Without having any pictures at hand, i will try and tell you the best i can
Mk1, has blued barrel and air cylinder with a gray/silver coloured breech block which has curved features, the barrel is glued to a brass transfere port tube, this part you will see when loading. Silver painted stock, butt plate and cheek piece have 2 steel rod adjusters.
Mk2, a whole new redesign satin nickel plated barrel and cylinder sharply angled squared off design on breech block, which comes in three different colours, red, blue or black ( no anti-tamper ), barrel and air transfere port is now machined into the barrel, stock is now laminated gray beech with metal adjusters that stay the same.
Mk3 looks the same as mk2.....but, the breech block has been lightened/machined away ( hidden in the stock ) and one of the height/length adjusters ( cant remember which one right now ) has been changed to a single post configuration, but the action is still marked as a mk2 but now with anti-tamper.
Mk4, this is the biggest change, again action looks the same as mk2 & 3, but has been lightend further, a modified reg, all stock adjusters are now a single bar, the hamster is much longer too, and anti-tampered, but the biggy.... a new barrel with a 1 in 14 twist rate, previous where between 1 in 16 to 1 in 17inch twist rate.
Which is the best?, ........there are some superb mk2's, if you can get one, they are the most reliable and consistant, the mk4 is also superb, its accuracy with that 1 in 14 barrel is mind blowing......if you can shoot it.
Hope this helps.
Crashing and burning
Last edited by fireblade; 1st July 2016 at 10:33 PM.