I ordered a cheap 300 blackout upper from bear creak arsenal. I threw a scope I had laying around on it and shot it this past weekend. There were no hick ups and it was not bad accuracy. I am planning to shoot mostly subsonic rounds through it and was hoping to get a chance to play around with dialing in out past 100yds just for fun. Although I am kind of a scope snob, I am not wanting to spend much money on a scope. Midway USA has a couple that I have been considering provided they don't sell out before I make a decision. The 2 I am looking at are
www.midwayusa.com
and
www.midwayusa.com
Being somewhat of a scope snob, I have never been impressed with vortex glass but I can make an exception for the price. Truglo has somewhat of a bad reputation but the Tx6 doesn't sound bad. I am trying to keep cost as low as possible without going over $300 max.

Vortex Optics Diamondback Tactical Rifle Scope 3-9x 40mm VMR-1 Reticle
Exposed tactical turrets built for dialing elevation and windage allow quick and precise bullet drop and wind drift compensation at extended ranges....

and

TRUGLO Tx6 Rifle Scope 30mm Tube 3-18x 50mm Illuminated A.P.T.R.
The TRUGLO Tx6 Rifle Scope features a 6x zoom system with a 1/10 mil adjustments. The multi-position quick zoom lever helps you switch between short and...

Being somewhat of a scope snob, I have never been impressed with vortex glass but I can make an exception for the price. Truglo has somewhat of a bad reputation but the Tx6 doesn't sound bad. I am trying to keep cost as low as possible without going over $300 max.