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https://www.ebay.com/itm/Univrsal-Reel-For-Speargun-Pelengas/132997261042?hash=item1ef74126f2:g:jQ8AAOSw2EJck1KuAnd the reel is the pelengas new model.
Titanium is very expensive, you want to use it only where you cannot use anything else, particularly titanium tubing. The larger diameter tank "Black Sea" guns used it so that they were not going to blow up! Wherever rubbing is involved it is not used, such as inner barrels as that is a job for stainless steel.Yeah, me asking this question is in preparation for a scratch build I am still hoping to get underway. So, just checking how people do it.
I remember seeing a very thin walled titanium cylinder with internal screw threads for a PCP airgun - and they hold about 200 bar. Can't remember how thin, but it was surprisingly thin.
At least towards the end of this video, the new muzzle is shown on a smaller gun with the regular hydroformed alu reservoir:That new muzzle looks like the one on the "Pelengas" carbon pneumatic gun, so they are fitting it to the other models would be my guess, or at least some of them. The inlet valve cap on their guns has up until now been a threaded plug or disk with a shallow curved screwdriver slot in it that really needs a coin to undo it. If you use a screwdriver then the slot will soon tear up as the threads are rather tight initially because the molded disk is a trifle big.
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Just speculation, but I am thinking that without the lip - or by loosening and then tightening the front when loaded in a lip less design - there's a risk that the cuff will be pulled towards the gun by the vacuum. I guess the same can happen at depth from the pressure if the foot of the cuff is not well supported.The new inner lip is probably to ensure concentricity of the vacuum cuff when you tighten the front cap up. The smart way to do it is with the gun cocked and ready to shoot you loosen the plastic cap, which has the line slide stuck in it and retighten it, then the vacuum cuff will be properly lined up. You do this with the gun not in the water, but pointing downwards for safety reasons, or you let all the air out first. On the "Taimen", which "Pelengas" forgot to copy in this respect, the vacuum cuff alignment is taken care of by the conical seat for the cuff inside the front hub.
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As for the barrels, I did some more digging and it seems Pelengas use both alu and stainless barrels depending on the guns.I might have missed it, but @Pete can you tell me how the Pelengas assembles at the front? Does the muzzle screw onto a thread on the barrel like on the Italian guns? I think it does, but I am asking because I have seen some of the Russian guns where the nose cones, and not the muzzle, screws into the front of the reservoir. Also, in case you did measurements, I would be very interested in how the SS steel barrel looks. I know it's 11.9mm ID but what's the OD at the front (where the thread presumably is)?