243 ar barrel questions

kato pup dog · Mar 20, 2019

I have a few questions for those with a lot more knowledge about building a 243 ar10/lr308 pattern rifle. Specifically twist rates, gas port location and optimum barrel lengths.

I already have an Aero M5 upper/lower setup with an Aero Atlas hand guard on it's way to match. I'm not a fad chaser so creedmoor is out. Already have 30cal covered so please, no go 308 crap. My hope is to run pills ranging from 85grain up to 110 or so. Will see target use, varmint use, and maybe used for a competition shoot if I can ever make it happen.

I have read of many issues relating to timing. If I run an 18 to 22inch barrel (still unsure what length I want), will the gas port need to go from rifle to rifle plus 1 or plus 2 (not finding any resources for detailed info on this, but 260 has a lot of issues)? Adjustable gas block will be run, most likely an Odin works set screw style.

Twist rates...I see everything from 1-7.5 all the way to 1-14. I have been leaning towards a 1in8, but truly have no idea what to base that gut feeling on. Researching bolt gun info doesn't always transfer to gas guns, so please keep responses relevant to gas guns and possible experience. I have run out of Google foo and ended up more confused than I began.

I know there are a few in this group who have dabbled with these.

slm9s · Mar 20, 2019

I had a dpms lite hunter in 243. LOVED it except for the 10" twist. I'm more into LR shooting, and not being able to shoot the 105 class of bullets led me to send it down the road. I think a 7 or 8 twist 243 AR would be a lot of fun, and actually do well in PRS type shooting.

kato pup dog · Mar 24, 2019

Progress so far...and after more reading, seems the 20 or 22inch 1in8 twist look the most appealing. Looked a lot at the 24inch option, but this rifle is going to be heavy enough as is. Still unsure of best gas length, but rifle gas seems the most logical with adjustable gas block.