yesterday i got a wild hair and decided to change the spring in my 300s. the original spring was easily removed without a spring compressor. when i tried to
install the JM spring it had a lot of pre load. i tried to do it without a spring compressor. to make a long story short i slipped and everything shot out the back and took the side of my right pinky with it. ran over to the dental office next to my office and they wrapped me up and i drove myself to the hospital. i will have to have a small skin graft about the size if a penny.

i hate to admit i did this but i offer it as an example of what can happen.
use a spring compressor. the only rifle i have that does not need it is a
TX200. all of the popular dianas need one i think. even my HW 50 needed it.
i have one of course but it was at home and i tried to do this in my private office at work.

Wow. Glad you're going to be okay and thanks for the reminder. We all tend to get careless at one time or another, and as you've shown us, once is all it takes to do real damage. Here's to a speedy recovery from your wound.

-TKM-

Thanks for the note - we all need a reminder from time to time. I find there's not a whole lot of preload on my 52 spring, but always use a compressor of some type - last time I used a pipe clamp - works ok, but an extra pair of hands comes in handy, or take it very slowly to make sure nothing is slipping. First time we did that, we had a 'human spring compressor' - were able to work out how to do it with two guys supplying compression on the edge of the bench - it worked, but don't think we'll try that again.

that i made to clamp to the top of a black and decker workmate. its at home and i thought i could do this on my dest at work.

glad you're ok!

dave@vabch

you should KNOW better, Larry:

simple mistakes are simple to fix, complicated ones are ?????

but we still live by our mistakes

warren

and remember "it's 30% the gun and 70% the shooter"

that after all of this the JM spring is giving me no additional velocity. about the same as the original double spring. i will say that it is smoother if that is possible and less twang. the spring fit the guide very tight. tighter than i have seen in any gun. it also fits very tight inside the piston so i suspect it will take some shooting in to reach full velocity. i am probably loosing velocity due to this tight fit but it should wear in.

i am sure the medical bills will be an amount equal to a new walnut pro sport or maybe a nice air arms S400.

But I'm really glad that the injury was minor. You're not the only one to cut corners when tuning a gun. I've done the same and have been lucky. From now on I'll be using my spring compressor. I hope you heal quickly and properly.

Making the world a safer place...One red squirrel at a time!
Best Regards,

Daniel
CIC; Squirrel Studies and Observation Group

get well soon Larry.
Wait till things have bedded down before you do anything to the guide dimensions.
After a few hundred shots, If the spring guide is that tight that it still binds on the spring when the spring is fully compressed, I would turn and skim it LIGHTLY with sand paper to make it fit well.
I presume the guide is synthetic and unless it was really oversize, it should wear down to the right dimension eventually. If its metal, it will take much longer.
Given that the coils in a spring are evenly spaced and is wound parallel, the best dimension for a guide is midway between the compressed spring's internal diameter and the released spring's internal diameter.
David

and inside the piston the piston stem swells as it goes deeper in the piston acting like another guide. they are very well constructed. i think its going to take some shooting. lots of it.

it can also be that i should replace the piston ring.these guns have a piston seal that is like an internal combusion engine piston ring. the compression chamber was pretty smooth and i did not do anything to it. if i replace the ring i will have to do a fine crosshatch on the chamber or it won't seat just like in an engine.

No tune is complete until the rifle has been accidentally-wetted in some blood, and the ensuing rust removed. I'm not suggesting you do so on purpose, and certainly not in the extreme manner in which you did it! But, if you can tune an air rifle around all those unpolished, stamped-metal edges without even a little cut, you have accomplished a great thing.

I hope your injury heals soon and heals well.

Happy Shooting!

Ed, The Airgun Tune-Meister

edward73@sbcglobal.net


"We can rebuild the squirrel. Make him stronger, faster...We have the technology"---Skyler M.