Spring change with rail and optics

Ordered a Rock River bullseye rib and an Aimpoint Micro yesterday.
I am still using the stock spring in my gun. Wondering if I will need to change the spring and if so, lighter or heavier?

Lighter. What load are you using? For 3.9 BE under 185 LSWC a 12 lb spring should be pretty close.

4.1 gr BE with a 185 gr LSWC

i use a 12lb. you could probably use a 14, but order a 12 and a 10 also--just in case.

probily more like a 11, but the only way to know is to shoot it then use the strongest one that still functions 100%

I'd also look at getting a variable rate spring instead of the conventional.

Well unfortunately the bullseye rib is on backorder from Rock River. The Aimpoint is pretty awesome but all I have right now to mount it on is my 10/22.

If you are referring to the rra bullseye rib, with the sights, it is quite heavy steal, 6oz I think. I have one on a range officer and I am using an 11# spring that was bought with the rib sight from RRA. I use the 200g swc w/4.0 of bullseye with a 1" UD, and 3.6 without the UD. It has functioned w/ the lower charge amout with the UD, but I bump it up to 4 for insurance. If you are getting the aluminum rail, then disregard.