10 mm PCC

There’s part of me that always thinks a rifle or carbine will always get better velocity/energy than a pistol/handgun/shorter barrel. This seems not to be true for 10 mm ammo (and others). There’s a diminishing increase above about 10”-12”, right? Is it actually diminishing out to 16”, or just no appreciable increase?

But, it seems that one can reload with slower burning powder and get better performance out of carbine/rifle length barrels. There’s also a bolt & barrel combination that delays the blow-back.

But, then, where’s the advantage? if i need pistol ammo for my G20 (clone) and different, specially loaded rifle ammo for a PCC, what have I gained? If that’s so, i may as well build a 10 mm AR pistol instead of a PCC.

Thoughts?


(Oh. I’m specifically thinking whitetail deer hunting in Iowa.)

Yep, good things to take into consideration. To maximize performance in a longer bbl you'd most likely be using a slower powder than would be ideal in the g20. My thoughts are completely uneducated as I've never had a 10mm.

Handy chart for barrel length vs velocity... link at the top of the chart to get muzzle energy chart.

http://www.ballisticsbytheinch.com/10mm.html

Handy chart for barrel length vs velocity... link at the top of the chart to get muzzle energy chart.

http://www.ballisticsbytheinch.com/10mm.html

Thanks. That’s a good chart. But it confirms. There is little to no to negative advantage to a 16” barrel over a 12” barrel.

If I build a 10mm PCC it should be an AR pistol not a carbine.

Now, if the alphabet agencies would just decide what they’re doing about barrels, braces, and suppressors I could get on with planning a build.