Umarex Ruger Mark IV Modifications

[Duane38]

Hey, gang.  I picked up an Umarex Mark IV.  I must say, the power plant in stock form is rather impressively efficient. 

There are a few modifications in store for this little shooter.  So far, the transfer port is ridiculously oversized.  Massive I say!  So, I made a new port using some Teflon bar stick with a port right at .125" and press fit in the existing port.  Wow!

Stick, with 7.48 grain was cutters it was shooting an average of 311fps.  With the new port, the average went up to 336 fps. 

Modifications to come:
- Stone and polish the sear surfaces.
- Make an all steel outer barrel sleeve, ditching
  the plastic.
- Experiment with piston head material and
  designs.
- Make a set of wooden grips.

[Duane38]

Woo hoo!  Got the trigger parts stoned and polished.  Factory trigger was pulling at 11 lbs 7 ounces.  Yikes. 

Now pulls at a smooth 3 pounds and 6 ounces. 

In fact, after shooting the stock gun for 100 rounds or so, the trigger has that "surprise!" Feel to it.  Gonna have to get used to it again.

The Taiwanese have consistently produced very nice replica airguns.  This is no exception. Now time to ditch the plastic outer faux barrel shroud with a steel tube.

Came up with a barrel locking concept, too, to ditch the questionable spring clip catch.  This way, there is positive barrel engagement to eliminate droop. 

[ray1377]

I've got one of these, I was hoping someone would start modding one of them.
Please post lot's of pics and keep the mods coming
Following

Thx
Ray

[Doug Wall]

Here are a couple of reviews for this gun:

https://hardairmagazine.com/reviews/ruger-mk-iv-pellet-pistol-test-review/ 

https://hardairmagazine.com/buyers-guides/two-quick-worthwhile-ruger-mk-iv-pellet-pistol-upgrades/