legal power limit

[jonny5]

Hello guys this is my first post and im starting with a question, i hope some one can help.
I recently bought an old HW80 0.25 (good working order) from a man at my local shooting range and set about servicing it, i was told the spring in it was an old square section with a few coils sawn off so i have bought a new factory spring and seal but after fitting these still found the power was quite low at just over 10 ft/pounds with 19 grain rhino pellets, the power was even lower (by 2.5 ft/pounds) with 27 grain HN rampoints. I am going to increased the power to the legal limit by adding piston weights. My question is regarding which pellets to use for setting the power. If i set the power at 12ft/p using the rampoints i will be well over the limit using the rhinos. The rhinos are the lightest of the 0.25 pellets available and are a loose fit in the barrel, the rampoints fit much more tightly and are among the heavier. i am going to buy some different pellets soon to check the variation I guess the most sensible thing to do is to use the pellets that register the highest power so that im definatly within the law but that would leave the power lacking with the heavier pellets.
the users manual for a AA prosport states that the power of the gun is set at 12 ft/p using AA hunter pellets and that the owner must test the power of the gun if using other pellets to make sure they are within the legal limit, does this implie the legal limit only counts in regard to the pellet that your using? I what to know what the laws view on this is since if different types of pellet can cause the power vary so much its quite possible that many rifles sold at the legal limit could be tested at over the limit if the pellets the police use to test with are different to the ones used by the manufacturer/gunsmith. The rhinos and the ramheads are the pellets that i got with the gun and the rhinos are not that common i think.
I am not sure the difference will be that great with a 0.22 or 0.177 rifle because the difference in pellet weight is not that much but i think an important question is raised. thanks for all replies.

[oldhw77]

I guess the most sensible thing to do is to use the pellets that register the highest power so that im definatly within the law but that would leave the power lacking with the heavier pellets.

That's it exactly.

[humperdingle]

Police testing the rifle will use a variety of pellets.

Best be on the safe side.

[steve.wain]

My understanding of air rifle power is that if you set a springer up to give 12 ft lbs with , say 19g pellets, anything heavier, or lighter will drop the power. It's different with PCPs, the power will go up with a heavier pellet.

I've got a .25 BSA lightning and use the lightest pellets so has to get something approaching a flat (ish) trajectory, still, over 25 yards there's a lot of guestimation involved in aiming. (unless I actually zero it at 40 yards or whatever)I don't use it for shooting furry/feathery things, just plinking, but I'm told they're great for rats at close range.

I've got a chrono, I'll try it out tomorrow with different weight pellets.

[jonny5]

Thanks guys,
I appreciate your replies, my mate has a prosport so the other day we tested it using my new combro chronograph. Using bisley LRG it registered 11.8 ft/lbs approx. However using AAfield diablo it was registering between 12 and 12.3 ft.lbs. Being responsible fellows we immediatly called the shop it had been bought from just a few months earlier, the guy told us that the combro chrono's are notoriously unreliable (not something said when i bought it ,however) and that the gun should be taken to the shop asap to be tested on the magnetic chrono they have just to be sure. He thought it would almost certainly test ok. well it didnt, it tested at 12.1 ft.lbs just over the limit. The rifle was confiscated and is to be de-tuned appropriately (free of charge). This incident has made me curious about the law regarding airguns and the power maximum. my friend had not modified or tuned the gun in anyway, and althought our airguns are not likely to be tested by police as we are quite responsible people, i wonder who would be held at fault if it was.would it be the manufacturer the shop or the user? what law is broken by having an airgun over the limit and what are likely sentences? does anybody know anyone who has fallen foul of the police, what happened to them and the gun? I am interested to know.