GTA
Airguns by Make and Model => Crosman Airguns => Topic started by: dryanw on December 29, 2012, 05:41:23 PM
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I thought about placing a thin peice of rubber between the tophat and the piston. Would this smooth out the shot cycle any? It may not make any difference but I think its worth a shot if its not going to cause any damage.
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I don't think it will do any damage, but it may make the cycle bouncy and therefore have the opposite effect of what you want to achieve. The rubber will be an extra "spring" with very low compliance, although being thin, the effect will be minimal.
Try it and report back.
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I will. I may try mousepad material, as it doesnt have much "bounce".
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How do you plan to accomodate the extra length that you'll add? Not following how that will do anything to the shot cycle.
Have you tried a lube tune and adding a polished washer over the rear guide, and polishing spring ends, to eliminate spring torquing?
That's a pretty light gun. I have added 4 to 6 ounces of lead weight to the bottom of the hollow stock, and I know that works to settle them down.
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I doubt it would help much if any, and may cause problems. The idea is for the spring to move freely, hence polishing, washers between the tophat and piston, and lube. The rubber might prevent the tophat from twisting, but the spring will still twist on the tophat, and it may cause more twang and buzz as a result since the tophat will not be able to spin with the spring a bit and absorb some of the inertial momentum of the spring twist. Essentially, you'll be increasing friction between the spring end and the tophat, which could cause some weirdness as the spring unwinds.
Think of it like this. If you are driving and slam on the brakes, you get a violent jolt as your momentum is checked and inertia is abruptly forced to look for somewhere to go, and in a hurry. If you hit the brakes gently, you slow down smoothly and quietly.
As your gun fires, the spring tries to return to its uncompressed state in a big hurry. It stretches and it spins. As it uncompresses, its innner diameter becomes smaller, and it "grabs" onto the tophat and rear guide gradually. As it grabs, some of its inertia is transferred to the tophat, whose mass absorbs some of the energy and dissipates it as the tophat also begins to spin, in effect slowing the spring down gradually rather than abruptly.
Tar dampens spring vibration, but better fitting tophats and guides do it more effectively. Since if I am not mistaken the rear guide is metal and a part of the rear block assembly in the Phantom and no easy aftermarket upgrades are available, I'd go with tar on the spring.
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Tbe Stoeger X20 suppressor has a thin piece of rubbery like substance, about 1/4"thick, in front of the tophat inside the piston. It's not rubber, it doesn't have that bounce to it. It's kind of like a piece of ptfe but soft like rubber, except it absorbs shock pretty well. The shot cycle was noticeable better with it than without it.
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I wonder if it was a spacer added for preload, vs just cushioning power. IDK. Either way, I'd guess it's probably a urethane. It would have to be a higher Shore A durometer, to last. Again, the added length (preload) could be a problem for the Crossman Phantom that is in question, since it's already harsh. Polishing and rear washer with lubing will go a long way to help.