I had really good accuracy using the Ranch Dog 165gr LFP dry tumbled PC'd at 1700fps in my PSA 300BLK. I had better accuracy without gas checks but YMMV.
I have hear good things about that bullet. Sometimes the cause of worse accuracy with checks can be gas checks coming off in flight, or if they were not seated straight. (One of the few downsides of powder coating is that it makes the gas check shank larger diameter, and more likely to shave coating and lead on one side when seating gas checks.) It can be hard to tell if checks are coming off though unless you can find either the gas checks on the ground or recover the bullets. Of course sometimes certain bullets just shoot better without gas checks.
Specific to the AR: just FYI you'll need to put some effort into cleaning out the piston area and gas key in your bolt carrier if you shoot many full power rounds without gas checks. Also be aware that a mid-weight bullet like that, run at full power, is a sure fire method of making the rifle overgassed. That 300 Blk AR15 system is designed around light weight full power bullets at high pressure, and heavy slow bullets at low pressure so that dwell time vs port pressure is balanced right; mid to heavy bullets at high pressure still have longer dwell time than the light bullets, but are also at high pressure, so it drives the carrier back a little earlier and harder. You can account for it with gas adjustment, but then it won't run the normal loads. Just food for thought, not telling you there's only one way to do it.