Reloaders, in general, need to get out of the mindset, that if two bullets weigh the same, then you can load them the same. Not necessarily so. The most obvious example is the difference in pressure and velocity between a 160 gr SWC and a 160 wadcutter loaded flush with the case mouth. Most everyone recognizes that one.
However, the diffence between a Hollow base wadcutter SWAGED bullet and a solid base CAST wadcutter are also significant. It's not always recognized but it IS there and the difference is REAL as "Smith Crazy" suggests.
In much earlier days, I was loading Saeco 190 gr SWC in a .45 ACP. Then I got a very nice H&G four cavity mould that cast a 190 gr #130 SWC. Since they weighed the same, I used the same powder charge. I was fat, dumb, and happy until I cracked the slide on my .45. I chronographed that load and it was over 1100 fps!! (the Saeco ran 950-1000 fps. The lower load was safe and the faster load was NOT. It turned out my recoil spring had "sagged" from 16.0 lbs to 12.0 lbs. That combination of a "too hot" load and a "too light" spring was more than my 1911 could take. The #130 bullet took up more powder space than the #68 bullet did. It is as simple as that.
The chronograph is NOT a pressure gun but it can sure indicate areas to stay away from. It certainly educated me. I use a lot of the H&G #130's these days but I am careful to adjust my powder charge to give me what I should have instead of MORE (that I shouldn't have
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Solid base wadcutters need a bit more powder because they are cast and are harder and the solid base does not expand quite like a soft, swaged hollow base wadcutter does.
On the other hand, the solid base can be driven faster, with safety, than a hollow base wadcutter (driven too fast, hollow base bullets have separated their skirts and left the skirt in the barrel to cause a bulged barrel on the next shot).
They are both FINE designs but MUST be used within their design limits for safety AND satisfaction.
Dale53