180 Grain 357 Magnum
Posted: 03 May 2021 13:38
I've been enjoying shooting some 180-grain cast lead bullets out of my R92 lately to work up a hunting load. I started out loading them over H110 according to Hodgdon's data, and the most accurate load was right at the max powder charge listed on the website. Charges from starting load data all the way up to the maximum load data showed case head expansion (I believe that's the term for what I'm trying to describe) greater than what I've seen in my revolvers, but I had no other signs and I read that this is normal in lever actions, so I kept going. The expansion is not uniform around the case. I'm measuring 0.380" across the narrow dimension of the ring and 0.384" across the wide dimension of the ring with cases shot w/ a book-max H110 charge.
I have some IMR4227 that I also wanted to try. I shot through a ladder working from Hodgdon's min to max with the 180-grain bullets and couldn't get the bullets going fast enough to stabilize. I had difficulty keeping shots on a 3'x3' piece of cardboard at 100 yards. Then I went and found some (probably older) compressed load data from some bullet manufacturers and worked up to a new maximum that brought me from a 3' group to a 3" group. At this new book-maximum charge weight I'm measuring 0.380" across the narrow dimension of the expanded ring around the case and 0.383" across the wide dimension.
I can see my groups getting smaller as I keep working up the load ladders, so I've been doing more research and I ended up downloading Gordon's Reloading Tool and modeling some of these charges. Gordon's shows that am under max pressure with all of these loads because they use the European maximum pressure for 357 magnum (who knew). I've since read that the SAAMI reduced 357 magnum max pressure in the mid-90s and the current IMR4227 may be the same as the old H4227 which was different from the old IMR4227 which may be the one referenced in some of the older load data I was using. After reading all of this, I'm leaning towards abandoning IMR4227 and just using H110. The expansion worries me a little, though.
Is the expansion of the cases just due to the way lever actions are chambered? Am I going to have short case life shooting these loads?
I have some IMR4227 that I also wanted to try. I shot through a ladder working from Hodgdon's min to max with the 180-grain bullets and couldn't get the bullets going fast enough to stabilize. I had difficulty keeping shots on a 3'x3' piece of cardboard at 100 yards. Then I went and found some (probably older) compressed load data from some bullet manufacturers and worked up to a new maximum that brought me from a 3' group to a 3" group. At this new book-maximum charge weight I'm measuring 0.380" across the narrow dimension of the expanded ring around the case and 0.383" across the wide dimension.
I can see my groups getting smaller as I keep working up the load ladders, so I've been doing more research and I ended up downloading Gordon's Reloading Tool and modeling some of these charges. Gordon's shows that am under max pressure with all of these loads because they use the European maximum pressure for 357 magnum (who knew). I've since read that the SAAMI reduced 357 magnum max pressure in the mid-90s and the current IMR4227 may be the same as the old H4227 which was different from the old IMR4227 which may be the one referenced in some of the older load data I was using. After reading all of this, I'm leaning towards abandoning IMR4227 and just using H110. The expansion worries me a little, though.
Is the expansion of the cases just due to the way lever actions are chambered? Am I going to have short case life shooting these loads?