jpaul,
You have a good one!
Search for and contact Mac-1 Airguns or Bryan and Assosiates for parts.
The 180 came in two versions, a thru the stock safety(early model) and the advanced, adjustable trigger model (yours).
Power and accuracy of the 180 are very good, though it comes at the cost of being a gas guzzler. Mine only gives 18-21 shots per powerlet.
The rifle has a number of possible owner adjustments:
hole in cocking knob is a power control, an allen key inserted thru will find a nut to set the power level. (You may need to rotate the knob to hit the adjuster)
Some models have 2 clicks on the cocking knob (Hi/Low Power), a gas saver...
The trigger housing has 3 screws:
Top- sear engagement.
Middle- trigger overtravel.
Bottom- trigger spring tension.
Adjustments must be made with the stock removed. Be carefull tho as you can either adjust the trigger UNSAFE, or set it to inoperatitive!
Start with heaviest contact on the sear, then adjust.
Overtravel, you need some to keep the trigger from locking, just not too much...
Trigger spring, leave a little to be safe.
I think you will be happy with this rifle!
Mine is an origonal first model, and just this fall, after over 40 years service, the seals went. They are long lived rifles that don't require messing with much at all to function very well!
These rifles can easilly keep ya fed with small game, and are a joy to just plink with!
Please b for safety's sake, be conservatitive with those adjustments, till you are very famillar with your rifle, OK?
Good luck with yours!
ZVP