its 4.5mm steel bb's. Single stack co2 magazine.
https://gunfire.com/en/products/kp-0...152217498.html
The KP-11 is a direct copy of the TM Hi-cappa 5.1 4.5mm steel bb double stack co2 magazine
https://gunfire.com/en/products/kp-1...152217500.html
you can spend silly money on upgrading these things.
The "Sig Sauer Max thingy" may look 'good' in the ad., but believe me it isn't! Cheap looking, child's toy-like 'nickel' finish; flimsy plastic, stick mag that sometimes auto-ejects with just the inadvertent brush of a finger; ultra thin plastic grips that ping off too readily; non-field strippable if you get a jam and the one I tried was probably THE most inaccurate of any blow-back BB pistol I've shot. I could go on but I'm sure you get the picture.......
I have ordered one of the above from mays of London they are supposed to be very good according to the reviews etc I own a Remington rac 1911 4.5mm steel bb which is as you say very loose and the finish is poor it is quite powerfull though.I will let you know when I get it.
I have one of these which is very good and robust reliable and blowback works great the only thing that lets it down is the matt finish which might be accurate for wartime issued weapons . I had one of the umarex pellet versions with the 8 shot revolver magazine it looked very nice but the grip safety broke so I took it back where I bought it and swapped it for the umarex beretta ie the one the us forces replaced the colt 1911 with.
I got the Umarex A1 Government pellet firer in the end and I'm very happy with it. The blowback models are fun to shoot but I am currently wresting with which calibre powder burner to get (.22lr cheap to run, 9mm faster with reasonable ammo costs, .45 acp cos its short, fat and slow, just like me) so the recoil isn't as important in the co2 one.
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