Chevota wrote:
The amt of shim you can put in varies since the gun and especially springs vary. I don't recall one that couldn't accept shim, but it's usually not much anyway, like one .062" washer or so, sometimes two.
There is also a risk of what compression the spring can handle, so an oem Crosman spring might make xxxfps as-is, then shim it and it makes more, but it'll likely settle and end up somewhere between the old and new fps, even all the way back to the old. How long it takes to settle depends on how much it's fired and total time it spends cocked. I figure just leave it cocked for a few hours to to get right to the end result. This is also why the guns usually lose a little power after use because even w/o a shim it's usually too much and they settle. So it's very possible shimming may settle right back to where it started. The chinese springs vary in quality and strength so you'll only find out for sure after you do it.
A quality spring would be the answer, but as far as I know there aren't any that exact size so you have to (should) mod the gun to accept the new spring. For example a better/stronger Vortek would need a fatter guide so you'd need to improvise. Not a big deal to many of us but very difficult to some.
You can also do things to increase the stroke which is the way to go since stroke is more important (within reason) than spring strength. By stroking it a few mm you gain that power and by default you'd effectively shimmed it too. Plus extra stroke helps increase the compression ratio which helps the gun shoot better and what not.
You can increase stroke a little by sanding the seal thinner, which I always suggest as long as it's done correctly. By moving the trigger housing back you can buy a couple mm, and will likely need the cocking slot lengthened a wee bit to allow that stroke. Another option is modding the piston by moving the sear hole fwd, which is something to consider if you're cutting down a long 500fps piston. I suppose you could make the new hole maybe 3mm fwd compared to the full power piston, then elongate the hole until the gun cocks. That way no need to move trigger and you know you have max possible stroke. Slot needs to be lengthened for that too, which will make sense when you look at it parts and watch them in action.
That's what I said....it won't accept a shim that's 1/8th of an inch..or .125...so you'd have to go less....that's all I said..A .064 shim...like YOU said is the same as what I said...its less than an 1/8th of an inch.Didn't say it couldnt be shimmed or anything about all the other various ways to increase fps.Was talking about the spring being so CLOSE to maxing out it wouldn't be worth it on its own with a .064 shim.……so its maxed out...more or less...sorry if you got confused....
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