Putting finishing touch to a Goldstar which had 20 mm of buffer/washers at piston end. https://imgur.com/a/jw0gawh
Spring is straight and square and producing 7 ft. lb. at 15 mm pre load.
Replicating the decomposed buffers/washers to 40 mm pre load gives 11 ft.lb. so quite acceptable methinks.
A trimmed Titan No 1 could give the power with no spacers so what's best option.
A bit of me wants to keep it as found. Thanks for looking.