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Bman
12-02-2005, 11:33 PM
In a thread about square cut 452424 moulds I asked what the difference was, other than the grease grooves, between the original Ideal square cut and the early radiused 454424 moulds. The one I have is the radiused mould. 45 2.1 clued me in. After some searching I found Glen Fryxell's artical on Hand loads. It looks like my bullets are very slightly longer and 10-15 gr. heavier than the original but otherwise have the same features. At least when sized all my driving bands are .453 and just a tad wider than the original.

I realize the weight distribution, bearing surface and crimp groove to meplat etc. do effect performance or we wouldn't have so many different and similar designs.

My technical Q is this do these changes make that much difference in performance with this bullet?

Char-Gar
12-02-2005, 11:51 PM
You have asked a very good question.

Keith was convinced the extra lube carried by his square groove was important. He go so frosty about the changes Lyman made, he recommended folks buy molds from Hensley and Gibbs. Later apostles of Keith are convinced the bullets with the square groove resist deforming better than those with the radiused grooves.

I don't pretend to be an expert on anything, but I have shot 452423 with square and radius grooves, 454424 with square and radius grooves and 429421 with square and radius grooves. I have fired many thousands of these bullets over the past 40 years.

If there is any difference in bullet performance due to the groove shape, I have never noticed it in real world shooting. Glen Fryxell reports the same experience.

Given a choice I would choose the original Keith square groove, but that choice is not based on any proven superior performance.