I recently finished a 10.5 SBR build. Its a spikes lower and upper with a low profile gas block. When I shot it I was having a lot of short stroke problems. I have a "frankenbolt" full auto bcg in it (which I'm less than pleased with). It has a psa lpk. I weighed the buffer and its 2.9 ounces. I'm wondering if the extra weight from the bcg could be causing the short stroke. The upper was complete from Mas Defense. I'm aware the gas port could be misaligned, but I'm wanting to rule out everything else before I tear the upper apart. Any suggestions on what to look at. A heavier buffer would just create greater problems as it would increase resistance when cycling correct? Is there ever a problem with the action cycling too fast?