TargetTalk

I own a Sp20 RRS, live in the Netherlands
The 280 and sp20 share trigger module, magazines and firing pin but certainly not the grips.
With minor work (10 minutes) you can fit a fully adjustable pardini trigger tongue to the hammerli.
In around 10.000 rounds the SP20 has had 1 misfire with CCI SV and Lapua Pistol King.
Eley club gave more problems. Its good ammo but the rim thickness is a few thou, thinner.
and it missfired 1 in 10 in my gun.
I always understood that the newer model has the one screw infront and is the more desirable.
The 280 is still sought after in Germany and sells for 600-800 euros.
If you have a look at egun.de you can get an idea. (dont forget the 2 dots on the a in Hämmerli, their search engine is a pain)

I’ve got a 280 in both 32 and 22, it has the screw in the magazine to change barrels. Serial # 70xx. It doesn’t have a safety, and I added a dot sight rail on the 22 barrel which I purchased from Larry’s last fall. I like the 280 a lot, it uses the same magazines and has the same same 2 stage trigger as my SP20, which is excellent.