325gr 45-70 trap door loads??
- Thread starter Klunk
- Start date
The Hodgdon data site shows a starting load with H4895 to be 41.8gr for 1327fps and 13,700CUP of pressure (max of 28,000CUP for trap doors). The data is for the Hornady FTX bullet but it's very low down on the pressure scale. I've swapped cast and jacketed bullets with each others data many times and never had an issue.
The Lyman Cast Bullet Handbook is showing data for a 330gr bullet (close enough) using IMR4198 at a starting load of 34.0gr and 1440fps with 12,100CUP. I've swapped H4198 and IMR4198 at start loads without issue many times, especially for cast loads.
Max pressure appears to be reached somewhere around 1950fps with any load with that weight so work your way up with a chrony if you're looking for max velocity. Personally I prefer H4198 both because I can use less powder (I'm cheap) and so I can save my H4895 for other loads that are more picky. I'd also give Trail Boss a whirl if you can find some easily; it's a wonderful powder for cast bullets and very easy to use. You don't even really need load data; there is a process to find your own loads available from Hodgdon in a PDF.
The Lyman Cast Bullet Handbook is showing data for a 330gr bullet (close enough) using IMR4198 at a starting load of 34.0gr and 1440fps with 12,100CUP. I've swapped H4198 and IMR4198 at start loads without issue many times, especially for cast loads.
Max pressure appears to be reached somewhere around 1950fps with any load with that weight so work your way up with a chrony if you're looking for max velocity. Personally I prefer H4198 both because I can use less powder (I'm cheap) and so I can save my H4895 for other loads that are more picky. I'd also give Trail Boss a whirl if you can find some easily; it's a wonderful powder for cast bullets and very easy to use. You don't even really need load data; there is a process to find your own loads available from Hodgdon in a PDF.
