I promised a shooting buddy I would do this and finally got around to it.
The factory provided end cap doesnt sound much different than the accessory product end cap with a 556 sized hole.
The recoil pulse on the 556 end cap is floppy and pushes the barrel around in an arc.
The recoil pulse on the factory end cap feels straight back.
I put the factory cap back on the second suppressor and perceive no compelling reason for anyone considering this mod to purchase an alternate cap.
My observations were made with hot 22-250 reloads with a 19" barrel.
@RandoneeView attachment 864058