SR-25 improvements?

AR/M4 Beyond 5.56/.223
1

Since I live in a ban state, I am considering getting pre-ban SR 25. Another option is a new (post ban) SR-25 ER. I am curious what are the changes that were made to the rifle design over the years. I assume that uppers are compatible between the two lowers as well?
My main desire for a pre-ban is the ability to have a collapsible stock, although I dont’ think it matters that much on a rifle that is mostly shot prone. Would a new SR-25 ER be a better choice?

Thanks!

2

The newer SR 25s are much more reliable than the older ones by far.
On the older SR 25s, you can’t swap around uppers and lowers. You can on the newer ones though.

3

Go with the new one, since KAC doesn’t sell updated bolts or other parts. You are better off getting the new better rifle. I live in Ban state and can’t get any KAC rifles aside from the SR30 since they are all banned by name.