Well, I can attest to the OCL cans. I helped them do pre-production T&R on the Hydrogen-S and Hydrogen-L .30 caliber cans back in 2022 before they released them. I actually have serial # 1 of the entire Hydrogen-S line, and # 5 of the Hydro-L cans.
They absolutely ARE every bit of the hype. What you hear about them being awesome cans, is 100% accurate. The TBAC tests have proven it on several occasions. I have 4 of the OCL cans now (Polonium 5.56, Hydro-S 6.5mm, Hydro-S 7.62, and Hydro-L 7.62), and will have more in the future.
Don't overlook that Polo-30... Nothing will touch it in the sub-$700 category. The same goes for the Polonium 5.56 cans...They will not be beaten for the price, and are one of the quietest 5.56 cans on the market...And at one point, they WERE the quietest 5.56 can on the market for a LONG time. Might still be, just haven't checked PEW Science in a while.
The best .300 BLK suppressor I've used to date is another one of the OCL cans, but it's a bit outside of your price point. If you don't mind spending a little extra for a MUCH quieter can, then I'd suggest spending the extra money on the Hydrogen-S 7.62... It is ridiculously lightweight, and has 3 more baffles in it than the Polonium...