I'm building my first AR, a 24" varmint.  I've been looking into sights and scopes and trying to make a decision.  I have a Weaver K3 scope off an old hunting rifle which is in great shape, and which I think would suffice for 100-yard shooting which is probably what I'll be doing most, other than when I'm out in enough space to shoot further.

If anybody has any suggestions, I'd appreciate it.  If I keep the Weaver I'll be looking for rings, and am not sure what to look for.  I'd also like to pick out a good set of iron sights which don't break the bank.

Thanks.

Post your question in the optics section, and you will get better results.  

I would use what I had, but then again, I would never build a 24" for 100 yard shooting (or any other shooting for that matter).

thanks. Actually I wanted to also ask at what range a varmint upper starts to become an advantage over a regular barrel.  Can you shoot the same groups with either inside 200 yards?  I'm still on the fence about the exact upper configuration and every time I read a little more I just start seeing myself building more than one gun... at least for now I;d like to think this will be the only one for a while

Quoted: thanks. Actually I wanted to also ask at what range a varmint upper starts to become an advantage over a regular barrel.  Can you shoot the same groups with either inside 200 yards?

Yes, the extra 4 inches of barrel gives you extra weight, bulk, aggravation (IMHO), and a little more velocity.  However, it is not more accurate.  If you were to see differences between the barrels, I would think it would be out much much farther.  200 yards isn't even close.  The actual differences become more apparent depending on what ammo/ bullet weight you are using, but again, its well beyond 200 yards.