I have the typical Colt 6920 so what is the best either reflex or holographic sight that will clear the front sight? I appreciate the input. I would appreciate a cost effective one.

Probably going to be tough to find the “best” one cheap.

Best and cheap don't mix but for the money the Sig Romeo 5 and a good 1/3 witness mount will get the job done.

Doesn't have to be cheap per say. I guess cost effective was bad wording. It more to benefit my son. He likes to shoot the AR but has trouble with the iron sights.

Any 2MOA or better reflex sight would be good, such as the Romeo 5. The only downside is if you use a magnifier, the red dot will still be at 2MOA, meaning it'll appear x times as large, where x is the power of the magnifier. A holographic sight doesn't have that issue with the aiming dot (a 1MOA dot goes to 1/x MOA with a magnifier), although the circular part of the reticle will appear x times as large. The cheapest you'll find a holographic sight at most retailers is around $400, although I picked up an EOTECH 512 on eBay for $340. A good reflex can be found for around $100 (that's what I paid for a Romeo 5).

I appreciate the help fellas. The Romeo seems pretty decent and one I thought about before. Hopefully it will help my boy out with finding the target better!

Those Holosuns are getting pretty good reviews.

https://www.amazon.com/s?k=holosun+507c&gclid=EAIaIQobChMI39b6or_c5wIVwZyzCh2g5AUsEAAYASAAEgI5XfD_BwE&hvadid=409991207198&hvdev=c&hvlocphy=9011825&hvnetw=g&hvqmt=e&hvrand=18002029105463231962&hvtargid=kwd-454685918295&hydadcr=9653_11535436&tag=googhydr-20&ref=pd_sl_66xw8v769g_e

I’d suggest figuring out what you want to spend. As others stated, the Sig R5 or Holosun are a good start. Your requirements are going to change as you go. I’d start there.

“Cost effective” can mean a lot of different things to different people. Pick your price range and go from there.

Where in pa are you i have a sig romeo 5 , lpvo, acog etc . If your near lewistown id be happy to let you check them out at the range.

I have a Colt LE6940 and the model you have is rated one of the best AR makes you can buy, not to mention that Colt stopped making them due to I guess being in Connecticut. If you want quality then you have to except that quality Reflex sights, aren't cheap just like glass. I use an EOTech I got through military/LE sales. I had a Sig Sauer before that. You can go on an Auction website and sometimes get lucky. Crimson Trace makes a $200 model that is pretty good, then there is Sightmark. I've heard they are good for the money to Chinese trash. The Sig Reflex I had was made in China also and once zeroed it was great. If you want cheap I shot my buddies M&P w/ a Sightmark and it was like any other reflex sight. I know what I'm getting with the EOTech which I used in the Army for CQC and they had a class action and fixed the issues. I ran an ACOG w/ an MRO in Iraq and Afghanistan. I'm not sure what your budget is but do research and save. You bought a 6920, at least your not asking about glass for a 300 Win Mag.That is what I'm saving for now.

If you want something a little up market from a Romeo 5, I’ve looked through a Romeo 4 and it was pretty nice. I also have an MRO which has been fantastically reliable and a big objective lens which has its advantages. Price of either sits between a Romeo 5 and an aimpoint. Holosun could be a good option especially if you are interested in a circle dot reticle.

I have the Holosun 510c Elite, absolutely love it!!!