Howdy, this is my first post. I hope it’s in a good location. I have a rock river arms predator pursuit. 20” heavy barrel, A4 upper, A2 buttstock. 4-16 scope The rifle shoots great! But I never use it because it’s heavy. It's not great to me to carry in the field, so I want a lighter, shorter AR. I think I want a 16” a4 with a collapsable stock and a light scope. I don't know if I should buy an upper and a stock or buy another AR. I don't know what uppers are compatible with the RR, and there are so many makers who is decent. I did order a 16” complete M4 AR blem. from Palmetto.

thanks for any help / advice

Welcome. Yes, this is a good place to start. What exactly did you buy from PSA? A complete upper or a complete rifle. Your RRA is compatible with any other standard AR parts.  Either keep what you have and build/buy a second AR, as two is better than one. Or sell off the parts you want to replace to fund the new ones.

If you bought a complete M4 style rifle, I wouldn't change anything on the RRA. I'd use it for benchrest, Prarie dogs, etc and set this new one up to suit your other needs

Loosing?

Seriously

So I ordered a PSA PA-15 5.56 AR-15 RIFLE 16" NITRIDE M4 CRBN 13.5" M-LOK. And have thought about buying another upper for the RR. and a collapsible buttstock. I have no idea of what brand or?