I recently purchased an FN P90TR, and it's a really fun little rifle. However, Dillon doesn't make a caliber conversion kit (shell plate & tabs) for this cartridge. Obviously the Dillon powder funnel "A" for .22 caliber cartridges will work, but without a shell plate I still can't reload this round.

I've been digging through the specs on several similar cartridges, and I think the .22 Hornet shell plate will work for the 5.7x28mm. The .22 Hornet has a base diameter of .298 in and the 5.7x20mm has a base diameter of .313 in. The rim diameters of the cartridges are a bit further apart though, .350 in for the .22 Hornet & .307 for the 5.7x28mm. In theory, if base of the 5.7x28mm fits snugly within the opening, and there is enough rim under the lip of the shell plate to hold the round in place, it just might work.

Before I go out and buy this shell plate, do any of you more experienced reloaders see any obvious flaw in this reasoning or have any of you done it?

Also, does anyone know anywhere one can buy brass for this cartridge?

My son has a FN PS90 that we have done some reloading for. When I bought the dies for it, it came with a shell holder (standard RCBS type). I wanted to use my Lee priming tool and when I looked up the number for which shell holder to use, it was the same as the .25 auto. Bought one and it didn't quite work. Had to anneal the shell holder to make it soft enough to work it over. If I recall correctly, the shell holder was too tight and contacting the case in the extraction groove. Not sure if Dillon's 25 auto shell plate would work or not. I would suggest calling Dillon and asking, or find a dealer in your town who has a conversion for 25 auto and try it with some of your brass. My thought is the call to Dillon will be more productive than finding a 25 auto conversion kit about any where. Should mention that I reload for a 22 Hornet and the shell holders for it do not work on the 5.7 x 28.

As for buying brass, you may be able to find once fired but I have not seen new brass available. It has all been once fired on various web auction sites. There is a unique coating FN puts on the brass to help with extraction. You don't want to tumble the brass to clean it, rather you want to wash it with simple green or a similar mild detergent. Learned the hard way on this as the brass I tumbled to clean feed and fire great but don't always extract because the coating is gone.

I recommend that you look at fnforum.net for more reloading info.

I would second calling Dillon, I would be surprised if they couldn't reccommend a suitable shell plate.

Thanks guys, I'll call Dillon tomorrow, or just go over there with some 5.7 shell casings, I live like 20 minutes from their factory/retail store. I joined fnforum.net shortly after I got the PS90, and they do have a thread over there with what is supposedly factory specifications including powder type and charge weight for this round.

I'm surprised about the coating and wouldn't have thought of that, but I'll take your advice and clean the brass with simple green and water. I wish I knew what that coating was made out of so I could re-create it.

Again, thanks for the help.