has any body used these and if you have do you get better acc and do you think they are 200 fps faster as they say.

If you are talking about MMP subbases, I use em for 150gr loads. It really helped my accuacy with heavy loads. You won't see any velocity improvement however. Just alot less variation.

I have some but have never tried them out, would they even work on a 777 100gr. pellet and 240 gr. Dead center load?? Or would this just be a waste of time??

Precision Bullet bulk prices have risen dramatically since this time last year with the DCs and QTs.... almost 33% since no winter sale has been forthcoming. Our dollar value is falling while the Canadian value has risen.. could be another reason to the price increase.

I generally just use a wonderwad ... same conclusion as those plastic sub bases for 1/2 the price.