Support the cause!
This site is maintained by volunteers and donations from people like you. If you'd like to help keep it alive, please consider donating!
All springs necessary to complete the projects can be found here: Wolff Gun Springs
PLEASE NOTE - This site and it's owners/contributors will not be held responsible as a resut of you performing these modifications on your own firearm. Missuse, negligance, or mishandinlng a firearm can result in serious injury and/or death. If you aren't comfortable doing this, a reputable gunsmith will charge very little to install these items for you. Be safe.
Replacing the mainspring (for lighter trigger pull)

side view side view side view side view side view side view side view side view side view side view side view
Materials: New main spring from Wolff Gun Springs

0. Put on your safety glasses ... you are working with compressed springs here so don't be foolish!
1. Remove the magazine and make sure that the pistol is unloaded.
2. Recheck to make sure that the pistol is really unloaded.
3. Lower the hammer to take tension off of the mainspring
4. Find a screwdriver that fits the grip screw and remove the screw.
5. Gently pry the grips off of the frame ... the first time they come off, they can be a little tough ... just go slowly and all will be well ... you shouldn't need tools to get them to come off.
6. Find the pin about which the mag release pivots.
7. Take your 1/16" punch and push that pin out. If you don't have a set of punches, get a set of "Pistol Smith Punches" from MidwayUSA (part #482764) or some such outfit ... they are cheap (11.50 or less) and worth the price!
8. Wiggle the mag release until it comes out ... there is a little tension on the mainspring, but not too much.
9. When the mag release latch comes out, the mainspring will just slide off of its retaining pin.
10. Slide the new spring on and label the old one with a piece of tape so you don't lose track of it.
11. Put the mag release latch back in place (You can use the same punch used in step 7 to help align the holes) I've never needed 3 hands, but it does help to have something that you can push against.
12. Replace the mag release pivot pin
13. Replace the grips.
14. Replace the grip screw.
15. Admire the improvement in your P64 ...
None of the pins that I have seen have required a hammer to remove, but that doesn't mean that there aren't any out there.
Hope this helps ...

Recoil spring (Replacement)

Materials: New recoil spring from Wolff Gun Springs

Wolff Gun Springs now offers this spring replacement from their factory. As such, the proceedure for cutting and re-working the H&K P7 spring is obsolete. Please use the Wolff spring. Your standard recoil spring is ~18lb.
Grip nut replacement

Materials: M3 metric hex nut .50 pitch @ Home Depot

New metric grip nutI thought I would show a picture of a nut that I found at the hardware store, simple metric hex nuts (M3, .50 pitch) that works pretty good. A blueing pen would be best, although I couldn't find mine so I used a black permanent marker. Not bad! They are approximately the same diameter and thickness as the original nut, but of course that one is round. Not a bad idea to keep a few handy.

Blueing cadmium plated screws and nuts
1. Hold over propane torch till red
2. Quinch in oil or water to cool off
3. Buff part with wire weel
4. Reheat with propane torch till red
5. Quinch in oil to harden part
6. The part will be blue black

I have been doing this for small parts for over 30 years.