and/or up the charge so the case is moved back against the bolt face.

 

[James2]

Maybe I am concerned about nothing.

Ya. They are not backed out enough to cause any problem I am aware of.

 

[BGD]

I think I can still add 1.7 grains more before I am at the maximum charge by the Sierra manual. Maybe I can try going up .5 grains to 40.5 and see what that does. I am using Winchester WLR primers. Do you think another primer would make a difference or just try increasing the charge a bit?

 

[243winxb]

The WLR primers have had some problems since they moved the plant. You dont seem to have them. Gas leaking between the brass and primer. Or pin holes in the primer cup. I would load the fired/formed brass again, see it it makes a difference using the 40 gr load. Plus load 5 rounds with 40.5 gr. and compare. You dont seem to have other pressure signs.

 

[BGD]

Wow. Those primers are ugly. How did they act when you shot them? Did Winchester recall those lots?