Reloading the S&W 500

[Roudy]

I'm having trouble finding information about which kind of primers to use for reloading the S&W 500 cartridge.  Some data says use a large rifle primer and others say to use a large pistol primer.  Another note that I found says that the case head will be stamped with a "R" or "LR" if it needs a large rifle primer.

My primary concern is for safety, namely the strength of the primer.  From a dimensional point of view both primers 'seem' to be at least similar if not the same.

I'm using Winchester cases and they do not have anything on the head stamp that would indicate the need for a large rifle primer.  The Winchester web site has no information about this case other than a product number and no place to contact Winchester with the question.

Are there any Gurus out there that have any insight about which primer to use??

Roudy

[Tom C.]

My understanding is that the .500S&W was originally designed for 50,000 psi and used large pistol primers. Someone got the idea to qualify it for 60,000 psi. That required large rifle primers to avoid primer flow into the firing pin hole in the recoil shield. Early .500 S&W brass was cut for LP primers. A changeover was made relatively soon after things got started to LR primers. The LR primers are the same diameter, but a little greater height, so LP primers in primer pockets for LR will be a little low and could cause misfires. LR primers in LP primer pockets could be a little high and cause hangups of the cylinder.

I have Starline brass with LR pockets. If your Winchester brass is fairly recent, it should be cut for LR primers. You can try seating a LR primer in an empty case and see how well it seats.  I use Federal 210 LR primers in mine (I think. I am at work at the moment.)

[S.B.]

Give this article a read and it may show some light on your question for you?
http://www.john-ross.net/pdfs/maghist.pdf
Steve