Just one point,do not confuse 3 50 gr equivlent pellets with 150 gr loose, they are not the same the loose is the original 777, The pellets give the same velocity as an equal amout of pyrodex as I understand it. The strain gage reads that 110 loose FFF puts out more strain than 3 pellets. I only test once as I barrowed the pellets from someone that just happened to be on the range when I was doing some testing,I personally would not load more than 120 gr of 777 in any thing.
You might ask Triple Se7en
Lee