I am interested in purchasing a scope for my 15-22 and want to keep the existing iron sights on it. Who makes a scope (on a riser?) where I can mount and keep the existing sights on. No special requirements on the scope (red dot or magnified) and would like to keep less than $100. I have looked briefly at Primary Arms.
I replaced the factory irons sights with magpul flipups on mine so I could run a scope (3-9x40 nikko stirling $84) with med rings (weaver 1inch medium $10 at walmart pn-49046) on a 1inch riser (about $12) without removing the sights. I would try and keep it as low as you can above the barrel
You don't need folding sights with a red dot sight mounted at the proper co-witnessed height which is with the "M4 Spacer". About 1/2" higher than what usually comes with the inexpensive clone dot sights.
A telescope will mandate a folding rear sight if you want any sort of consistency in trajectory vs. the iron sights. The optics will generally ignore the front sight post.
The high trajectory of .22LR requires hold over/under even when zeroed at 50 yards where it peaks.