jeesh, has so much money shooting it up :p

16" and 18" are just fine, imo. I had a friend who built an AR on a 16" barrel and took it a sniper competition with me. He was making successful hits at 500 yards.
Any farther than that then I would recommend a heavier caliber.

wow 500 yards, I can not even think out that far! Super cool. We have range that goes to 1000 yards, I took a buddies rifle set up for the course and tried at 600 yards couldn't hit SH*T....very cool to hit something that far out!

I got lucky. I hit a bowling pin at 600 yards, known distance. Another time at a timed event, unknown distance, I manged to range and hit a steel plate the size of a torso, also at 600 yards. Both with a scoped rifle.
That's a warmup distance for someone like pig, though.

Yup, 500 would be a stretch. Not really any ranges out here that are past 300yds without doing a "special" event ($$$$$). So, at 300yds I think i will be just fine with the 16" or 18".

Oh Tony.... What power scope did you guys run?

I ran a Luepold Mk 4 3.5 X 10. But, that was more set up for the. .308. He ran something diferent. He's since retired. I'll find out, though.

mighty cool
 

Way way way back in the middle of the last century the USMC took my dead eye dick 22 caliber bolt action rifle away from me in exchange for a skunk greased, nearly 11 lb. w/ bayonet (the only attachment) piece of iron sighted ugliness, named the M1 with the instructions to be careful of my thumb. I was still trying to figure out how not to be one of the last 5 recruits down the ladder at 5am thereby earning the privilege of running circles around the platoon during our still dark 2 mile "build an appetite" run before breakfast. A few weeks work on the boat anchor turned it into fine looking weapon. I was proud when my Drill Instructor took my stocks for his rifle when we graduated. I had no idea what a wonderful piece it was until we hit the rifle range and I surprisingly found I could center punch Baker targets not only prone but standing offhand from the 500 yard line. My DI thought it was a stupid pet trick to show up other DI's. It was the rifle not the shooter, although everything my dad had taught me about safety and marksmanship were gospel. Today's weapons are so different. Are they as much better as I think and as they look? I need to find out. I have been away from long guns for way to long.. Congrats on your build. Do NOT forget the chocolate s'moores attachment. Everyone likes desert.

All right, I got an answer for you. My buddy used a Leupold 2.5 X 8.

Ok thanks, I'm thinking I would run at least a 4 power. A 3 x 9 should be fine for my 300yd target.