Another option ,if you're reloading pistol rounds, is the Everglades "hold down thingy". Not spring loaded, but much cheaper.
https://www.evergladesammo.com/reloading/machine-parts/dillon-super-1050-parts/ega-hold-down-die.html
Are there rub mark on the side of the hammer? Does your hammer have side to side play? Poor hammer alignment could cause inconsistent hammer fall. With almost every 929 I've worked with... shims were necessary to center the hammer and avoid rubbing on the frame. Just my experiences... just trying to help.
Case checkers??? Try here: https://www.speedbeez.com/product/speed-beez-moon-clip-tool-38-super-8-shot/
Sent one in for repair January 20th... got an email discussing repairs needed, then nothing since.
My last order for a timer took 7 months to fulfill... I have 2 more on order.
My SpeedBeez belt rack works fine... once I went through all my clips and checked for hold strength. Pulled out a couple clips that were marginal... haven't lost a clip since.