I think there is a disconnect occurring. You are mixing the responsibilities of the two different vendors involved and the SAAMI's guidelines.
Think about it. SAAMI sets a pressure guidance. 37.5 in this case. They also have guidance on the case specs and there are some assumptions of the brass type etc.
Now along comes BB and they come up with a load that meets SAAMI pressure guidance, but just barely. Say (and I am making this up) that they run the MAP at 37.4. In spec, but close to the edge. In a pressure barrel it is fine. They are an ammo manufacturer so they held up their side of the bargin.
Now the gun makers come along. Say Les Baer (since he built one of my 10mm's). He says to me (when I called him and asked him to build me one), hey, that is a high pressure round, I am going to fully support the case instead of the standard 1911 feed ramp. I of course say, go for it as you are the expert. The gun shows up and it can take anything I care to shove in it even nuclear loads that would make BB blush in embarrassment.
Now Glock comes along and says well, heck I need reliability and I don't care about reloads so I will over throat my G20 and make the chamber large. Me the buyer comes along, fires a few rounds and says "wow my g20 really trashes the brass and I am getting "glock smile". So out comes the barrel, in pops a fully supported KKM and now I shoot reloads that both Baer and BBore would be embarrassed to even contemplate. True over pressure, nearly 41 mag power level nuclear loads.
Next comes EAA with the witness (I am going in sort of reverse time here...), they say wow, High pressures. Fully support the chamber. I come along as a buyer and wow, great gun, rifle like power. I can shoot nuclear level reloads out of this thing that can never be repeated because what the heck. Fully supported solid steel and it is cheap ($285 with 5 mags when I bought mine).
Time passes and I get another Witness hunter and have the same results, fully supported, nuclear power levels.
Time passes and I get a Contender. This is really supported and now I am case limited. I just can't practically cram enough powder into the little 10mm case to really push the limits anymore. Cool gun though.
Other ammo manufacturers come along and say wow the 10mm is really powerful and we can sell a bunch. So they make up a bunch and we quickly find that it is more power than most folks want to deal with. They huddle for a while, S&W gets involved, time passes and the 40 S&W is born. This is the power level most folks can handle so they say, hmm, what to do with the 10mm? Well, lets wimp the power level down to about 100 fps more than the 40 and call it good. Since the 10mm case is so much bigger, this power level can be had with less pressure and so we have the 10mm power level of today from most big name ammo companies.
Now we get to the Delta Elite. Colt, has a long history of conventional 1911 format barrels so they say, "good enough". They make a great gun that can take the now conventional 40+P version of power that is vended by most companies today. It is not fully supported as the pictures above show. Life is good.
So now along comes cheap chrono's, more shooters and the demand for higher performance products. Buffalo Bore, Double Tap, Cor-bon come along and say, wow, there is a market for high performance 10mm ammo that actually can be made in SAAMI pressure spec that is real power. Great. They do it and the market IS there and folks buy it.
Now mix real SAAMI max 10mm ammo with an unsupported barrel and your casing blows. Had this been fired in my contender I strongly doubt it would have blown. In my witnesses I doubt it would blow. In my Baer, Glock (KKM version) or my other 10's I doubt it would have blown. In the Delta elite shown it blew.
So who is at fault here? Good question. Each party came to play making certain assumptions. Put them together correctly and no issue. Put them together wrong we have a classic case blow out from an unsupported chamber.
