Making a Self-Centering
Spring Return:
An Easy Hop-up for your old Sniper II.
I bought my Sniper
II used. And not just a little used, but pretty near worn out.
It's the chance you take buying off the Internet. First thing I noticed
about it was that the pump did not return foreward on its own. This
is not a good thing. If the pump isn't all of the way foreward, neither
is the bolt. If the bolt isn't foreward velocity won't be consistant
and blowback can result. A spring between the main body and the pump
is the simple expedient solution. But the spring needs to be strong
enough to return the pump fully foreward against the natural tension of
the users arm, without being so strong that it prevents the user from cocking
the paintgun. I popped into the local Lowe's store and found just
exactly what I need. Item no. 57028 is a pair of compression springs.
They are C-756, 23/32 x 3.5 x .041 Compression springs. Price was
$2.90 for the pair. They can be found in the hardware department
with the nuts, bolts, and screws. You only need one of them, think
of the other as a 'spare'. The other problem is that the spring needs
to remain centered on the pump shaft. This is primarily cosmetic,
the centered spring looks like a natural part of the marker, but it also
prevents the spring from kinking up. The key to making the spring
self-centering is a pair of No. 14 Nickel Plated Finishing Washers.
These can be found in the same place as the springs themselves. Price
was 15 cents each. The center hole of these washers is too small
to fit the Sniper II straight out of the package. This is where you
have to do some work.
The finishing washers
are pretty flimsy things. You can't just drill the hole out without
crushing them flat or bending them. Fortunately I have a Dremel Tool.
Using a small grinding stone I ground the center hole to the proper diameter
after carefully mounting the finishing washer in a vise. You could
perform this operation with a drill and a small grind stone. A countersinking
reamer does an excellent job. Once both washers are ground out
to the proper size, simply remove the pump from your Sniper II, slip on
the first finishing washer, it's rounded face pointing toward the Sniper
II's body. Then slip on the spring, and then the second finishing
washer with it's rounded face pointing away from the Sniper II's body.
The finishing washers will neatly cup over the ends of the spring and keep
it centered on the pump shaft. Now simply replace the pump.
It will compress the spring somewhat as you put it into place.
The end result looks great and works even better. The pump stroke
is very natural and crisp with the spring in place and inspires confidence
in the marker's ability. You should experience a slight improvement
in shot to shot velocity consistancy and a reduction in blow-back.
Not bad for a couple of bucks spent and a few minutes of your time.
Return
to Tech Links
Copyright 1998,99,00 © Bradley King.
All Rights Reserved.