It depends on the intended use. As you will lose approx. 50 fps per inch of barrel lost, you'll be dropping 200 fps going from 24" to 20". If you're thinking of 600 yard-1,000 yard shooting, go with the 24". If you want to be tacticool, call your rifle a "stick" and pretend you're a scout sniper, go with a 20".
FH
