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Some information is difficult to find because it is poorly documented. Either it is of no interest, or no one has thought to organize this information and make it available to the general public. Let me present one of these rare pieces of information: how is the barrel of a Fein 65 (air pistol) mounted onto the receiver ?
Having a mediocre-conditioned specimen of this weapon on hand, I took the opportunity to answer this question.
Barrel Disassembly
Before trying a specific disassembly method, one must define what the expected barrel mounting method is. The possible mounting methods include :
- Threaded/Screwed ;
- Press-fitted ;
- Pinned ;
- Glued/bonded ;
- Welded (highly unlikely here) ;
- Several of the solutions mentioned above ;
- …
As for me, having no certainty, I hesitated between several likely choices (press-fitting or threading). I considered two options:
- Placing the barrel under a press and attempting to extract it forward. If the barrel is threaded into the receiver, I risk damaging the parts by stripping the threads ;
- Machining the receiver to relieve all or part of the tension around the barrel, thereby checking whether or not the barrel is threaded into the receiver. This is a destructive method.
I decided to test the first option. If it didn’t work, I would fall back on the second one. To do this :
- I drilled a steel plate approximately 10 mm thick with a 13 mm diameter drill bit. This will serve as a stop for the receiver ;
- Creating the barrel housing on the barrel pusher (since the barrel is tapered) ;
- Setting up the assembly on the press ;
- Following the first pressurization, it turns out that the pusher is not suitable. The first pusher used was a car cylinder head bolt. The latter bent under the pressure of the press (see photo below). The second pusher used is a solid steel bar with a diameter of 20 mm.
- With this new pusher, the force of the press was fully applied to the barrel. After a loud snap, the barrel came out of its housing. The snapping sound was caused by the breaking of two steel circlips.
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- Looking at these circlips, it would seem that the barrel is mounted by pushing it from the inside of the receiver. Therefore, I should have removed it by pushing it towards the inside of the receiver. This would not have broken the circlips.
- The barrel housing on the receiver is clean. The diameter of the barrel housing in the receiver is 13 mm. The breaking of the two circlips (which act as a barrel stop on the receiver) did not damage the barrel housing.
Possible next steps
What could be the follow-up to this article? It would be quite interesting :
- To cut a thread on the receiver and fit various barrels. We could then test a Fein 65 in .22 (5.5 mm) or .25 (6.35 mm) caliber, for example. Given that the barrel housing on the receiver is 13 mm, the chosen thread could be M14 x 100 ;
- To see if the volume of compressed air produced by the original mechanism is sufficient to propel a larger and heavier projectile than the original one ?
- To measure the velocity of the different calibers for various barrel lengths ?
- To fit longer barrels to test if the air volume is sufficient ;
- If the trials prove successful, it would then be possible to adapt the Fein 65 into an air rifle version…, or even a take-down air rifle ;
- To consider this removal method to replace a worn barrel and thus refurbish shooting club Fein 65s ;
- To dismantle a second Fein 65, but this time by pushing the barrel towards the inside of the receiver to compare the two methods ;
- …
