I'm no gunsmith and open to be corrected, but based on past experience I'm not too worried.That looks like a nice job, and I don't want to be critical, but does that kind of rubber give enough cushion to actually make firing the rifle "safe" for the firing pins? I suspect that it would be easy to dimple the rubber after a few sessions, and then there is only a false sense of security and not much more cushion than dry firing.
I have purchased the very expensive spring loaded type snap caps from NECG in the USA, but they are not available in all calibers. For instance they do not stock a snap cap for my .30R Blaser.
This option looks attractive, but I'm being cautious. Anybody with a more educated opinion want to pass judgement?
Depends. A Holland & Holland Royal, Rigby rising bite, or Westley Richards have the hammer and spring system as they did before WWII. Those old boys back in the day might even have had an better eye for quenching springs than today. I would always use snap caps in a traditional double. A fired case offers no controlled deceleration of the hammer.I'm no gunsmith and open to be corrected, but based on past experience I'm not too worried.
I reckon the actual risk of damaging modern rifle firing pins (even on a double) is pretty low generally, and as long as they've got something with a bit of give to hit into and decelerate the pin before the end of travel then you're golden. I mean, the primers themselves are't providing more than 1mm of deformation (read deceleration distance) to slow the pin and they don't deform that easily either.
I'm sure that folks producing fancy spring loaded snaps will disagree, but for my part, rubber eraser, hot glue, a spent primer, a bit of soft, flexible plastic (polypropylene for example), whatever.
I'd personally lean towards the hot glue or another similar plastic as the 'best' option, being a bit firmer than the rubber eraser, giving a bit more resistance and possibly providing a bit more 'spring back' to prevent you just forming a permanent divot with repeated strikes, but i reckon they'll all be fine.
Something else to think about with the NECG caps. Considering the impact velocity and mass of the firing pin, the malleability of the metal (often aluminium or brass) of the impact 'anvil' at the back of the snap, and the mass and spring tension in the impact surface/spring assembly that they're using, do you think there's time for the pin to impact, the anvil to get over its inertia and friction, and for the whole assembly start to move back and compress the spring before the pin just deforms the anvil and stops decelerating / rebounds?
I can't say for certain either way, but I do wonder if actually, the spring is just for marketing and it's actually just the pin deforming that soft metal surface that's doing the real deceleration, just the same as it would if you just left the spent primer (or some hot glue) in a used case and got on with life.
Maybe our more learnéd members can offer a more informed perspective, but food for thought anyway!