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DON'T JINX IT!!!Great progress and a magnificent job, this is one of the best considered pneumatic speargun projects ever. The real pay-off will be when you use the pumping barrel and can feel the pressure progressively falling away in the rear of the gun. Transfer and insert the spear into the main barrel with very little effort, then the KABOOM moment when you pull the trigger for the first underwater shot and see the shaft rocket away in a blur of cavitation bubbles.
Yes and Mares must have rocks in their head for not fixing it 40 years ago, instead they fiddled around with it making the smallest die changes that they could get away with. They even failed to update the parts diagram properly, something that I had to do myself with respect to the short boss handle, longer bulkhead gun. How lazy can you get!DON'T JINX IT!!!
Haha, just kidding but thanks so much for the nice words. In reality, I have more or less just reverse engineered an existing product, tweaked a few things and made some new parts. I haven't really brought anything new to the table - except hopefully show that 3D printing is a potential way for the home tinkerer to make certain gun parts.
And you are absolutely right about the feeling of loading a Mirage - the first pump stroke can be a bit hard depending on your pressure, but then they get easier and that last insertion into the shooting barrel where it almost feels like you cheated. Flick the regulator, hear the swoosh and know you have a high pressure gun in your hands. It's a sweet feeling, indeed.
Double o-rings on the power regulator front?A photo would be good as is, I am sure the set backs are only minor. A quick fix may be double "O": rings as Mares tried that themselves, not necessarily the same size, one stacked behind the other.
On the regulator shaft and the pumping barrel nose, that is where "O" rings were doubled up in the past. The photo being of the fully assembled gun, as it is right now. I don't know why the "O" ring on the piston plug is blowing off unless it is being peeled off by being not a tight enough fit in the transfer port.Double o-rings on the power regulator front?
Can't really do pics yet - the gun is still assembled from yesterday (that's how I know that at least it held air). Also, the the check valves are kinda hard to shoot. But will go take the gun apart now and share findings later.
This is the culprit:On the regulator shaft and the pumping barrel nose, that is where "O" rings were doubled up in the past. The photo being of the fully assembled gun, as it is right now. I don't know why the "O" ring on the piston plug is blowing off unless it is being peeled off by being not a tight enough fit in the transfer port.
Maybe on the parts diagram you could indicate which "O" ring you are talking about.
You can obtain higher shore hardness "O" rings that are more likely to stay put. When I think about the early "Mirage" which had much the same hardness "O" rings everywhere except one, the reason the "O" ring never was peeled off the brass piston plug was the stifled airflow as the air rushed to fill up the inner barrel and pre-chamber. That saved the "O” ring, but the same effect applied during the shot and that effectively throttled the gun while on “full power”. No wonder then my "Sten" 90 cm pumped up until the hand pump shrieked and then cocked with my double-handed loader could outshoot the "Mirage" 80 cm, but it was too hard to load like that and I let the excess air out before I busted something, either myself or the gun!
Yeah, I always thought that video and its mentioning of a 6mm bore was weird. I think it would be 7mm.Instead of relying on memory I measured my "Mirage" (Version 1) brass piston plug at 6.96 mm OD and the rear entrance of the transfer port at 7.52 mm ID. My digital Vernier calliper jaws are unnecessarily sharp as razor blades, so I did not push them into the front side for fear of scratching the bore. I have a plastic set of callipers which don’t scratch, but they are about as accurate as measuring with a kid’s wooden school ruler (now made of plastic these days, but you will get the idea).
Another check on the sizes are the "O" rings used and I recall I listed them here: https://forums.deeperblue.com/threads/difficulty-determining-correct-o-rings-for-older-mares-pneumatics.91719/#post-853873