Setback problems with 135gr JHPs in 10mm

[mobocracy]

I've been working on some loads for the 135gr 10mm Nosler bullets and have noticed an issue with bullet setback on these bullets that I don't see with my usual 10mm plinker bullet (R-P 180gr JHPs).

Using load data from the Alliant manual, I've been using 9.6gr of Power Pistol and Federal 150 primers. I'm using a set of Redding TiC Pro Series dies on a Dillon XL650 to load them, and my crimps are returning the case mouths to .423".

When loading 4 rounds in my Kimber Stainless Target II mags, I check the 4th round after firing 3 and find obvious setback. In my S&W 610 revolver, I get pullout, also obvious. By obvious, I mean I can see it without having to check it with the caliper. Accuracy has been good on the first 3 rounds.

The cases I've used thusfar are my own used cases, and there's always the outside chance that they lack grip, although I have yet to see a problem with my 180gr loads of the same vintage. I figure with as short as these bullets are, it takes some amazing case grip to hold them -- perhaps either brand-new cases (loading a test lot of 25 tonight) or even an undersize size die.

Any suggestions?

 

[fredj338]

There is almost 1.5x the bearing are on a 180gr vs a 135gr JHP. I have found quite a diff. in case mouth thickness from one brand of brass to the next. You could try diff. brass & maybe just a bit more crimp.

 

[mobocracy]

I tried new Starline cases and had the same problem. I tried crimping a few down to as small as .420 and it didn't help either -- these bullets seem a lot softer than the R-P 180s, too -- I pulled a couple of the .420 crimped bullets and there was a noticable ring that wasn't as defined on the 180s.

I'm going to get an EGW undersize die and see what it does for me. I want one anyway to get a little more life out of my brass.

 

[fredj338]

Interesting problem. I have not tried any of the 135, 155gr is as light as I have gone. Maybe I'll have to buy a box & give them a go.