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Joined: 08 Feb 2009 Posts: 1308 Location: Western WA

I have figured out how to comfortably fill 2 1/2" shells with 1 1/8 oz of lead by using the Hartin crimp method. Hint: Rem hulls and SP16 wads.

The OAL of the loaded Hartin crimp round is the same as conventional 2 3/4" shells but the empty hull is 2 1/2" so it properly chambers and ejects from the 65mm A-5.

So the question is whether the pressures from the load tables for conventional rounds are valid for identical rounds with Hartin crimps. In other words, does any pressure test data exist which confirms that the pressure from a Hartin crimp round is the same as the equivalent conventional fold crimp round.

BTW implementing the Hartin crimp procedure was not straightforward, and required careful tuning of the MEC 600 jr setup along with some extra finishing steps. But the results are splendid.

TIA

Brewster

Brewster11 -- Somewhere I have the original article by Hartin on his crimp. I can't find it now. He did it to make 2 1/2 inch 12 gauge shells. He was using typical 1 1/8 oz and 1 1/4 oz loads as I recall, He loaded all the same components in both star crimped CF Win AA's as well as Remington STS's, if I recall correctly. Paradoxically, he found lower chamber pressures and higher velocities! You can never tell exactly the conditions of the tests, because folks aren't so "scientific" about their methods. For my own part (and this is purely my own speculation), I believe pressures would be slightly reduced as found in roll crimping, and velocities would not be reduced in any significant amount unless very slow powders and heavy shot loads are used. That is to say, if you used Green Dot or International with 1 ounce loads or less you'd probably see very little internal or external ballistic difference. If you used Longshot and 1 1/8 or 1 1/4 ounce loads you'd probably see the difference, but it would be not detrimental overall. Again, this is speculation, and only testing (a lot!) could prove any of this -- I could be just plain wrong (but I doubt it Shocked

).

Joined: 08 Feb 2009 Posts: 1308 Location: Western WA

Max,

Thanks for the info.

Brewster