I have just bought some Alliant Reloder 11 powder and am having trouble finding loading data for it. I have been told to use the same amount as for Reloder 12. This seems logical,,, but?
Has number 11 been replaced by number 12?
Any information would be greatly appreciated.

I believe Reloder 11 and 12 are different formulations. You have some pretty old stuff, but that doesn't mean that it's not good. Here's what I found:

www.huntchat.com/showthread.php?threadid=43461

You'll need some older reloading manuals; you could also go to Alliant.

First of all, years ago when Reloader 11 was being produced, the owner of the powder company was Hercules, not Alliant. Secondly, Reloader 11 is only related to the current Reloader line by ownership succession, not chemically. The Reloader line at the time 11 was being made was manufactured in the U.S. and was a double base powder. The current line of Reloaders are made by Bofors in Sweden (although I believe that the recently introduced RL-10 is from another manufacturer and is perhaps domestic in origin).

Look in reloading manuals from the 1970s for RL-11 data. If you don't have any such manuals available, drop me a PM with the cartridges you wish to load and I'll send you some info from yesteryear.

By the way, if you run across any Reloader 21 (often styled on the label "RxelOdeRx-21" with pharmacy symbols as the first and last letters and a large, stylized target "O" in the middle), it is of the same generation and is very different from the current line. It would have been much faster than RL-22, even faster than RL-19. It was usually abbreviated Rx-21 in the loading manuals.

RL-7 is the only powder carried over from those days in the current line and although its burning characteristics pretty well match in both incarnations, I think its chemical make up is different.