Parker Brothers Kelsey’s Patent” Capper:
 

Received the “Kelsey’s Patent” capper tonight. Wonderful design concept. However, it will only function with 2-5/8” shells as shown in the photo. Since I load 2-5/8” shells it is useful, otherwise it’s a paper weight. It’s is not suitable for 2-7/8” shells. Shorter than 2-5/8” shells can be supported with dowel and would work well.
I’m going to cut a length of dowel to support the case when capping to eliminate potential case mouth damage. From experience, pressing the large pistol primers in the Track of the Wolf brass cases require a lot of force. Perhaps a slight reaming would help. I tried various primer brands, it didn’t matter, still very tight. I’ll find out in the next round of loading.
I snapped off the cast iron handle on a vintage hinged hand capper. I don’t care for those anyway, they easily dent the primer. I ended up supporting the case with a dowel and using another smooth ended dowel to pound in the primers flush with the case head using a nylon hammer. I’m not recommending that method, it’s not pleasant.
IF someone made a 10 gauge shell holder, my Rock Chucker press would significantly simplify the process. Thankfully I have a 12 gauge shell holder for the press.