I hope you are aware of "Dieseling" effect you can induce in your Beeman !
When oiling and cleaning, make SURE to never allow any combustible lubricant / anti-rust agent into the air chamber.
I have a RWS from the Albert Nobel Dynamit Factory in West Germany, yes "Dynamit" is how they spell dynamite.
If you do, it will sound like a .22 and possibly do damage to the spring chamber or other components.
Only use the .22 when hunting, and be prepared for a long and painful demise of the target.
For maximum knockdown, use RWS Hollow Point Pellets, they really make a tremendous difference !
Also, on a unit like yours, it takes a Dedicated Air Rifle Scope. I have about $375 in my RWS and bought the rifle used.
The scope, mounts and muzzle brake/stabilizer cost a ton.
When shooting, don't try to hold "dead-on" target, instead rotate in small circles and squeeze the trigger just before the target enters the zone.
I seriously HOPE you're NOT killing Rattlesnakes !
Here in the south, the only way to get bit is to catch one sleeping, otherwise they'll beg you to leave them alone by buzzing.
Copperheads, PLEASE, KILL them All !
These are aggressive and territorial critters.
I was mowing in front of the barn some years back, approaching the steps, I begain to get off to move them out of the way to mow.
Just as I touched the blade dis-engagement handle,
BLAM, snake flew out of my discharge.
The snake was about 28" long, but almost 3" in diameter !!
The snake attacked the mower !
Lucky for me.. Now I spray a tiny mist of Diesel Fuel under the dry section of the barn on the floor as snakes dislike the odor.
Many years ago, I became friends with a Ga DNR Game Warden. He educated me on the animals we fear and why we should NOT kill or remove the habitat for many of them.
Among those is the "Wolf Spider" this one is BIG and has two large fangs. They do NOT run from you, just stare.
A search confirmed they are harmless, if you look closely when they appear "hairy" they will have dozens of little spiders hanging on.
The spider to fear will run and hide when he sees you, the Brown Recluse or Fiddle-back Spider.
To see the "Fiddle" you'll need some serious glasses. These spiders cause more harm to humans than any other in this area, the wounds are Gross and take months to heal and sometimes do permanent damage.
) while looking up the old B5-10 and saw my reply here in the google search and saw the rest of the repluies. Interesting note, in Canada as far as I know there is no minimum length on shotgun barrels as long as the over all length of the gun is 16" total. Hence why Dominion Arms can sell it's 8" (8.5" ??) factory 12ga shotgun here on the regular 'unrestricted' firearms licence. 
