FL Sizer and Chamber Mismatch Question

[243winxb]

Shell Plates- The thickness can be a problem when working with bottle neck cartridges. To thick & the shoulder can not be pushed back far enough for the round to chamber. To thin & excessive cartridge head space is created, causing case head separations. A standard shell holder measures .125" +/- .001" Measure your shell plate at each station, each could be different.

 

[Cool Tool]

Here's the setup. I'm loading for 2 squirrel rifles on a Dillon 550 with the goal of being able to produce 1/2 minute-of-squirrel ammunition in mass. Both rifles are chambered identically. Redding Full Length Sizing die is the only sizing step. Formed 20 cases to load and shoot a few times to check for gremlins in the setup. Firings 4 and 5 led to case separations.

Accordingly, the detective work began. Both rifles just BARELY close on a GO gauge. I wouldn't even call it resistance in the last tiny bit of handle travel, but you can just barely feel the gauge. I put the go gauge in the full length sizer and the head protrudes roughly 0.134". I say roughly because I used the caliper like a depth gauge from the go gauge head to the bottom of the die, not very precise. The problem is, the Dillon pushes all but 0.120" of the case into the die. Anyone have a quick solution besides backing the die out and using the linkage stop to stop the up-travel of the ram? Long term fix will be a custom die.

Thanks for your time!

Let me get this straight you have a go gauge that protrudes .134 out of die an your case protrudes .120 after resizing did I read this correctly.

 

[Ein]

Shell Plates- The thickness can be a problem when working with bottle neck cartridges. To thick & the shoulder can not be pushed back far enough for the round to chamber. To thin & excessive cartridge head space is created, causing case head separations. A standard shell holder measures .125" +/- .001" Measure your shell plate at each station, each could be different.

Yeah, mine is .119-.120 at each position.

Chuckshooter, Nevada. A squirrel shooters paradise.

 

[Ein]

Let me get this straight you have a go gauge that protrudes .134 out of die an your case protrudes .120 after resizing did I read this correctly.

Gauge protrudes .134, shell holder is .120 from top to casehead datum. Consequently, if sized to shellholder contact, shoulder is pushed back .012". Clear recipe for separations.

 

[chuckshooter]

I will sometimes use the redneck method of checking my cases for proper sizing by adding a piece of cellophane tape to the head until the bolt is starting to show resistance because isn't the goal that the case fits properly. then I adjust my die accordingly.

 

[chuckshooter]

you never did say the cartridge other than wildcat, I know I had a great deal of problems with my 20ackley bees at first because the reamer was a 40 deg shoulder and the die was a 30deg shoulder, reamer company sent wrong print originally but finally got problem solved with a Whidden custom die. and never order reamer again without a copy of the right print in hand. the left print just doesn't work.

 

[Sheldon N]

As others have stated, the dillon press is not made to have hard contact between the dies and the shell plate holder. Not only is that going to give you bad sizing, it's also going to flex all the other dies off axis. Just run the press up to max height, back the die out until the headspace is set properly, and it will work great for exactly what you're trying to do... and you won't have case head separation problems anymore.