Canadian Airgun Forum

im totaly new to this bro i need help me and my brother in law started this project 1 v 1 buy a 250 ish$ air rifle tax in mod it and put in trough the chrono the fastest one wins the other rifles

LOL! If it's a fastest wins, do your mods, and on the day of the shoot get the lightest pellet you can (usually the lead-free), and smear it with oil or vaseline. Both will give you an instant kick in FPS. The oil trick will stink up your barrel, but if it's only a few shots it's worth a try to get that edge.

Full power piston is 5.91" long. Reduced power is longer by at least 1/2". Don't. Remember exact length. Full power spring has 36 coils. Wire is .121" in diameter. Believe Quest 1000 piston will fit, if you have long piston. Quest piston # is B18-04-100A.

Ron

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If your airgun is broken, fix it. If it works, you CAN make it work better. Usually...

but how a longer piston is reducing the power? i mean the riffle wong crank the springer further unless the cocking is done at a closer point to the front aint it?

A longer piston gives a shorter stroke and less spring compression. So less air is compressed to lower pressure. So lower velocity.

Ron

_________________
If your airgun is broken, fix it. If it works, you CAN make it work better. Usually...

The cocking slot is longer on longer piston so when you break the barrel it moves down further before it engages back of slot. When you finish cocking stroke barrel is in same position as a short piston stroke but the front of th piston is closer to the transfer port.

Ron

_________________
If your airgun is broken, fix it. If it works, you CAN make it work better. Usually...

Sorry. Been a while since I worked on this so bad memory. Cocking slot is not longer. Longer piston latches in trigger sooner and the barrel stops a a different angle. You can actually cut a long piston down to short piston length. You then have to make a new hole for trigger to catch in.

Ron

_________________
If your airgun is broken, fix it. If it works, you CAN make it work better. Usually...

ok thx, any idea where i could order a kit like that?

Sell it. A piston and spring kit your looking at like 57 + taxes and shipping. For 109 you can get a Vantage 1000 fps.

Did you even check if its got a long or short piston in it? Because if its a short piston, its only a 18$ spring to upgrade.

The Super Streak is a different gun, a B22, so only the trigger assy is interchangeable. The Classic is a generic Crosman B18 coil spring with what appears to be a Trail Hardwood stock. So you can use whatever other B18 Crosman parts for it.
So being a .22 you no doubt have the 170/175mm piston, the full power is 150mm which is ~$35CA from Gravel Agency.
The full power spring is ~35-36 coils and ~.122" wire. The next size down is .118 wire, so check yours. A new spring is ~$13CA.
You can cut you piston down to 150 if you want to save the $, which is what I'd do. I posted the details on the site here somewhere, but if you can't find it I'll post again or send it to you.
Someone mentioned the nitro conversion which is pretty easy to do (posted that too). And the poster is not crazy, it is in fact harder to shoot than the coil despite what the mfg claims. It can be calmed down with mods and if he/anyone wants I can go into more detail.
Poor accuracy is usually the barrels fault, but could also be the scope, the shooter, other parts of the gun or all the above. Have details on that too, which I can send to whomever wants it, just write me at chevota at hotmail, say what gun you have, what your goal is and I'll send info along with lots of other useful performance info.

Does anyone know out there what each power differences are regarding detune from Crosman? If you have a full power piston, is it a weak spring, or a hole in the piston? Do they use both? What combinations do they usually put together to get the detune? I think I have a full power piston, but the spring is so weak, I can't see them also having a hole in the piston. I have a NP lying around and would like to possibly add it, but not sure what else I'd need to complete the install..

Thanks in advance
D

Who knows with Crosman, they seem to make rifles with whatever parts they got lying around. Been covered alot.

So could be a short piston, weak spring. Short piston heavy spring with relief hole. Or long piston, full spring.

Only really way to find out, is take it apart and measure the coils and the thickness, and inspect the piston.

But be aware, modifying an airgun to shoot over 500 FPS without a firearm license, is against the law.

Yes, I fully understand.. I have powder burners also.. Pelletguns are seriously fun hobby toys to me.. Lol

D

Cool, yeah they are simple to take apart. You just need a long bar clamp, or can use a door frame, and some wood and scissor jack.

Once you get it apart, be easy to tell.

I bought a Canadian .22 Phantom from Walmart when they sold off their airgun stocks several years ago. The only difference from a full power gun was the spring. It has a standard piston with no hole. I installed a full power spring and got 720 fps. The gun didn't shoot well. I changed the spring to the 12fpe spring (can't remember the part #). It now shoots at 630-660fps and is less hold sensitive. I sure don't miss the 80fps. After much cussing and muttering, I discovered the reason for the mediocre accuracy. The detent spring was weak. Not weak enough to notice when cocking and shooting, but after replacing the detent spring with a much stiffer spring, the fliers disappeared. The gun now betters my accuracy standard of .5" at 20 meters and is not pellet picky. I don't tune my springers for maximum velocity. I tune for accuracy and "shoot-ability". Three of my springers shoot well with a full power tune, all the others are detuned to the "sweet spot".
I have had an RPAL since it was called a Firearms Acquisition Certificate (FAC). I'm old.

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Theory is when you know how something works, but it doesn't.
Practice is when something works, but you don't know why.
In my shop, Theory and Practice are combined!
Nothing works and I don't know why.

Two lathes and too many projects