Differences I saw:
1. Lacking a spring to reset the part that pulls the sear down. Looks like it relies solely on the trigger behind the trigger for this.
2. Extra nub sticking out of the bottom of the back cap.
3. Non-ST (soft touch) bolt. All Tac 8's have the ST bolt. Only T9-STs have the ST bolt. Original T9s have the non-ST bolt. I like the non-ST version better, no bumpers to lose.
4. Obviously the relief valve differences. The inside part of the relief valve is milled as part of the back block instead of being a removable brass screw-in part.
5. Bolt spring looks a bit different. A little heavier I think.
6. Hard to tell, but almost looks like the power tube is bored out a little more.
Originally Posted by Stuffy
Second, the two bolts on the back section are new also.
The extra two bolts on the back cap are not new to the SA-8. They were added somewhere after the first couple thousand Tac 8s. All Tac 8s have been coming with 4 screws on the back cap for a few years now.
Also: Anyone that bought one of these and might want to sell off the mags, let me know. Interested in buying a few.