I have also used the RCBS scale for decades. Midway doesn't have them anymore, but here is a source that I found online that has them, there may be others:
https://jet.com/product/detail/42a248406f334301a4a301ccbe61a881?jcmp=pla:ggl:nj_sporting_goods:sporting_goods_hunting_fishing:na:PLA_276082155_1213860847237782_kwd-4579465929720638:na:na:na:2&code=PLA15
Midway offers their own cheaper Wheeler version, but I have never seen one to compare. I do like the RCBS unit.
http://www.midwayusa.com/product/192807/wheeler-engineering-trigger-pull-gauge
