Dave,
Unfortunately there is NO way to determine pressure from the combination of dram equivalence and shot load. Cartidges with lower dram equivalence "tend" to be lower pressure, but you cannot determine that for sure simply from reading to shell box.
Dram equivalance is an archaic term now used to give an indication velocity. However, you have no way of knowing how the manufacturer is achieving that velocity - i.e, the specific powder the manufacturer is using, and what that powder's pressure curve looks like.
Often with promo "lite targte/field" loads, the maufacturer will utilize relatively small amount of fast burning power (to achieve cost savings) but these loads still bump up against the SAAMI-maximums in regard to pressure.
Lower pressure loads are readily availble via mail order so why risk pounding you old gun to save yourself $20/flat.
Good luck,
Ken
