A JP lightweight rifle buffer is 3 oz.
Here's the process I went thru-
Standard rifle buffer 5.1 oz
Standard rifle buffer with 2 steel weights and delrin spacer 2.9 oz
Gutted rifle buffer 1.7 oz
Taccom rifle buffer .6 oz recprocates I believe
I've ran all 5 setups with my 18" Nordic barrel, fixed gas, JP LMOS bcg, JP rifle buffer spring. Standard buffer short strokes and will not run. Between the other 4, I'm not confident that if someone put one of them in my rifle that I would be able to tell which one from shooting feel. No malfunctions from any of the 4 setups. Taccom of course would not recommend using their buffer in my setup.