Tuesday, September 16, 2008

Fixing a Benjamin 312, Part 1

I bought a Benjamin 312 rifle off the Yellow classifieds the other day, listed as "missing pivot pin". The price was right so I bought it. I figured it would be pretty easy to fix and I was already comfortable with the design having fixed my 317.

I stripped the end plug. The pin screw was worn at the end, should have a point.

The piston was very greasy, but that cleaned up fine.

I made a new pin from a dowel pin.

The pin in the plug.

I ground a flat, rather than a vee groove as on the 317, because of the missing tip of the plug screw.

The rifle. Worn and used, but I think it's beautiful in it's own way...

As with all of life, you never think to check things that should be obvious (and I'm sure it didn't occur to the seller either). The hole for the pivot pin is wallowed out on both sides of the tube. I'm not entirely sure how that would even be possible unless the rifle was pumped without the plug in place, but there it is. This means that the pumping force is bearing on the two skinny little screws that retain the plug in place.

I don't want to solder in a patch as the entire barrel is soldered to the tube, and heat would discolour things as well. Plastic steels are unlikely to work and besides I want to be able to tear the rifle down again for maintenance. So I will do a little thinking and come up with a solution, as always.


Anonymous said...

I think a good solution for out of round (oval) holes that hold cross pins in place, is to end mill them round again and use a thicker pin if the design permits.

Nick Carter said...

Did you see part 2?