Lyman 9x19, 9x21 -- Why the difference?

[Dannix]

Came across some insightful info here:
http://forums.1911forum.com/showthread.php?p=2731681

Their local guru also specifically mentioned the Lyman #49 manual's 9x21 data as no good. So my question is now moot.

Best Regards to all here.

[RobW]

For all you can stomach on this topic, head over to the Enos forum and search for '9mm Major'. Done to death. As one poster has already mentioned, the 9x21 reportedly owes its existence to Euro laws about "military" calibers. The 9x19 vs. 9x21 debate in IPSC/USPSA circles revolves around an old rule that would not allow 9x19 to shoot Major. Nowadays, plenty of people push the envelope as the loads are more or less equivalent for the same charge weight, bullet weight, and OAL. YMMV in your gun/chamber/reloading room, of course. I've still got a bag of 9x21 brass laying around somewhere if anyone wants it! The Springfield P9 Custom Shop was killer, I had a pair of them set up for a one-season foray into Open division way back when.

--RW

WVBob, I know Glock did make a few 9x21s. I'll have to see if I can find if they designed it any different. You got any links to how 9x21s operate at a higher pressure level? The closest thing I've found is the imprecise blurb in the Lyman manual.

sleeper78, some if your information has been misinformation, some shows a lack of basic research. If you just want to learn along with me, awesome! Welcome aboard! Hopefully we'll both learn something.

phill, indeed your are correct. 45 Auto and 460 Rowland is probably one of the most acute examples I can think of. I'm not seeing any pressure differences between 9x19 and 9x21 in the manuals though. Got any info on differences? I'm not assuming there is not difference -- that's why I posted. I would like to know what they are. I'm also interested in why of the manuals lack of 9x19 1.169 OAL loads.

[Dannix]

Thanks RobW. I'm only just getting started into sinking my teeth into all the great info there! I guess we have the wrong general audience to post this question here.

RobW, I'm interested in your bullet weight, type, powder preference (I know Solo 1000 is getting popular) and the like. Shooting you a pm.

[RobW]

PM answered ...

Thanks RobW. I'm only just getting started into sinking my teeth into all the great info there! I guess we have the wrong general audience to post this question here.

RobW, I'm interested in your bullet weight, type, powder preference (I know Solo 1000 is getting popular) and the like. Shooting you a pm.

[Flash]

Lyman 49th Edition
9x19
147 gr. TMJ
1.115" OAL
Max: AA#7, 7.2gr, 1014 fps, 29k CUP

9x21
147 gr. TMJ
1.169" OAL
Max: AA#7, 9.2gr, 1228 fps, 33k CUP
The Lyman manual mentions the above 9x21 load is their only load within SAAMI spec that meets IPSC major requirements. But why isn't this load mentioned in the 9x19 section? The only difference between these guys is brass OAL, nothing else...right?

With all due respect for your reading of the Lyman manual, you have indeed missed one salient point. Sleeper78 pointed to it, in his first response to your inquiry:

Coupled with a 2mm length difference you are talking a huge difference. 9.2 grains in the 9x19 could and probably would make pressures well in excess of the 33k cup of that load in the 9x21. The bullet sits a lot farther into the 9x19 case than in the 9x21 thus leaving less space for powder. This translates into substantial pressure increases on ignition.

To explain in a little more depth:
OAL is not only specified to permit functioning in the magazine of the firearm. It is also a shorthand way of addressing the internal case volume of the cartridge, behind the bullet (where the powder resides - that finite volume in which it is ignited and begins its expansion) . Allowing approximately .200” for the web of the cartridge and the internal diameter is approximately the size of the bullet = .355” (yes, I know, it rounds off toward the bottom, and the bottom is radiused, too) just bear with us here for the sake of the, albeit rough, mathematics.

So, .355” x depth .630" for the 9x21, meaning (approximately) .22365 cubic inches empty case.
Then, .355" x .550" for the 9x19 = .19525 cu.in. volume empty case.
A difference of .0284 cu. In., or 12.6 percent smaller, already, just the emty cases.

Now the heel of the bullet will occupy a sizeable portion of that case volume.
The average 115 gr RNFMJ is @.575” in length, (Lyman 49 lists COAL for the 9x21 115 JHP at 1.063”, a fair figure for the RNFMJ, too actually) ONLY .027” difference. The case is .833”, so that means .336 of the bullet protrudes from the case, thus .239” of that bullet is in the case, further reducing the available space behind the bullet. That makes the internal case volume now .355”x .391, or only .1388 cu.in.
(Lyman 49 lists COAL for the 9x19 115 JHP at 1.090”) The case is .754”, so that means .336 of the bullet protrudes from the case, thus .239” of that bullet is in the case, further reducing the available space behind the bullet. That makes the internal case volume now .355”x .311, or only .1065 cu.in.
A difference of .0323 cu.in, now a 23 percent reduction in available internal case volume from the 9x21.

