The testing I did last year with the sub bases was a mixed bag. Some loads shot lower, some didn't. Some shot better andmany shot worse. I think generally they tend to insulate the bullet from the heat and pressure of the burning powder charge - which in the case of smokeless charges or magnum BP loads, can be a good thing. I wouldn't expect them to offermuch to the shooter who uses regular loads - might even make them shoot worse because a certain degree of bullet upset is known to produce good accuracy in many cases.

The only load I am currently usingwith the MMP sub base is the 410 gr. Hornady Great Plains using either 130 grains of Pyrodex pellets or 120 grains of loose 2F Triple 7. My hunting buddy uses the same bullet/base with 110 gr. of 2f Triple 7. Accuracy is very good and, without the sub base, is marginal - at least with charges this stout. Both are good elk loads.