Picked up an aftermarket outer barrel for the FN57 which is supposed to stop the Hop unit and such from wearing out. I fitted the barrel and test fired at 5 metres and seemed fine.
I immediately took it to Cornwall and I am here for the next few months with no tools, (though I still have the original outer barrel with me).
I took it to a game day today and noticed the O-Ring that is on the Outer Barrel to prevent the recoil spring and stopper from falling off had broken in half and fell out.
When firing the pistol about a third of the shots immediately fire a good 5-10 degrees to the left and then curve around to the right. Some shots have too much hop and the rest not enough.
Now considering I have no tools, what is the most likely culprit?
The new outer barrel?
The missing O ring which is there specifically to stop the recoil spring going too far forward and going missing when disassembling? (it may have a secondary barrel stabilising function, but I can't prove that without a working O ring)
Here are photos of the new outer barrel and the old one.
Any idea what size O ring the stock one is?