The two simplest modifications to bring your fps up to 700+ is to do the following:
1) Drill out the transfer port to .118
2) Get a GMAC 22XX Heavy duty spring and replace the OEM hammer spring with it.
3) Having done this, you can then play with the hammer spring throw and tension if you want. Just be sure to
note the factory settings so you can return to their original settings if you get lost doing all that turning
and changing sizes of Allen wrenches.
No other adjustments should be needed. I've done this three times and it worked
every time. The transfer port is four bolts away and easy to do with a hand drill.
The GMAC spring is ordered on-line and costs about $15.00 shipped.
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