In this post, we discussed the 400 Corbon round. Since then I worked up [what I consider] maximum loads around 155gr and 180gr bullets and performed apples-to-apples comparisons of muzzle velocity. In both cases, the powder used was Alliant Power Pistol. Here's some powder weight vs. muzzle velocity graph.
First, a Hornady 155gr XTP/HP bullet and Speer 155gr JHP-GD bullet.
Second, a Winchester 180gr JHP bullet.
We can see that for all powder weights, a bullet launched out of a 400 Corbon will be about 100fps slower than when launched out of a 10mm cartridge. This is because the 400 Corbon has a larger effective volume than a 10mm cartridge and hence the chamber pressure is lower for any given powder weight.
However, one can achieve equivalent ballistics from the 400 Corbon as from the 10mm.
So, in conclusion, the 400 Corbon is at least as good a round as a 10mm with the addition of the following advantages:
- An existing 45 ACP firearm can be readily converted to shoot 400 Corbon by the mere drop-in installation of a barrel. The same cannot be said for 10mm as the conversion to fire 10mm is more complex, requiring, at a minimum, a different breech face, magazines and barrel.
- For the handloader, 400 Corbon brass is cheaper and more readily available than 10mm brass -- one merely necks down 45 ACP brass.
- A bottle-necked cartridge (e.g. 400 Corbon) feeds more reliably than a straight-necked cartridge (e.g. 10mm).