Hi David and welcome. One of the best is the 5.56/.223 calibrated Bushnell AR 1x8 Scope for close up and distance work; -- budsgunshop.com/product_info.php/products_id/104966/bushnell+ar+optics+1-8x+24mm+rifle+scope ---------- It is calibrated for 5.56/.223 Bullet Drop at distance. Cheers, stay safe and enjoy!

Hi David, the Vortex Strike Eagle 1-8×24 FFP is highly recommended for the Ruger AR-15 5.56 due to its versatility and excellent glass quality, making it suitable for both close-quarter and medium-range shooting. Other good options include the Trijicon ACOG TA31 and the Primary Arms GLx 1-6x24 FFP, depending on your specific needs and budget.
Stay safe & have a great day!

Good evening to you!! See the links below for suggestions in the low range, mid range and high end. Hope this helps. Have a good rest of your day.
🇺🇸🇺🇸 'Merica' 🇺🇸🇺🇸
budsgunshop.com/product_info.php/products_id/27112/burris+rt-6+1-6x+30mm+matte+rifle+scope --
budsgunshop.com/product_info.php/products_id/100968/sig+sauer+sierra3+bdx+4.5-14x+44mm+rifle+scope --
budsgunshop.com/product_info.php/products_id/59376/trijicon+accupoint+1-4x+24mm+german+4+crosshair+green+dot+reticle+rifle+scope

It definitely depends on use and budget! Defense or long range? Good choices are: Trijicon ACOG, Vortex Strike Eagle or even a Sig Romeo 5.

The best scope for a Ruger AR-15 (5.56 NATO) depends on use, but top choices include the Trijicon ACOG 4x32 for rugged versatility, Vortex Strike Eagle 1-8x24 FFP for ranged flexibility.

It depends on your shooting. I grew up on 3-9x40 scopes. They do well for my shooting. My son wants a 1-4 power scope for his AR-15. It really is all personal.