Hey all, been trying out some subsonic loads for my 300 blackout and my 308 bolt rifle. Chrono says everything is going about the right speed (950-1000). I would like to see if I can get any expansion from my 180 gr sst at that speed. Been searching and bought some Knox Gelatine today. was gonna try to make my own test media but saw some stuff called sim-test and also saw where a guy was using what he called wetpack (wet newspaper stuffed in milk jugs).
Trying to do this cheap....any suggestions on what might work? Jugs of water,clay,wet phone books etc. or, or go for the sim-test? Thanks for any info or your results with any of these!

sim-test works pretty good and its reusable which is nice. the only draw back I dont like about it is its opaque and had to see the cavity from the outside. Ive been wanting to try this stuff. which is reusable like sim-test but clear. Im right now using sim test for my testing, and it works great.

Well thanks for the info. I went on their web site and it looks pretty good. Woulda thought more response on this....guess most just punch paper or maybe shoulda named it something else?