For .177 fans you can now get Crosman pellets in 10.5 grains and also JSB Jumbo Monsters in 13.5 grains. This higher weight of 13.5 grains is as heavy as some .22 pellets. This will result in higher downrange energy. This was my concern with .177 as the lighter pellet loses more power downrange than the .22 calibre. I know it comes out faster but it slows down a lot quicker, unless you use the new heavier pellets mentioned above.
.22 LR Subsonic bullets (made for use with a silencer) weight 40 grains and the velocity is just below the speed of sound so the report can be silenced, if a good silencer is used.
Some claim to be around the 950 fps to 1050 fps. The energy is around the 90 to 98 ft lbs.
New law comes into force now. Airgun owners are responsible for keeping their guns safe from children or thieves. The BASC fact sheet can be viewed at: www.basc.org.uk.
We recommend joining the BASC for support and insurance.