My experience with the Grizz I purchased is somewhat better than B's. It did require a little TLC (polishing) on the inside to slick it up. Now it compares very favourably to my 870 Wingmaster. I have had no reliability issues so far, but I have only put about 200 slugs and 50 rounds of birdshot through it. I can't comment on the HP9 but as previously stated I am pretty sure it is the same gun from the same factory. You can check out a thread I have on what was done to my Grizz here:
http://www.canadiangunnutz.com/forum/showthread.php?t=332120
250 rounds..........so few.
I'm over 9000 rounds as of Sunday night that just passed and nothing has worn out or broken.
Had a few shells fail to eject or fail to load but it was traced to mud snow and dirt debris from throwing the gun on the ground too much and loading a lot of dirty shells that I dropped on the ground.
It was $320 and its chinese, I beat on it like there is no tomorrow and yet the gun won't fail me.
Mine is a later model with the choke installed but its useless anyways. I've shot so many bloody slugs out of it the choke is useless now.
Birdshot can drop foul out of the air out to about 70 yards. Buckshot I shoot out to 100 yard area and slugs.....well how far is the target?
I can consistently place 1oz an 1 1/4z oz slugs onto a 4ft x 3ft boulder at....200+ yards I think was the farthest I've placed them.
I'll pace out the distance next time I go shooting.
As for mods....Command Arms M4 stock, generic pistol grip foregrip and happy cap or +1 extension at times.
The gun will spit out anything you put it in in 2 3/4" or 3" shell size.
2 3/4's in that video, used up my 3's but I'll post video of the gun with 3's soon.
Barrel picture was taken around 8000-8500 round mark.
Best bang for your buck as far as I'm concerned.
EDIT:
The Griz & HP-9 are the SAME GUN. Both come from the same factories...hence why the Griz ships in an HP-9 box. I bought mine brand new and noticed this.
Only difference is the Griz offers Ghost ring sights and the a 12.5" barrel as where the HP9 has bead sights and a 14" barrel.
Mechanically identical in all aspects, same #### just 1.5" longer.
So ya know.