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Please explain your entire sequence for this process...inquiring minds & all that $hit....


You mean to tell me that not everyone reading this thread is 'cracked up' by my post? You don't know everything useful there is to know about handloading already? Someone is actually interested in advanced handloading techniques? Imagine that....even if I'm a Texan. wink

I prefer Lapua .308WCF brass, but any quality unfired brass works. I lube the case with the old Imperial Sizing Die Wax and run it into a cheap gun show Lee 7-08 FL die to reduce the neck a bit. Then into the .22-250AI die to set the shoulder back. If you're sizing for a standard .22-250 then you'll probably have to do this in stages since the .22-250 case has a lot of taper and is more difficult to size down in a single pass. Care in this step saves cases.

Now trim the case back to .22-250AI length. Seat a bullet and measure the loaded neck diameter. Compare this to a fired .22-250AI case neck diameter - this is the maximum you'll want for a loaded neck diameter (unless you have a chamber cast of your neck area) since it guarantees clearance. Turn the necks to obtain the loaded neck diameter you want. Only you can decide how "tight" you want the neck, if at the max then you'll have to check the loaded diameter often to make sure you are still safe - pinching the bullet in the chamber with a too-tight neck makes chamber pressure soar (this neck thickening is much less of a problem with the AI case shape).

The result is a rifle that acts like it has a custom tight chamber. This means less radial expansion for improved concentricity, longer case life, and improved accuracy in most rifles. The accuracy improvement will depend on the fit of the original chamber with factory .22-250 brass and on the overall quality of the rifle. This is a lot of trouble for a rusty 1975-vintage M788, but on a real varmint rifle it's worth the trouble to me. A lot cheaper than a new barrel...

I've never tried using 7-08 or .260 cases to begin with, they may work just as well with less neck turning. I started doing this long before the .260 brass was available. Thanks for the interest.


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