I've shot and carried this ammo for years. I just picked up a Kahr CM9, and it packs more of a wallop than I anticipated. Just curious if there is a defensive round with less felt recoil that will still perform well out of a short barrel. Maybe standard 124? Or Federal HST?

What got me thinking about this was firing Precision One and Buffalo Bore +P back to back in my CW380. The Precision One performs well and had significantly less felt recoil than the Buffalo Bore +P.

I just use standard pressure 124gr Speer Gold Dots. I bought a few boxes of +p but they are only 20 in a box. I order 50 round boxes of standard pressure Gold Dot rounds online.

Personally, Federal 147 grain HST, standard or +P. This load seems to expand quite well even from shorter barreled pistols.

Standard pressure gold dots or HST expand just fine from short barrels. I prefer 147 HST, but it's impossible to find so I alwas have 124 gold dots or HST as a back up.

124 grain HST here, at least I can find it

You can get on an email list for both 124gr and a 147gr HST rounds at SGAmmo.com. They sell 50 round boxes. I did manage to get some 124gr HST rounds several times now.

I'm on the list, and scored 5 boxes last time they got 147gr in. But it goes quick, easy to miss out.

Standard pressure 147 Grain Gold Dot.  Always go with the heaviest bullet in a shorter barrel.

Yes I got the email to but missed out on 147gr HST. I did manage to get some 147gr RA9T rounds when the had them.

Why is that? Because out of a short barrel, there is no gain in velocity using a faster round so go with the heavier, slower round for deeper penetration?

Because with the 9mm Luger, the heavier bullet will loose a smaller percentage of its muzzle velocity in a shorter barrel compared to a lighter bullet.  This means the heavier bullet will stay closer to its ideal expansion velocity threshold.





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Fascinating. So, even though 124+p has more than 200 fps on the 147 grain, it may not expand reliably because it is still not attaining optimal velocity out of the short barrel?

Are we assuming that, all things being equal, these round are all designed to penetrate to between 12"-18" with the only change being the velocity and consequent energy dump?

I went with 115gr as they seem to work better out of a 3" barrel than standard 124 or 147 in all the testing videos I've watched.

two reasons:
1 - a lighter bullet not only looses more velocity than a heavier bullet but it also looses it disproportionately.  So while a heavier bullet might loose 5% of it's velocity a lighter bullet will lose 10%.  This is more pronounced in higher pressure rounds like the 9mm compared to say the .45.   For example a 230 grain .45 bullet out of a 5" barrel will usually be around 875 fps, out of a 3" barrel it will be about 805.  The 185 grain bullets loose a LOT more velocity.

2- heavier bullets have a lot more mass and volume to work with for the designer.  As a result the performance envelope (range of velocities where the bullet works as designed) is generally quite a bit larger than with lighter bullets.  The lighter bullets will tend to have a smaller cavity and thus need more velocity to open up at all.  If you examine a 124 and 147 grain HP of the same design you will see that not only is the 147 deeper, the bottom of the HP cavity is probably more squared off as well.

1-No such thing as "energy dump"
2-Quality ammo is designed to meet the specs you listed in service size pistols (usually).

This.





"As clearly illustrated in the relevant scientific literature over the past 20 years,
kinetic energy or momentum transfer from a projectile to tissue is not a wounding mechanism."

Dr. G.K. Roberts





WHAT'S WRONG WITH THE WOUND BALLISTICS LITERATURE, AND WHY

by M.L. Fackler, M.D.
Letterman Army Institute of Research
Division of Military Trauma Research
Presidio of San Francisco, California 94219
Institute Report No. 239




The “Shock Wave” Myth

By Dr. Martin Fackler

Wound Ballistics Review, Winter 1991 and the Journal of Trauma, (29[10]: 1455, 1989).





Ballistic Injury

By Dr. Martin Fackler

Annals of Emergency Medicine, December 1986




Bullet Penetration

By Duncan MacPherson





Handgun Wounding Factors and Effectiveness

By Special Agent Urey W. Patrick
Firearms Training Unit
FBI Academy

I go a bit against the grain and carry Magtech First Defense 92.6gr +P SCHP (solid copper hollow point) in my CW9 and CM9.  It moves at about 1300-1350 FPS in the short barrels, holds together better than bonded and penetrates deep.  Also the plus side is since it's light for caliber with the +P the recoil isn't horrible.