Based on the shape of the side plate (it's a box lock) it looks like my Merkel but I couldn't see the barrel mounted sling swivel.

My Merkel (500NE) will double every time if I pull the rear trigger first and use 570gn loads - it's never happened but I've noticed both strikers firing when I've put single rounds through it.

In my case it could be one of three reasons:
1. The front trigger is lighter than the rear;
2. The front trigger is articulated (swings forward so the trigger finger doesn't get belted into the back of it when firing the rear trigger) and, with the rifle cocked, when I swing that trigger forward and let it snap back by itself it will trip the sear;
3. The rear trigger internal mechanism has an recoil operated (inertia?) interceptor (?) that blocks the sear whereas the front trigger mechanism doesn't.

The Merkel manual says to fire the front trigger (RH barrel first) for reasons of regulation but I wonder if this is the only reason. Many people will argue that you should be able to fire whichever barrel first but I'm happy to live with RH first.