Pressure Too Low
Q: A friend of mine gave me a load consisting of 35gn of W-760 for my Howa .22-250 with the Sierra 55gn bullet. I didn't have any 55gn bullets but I did have plenty of Sierra 50gn bullets, so I tried his load with these bullets thinking there would be no danger since I was using a lighter bullet. Boy did I get a surprise!
There was a lot of smoke when I fired the first round and when I extracted the case from the chamber, it was smoked black on the outside. I am wondering if the load he gave me was too hot for my Howa. I only own one reloading manual and it's a very old one.
A: The reason you got smoke and a blackened case was not caused by too-high pressure. The load wasn't powerful enough to cause the case walls to seal against the chamber. Gases leaked around the outside of the case, causing smoke to come out of the action and blacken the outside of the case.The load you used is way to mild for the powder and bullet weight you used. About 40gn is more like it for a 50gn bullet in the .22-250. You should getyourself a current reloading manual.
Never assemble and fire a load which has been passed along by a friend without first checking it in a reliable loading manual.
Past experiences with my mate's reloads has convinced me never to fire someone elses reloads.