10mm Subsonic?

N

Nightcrawler

New member
Been thinkin. Now, whether or not a load is subsonic or supersonic doesn't really matter most of the time, and unless you're talking about .22LR, really doesn't make a difference noise-wise in a handgun.

But, I'm curious. Most common handgun cartridges have a common bullet weight at which they are subsonic from the muzzle. All velocities are approximate.

9mm: 147gr @ 950 FPS
.40: 180gr @ 950 FPS
.45: 230gr @ 800 - 950 FPS


But what about the 10mm? There aren't any factory subsonic loads that I know of. .40 is subsonic @ 180grs, but even practice ammo for the 10mm (usually 180gr @ 1100 fps) is supersonic. With the high pressures that the 10mm round can handle, I think you could push a very heavy bullet if your goal was no faster than 950 feet per second or so.

Whaddaya think? Maybe 250 grains at 950 FPS? Even more, depending on how hot you loaded the charge. Any 10mm reloaders care to comment?
 
When the FBI decided to adopt the 10mm, the load developed and later specified was one using a 180gr JHP with a velocity of approx. 950-980 fps. It was a subsonic load, and sometimes jokingly referred to as fed-lite.

Since the same bullet weight and velocity window was reached by the .40S&W, which would also fit within the smaller 9mm pistol platform, the full size 10mm reduced loading wasn't as popular in the long run because of the extra size & weight of the pistols required to hold the longer rounds.

Of course, in retrospect, S&W bringing out and completing a previously shelved wildcat project ... which became known as the .40 S&W, which duplicated the bullet weight & velocity of the downloaded 10mm ... just after completing work on the full sized 10mm platform pistols for the FBI was a good marketing move. We all benefited from their development of this cartridge. For most of us, the pistols that would chamber the reduced power 10mm just aren't conveniently sized ... and it's sort of a waste of a caliber when downloaded, since it's so potent when loaded to its potential and chambered in large framed pistols.

I sort of wish I'd kept a box or two of the factory 10mm reduced ammunition, though, since it might be an interesting addition to someone's collection someday.
 
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I want a 10mm, and I think the whole point for me is screaming fast loads and huge fireballs. Now if you take that same 250gr and push it to max load, then maybe you got sumptin.
 
The .40 S&W and the 10mm work at approximately the same pressures. The 10mm big advantage is the extra powder capacity from its longer length. Slugs heavier than 200 grains would seriously limit volume unless you could exceed the length standard. I think there are some 220 grain loads approaching 1000 fps but that is about the balance point for pressure and volume.
 
When I was shooting a Colt Delta Elite stainless I tried some Winchester subsonic 180gr JHP, marked "Law Enforcement Use Only". Results were rather disappointing. I had far better accuracy from full charge 10mm loads, both factory and handloads.
 
Here's the idea. HK Made a 10mm MP5, with suppressor. Suppressors are a lot quieter with subsonic ammo.

I was thinking that 10mm could push a heavier bullet to 950 feet per second than .40 or .45. Was I wrong?
 
Approx:

.40 S&W = 180 gr/950 fps
10 mm = 220 gr/950 fps
.45 ACP = 230 gr/950 fps (+P)

The .45 acp can do this at much lower pressures than the smaller diameters. I think the .45 Super can push 265 gr at 950 fps and still be lower pressure than the .40/10mm.
 
If 10mm can push 200 grains to 1250 fps, how to you conclude that 220 grains would go 950 fps. A 300 fps drop due to 20 grains is not what I've experienced. Am I interpreting things incorrectly?
 
I think the .45 Super can push 265 gr at 950 fps
Click to expand...

Cal4D4, where did you get this info? Sounds good but is the case within the same margin of error as the ACP w/ 230 gr.? I think a good portion of the case capacity would be eaten by the extra 35 grains, which would drive the pressure up lots even with the enhanced Super shell. I wonder what the 450 SMC could do?
 
10mm "Lite"...


... or what some refer to as the 10mm "FBI-Lite" load is a 10mm/180gn bullet @ 980fps.

This subsonic load is at the anemic end of the 10mm's power range.

AFAIK, the heaviest 10mm/.40cal bullet currently available to reloaders is the 220gn from Rainier (sp?).

Yes, "heavy & fast" 10mm ammo is available in "factory" form:

1) Winchester 175gn STHP @ 1200+ ;

2) Corbon 180gn Bonded SP @ 1300 (more of a hunting load);

3) Geo. Arms 180gn Gold Dot HP @ 1150fps (very accurate);

4) Texas Ammo's 2 200gn loads @ 1250fps (694ft-lbs); your choice of an XTP/JHP or FMJ-FP.

Check out: http://texas-ammo.com

http://glocktalk.com/showthread.php?threadid=84117
 
krept:

I feel the top performance .45 Super/.450SMC/.460 Rowland group of cartridges which all have the same OAL length/case volume (NOT EXACTLY THE SAME!) as the .45ACP but pressures greatly exceeding the SAAMI spec of the .45ACP are best left to people who have no fears of primer piercings, peaky loads and case mixups. Some pretty awesome performance is available. As a reference point only, I found some .460 Rowland data. It may be slightly above .45 Super capability but that may be more an issue of the platform and not pressures only.

Published at:
http://www.sixguns.com/tests/tt460r.htm
This is John Taffin's site

RCBS cast bullet #45-255 12.0gr AA#7 968fps
13.0gr AA#7 1119 fps

Clark no longer recommends using AA#7 in the .460 Rowland
If I find the .45 Super loads I'll edit them in.

All cautions of unverified by pressure barrel internet load data should be applied.:)

WESHOOT2: That data requires a couple of grains above factory listed max for the 200grainer, do you recommend fairly fresh brass?:eek:

Ace Custom Guns holds the trademark on the .45 Super and they only reference that they achieve 1100fps for a 230 gr @ a 28000 c.u.p. Dean Grennell tested the original loadings at around 34000 c.u.p. I am sure a custom loader like WESHOOT2 could extrapolate a bit and load some heavy slugs at 950 fps and reasonable pressures. The feeding and nose shape may be an issue. I recommend a loader with access to a chrono and who is very familiar with pressure signs and powder quirks.
 
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I like the concept of the 45 Super, but the fact that such a hot round could be chambered in any 45 ACP gun is a little frightening. I know that the 45 Super brass has a much thicker case head, buy wouldn't it be better to chamber such rounds in a fully supported barrel? The other problem encountered with 45 Super is the heavy recoil spring. I read one article that indicated 28 pounds was the minimum! That has got to be hard to cycle by hand and the slide stop pin and the pin holes in the frame have got to be taking a beating.
 
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