In regards to using a recoil reducer(Garmil), I didn't buy one but I filled a thin sock with about 3000 .177 bbs from Walmart and stuffed it in the stock (total cost was 9 dollars for 2 socks and 6000 bbs). It still has a little bit of room and the exact number is unknown. Weight wise I would say about a pound and a half. I took my M3000 out for the first time since picking it up a couple of weeks ago. I forgot to pick up some sub 1200 fps shells so 1200 was the slowest I had.
Here is what I shot out of it in order of what was fired:
25 - Estate "Game and Target Load" 1 oz 8 shot 3-1/4 Dram 1290 fps (No issues)
25 - Winchester "Super X Upland and Small Game" 1 oz 7-1/2 shot 1290 fps (Multiple extraction issues, but I attribute it to the rim of the shell, it was quite a bit more rounded than the others)
25 - Remington "Game Loads" 1 oz 7-1/2 shot 1290 fps (No issues)
25 - Winchester AA "Super-Handicap Heavy Target Load" 1-1/8 oz 7-1/2 shot 1250 fps (No issues)
25 - Federal "Blue Box Target Load" 1 oz 3 Dram 7-1/2 shot 1250 fps (No issues)
25 - Federal "Bulk Pack Field and Target Multi-Purpose Load" 1-1/8 oz 3 Dram 7-1/2 shot 1200 fps (No issues)
10 - Remington "Gun Club Target Loads" 1-1/8 oz 7-1/2 shot 1200 fps (No issues)
I stopped at 10 of the Remington "Gun Club" because to be honest, my shoulder was not liking me at that point.
This was with the stock pad (waiting for my new one to come in), added weight in a sock stuffed in the stock, extended magazine tube and loaded the gun with 10 + 1.
I tried shooting from the hip and had no issues at all. Next week or so I am going to try and get some 1145 fps stuff and see how that works out. I seriously doubt it will cycle the sub 1000 fps low recoil low noise stuff with or without the added weight, but I'll try it if anyone wants to know if it works.