This. If your barrel isn't 1:8 or faster, it likely won't shoot 77 grain bullets well.
Looks like all of Maple Ridge's barrels are 1:8, so you should be good? I have an S&J stainless match barrel on mine, also 1:8. I'm looking at picking up some heavier bullet ammo and see if I can find something that it likes. Accuracy with surplus 5.56 and Norinco ".223" (With a military headstamp. Super convinced that it's .223 remington and not 5.56 Nato, lol) was pretty meh. Good enough for 3-gun, but not great by any means. I also only have a 1-6 strike eagle on it, so not an ideal reticle for attempting to shoot tiny groups. I ordered in a 4-16 for accuracy testing, so that will hopefully help a little bit.