ASK THE GUN EDITOR
Letters containing questions for answering by Nick Harvey must be accompanied by a stamped self-addressed envelope. Mail your letters to: The Technical Editor, 3 Reef Street, Hill End, NSW 2850.
Variation In Powder Burning Rate
Q I dug out some old canisters of Du Pont IMR4320 powder I’ve had in storage for years. It was the best powder for use in the .17 Remington and original .22-250 Ruger, so I thought I’d use it up in my new Browning .22-250 with the 55gn Hornady V-Max. My old load was 34gn with the 55gn Hornady soft-point for about 3540fps, but that same charge in my new rifle gave barely 3340fps. Is it possible that the powder has lost some of its punch due to its age? Or is it caused by the difference in the two rifles?
Fred Potter
You’re using IMR 4320 in your .22-250 reminds me that I have six cans of older IMR 4320 here, and every one I’ve opened gave lower pressure than it did when the powder was new and hence lower velocity. I don’t know the exact age, but as they get older I believe some powders do lose some power. Funny thing though, I have a good many cans of the old original ex-military H4831 and that old standby powder varies very little despite its age. In fact, I recently duplicated some loads of H4831 for a mate’s
