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View Full Version : How I convert centerfire cases to rimfire



ndnchf
04-24-2021, 09:17 AM
There has been a lot of interest in the rimfire cases that I make from centerfire brass. Since I'm in the process of making 10 more .44 long rimfire, I made a two part video on the process I've come up with. Maybe this will inspire you to makes some of your own :-)

https://youtu.be/MeQcElAGCBE

https://youtu.be/Fxz9s9kjflI

ndnchf
04-28-2021, 01:07 PM
A follow up to the process of converting centerfire cases to rimfire. When making the new offset rimfire primer pocket, the hole is finished with a .224" diameter reamer. This gives the .225"- .226" diameter acorn blanks a press fit. This is good to minimize gas leakage when firing. Sometimes the acorns can be thumb pressed into place, other times it takes a bit more pressure to seat them.

After chewing on it a while, I came up with a way to seat the acorns in the loading press. First I rummaged through my dies to find one that the .44 long rimfire case would slip easily into, yet the rim would seat against the bottom. It turns our that a .45acp sizing die was perfect.

Next a flat topped ram was needed to press the acorn into the pocket, flush with the back of the case. Basically a replacement shellholder, but with a smooth flat top. The critical measurements were taken off an RCBS shellholder. Then over to the lathe to turn it out.

I just primed 20 cases and it worked great.