check shanks: stepped or straight ?

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mtngun
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check shanks: stepped or straight ?

Postby mtngun » Tue Feb 19, 2008 1:20 pm

from the old forum:

What is the difference? I'm looking at a 180gr 359 gas checked LBT type bullet.

--Ian
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Here's a pic of a stepped shank.

The bottom portion of the shank is 0.460", the normal shank diameter for 500 caliber.

The upper portion of the shank is 0.457", the normal groove diameter for 500 caliber. (update: the groove spec has since been changed to 0.455" - 0.456")

A miniature step is formed where the shank steps down from 0.460" to 0.457". If everything goes well, the step gives the crimp of the gas check something to hang onto.
Image
These particular checks went on quite easily, yet I had to use a screwdriver to pry one off for the photo, even though it hadn't been crimped on yet.

A straight shank would have been 0.460" the entire length of the shank.

IMHO, the stepped shank is the only way to go. If everything goes well, it will be more user-friendly than a straight shank. Worse case, it will work the same as a straight shank. The only time there is a disadvantage to the step is on short Keith shanks, where the step can sometimes create a narrow crevice that can cause casting problems.

As far as I know, there is no difference in how they shoot. It's just a question of which one is more user-friendly at the reloading bench.

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