Fully adjustable Pardini trigger mounted on SP20 RRS

With Pardini trigger in middle position

Stock trigger in most forward position

The standard SP20 trigger shoe is limited in its adjustability.
You can only slide it forward and backwards for about 1 cm.

Due to its rather big curvature it is impossible to move it forward enough if you have medium or long fingers.

The trigger slides in a U-shaped rail and is held in place by a 2.5 mm allen head bolt which screws into an square nut under the U-rail.

There is a flat Walther/Hammerli (part no.1301860 or 861, 862)  trigger available but I was unable to locate one.I also found an aftermarket trigger online that would suit my purpose, ordered it and received a stock trigger instead.

I looked at the Pardini trigger online and thought that this might be adaptable.

At first I considered making a small adaptor block which would sit in the original trigger rail and bolt the Pardini trigger to that block.

When I visited the gun shop and had a look at it and after some discussion I found out that it would basically be a drop in swap.

The distance between the rails (width of original trigger) was 6.2 mm, The Pardini mounting lug was 6.8. I filed  away some material on both sides and the job was done. (It took me less then 30 minutes)

The trigger is now adjustable in 3 axis. (forward/rearward, Up/down, left/right)

The up/down movement is limited but the adjustment range allows enough movement to centre my finger properly on the trigger.
If you look at the 2 pictures above and compare the red line you can see the improvement.

I made a  peculiar observation: After switching to the Pardini trigger the trigger pull dropped from 1200 to 1090 grams.  When I noticed this I switched back to the stock Hammerli trigger and it was back to 1200. Probably due to the fact that the Pardini trigger mounting bolt is now closer to the trigger pivot point. I did not measure it with the stock trigger in the most rearward position.

Pardini left, Stock Hammerli on the right

Hammerli underside, grip removed.
Shows trigger U-shaped sliding channel and square 2,5 mm mounting nut visible.

Hammerli part no.1301860  (I could not locate one)

Aftermarket Hammerli trigger