Steel roundball ammo from Germany...

This first photo shows over a thousand rounds of carbon steel alloy roundballs in the caliber 10.85mm and weighing at 4.8 grams/round.
That makes these 0.4 gram/round lighter than the chrome alloy steel roundballs which I bought on eBay for my .43 caliber Walther PPQ M2 T4E Co2 pistol.

(My Walther PPQ M2 T4E .43cal Co2 Pistol & Beeman P-1 Magnum .22cal. spring piston Pistol)

I ordered 2000 rounds of these carbon steel alloy .24cal/6mm roundball ammo for use with my SocomGear Kel-Tec PMR-30, Tolmar/Grand-Power X-Caliber, Steyr M9-A1  & TSD Sports M1911, all of which have muzzle velocities above 400 fps with .30 gram Aluminum alloy BB's, and should be powerful enough to shoot 0.9 gram steel balls.
These 6mm roundballs are being shipped from Germany on Tuesday, July 2nd, and should be here with 10-14 days, hopefully.

The 2000 rounds of .24cal/6mm  0.89 gram carbon steel alloy roundball ammo arrived the other day, an I almost immediately charged my SocomGear Kel-Tec PMR-30 and Grand-Power X-Caliber Co2 pistols with gas, loaded a half dozen rounds and shot them across my chronograph 🔫
The results were decent 👌
My Kel-Tec PMR-30 shot in the 310-325 fps range and the Grand-Power X-Caliber shot around 275 fps.
Based on the results,  the PMR-30 is obviously better suited for such heavy 6mm ammo.
I still have a STEYR M9-A1 and TSD M1911/Colt Defender to test and I will update this post after that.

(SocomGear Kel-Tec PMR-30 .24cal/6mm GBB Co2 pistol)

(Tolmar/Grand-Power X-Caliber .24cal/6mm NBB Co2 pistol)

As reported in a recent post, the SocomGear Kel-Tec PMR-30 just loved devouring these 13.3 grain carbon steel alloy balls!
With muzzle velocities consistently between 310-330 fps, this Co2 pistol and this projectile is a perfect combination.
From 10 feet it blasts the steel balls straight thru Campbell's soup cans!