Standard recoil handles 147s well. When you put a can on it, the back pressure increases, sometimes a lot; causing the bolt velocity to increase to a point that stripping the next round off the magazine happens too fast and the bullet nose slams into the feed ramp at too shallow an angle. he should've tested his rig a bit more. If it needed a different recoil spring, it'd be heavier, not lighter, to slow the bolt velocity down and get it back in timing giving the round a chance to rise a bit more on the loading sequence and hit the feed ramp at the design spec angle.
Not potato. It's just one of those things where changing one variable throws off the finely tuned balance of things. Cans do funny things and this is never more so than with pistols; especially ones that use tilting barrels in recoil operated systems, like Saint John Browning designed.
I've got a couple of .22 autoloaders that are super reliable and accurate without a suppressor, but put a can on it and one shoots way low and right and gets super picky about ammo. The other one is similar but not as dramatic. Pisses me off actually since the can is just a fancy piece of tubing with baffles in it that costs more than both guns combined and it useless in that application. On rifles, it's deadnuts accurate and quiet. Can science. Voodoo is more like it.
Prefer the version with the rake.