hi i have a mk2 in my collection and its a 177 cal , its super accurate and i was going to buy another spare buddy bottle but decided to get a 500cc top up bottle to take with me as you will all know the shots dont last long , just to mention about brands of pellets i was using aa fields and they were great but i did have to nudge them into the mag at times which was a pain as i still aint plucked up the courage to get the timber drilled to fit studs to attach a sling to the riffle , i did pick up a couple of tins of falcon accuracy pellets in 177 cal and tried them in the phoenix and they are great and also they just drop into the mag without any help and again supper accurate , cracking gun tho