Tuning 850 air magnum conversion

[reptist11]

I converted this 850 air magnum about 10 yrs ago as per instructions by Roald and a few others around back then but i just thought id post some pix, its been a super gun, i built 3 of them and this was my favorite so i kept it, still holds air forever and shoots 14.3 gr at around 900-920 for over 60 shots per fill, it is as accurate as any of my pcp guns and the shot count is great... the project was a blast and id recomend the exp

erience of converting an 850 to anyone with a serious airgun addiction, like me, just be meticulous about drilling straight holes and cleaning them up good and youll be fine... thanks for looking and PEACE, B.

 

[mgd]

What did you change on it?

 

[reptist11]

Hammerli 850 Air Magnum .22 CO2 Pellet Air Rifle : Umarex Airguns

buy Hammerli 850 Air Magnum .22 CO2 Pellet Air Rifle : Umarex Airguns online

www.umarexusa.com

This is what this gun started at, a co2 repeater, verry accurate gun but only about 600 fps in 22 cal. I put the tank and reg on it, carved the stock, put a heavier hammer spring in it as well as a spacer or two in the hammer system, drilled out the port, and some other little mods to keep the ES down and modded the trigger to add a crisp 2nd stage now I can adjust it to over 1000 fps and it's got good accuracy, but turn it down to about 860 to 900 and it is a tac driver, really neat guns...

 

[reptist11]

Also I've only got 450.00 into the build, including the gun, lots of labor but that's alot of the fun for me..

 

[reptist11]

Built this one as well...

 

[scubajeeper]

I did this also as my first PCP. It was a pain to degass and take apart. I had valve lock when I first put it together but after putting one of Roalds hammer springs in it, I finally got it sorted out. That was 8 years ago and it still holds air. I gave it to my good buddy to get him started and he loves it. His five year old grandson is racking up the blackbirds with it.

 

[reptist11]

Nice, they are really accurate for the price point for sure. I built mine 12 yrs ago and it is still holding air and shooting great....