Tunining Information
The following information is published with the kind permission
of Chris or 'Vulpes Vulpes' of UKCAF
Thanks to Chris for permission to copy his excellent post :-
I have added some of my experiences at
the bottom of the page ...
My gun is now running just over 11 ft lbs
Three pins to be removed before you can remove the pump rod assembly
and get to the anti-tamper pin to do the mod! (1)
Knock out the front roll pin with a punch! (2)
Remove circlip with a small bladed screwdriver, and knock out pin! (3)Remove
front sight block, and carefully slide pump linkage, so that
retaining pin lines up with the second hole in the pump tube. Poke
out pin with screwdriver (it's quite a loose fit). Pull
out pump rod assembly and measure distance between blocks, mine was
122.2mm, but yours may be different? **Make sure after you have done
the mod, this measurement is no greater.** Two nuts on the
assembly, one silver and one black, silver turns anti-clockwise.
Loosen the silver nut and undo the rod!
Next you want to remove the anti-tamper pin shown here! Look
down the end of the valve and you should be able to see the end of
the AT pin. Lever
the pin with a screwdriver, until you can grab it with a pair of
pliers and pull it out. The next bit you may
need to experiment with, the "mod", turn the black nut clockwise
between 1/2 & 3/4 turn.
Re-assemble rod making sure the measurement between blocks, does not
exceed the original measurement. Lubricate assembly and reassemble
in reverse order, Test with a chrono and make sure you are SUB
12fpe.
**Note*** Getting the pump seal into the pump tube can be tricky,
suggest de-burring the pump tube with a small radius, makes things a
lot easier! Idea
Enjoy a full power rifle!
My Input to this instructional page
!
Some additional thoughts after I stripped my gun
The gun is easy to strip for this mod so no worries there
my gun came apart quite easily - the adjustments needed are small
one 1/6 of a turn can make a lot of difference - it is aesy to go to
fat I had my gun apart a lot of times
I was worried about damaging the seal so use a coke can to help out
(and some beer ! Old Specked hen is good for this job !) back
to the coke can
a picture tells some words :-
this guided the seal in perfectly - saved any damage to the lips of
the seal
the bottom of the slot where seal needs to go simular trick :-
Again this worked a treat and prevented any damage to the seal .
