couple of odd-ball questions related to 10mm SUBSONICs

[undeRGRound]

Yeah, seemed like an oxy-moron to me as well, at first. But my son has just bought a Kriss-Vector 10mm SPD-E (E for enhanced) with a 6.5" barrel and folding tube for a brace. Threaded barrel, and he already has his Silencerco waiting for him in ATF "jail" until his sticker comes in. I saw an old reference to DoubleTap 230gr Subsonic but they don't list it on their site anymore.  I have found several places that make 180gr, 200gr and 220gr that include "sub-sonic loadings" of under 1100fps. This in my opinion, is basically "40 S&W Long" in some weights. The 2 questions are:

1. How heavy of a 40 cal bullet have you all heard of?

2. What Mfg's may have a true Subsonic 10mm round?

These are strictly for use with the can, I could foresee using a can and then using the gun for hunting with the heavy-hitters (supersonic).  It's really just that neither one of us wants to have a 40 S&W when we both have multiple 10mm arms and plenty of ammo.  I am also looking at the KV in the near future. I shot his and it's a really great platform!   

[The_Shadow]

Well any load under 1100 fps would be considered (SUB SONIC at sea level).
230 grain is about as heavy bullet you can get in the 10mm and still have room for powder to give it a good push.
Most factory loads are under the 1100 fps with shorter barrels, however the 6"+ tube adds some velocity and can exceed the Sub Sonic velocity window.

Now handloading would allow you to detune your ammo for just the right performance level using the KV with the barrel length and can.  Staying with the 200 grain bullets (more common) you could load them to right at 1020 fps and stay under 1100 with the KV.

Remington, Speer, Federal, Winchester usually fall in the Sub Sonic as factory ammo even though its not stated on the box!  Testing has shown many don't reach their advertised velocities.

Check Lucky Gunner https://www.luckygunner.com/labs/10mm-auto-self-defense-ammo-ballistic-gel-tests/

[Taterhead]

The heaviest 10mm bullet I've heard of is the DT 230 gr WFNGC, but it was reported to actually weigh 220. 220 being the upper end of the practical range.

Quite easy to get subsonic. I have a few pet loads that are charged with quick to medium burning powders that are very suitable for that task. The quickest burners are relatively quiet ander a 200 gr bullet. I've used 452AA (substitute WST), 231, No. 5, Unique, WSF, etc.

[undeRGRound]

Well any load under 1100 fps would be considered (SUB SONIC at sea level).
230 grain is about as heavy bullet you can get in the 10mm and still have room for powder to give it a good push.
Most factory loads are under the 1100 fps with shorter barrels, however the 6"+ tube adds some velocity and can exceed the Sub Sonic velocity window.

Now handloading would allow you to detune your ammo for just the right performance level using the KV with the barrel length and can.  Staying with the 200 grain bullets (more common) you could load them to right at 1020 fps and stay under 1100 with the KV.

Remington, Speer, Federal, Winchester usually fall in the Sub Sonic as factory ammo even though its not stated on the box!  Testing has shown many don't reach their advertised velocities.

Check Lucky Gunner https://www.luckygunner.com/labs/10mm-auto-self-defense-ammo-ballistic-gel-tests/

I am with you, but I am using the term SUBSONIC like the 22lr mfg's do,  Standard Velocity is below Mach 1  but they use subsonic for QUIET.  We want custom loaded, subsonic, quiet 10mm capabilities. I am thinking about a 950fps loading (5" test barrel) specs would do it.  The extra weight is for better momentum and penetration once into the "absorbing medium" is encountered. Like pine boards, water jugs, 4 legged critters or the hopefully never encountered BG. (bad guy!)  We have a Town Marshall for a neighbor, and whilst he is a good guy, and an Air Force Vet, well, his wifey with young kids is just  bit paranoid and hates hearing gunshots. So we are limited to 22's and whatever we can get away with on a can.  Good neighbors and all that.    
I also see a lot of value in a thumper 10mm "SUB" and might even go 45 ACP with a caliber change for one or both of us, but doing something pretty new (at least for us) will be a great project for me and Sonny   

[undeRGRound]

The heaviest 10mm bullet I've heard of is the DT 230 gr WFNGC, but it was reported to actually weigh 220. 220 being the upper end of the practical range.

Quite easy to get subsonic. I have a few pet loads that are charged with quick to medium burning powders that are very suitable for that task. The quickest burners are relatively quiet ander a 200 gr bullet. I've used 452AA (substitute WST), 231, No. 5, Unique, WSF, etc.

GREAT Info, we have a batch of 200gr bullets coming.  I want to further explore the heavy stuff, 41 Magnum bullets resized to .401 ca easily be found for 230, 240, 250 and up, but I think 250 is gonna be plenty.  I will likely just get a hundred 230gr and see how that does, checking case volume and so forth, then decide if a hundred of the next size is worth messing with. OAL's 1.250 and 1.260 are pretty common and I know it will likely feed very well. If I end up with 100 bullets that are "too heavy" it is not much money   About $16 from what I have seen, plus shipping. $25 is cheap R&D imo