new to the highroad

Primers backing out is often due to light loads, rather than heavy or dangerous loads. Primers back out a little under ignition pressures and then the recoil of the case against the breech face re-seats them flush. Sometimes with lighter loads they don't get the force necessary to re-seat them fully and it's nothing to worry about. Long headspace can also contribute in some cases.

I don't know if your loads are on the hot end but if they aren't, the above is IMO the issue.

When your primers are flat all the way to the primer pocket or are flowing out, pierced, or leaking gas around the edges, then you can be concerned.

I think @1KPerDay nailed it. I would add that if they're protruding more than ~0.005, you should look at sizing with less shoulder setback. The protrusion is <= you excess cartridge headspace.

In a bolt, I would want <0.002, but in a lever you might need more for easy feeding. I think 0.005 is a reasonable max.

Hornady 150 roundnose bullets and the following powders 34 to 36 grains RL 15;

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RELOADER'S GUIDE
Alliant Powder Reload Recipes
https://www.alliantpowder.com/reloa...wderlist.aspx&type=1&powderid=12&cartridge=78

This never copies well but from Alliants Reloading web site, 34grs of Reloder 15 with a 150gr bullet is maximum load.
I don't think it is to light of a load.

Welcome to THR timberwolf60
lots of great people here.

How do the cases extract from the chamber?

When I read your post I thought the same thing, too light a load. You tell us you charged 31.0gr to 31.5gr LVR under a 150gr bullet. Hodgdon lists the range as 35.0gr to 38.5gr LVR. Your LVR load is very light and would explain the primers. I didn't check the other 2 loads.

That is actually good news and easily fixed.

Welcome to THR...

Welcome from Fort Worth

I didnt check the other two loads either, shame on me!

Welcome to THR!
Published data on those loads: (all COL 2.550")
RL 15 - 34gr Max
Varget - 31-34.5
LVR - 35-38.5C
Alliant publishes the max load and you're supposed to drop 10% and work up, that would be 30.6-34gr of RL15.
So the RL 15 and Varget are maxed, and the LVR is really light, and the primers all look the same? That is the picture above is all the loads? I'd suggest there's a headspace issue if your powder charges were accurate. I didn't see the pic of the unfired case but will assume your primer is flush or slightly below, that is seated properly.
I'd try some factory ammo and see if it does the same thing.
Also, on the reloads, you say you've been reloading for a long time, but verify your powder charges. If you're using a digital scale calibrate it, and/or use a balance scale to verify it. When I do load work up, I load 2 extras that are saved so I can deconstruct them later in a case like this to verify the loads.

timberwolf60 said:

greetings fellow shooters. Have been reloading for too many years to count but ran into an interesting result Tuesday while shooting. I was load testing a 336 of mine, not a new gun but lightly shot. I was using new starline brass, Hornady 150 roundnose bullets and the following powders 34 to 36 grains RL 15; 33 to 34.5 grains of varget, and 31 to31.5 grains of leverevolution. All of the fired cases show primers backing out a little. Enough to concern me. the last pic is an unfired case. Any suggestions?

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Welcome to the highroad. I think you're running a little light on the Leverevolution load. If I remember correctly, I was running more in the 35-37 grain range.

max saami pressure for this cartridge is only 42,000 psi. this scenario tells me the breach (bolt) thrust from your loads is not enough to stretch the case back over the primer. on the upside, you now know the headspace of that gun. measure the primer height above the case base and add that to the rim thickness. that rifle of yours may have a bit too much headspace.

but all is well. the only bad thing about those rounds is their appearance after firing.

luck,

murf

double post