Try a lipo with a lower discharge and/or mAh rating.
According to how the number of amps delivered are calculated with your current battery, you're discharging at a whopping 64amps.
20C x 3200mAh / 1000 = 64A
The average discharge for lipo's in airsoft are in the 30A to 40A range, With the upper end being just over 50A.
I'm not an expert on the subject by any means, but the bit of research I just did would seem to indicate that you may simply be drawing much more current than necessary.
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