SAFE,
Ah, OK, and looking forward to your results!

Overwhelmingly I tend to see stuff too out around 250g with…… questionable load data. I am pretty sure the 300 range would be possible given length of projectile but with all of the available pistols we have being Glock based for Rowland there is a reluctance to try anything in cast lead even with the poly coat. If I end up going the USP route anytime soon I will let you know what I figure out as I am more focused on 357 Sig/mag, 475 linebaugh, 10mm and 44 mag experimentation in about that order currently.

SAFE,
I haven’t looked into it much, but has anyone been doing anything with heavier bullets in Rowland?

There comes a point where one has to say fuck it bring back 50gi and/or go for the dd stamp and wildcat something bigger when subsonic ammo is the major feature and min maxing gets involved.

You raise some good points (e.g. I honestly hadn’t noticed the lack of 220 10mm JHPs because, like SAFE, I favor the light/fast end). I wouldn’t necessarily say “if you’re limited to subsonic velocities .45 beats 10mm,” though. Moving around a house constantly requires the “support hand” to do everything but support, and IMHO a 42″ suppressed full-length rifle is hopeless as a “hand and a half” gun. From a PDW barrel, 10mm drives those 200gr JHPs right up to the threshold of subsonic, getting better KE than 850fps .45.

I can never find exactly what I want either, so I make it. I think my next project may be a 9mm fixed-barrel Witness upper for suppressed use.

As for the length of the gun, yes a 10mm 5″ barrel Extar would be almost a foot shorter than a .45 16″ carbine. That’s a big deal and a very substantial consideration. And truthfully, the Extar .45 with a 10″ barrel would extract all the velocity you want from that .45 HST, so the last 6″ is just wasted. If Extar offered a long barrel option I do believe I would have bought it already, as it’s otherwise pretty much perfect and I’m very very interested in it.

“10mm goes up to 220 – a marginal difference in both weight and diameter from the .45. ”

Yes it does, but that is definitely not an apples-to-apples comparison to what I’ve been talking about. Yes, the 10mm has 220 loads available for it, but only in solids (hardcast, etc). No expanding hollowpoints exist in 10mm at 220 grain, and certainly not from recognized commercial suppliers like Federal HSTs or Speer Gold Dots.

As for the size difference, it sounds minimal on paper but it’s not so minimal just looking at them. The .45 is 11.5mm, the 10 is (naturally) 10mm, and the 9mm is 9mm. So 10mm sits almost halfway between the .45 and the 9, and actually a tiny bit closer to the 9 than the .45. Which, of course, is why it has more rounds in a mag than a .45 does. It’s a big bullet, but I’d argue that the difference between the .45 and the 10 is definitely quite noticeable. Especially if we’re talking about a hardcast 10 vs an expanded .45; there the diameter difference will be drastic; you could literally fit four 10mm hardcasts in the hole that a single expanded .45 HST makes.

Here’s an actual expanded HST .45 compared to a pixel-level accurate 10mm circle.
https://ibb.co/N2P0ytsJ

Now, expanding bullets tend to expand bigger the faster they travel, and that HST was shot at the typical 900 fps range for a .45. From a carbine I’d expect another 150 fps, so it may expand even bigger.

I’m not knocking the 10mm. I love the 10mm. Look at my username. I carry the 10mm daily, loaded with HSTs, and am supremely confident in it. I’m just saying that if you’re limited to subsonic velocities (such as I would like a home defense gun to be), .45 beats 10mm. As a defensive load, it’s 15% heavier and has a larger starting diameter which will lead to a larger expanded bullet diameter.

In any case other than a suppressed home defense gun, I would always take 10mm over .45. Always. I’m just saying that in this one specific use (suppressed) at the same velocity, the .45 produces bigger holes and delivers more energy on the target at subsonic velocity. Energy for 230 grains at 1100 fps = 618 ft/lbs; for a 200 grain 10mm at 1100 fps it’s 537. Not a drastic difference, but there is a difference to be had, and when defending my home I want that difference.

Truthfully, if I could just find a carbine conversion kit for my 10mm 5″ XDM I’d just get that instead of a whole new gun. But so far I can’t find one, the MCK doesn’t work with an XD with a threaded barrel and I haven’t found a serious contender from anyone else yet.

10mm goes up to 220 – a marginal difference in both weight and diameter from the .45. Suppressed, a carbine with that 5″ barrel will be nearly a foot shorter than the .45 (and tucked just as close to the body); it’s about 5″ shorter than the unsuppressed Extar. When muzzle energy is more important, it’s a mag swap away from beating the much clumsier 16″ gun.

Given my current location in NY the only NFA I can potentially get would be destructive devices and only non-explosive. With that said given the option short barreled suppressed would be my starting point for anything pistol caliber and fun.

Never really looked at 45acp in the lighter loadings as much as super and Rowland but that is a sufficiently quick to create problems for the other side of the muzzle possibly even for lv 2 kevlar. Not sure about 3a but will make a not to try it if we ever get someone with a 45 carbine.