It is important to note that the ejector for this platform is the left side feed lip, just like every other firearm that uses 10/22 style magazines.
Below are notes regarding our results with PSG 22 compatible magazines.
Ruger Rotary 10Rd AKA BX-1:
Most consistent but should be cleaned on a regular basis. Factory spring tension can be inconsistent. If the magazine is not dropping free it is due to inconsistencies in the mold of the magazine. A light 30 sec sanding on each side of the mag will reveal the high spots and then the mag will drop free no problem.
Ruger BX-25 / BX-15:
Known for inconsistent feeding and feeding related issues. The springs are inconsistent and get bound up and just in general are not linear. The only solutions for this are the quick fixes found online with a quick google search of BX-25 feeding issues or just trying out several mags till you find one that works well. Also, the ejector on this magazine is the smallest ejector on any mag we have tested. This leads to issues with ejection. The BX-25 is also the narrowest magazine and has side to side play.
Butler Creek Steel Lips:
Same issues with spring tension as BX-25. When buying new ones you can usually break it in by loading the magazine and letting set for 48 hours, unloading and repeat. Unfortunately, these mags are friction welded together so cleaning them is not really an option. These magazines tend to feed well and also have the biggest ejector out of any of the mags that we have tested.
Butler Creek Hot Lips:
Have plastic feed lips and are not recommended. Any 10/22 magazine with plastic feed lips like the old Ramlines and Promag mags are also not recommended. The plastic feed lips wears out due to the feed lips doubling as the weapons ejector.
Very smooth-running magazine, no spring tension issues in our experience. This magazine also has a very large ejector and is the tightest fitting in our mag well. They are friction welded and they are not very consistent, but they always lean on the wider side.
GSG Drum Mag:
Ours had horrible spring tension issues and we never could get the rounds to present well and could not do much testing with it.
In testing a variety of the Promag magazines we noticed that every mag had different feed lips and ejectors. This caused major feeding and ejection issues. We never could get the rounds to feed and eject consistently and could not do much testing with them.
Any other magazines on the market we have not had the opportunity to test.