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Author Topic: Crimp Bulges in 12 gauge Shotshells. Wassup with that?  (Read 3825 times)


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Crimp Bulges in 12 gauge Shotshells. Wassup with that?
« on: October 24, 2008, 02:23:07 pm »

I've got this problem reloading my 12 gauge Winchester AA hulls, 2 3/4". They seem to want to bulge UPWARD after the last crip step.

Could somebody please help with a solution?

I'm using a Lee LOAD-ALL. Everything else seems to be going okay, but after that last crimp step, the end of the shell is not flat at the top, nor depressed slightly [preferred?] but it bulges upard about 1/16" to 1/8" and that just isn't right.

All my loading specs are standard for Lyman 1 1/4 oz loads:

using IMR 800X (25 grains),

Win 209 Primer, CB1114-12 Wad, and 1 1/4 oz #4 lead shot.

Anybody else ever have a problem with this Midriff Bulge stuff at the Crimp?

Is it the fault of the Press? Is there something inside the Crimp Station on the Load All that is ADJUSTABLE?

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    Re: Crimp Bulges in 12 gauge Shotshells. Wassup with that?
    « Reply #1 on: November 02, 2008, 11:42:08 am »
    Hey Bruce,

    The short answer is:  Too much stuff in your shot column.

    There are a couple of things that make reloading shot shells a little different than reloading metallic cartridges.

    The first is that the base wad height is not necessarily consistent from one production run of a shell to the next.  The factory accommodates this when it loads, but it means that there will be minor differences for you every time you reload a shot shell.  The way for you to accommodate this when you reload is to use a load that incorporates felt wads in the shot cup.  This felt wad will be slightly compressed when you crimp, essentially taking up any "slack" in your load column.  Also, always use an overshot card of some kind to ensure a nice, even crimp.

    The other thing to remember is that different sizes of shot occupy different volumes of space for the same weight.  One ounce of larger shot takes up more space than an ounce of smaller shot because the unoccupied spaces between the pellets are larger.  Thus, if it was already a "tight" load with #6 pellets, using #4 pellets might result in a shot column that is too high to obtain a good crimp with.  Again, selecting a load that incorporates fillers like felt wads in the shot cup helps to accommodate issues like that.

    Hope that helps some.
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    Re: Crimp Bulges in 12 gauge Shotshells. Wassup with that?
    « Reply #2 on: November 03, 2008, 04:26:25 pm »
    Try to leave 7/16" above the shot charge to make your crimp with.
    Hope that helps.


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