Home Forums Reloading Handgun Reloading 9mm pistol/rifle question

All of my reloading manuals list loading loading data for pistols and cite a 4" barrel. I see listed some AR9 (9mm) rifles with 16-20" barrels. Are the rifle guys shooting pistol rounds, or is there 9mm rifle data somewhere? Just curious - Thanks

Just curious is there a way to make the 9mm hold more powder? In reality the whole point is to be able to shoot the same ammunition in rifle, sub mg and pistol.

No rifle data per se but you can search the internet for "9mm Major load data" and find a few articles with tips and recommendations to put the pedal to the metal with 9mm loads. I just did that and got mostly posts in other forums.

The first forum I looked at had a comment saying you will gain 150-250 fps just firing normal 9mm pistol ammo in a 16" barreled carbine and that agrees almost exactly with my findings chronographing four different kinds of factory ammo in a Beretta 92 vs. a 16" Ruger PC - my results were 160 to 260 fps additional, with the 260 coming from +P ammo.

It's an interesting idea but there just isn't that much room for improvement with the small case. However, it's not a creampuff in a longer barrel. With factory Hornady 124 XTP +P ammo the carbine was pushing 1400 fps, that duplicates the performance of a 125 gr. .357 Magnum load from a 4" barrel which is nothing to sneeze at.

I’d use the same load data for both.
A 9mm round is just that. The ar9 is simply a rifle chambered for a pistol cartridge and designed to shoot factory 9mm handgun ammunition.

Not unlike a 22lr. Same ammo/different gun.

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That kind of thinking will get you a blown up gun and if you're not lucky, some shrapnel damage to your body.
Use the same ammo in pistol and in PCC.

There were some British high pressure 9mm loads (L7A1) intended for MP-5 on the surplus market back in the day. They were defiantly bad juju in 9mm pistols.

I would have to go get my notes with the exact velocity difference in 9mm loads in a 4" barrel handgun versus 10 1⁄2" barrel AR Is very significant with the exact same ammo

9.9” barelled MP40/41 was rated @500-550 rpm standard 124 grain @1312 max effective range 200 meters.

What started me thinking about this is the idea of finding the correct powder and the exact amount of that powder to cause the bullet to exit the barrel just as the bullet exits the barrel. Any more would be waste and too little would cause drag on the bullet for a portion of the barrel. Thus, a 9mm pistol load optimized for a 4" barrel would cause the same bullet to be exposed to 12" of barrel drag in a 16" barrel, AND the vice versa would be a lot of powder wasted. I have seen, in one of my reloading manuals, data for a RIFLE .44 mag load and it warns not to use the load in pistols - why not the same in 9mm, or .357 mag? I acknowledge that there would be a few idiots that would try the rifle load in their pistols, if it were available.
Again, just curious......

I would look at typical powders used for 9mm but opt for the powders that are a slower burn. i.e. Use HS6 over HP-38. Remember that carbines are usually blowback actions and have no lockup. I wouldn't recommend just adding more powder to gain speed. As they say in the engine world, there's no replacement for displacement. If you want more, go with a bigger cartridge. I think this is where the .357 shines in a carbine when talking pistol caliber carbines.

Been shooting 9mm majors for 40 years. Don't try it. As stated above its a blow back actions and at the very least you will have to mess with the spring bolt return rates of compression. The very least amount of dirt or debris stopping complete lock up will blow the case head, even though the 9mm is a relatively strong case. Stryker fired pistols are very sensitive to this tolerance and the main reason Glock says No-No to reloads. Optimizing the end burn to the end of the barrel, is not the way pressure curves work.
As a side note, it usually takes a lock up action such as a 1911, and a throat reamer, and bullet seating to 38 Super specs.