Harry O
09-08-2009, 08:16 PM
I tried an experiment and it shot better than ever.
I bought a second Rapine 41LC 386185 mould at a good price a while back. I was hoping to use both of them alternately to speed up casting. It did not work. The center pin cooled off too much doing that, which gives voids at the point of the pin. Besides that, the two bullets were different enough that they would have had to be separated (about 10gr difference between them). The tapered part of the pin was a different length. Back to one mould at a time.
After thinking about what to do with with the second mould I decided to shorten the center pin and increase the weight of the bullet to about 210gr +. The hollow-base bullets are fairly light at 188gr vs several of the heel-base that are 210-213gr. I figured what I would have to take off to get it up to about 210gr and machined off that amount. Unfortunately, it came out heavier than I wanted (about 245gr). A washer the right thickness in the right place lengthened the pin a little bit and it started casting right at 218gr, an increase of about 30gr.
I loaded up 50 of the original 386185 with 18gr of Swiss 3F powder (my standard load with this bullet). Then I loaded 50 of the 218gr version with 17gr of Swiss. Then I took them to the range.
After shooting 24 rounds with the 188gr version, I cleaned the gun and shot the 218gr version. The heavier bullet was shooting groups about 2/3 of the size for the lighter bullet. After 24 rounds with the heavier, I cleaned the gun, switched back, and shot up the remainder of the 50 lighter bullets I brought. Then I cleaned it again and finished off the heavier ones. Still smaller groups. All was offhand at 7 yards.
I am definitely going to cast up some more of the heavy hollow-base and do some bench work at 15 yards (where I have my data on other 41LC experiments) and do some serious measuring. It is VERY close the the best groups I have gotten so far (with a heavy Old West heel-base bullet), and may even be a little smaller. Time will tell.
It was a good day.
I bought a second Rapine 41LC 386185 mould at a good price a while back. I was hoping to use both of them alternately to speed up casting. It did not work. The center pin cooled off too much doing that, which gives voids at the point of the pin. Besides that, the two bullets were different enough that they would have had to be separated (about 10gr difference between them). The tapered part of the pin was a different length. Back to one mould at a time.
After thinking about what to do with with the second mould I decided to shorten the center pin and increase the weight of the bullet to about 210gr +. The hollow-base bullets are fairly light at 188gr vs several of the heel-base that are 210-213gr. I figured what I would have to take off to get it up to about 210gr and machined off that amount. Unfortunately, it came out heavier than I wanted (about 245gr). A washer the right thickness in the right place lengthened the pin a little bit and it started casting right at 218gr, an increase of about 30gr.
I loaded up 50 of the original 386185 with 18gr of Swiss 3F powder (my standard load with this bullet). Then I loaded 50 of the 218gr version with 17gr of Swiss. Then I took them to the range.
After shooting 24 rounds with the 188gr version, I cleaned the gun and shot the 218gr version. The heavier bullet was shooting groups about 2/3 of the size for the lighter bullet. After 24 rounds with the heavier, I cleaned the gun, switched back, and shot up the remainder of the 50 lighter bullets I brought. Then I cleaned it again and finished off the heavier ones. Still smaller groups. All was offhand at 7 yards.
I am definitely going to cast up some more of the heavy hollow-base and do some bench work at 15 yards (where I have my data on other 41LC experiments) and do some serious measuring. It is VERY close the the best groups I have gotten so far (with a heavy Old West heel-base bullet), and may even be a little smaller. Time will tell.
It was a good day.