Lotta labor in that work by Larry Gibson. Many thanks, sir.
Even the 38/200 loads (3.0 grains of Unique or 3.3 grains of Herco) haven't produced any indicia of even warmish pressures in the W-E or the M&P. Only after extended shooting sessions does the need for an extractor come about due to grittiness. Brush out the chambers every 50 rounds or so, and cases fall out via gravity if given the opportunity. Think "22 LR swing-out revolver" in this context.
A few years ago I was shooting both the Colt and its 150 grain SWCs (#358477) and the M&P (202 grain NEI #169A) at iron silhouettes at 25 yards. The 150s made a nice "pa-TINK" sound when hit--the 202 grainers gave a pretty stalwart "WHANG" when they connected. That 50 grains of lead made a difference of some sort.
There have been a number of threads here concerning the 38 S&W in the recent past, and some of those threads have REALLY "gotten legs". People like the little popgun round, and have for a long time. The 38 Special and 357 Magnum have thrown shade on this caliber, which is not really fair. Someone in another thread--Outpost 75, I think--pointed out that the terminal ballistics of the 38 S&W/4"/146 grain bullets differ little from those of a 2" 38 Special that was the mainstay of plainclothes police work for decades. Just sayin'......
The 38 S&W will remain a recreational tool for me. There was a time when a significant portion of my shooting "R&D" was concerned with defensive action training & prep; I still keep the edges sharp with my social iron, but 95% of my shooting these days has to do with hunting prep or just plain fun shooting. The 38 S&W is VERY cheap to reload using cast bullets and its very small sips of powder. If bullets conform to barrel dimensions, the caliber can be quite accurate--sufficiently so to enable small varmint harvesting to 50 yards in the Police Positive or the S&W M&P.