copper jacket remained in barrel in 357 mag

[boston]

While shooting outside today, temp 22 degrees, copper jacket remained in barrel but bullet exited.

Shooting a S&W model 686, 357 mag.with 4 inch barrel. Using zero brand 158gr jacketed hollow points, behind 6.3 grains of Bullseye and Wolf small pistol primers. A medium crimp with Lee FCD. Had fired 16 shots without incident, all same specs. The round in question felt and sounded light, leading me to believe it was a squib load. Surprised to find just the copper jacket in the barrel. Jacket was removed easily with brass rod. Gun has about two thousand rounds through it and no problems. Have shot at least a thousand rounds with this same configuration of bullet, powder and primer.

Couldn't find any info on searches, so thought I'd throw it out for discussion. I think it was probably a light load, but why did the bullet not remain with the jacket?

 

[Fullthrottle]

Don't hold me to it but that sounds like a bad bullet to me. Maybe wasn't properly formed? Never came across that one before!

 

[Longdayjake]

That is very odd indeed. The zero bullets are kind of a semi jacketed bullet. If you had a soft enough load maybe it just squeezed the lead out of the jacket and spit it on the ground. Do you have a picture of the jacket?

 

[m&p45acp10+1]

In my Lyman Manual it says to crimp Jacketed Soft Points below where the jacket meets the bullet to prevent just the problem you are describing.

 

[boston]

I will try to post a picture of the jacket.

This bullet has a cannelure which is where I crimp.

 

[Fullthrottle]

^^ That is what makes it so strange to me, all of the .38/.357 bullits I use have that cannelure. I have never had this problem. I have used Rocky Mountian reloading, Sierra, Rainier, Montana Gold, and Speer without this problem.

 

[res45]

Speer used to make a very nice 3/4 jacket 146/160 gr. jacket HP and SP bullet,in there reloading manual they specifically warned about shooting those bullet at below listed starting loads or the bullet jacket would separate from the core and be left in the barrel. This would also apply to a squib load.

Evidently either people didn't heed the warning and it became more of a liability so Speer discontinued making the bullet a number of years ago to my disgust. My Ruger 357 Mag. loved that bullet in a full house load and I never had any issues with it. I've seen it happen with Magtec bullets as well,most likely what happens is the the initial force of the squib rd. is enough to start the bullet on it way down the bore but the lighter copper jacket due to friction gets wedged in the bore and the original inertia causes the lead core to separate from the jacket.

Most of these type bullets are not bonded and the lead core is held in places only by the cannelure or in the case of the Speer 3/4 jacket basically a roll type crimp over the edge of the exposed lead core.

 

[spacecoast]

While not a barn-burner, that's not a significantly underpowered .357 round. Could have been a bullet that slipped through with a loose jacket, this would be more likely I think with a semi-jacketed bullet than a FMJ.

At those velocities I shoot plated Berry's bullets, they're more economical.

 

[res45]

If he actually had 6.3 grs. of Bullseye in the 357 case and it ignited as prescribed both core and jacket would have exited the bore with no problems. That should be pretty close to a Max. load for that combo.

I would suspect it's either under charged,primer failure to ignite the powder completely or being he was shooting in 22 degree weather depending on the amount of time the ammo was exposed to the cold that could also have affects on the powder burn a well as velocity.

 

[Jim Watson]

I saw a guy stick the jacket of a 158 gr Speer - modern style with 7/8 jacket and cannelure, not the old 3/4 jacket SWC type - in the barrel of a S&W M15. The core actually hit the rather close target so he shot again and bulged the barrel. We found all the separate pieces in the berm the next day after he found the bulge while cleaning the gun. He was using a light load more suited to a wadcutter, though.

Perhaps this was one of those cases you can read about of the Lee CFC die distorting the bullet and leaving the core loose in the jacket.

 

[WANT A LCR 22LR]

I've run a few thousand of these through a GP 100 4" ( "same" gun but different brand than the SW 686 ) and a LCR ( 2" snub )

Zero 125G jacketed soft points and hollow points. 4.8 G Bullseye, 5 1/2 remington magnum primer in a 38 case. ( the top of a 38+P load and it still feels a bit light compared to Remington Golden Saber 125g )

Have not had any bullet failures.

Also ran some very low loads with Unique, no problems.

The Zero bullets are a copper cup filled with lead, the forward end is tapered with a flat point. The copper cup is formed on the tapered end so the lead does not fall out. The crimp groove is far enough down to the jacket won't strip off. I wonder of the OD was a bit too big , got stuck in the forcing cone allowing the lead to extrude from the jacket.

I'd say measure the OD of some random ones to test that theory.