Swapping the locking block in a Grand Power Stribog takes a few minutes and no tools. This guide walks through installing the Rokin 35 degree locking block in an SP9A3 or A3S, step by step with photos. The same steps take the standard US-spec 45 degree block back out if you ever want to swap back.
Before you start
- Fits: Stribog SP9A3 and A3S.
- Tools: none.
- Safety first: remove the magazine and check that the chamber is empty before you start.
Removing the bolt group
Step 1: Push out the rear takedown pin
Push the rear takedown pin out of the lower frame.
Step 2: Swing the lower frame away
With the rear pin out, swing the lower frame away from the upper.
Step 3: Slide the rear cap down and remove it
Slide the rear cap down and off the upper.
Step 4: Push the bolt group out with the charging handle
Use the charging handle to push the bolt group out of the upper housing.
Tip: hold the housing upside down. Everything comes out together in one assembly.
Swapping the locking block
Step 5: Remove the pin
Pull the pin that holds the locking block in the bolt group.
Step 6: Remove the 45 degree block and install the 35 degree block
Take out the standard 45 degree locking block, set the Rokin 35 degree block in its place, and reinstall the pin.
Reassembly
Step 7: Reassemble in reverse order
Put the bolt group back in the upper housing, refit the rear cap, swing the lower frame back up and push the rear takedown pin back in.
Tip: hold the housing upside down again so everything slides back in with no hang-ups.
Step 8: Function-check
With the firearm still unloaded, work the action and check that the bolt cycles and the trigger resets normally before you shoot.
About the 35 degree locking block
The Rokin 35 degree locking block is built for suppressed shooting: it changes how the bolt unlocks, to cut down the recoil and the gas you feel with a can on. It’s made from 4140 steel, matched to the hardness of the US-spec 45 degree block, and finished in black oxide. Some of that black oxide will polish off where the block contacts the bolt during use. That’s normal wear.
More Stribog parts: Grand Power Stribog Parts.
Not affiliated with Grand Power. If you’re not comfortable working on your firearm, have a gunsmith do the swap.