Backing out primers mystery

[jtcarm]

My guess is insufficient pressure due to light to no crimp.

The Bayou 160 grain bullet appears to have no cannelure.

That's all I have!

Bruce

I’ve used that bullet. It needs a taper-crimp, and a fairly snug one. Even with a light load I’ve had them creep.

Re: wax bullets or popping primed cases.
I’ve done both and never had a primer back out.

The one time it happened to me was with a load that was too hot. The primers were nice & puckered.

 

[Eddie Southgate]

To my knowledge primers backing out occurs because of low pressure. For example if you've ever shot wax bullets with just a primer you know the primers will back out if you don't drill out the flash holes. If you fire an empty case with a live primer it will back out.

But I would think you would have noticed other signs of low pressure. I have had some problems with Remington brass and bullet pull on 125gr bullets that don't have a whole lot of bullet in the case. Remington brass is very thin. I resolved the issue with the 125gr by using a Lee U die, with the U being for Undersized.

Doesn't really sound like that's your issue though. It's a conundrum.

All primers in revolvers back out to an extent and get partially re seated when they hit the recoil shield. Low pressure wont be any more likely to push them out farther but will be less likely to cause enough recoil to reseat them when the case head hits the recoil shield.

 

[Eddie Southgate]

What's weird is these primers are struck, but rounds did not fire.
Bullets not dislodged as in a no powder case.

That's why they backed out and stayed that way if you find that the primers are fired. Didn't know the cartridge didn't fire but just popped the primer. That being the case the unseated primers are the most common result. Hard to believe at least one bullet didn't jump the crimp if the primers popped.

 

[WR Moore]

The stated velocity is 755 f/s. My usual .38 practice load does better than that out of a 2 inch model 60. I suspect that the more slippery powder coated bullet isn't developing the pressure that a lead or jacketed bullet will. That might account for the primer set back.

 

[AlHunt]

What's weird is these primers are struck, but rounds did not fire.
Bullets not dislodged as in a no powder case.

I missed the part about misfires in the first post.

Have you taken them apart to see what's happening inside?