Putting together a 223 bolt gun, paper puncher maybe a little Varmint or deer hunting also, optic budget is $500ish 4-X x40 type optic I’m thinking, prefer some type of. BDC/Mils something other than a duplex, I’ve got a Leupold MK IV  on another gun I love but that’s not really in the budget, How are the Nikon blacks?  Think I saw a Monarch and Pro Staff 5 also?  Side focus is a must.

Will you solely rely on the reticle or do you dial holdovers with your turrets?

I’d prefer to use the reticle, but neither is set in stone

You can find the Leopold VXR patrol in 3x9x40 in that price range.

Checkout the new Primary Arms 3-18x. It has sever reticles and you know PA knows how to make good BDC reticles. This scope also has a nice MIL and MOA reticle, the Athens and Hera. It’s $500.

or the PA 4-14x44  Many different reticles and ~$240.  Check Amazon before you buy direct from PA.  They have a store on Amazon and Prime will save you the shipping cost.

+1.  Came here to suggest the Leupold VX-R Patrol 3-9x40mm.  It is mil/mil matching turrets and reticle.  The TMR reticle has finer 1/2 mil intermediate hashmarks, making holdovers more precise than with a mil dot reticle.  If you do decide to dial elevation or windage, the turrets do track true.

It has the amazing motion-activated Firedot illumination system.  The dot can be made daylight bright should you need it.

Battery life is insanely long - several years left on 24/7 with typical use.  Mine is 4, almost 5 years old now and I've replaced the battery only once.

Glass is up there in VX-3 level.  It's a very good scope at its price point.

As others have stated, the Leupold VX-R Patrol 3-9x40 is an excellent scope, especially if you want illumination.  I have one on my lightweight SPR build and like it so much that I just bought a 1-4x VX-R for my pistol.  Good deals can be found on eBay if you search around.

However, if illumination isn't important to you and you want a little extra magnification, you might want to consider some of the Weaver Grand Slam scopes.  I don't have first-hand experience with them, but in all of my research they were right up there in consideration with the VX-R, Vortex Viper, and SWFA SS scopes that I was comparing at the time.  They are made in Japan, and I have read that the glass quality is very good for the price.  They have 3-12x, and 4-16x versions in the $500 range, and I think the 3-10x is much less.  You'll just need to see if any of their reticles will be useful to you (they have some traditional Mil-Dot, and some other more unique options).

Speaking of the others, SWFA and Vortex make similarly priced optics that are good quality.  If you extend your budget a bit, the SWFA 3-15x42 FFP scope is on sale for $699 WITH over $300 in extras including a really nice Bobro mount.  It's on the heavy side, but is built to last.