I pretty much made up the same thing, bufferwise for my .260 Rem. I had the DSG bodied buffer weighed at 5.15oz, and another hybrid combo at 5.7oz (for 2.500" buffers). In the .260, sometimes the 5.7 wouldn't lock back - maybe a touch too heavy, I was thinking? I swapped in the DSG hybrid at the 5.15, and I've never had another problem.
In my case, I know what it is, with that 5.7 buffer - that Wilson Combat .260 barrel had a 0.070" gas port, and I know in my heart that thing needs to be 0.080." That's the difference with those buffers. That gun comes apart for paint soon, so....