My sub-caliber trainer (9x19mm Springfield Armory 1911A1 Loaded) has taken on a life of it's own. It's PRIMARY job is still low-cost training with inexpensive 9mm ball ammunition.
When the pistol is loaded with CorBon's 9mm Parabellum (9x19mm) DPX (115 grain solid copper hollow-point at 1275 fps), I do NOT feel underarmed for
carry/defensive purposes, BUT I just ordered a Nowlin drop-in barrel and bushing in 9x23mm as a special order from Brownell's. The 9x23mm drives a 125
grain .355" projectile at 1,450 fps (.357 Magnum ballistics).
The 9x23 case head is thick (like a rifle case) and operates at 40,000 psi while 9mm+P is 38,500 and .38 Super+P is 36,500 psi. For comparison, some
other common SAAMI pressure specs are as follows: .38 Spl is 17,000, .38 Spl+P is 20,000, .357 Magnum is 35,000, "regular" 9x19mm is 5,000, .45ACP is 21,000 and .45ACP+P is 23,000 psi.
Other than the additional 9x23 Nowlin-ramped barrel, my 9mm SA 1911A1 only needs .38 Super Mags (I'll use Wilson-Rogers) and a 20# recoil spring.
Otherwise, it is good to go. The 9x23 is said to be the BEST feeding round in the 1911 platform and is essentially a 11-shot .357 Magnum from a flat
semi-automatic pistol. It's too good a concept to ignore.
CorBon is going to make their DPX in 9x23 and I will soon get and test some of this ammunition in my SA 1911A1. My 9x23 carry ammunition until the DPX comes available is the CorBon 125 JHP at 1,450 fps. (W-W also makes two loads for the 9x23: a 125 JSP and a 125 Silvertip Hollow-point, both at 1,450 fps.)
"If you are going to shoot small bullets, shoot FAST small bullets."
A good link to 9x23 information: