quote:

Originally posted by sigfreund:

quote:

Originally posted by 3/4Flap:
I cannot imagine a wholesale switch away from 5.56 for 9mm in longarms! Such a move would be just plain stupid.

Indeed.

A properly trained and experienced shooter can get multiple hits with a rifle chambered for 5.56mm just as fast on a practical level as with a 9mm—and multiple hits are less likely to be required to neutralize a hostile threat because the former’s wounding effects are so much greater.

Except as a range toy the whole idea of a long gun chambered for a short gun cartridge is inane, and we can only wonder what the fascination with the notion is.

Mp40/Thompson/M3/MP5/Uzi - range toys?

quote:

Originally posted by HawkeyeJohn:

quote:

Originally posted by sigfreund:

quote:

Originally posted by 3/4Flap:
I cannot imagine a wholesale switch away from 5.56 for 9mm in longarms! Such a move would be just plain stupid.

Indeed.

A properly trained and experienced shooter can get multiple hits with a rifle chambered for 5.56mm just as fast on a practical level as with a 9mm—and multiple hits are less likely to be required to neutralize a hostile threat because the former’s wounding effects are so much greater.

Except as a range toy the whole idea of a long gun chambered for a short gun cartridge is inane, and we can only wonder what the fascination with the notion is.

Mp40/Thompson/M3/MP5/Uzi - range toys?

Long gun, not PDW.

quote:

Originally posted by sigfreund:

quote:

Originally posted by 3/4Flap:
I cannot imagine a wholesale switch away from 5.56 for 9mm in longarms! Such a move would be just plain stupid.

Indeed.

A properly trained and experienced shooter can get multiple hits with a rifle chambered for 5.56mm just as fast on a practical level as with a 9mm—and multiple hits are less likely to be required to neutralize a hostile threat because the former’s wounding effects are so much greater.

Except as a range toy the whole idea of a long gun chambered for a short gun cartridge is inane, and we can only wonder what the fascination with the notion is.

+1.

What would possess the Powers That Be to make such a decision if such a decision was in fact made?

I think a 9mm carbine would be fun as heck...I've owned a Marlin Camp Carbine and when it actually worked {rarely...} it was a fun toy, and I've owned a couple .45 submachine guns, also very fun...but...compared to a 5.56 carbine there is, well, no comparison! What are they thinking?

Well, that depends. Was the decision made by those who use the ammo, or by those who just buy, store and transport the ammo?

Not as important but the P320 is an armorer's dream gun. Logging and tracking duty gun, off duty gun, going from patrol to detective or TDY to a certain unit and getting issued a smaller gun then logging and tracking maintenance on the new serial #. With the P320 you get one gun and if you want smaller or larger go buy you're own kit, serial # stays the same!

quote:

Originally posted by sigfreund:

quote:

Originally posted by 3/4Flap:
I cannot imagine a wholesale switch away from 5.56 for 9mm in longarms! Such a move would be just plain stupid.

Indeed.

A properly trained and experienced shooter can get multiple hits with a rifle chambered for 5.56mm just as fast on a practical level as with a 9mm—and multiple hits are less likely to be required to neutralize a hostile threat because the former’s wounding effects are so much greater.

Except as a range toy the whole idea of a long gun chambered for a short gun cartridge is inane, and we can only wonder what the fascination with the notion is.

Interesting conversation.

I came up in the heyday of the MP5. And it was a great subgun. The problem with it, and by extension the MPX, is the fact that it is still a shoulder fired pistol. Such as why the MP5 died a quiet death in the US LE special operations community.

Now, one potential upside is working in and around vehicles. Some of the stuff we have done shows that the higher bullet mass of a good 9mm pistol round does a pretty dang good job on windshield glass.

Dumping all the MPX Gen1 @ a heavy discount?? I could think of better weapons for both roles including the already in service HK P2000

The important question is will a 9mm from the MPX defeat soft body armor. One reason we went to 5.56mm was bad guys wearing body armor (Bank of America LA robbery!) The higher velocity from a sub-gun may defeat body armor but it needs to be tested.

quote:

Originally posted by 10round:
The important question is will a 9mm from the MPX defeat soft body armor. One reason we went to 5.56mm was bad guys wearing body armor (Bank of America LA robbery!) The higher velocity from a sub-gun may defeat body armor but it needs to be tested.

No. Most IIIA soft armor now days will stop full power .357magnum and .44magnum loads from a 6" revolver. Armor has continued to be more protective over time, while cartridges have not really become more armor piercing. Some of the new hybrid armors that incorporate ceramic scales between the soft armor panels stop the PDW calibers too like .30 Carbine, 5.7mm, and 4.6mm.

In order to defeat the best armors of today, and the future you will really need a larger case capacity. Yes high velocity projectiles work well for this, but you can also use very high sectional density and momentum to achieve armor penetration. For instance the Russians use a 9x39mm subsonic cartridge which fires 262gr steel core bullet. This 9mm bullet has such a high sectional density and momentum that it passes through soft armor like it wasn't even there......and will defeat hard armor rated up to a .30-06 black tip penetrator.

quote:

Originally posted by jljones: Some of the stuff we have done shows that the higher bullet mass of a good 9mm pistol round does a pretty dang good job on windshield glass.

That is a good point.

Speaking of points...

There shouldn't BE an unsolvable problem defeating glass with the 5.56 round.

I'd think a heavy 80-90 grain bullet with a thin nosecap over a square-shouldered blunt conventionally constructed {lead core} bullet should do the trick. I'm thinking of some of the developmental configurations in Labbet & Meade's excellent technical history of the .303. For that matter, for police work {if they'd feed reliably} a good 80-grain round nose bullet just might work {?}.

only time will tell...sometimes rumors are just that

Hopefully it goes over better than the FAMs adoption of the P250.

quote:

Originally posted by 3/4Flap:
There shouldn't BE an unsolvable problem defeating glass with the 5.56 round.

There isn’t if the proper bullet is used. I’ve mentioned all this before here, but a series of photos showing the performance of various bullets fired into an old (1976) pickup.

Shots fired through the partition between the wheel well and the engine compartment (above the tire which is very over-exposed in the photo and looks almost white). (Speer 64 grain Gold Dot.)



Effects on the engine that caused coolant leakage. (Speer 64 grain Gold Dot.)



Several shots were fired through the windshield of the vehicle. The first Gold Dot shot traveled through the windshield, the test medium and through the back window. The medium was about 8 inches of water-soaked and drained newsprint positioned on the seat of the vehicle.



One Gold Dot bullet was captured by the tape at the back holding the test medium together. The recovered weight was 29 grains. There was no deviation in the bullet path after going through the windshield. Intact M193 bullet for comparison.





No other bullet performed as well as the Gold Dot, including the full metal jacketed M193 and M855. A piece of cardboard was placed in front of the newsprint stack as a witness. In the below photos the small scattered holes were evidently caused by glass fragments, although in some cases they may have been bullet fragments. No bullet except the Gold Dots perforated the test medium stack, and IIRC none of the fragments penetrated more than about 6 inches at most.

In addition to this test, I once fired the Gold Dot load at a shallow angle through the side window of a car. The bullet produced a minimally-distorted hole at the expected point of impact. I believe the Gold Dot bullet performs very well when fired through barrier glass.

M193. Note that the bullet tumbled after striking the glass and appeared to have partially fragmented.



M855. The bullet broke into two major pieces after striking the glass.



Hornady 75 grain TAP. The bullet broke into multiple pieces.



Hornady 75 grain FPD. The bullet broke into two major pieces.



Speer 64 grain Gold Dot. The hole below the red dot aiming point was caused by the bullet that evidently did not tumble or fragment excessively.



Added: As for handgun bullets, in experiments 357 SIG 125 grain FMJ and Gold Dot bullets were stopped by “expired” level IIIA Kevlar body armor. Although I don’t recall the 5.56mm NATO load I used, it was probably M193 and the bullets perforated the same armor with no apparent difficulty.

THANKS for posting that, sigfreund.

That is very interesting. We shoot all sorts of stuff here but I've never shot auto glass. That is really interesting information.

quote:

Originally posted by 3/4Flap:

quote:

Originally posted by jljones: Some of the stuff we have done shows that the higher bullet mass of a good 9mm pistol round does a pretty dang good job on windshield glass.

That is a good point.

Speaking of points...

There shouldn't BE an unsolvable problem defeating glass with the 5.56 round.

I'd think a heavy 80-90 grain bullet with a thin nosecap over a square-shouldered blunt conventionally constructed {lead core} bullet should do the trick. I'm thinking of some of the developmental configurations in Labbet & Meade's excellent technical history of the .303. For that matter, for police work {if they'd feed reliably} a good 80-grain round nose bullet just might work {?}.

Oh, not saying it wouldn't. But, most of the time, we don't have the luxury to swapping between six different loads for different operations. A good middle of the round load and bullet weight usually is what wins based upon the ballistic performance. The only round that I have seen best the Gold Dot is the Federal 55 grain T1. Both are good rounds.

Comparing a specialty load with common run of the mill pistol loads is the thing. You could also compare swapping calibers to a .308 to enhance the performance, but in the end it is all academic. The best load is the one that passed testing, and that you have on you at that particular moment I suppose.

I have two different load outs only, and one is extreme specialty stuff for use inside of correctional facilities (only a couple of magazines in my trunk). The rest of the time, all the magazines I have available are 55 grain T1.

Again, this is a largely academic conversation. The T1 does a great job on auto glass, but this has really turned into a good/better/best roundabout. I spent two weeks recently teaching shooting through cars from various approaches and angles recently, and can tell you that even the best of bullets do strange things, and there really is no magic bullet, just a whole lot of "good enough" ones.

Thank you sigfreund and jljones.

Additional photos from the above series of tests.

Fragments from multiple shots recovered from test medium.





Some shots were also fired though the double wall of the pickup bed. Through steel the M193 did the best, although the 64 grain Gold Dot seemed to do well despite losing part of its weight. The M855 was erratic; sometimes it penetrated well, but other times it tumbled immediately.

Note that in the below photos some bullets that penetrated well produced two holes in the register paper with a single shot. I believe that the secondary holes were possibly caused by plugs of the barrier metal that’s punched out and driven ahead or along side of the bullet. But I’m not sure. The “long range” annotations refer to the fact that the register paper was set farther away from the barrier metal, on the other side of the pickup bed. The close range shots had the register paper close to the metal.

The gray swirls or blotches on the register paper were evidently caused by the lead in the cores of the bullets. In some of the photos it’s obvious that the lead was being extruded in a fine spray from the bullet bases.

Gold Dot through double wall sheet metal.







Hornady 62 grain “Barrier” load



Hornady 75 grain FPD; again these heavy OTM-type bullets did not do well through barriers.



Hornady 75 grain TAP.



M193






M855





In less formal tests of M855 and car bodies, the load did not do particularly well when shooting at angles or into portions of the vehicle that contained multiple layers of barrier materials, controls for windows and doors, etc.

Finally for the professional or amateur scientific investigators among us:
I fully realize that my test conditions and protocols did not produce statistically or general scientifically valid results. My efforts were not for the purpose of producing a paper to be published in the Science or Nature journals. The results should be viewed as indicators only, but if you want scientific-level information they might serve as a starting point for your own research.

jlj and sigfreund, thanks very much.

A LOT can be learned from such testing in fact. I have done very little 5.56/.223 testing but have a "protocol" for big game bullets and don't hunt with anything I haven't tested anymore. Truth is, tests can be set up that are very useful. We have seen weird and unpredictable things occur with some bullets we expected something else of.

Some more of the story:

This shows some of the exit holes for the above-referenced tests through the pickup body. At this point I can’t say how they correlate to the photos above. “FMJ” refers to the M193 and the M855; “75 LE” is the Hornady 75 grain TAP; “GD” is Gold Dot; “FPD 75” is the Hornady 75 grain For Personal Defense. Not all shots produced exit holes in the opposite side of the pickup.



For comparison purposes the following photos show bullets fired directly into soaked newsprint with no intermediate barriers (separate session from the above with vehicle).

Speer 64 grain Gold Dot (sri for lack of focus on the first). The average penetration was about 11 inches.

Side:



Top of same:



Hornady 75 grain FPD.



Hornady 75 grain TAP.

Top:



Bottom of same:



Hornady 62 grain Barrier

To return to the original topic:

quote:

Originally posted by HawkeyeJohn:
Mp40/Thompson/M3/MP5/Uzi - range toys?

Yes, in my opinion that’s mostly what such weapons are these days. Under some limited circumstances the small size of some of them (but not all) along with their automatic fire capability would allow them to fit a narrow niche better than a handgun or M4 or AK type rifle. For the most part, however, it would be far better to have a (maybe) slightly larger weapon that fires a much more ballistically effective cartridge, not to mention having the capability of mounting far better sights and accessories such as lights.