Sleeper was absolutely correct –

Any time you talk about adding 2 grains of fast burning pistol powder and shorting the case by 2mm you are risking the potential of increasing the pressures by a huge amount.

This reduction in available volume coupled with near-maximum amounts of a fast powder would cause such a pressure spike as to likely disintegrate any firearm designed to 9x19 SAAMI specs.

sleeper78, some if your information has been misinformation, some shows a lack of basic research. If you just want to learn along with me, awesome! Welcome aboard! Hopefully we'll both learn something. .

To the contrary, his information was spot-on, his research was correct. Having other reloading manuals is a highly recommended practice, for comparison, corroboration, or contradiction.

Flash

[Dannix]

I am genuinely flabbergasted and don't quite know what to say.

Only that were not talking about anything but the most minuscule of case capacity differences. To assume that brass OAL implies cartridge OAL seems to indicate a complete lack of understanding of these two calibers. Guys, this whole discussion is approaching absurdity!

Please guys, I beg you -- think. I can now appreciate RobW's probably one of the few 9x19 Major guys here. But the above point is one most basic.


Thanks for the PM RobW.

[sleeper78]

I am genuinely flabbergasted and don't quite know what to say.

Only that were not talking about anything but the most minuscule of case capacity differences. To assume that brass OAL implies cartridge OAL seems to indicate a complete lack of understanding of these two calibers. Guys, this whole discussion is approaching absurdity!

Please guys, I beg you -- think. I can now appreciate RobW's probably one of the few 9x19 Major guys here. But the above point is one most basic.


Thanks for the PM RobW.

I am done arguing with you. To tell me that my information was misinformation when I am quoting the exact same manual as you is quite disheartening. To tell me that the company that produces the bullet that you are referencing gave me misinformation is disturbing. You accused me of not researching the topic and when I do you blatantly dismiss my findings because you do not agree. That is fine but you used the same manual as me. But since you seem to know it all I'm confused as to why you posted the question to begin with. Anyway, enjoy your reloading and I hope that you never have the misfortune of a blowing your gun or yourself up.

[Dannix]

Brass length does not mean Cartridge length. It just doesn't. That seems to keep coming up. If you're headspacing on the extractor or leade and hold constant the OAL, you could use even .380 Auto brass in 9x19 or 9x21 for lower pressure loads. This isn't that complicated.

The very reason I'm posting is simply asking the 'whys' of Lymans data. Why don't they included a 1.169" 9x19 load? How is 9x21 'safe' for IPSC major and 9x19 not? Is that heresy here? Did you take a look at that 1911 link I posted above?

I'll take these questions elsewhere. Thanks for the best wishes. Personally I'd probably just look into rebarreling for .356TSW or .400 Cor-Bon if I ever want a hot 9mm load in my 9mm Glock, or going 10mm or .460 Rowland otherwise, but inquiring minds want to know.

Rest regards. out.

[RobW]

IIRC, you can sometimes find 'factory' major 9 load data with the caveat that the loads are designed for use in 1911 style pistols only, but I'd guess if Lyman doesn't make the distinction it is to avoid having nimrods try to jam 1.169 OAL loads into glock magazines.

To clarify for passers-by - if the internal dimensions of the cases in question are the same (theoretically, for 9x19 and 9x21 they are) then all other things being equal only OAL matters. Same OAL, same load whether 9x19 or 9x21. In theory anyway, this ain't my bag.

Brass length does not mean Cartridge length. It just doesn't. That seems to keep coming up. If you're headspacing on the extractor or leade and hold constant the OAL, you could use even .380 Auto brass in 9x19 or 9x21 for lower pressure loads. This isn't that complicated.

The very reason I'm posting is simply asking the 'whys' of Lymans data. Why don't they included a 1.169" 9x19 load? How is 9x21 'safe' for IPSC major and 9x19 not? Is that heresy here? Did you take a look at that 1911 link I posted above?

I'll take these questions elsewhere. Thanks for the best wishes. Personally I'd probably just look into rebarreling for .356TSW or .400 Cor-Bon if I ever want a hot 9mm load in my 9mm Glock, or going 10mm or .460 Rowland otherwise, but inquiring minds want to know.

Rest regards. out.

[WVBob]

What I've seen on the 9x21 tells me it not so much that it's high power, it's because the 9x19 will not fit in a 9x21 and the 9x21 will not fit in a 9MM. They had to make something different. It's why the .38 Super is used a lot in South America. They can't use 9MM or .45ACP because the local Army uses them. The 9X21 came about because it was not a 9x19, not a search for more power. Someone did that with the 9x23.