7.62x39 reloadable brass differences

I may be reloading 7.62x39 for my AK47. I have heard that reloadable brass comes in 2 different primer sizes ie: large and small rifle primers. Is this true?

Yes it is true. The vast majority is in large rifle size but Remington and they are the only ones I know of who loads it using small rifle primers. All the others use the large primers.