Question on de-tuned handguns....

[Houdini]

Hi everyone, Sorry if this is a dumb question, but  lets say a handgun bought in England is "de-tuned" what does that actually mean? What is done to it?

More importantly, can it be undone? They mentioned that they could drill out the port and sticking in a heavier hammer spring? Not sure what that means or how hard it is to do, but also worried if it makes the pistol unreliable.

Any info/advice would be appreciated.

[happymecanic]

In England, if you don't have a firearm license, the max power an air handgun can make is 6 fpe, and for an air rifle it's 12 fpe. I'm not too familiar with the ways they use to de-tune the power, but I believe their Crosman 1377 is de-tuned like here in Canada with a vent hole in the back of the valve. Pumping is not affected, but some of the pressure is vented to the atmosphere when you shoot, thus lowering the output to legal levels.

I heard of smaller transfer ports and weaker hammer springs in pumpers, PCPs and CO2 guns, and weaker main springs in spring/piston guns.

Yes it can usually be un-done, one can get the gun to ''full power'' relatively easily. You can often buy the ''full power'' parts from the maker/dealership. Here in Canada the max power without having your firearm license is 500 fps/4.2 fpe, and guys may buy a less expensive de-tuned airgun and up the power if they have their license.

HTH.

[subscriber]

Harry,

The quoted fix would be for a PCP.  If the detuned pistol uses a light hammer strike to open the firing valve, then increasing the strike energy will often increase the volume of high pressure air released, boosting the projectile velocity.  Many PCPs have throttle of sorts somewhere in the transfer port passage.  Some are adjustable.  Power limited PCPs may have that screw limited or the passage has a smaller bore for a given market.  Finding a way to open up that throttling choke point is often part of restoring free market airgun performance.

As you probably know there are other handgun power plants, such as spring piston.  With the latter, not too many exceed 6 foot pounds, anyway.

There are so many different PCP pistols that getting them to full power needs to be looked at on a case by case basis.   There is also a question of how much power is enough for your purpose, because tuning for the maximum tends to make PCPs inefficient (use a lot of air per shot)

The link below is about increasing the power of a German legal PCP rifle to its full potential.  I am posting this here because many PCP pistols would have similar adjustment procedures in principle:  https://hardairmagazine.com/reviews/power-tuning-air-arms-t200-sporter-air-rifle/

[Houdini]

Thank you very much guys, I appreciate the help.