The idea of having a handgun and a rifle or carbine that shoot the same cartridge is an old one, dating nearly to the infancy of cartridge firearms. However, the success of these pairings today depends on some educated choices, whether you shoot factory ammo or handloads.
How you proceed depends on whether the handgun cartridge is for a revolver or a semiauto pistol. We'll consider them separately.
Revolver Cartridges in Long Guns
This is the pairing that started the trend. With modern components, many revolver cartridges can show significant increases in velocity when used in a rifle or carbine.
Among modern revolver cartridges, the best choices for a combo are .357 Magnum, .41 Magnum, and .44 Magnum. Differences between a revolver with a 6- to 7.5-inch barrel and a carbine with a 16.5- to 18-inch barrel can be impressive. Still, getting good terminal performance within safe practices means considering the bullet weight and style and, if you are a handloader, the choice of propellant.
Bullets have to be up to the task.
Hollowpoint bullets that give good penetration and expansion in a revolver at 1,200 to 1,300 fps can become fragile, varmint-class bullets at rifle velocities. That's bad for deer hunting. Softpoints are best in rifles. One way to maintain parity of terminal performance between the rifle and the revolver is to use "full-weight" bullets. That usually means the bullet weight loaded when the cartridge was first developed.
For full-power loads, jacketed bullets generally do better in rifles than cast lead bullets. At 1,800+ fps, barrel leading can be miserable. For best lead-bullet results, select a bullet with a generous capacity for holding lubricant that's cast from linotype. Older .44 Mag. carbines may have shallow, multi-groove rifling. This style of rifling definitely prefers a jacketed bullet.
Most factory ammo features bullets profiled to feed in repeating rifles. Semiwadcutters or other shapes intended for revolvers may snag in feeding. Handloaders must also respect cartridge overall length (COAL). Failure to do so can result in a badly jammed lever gun.
You can go with heavier bullets. The big .44-caliber 300-grain softpoints from Hornady and Speer have an extra crimp cannelure that sets the proper length for a rifle. However, the necessary deep seating required for a rifle can reduce propellant space and, therefore, velocities from a revolver. For the .44 Mag., a 270-grain softpoint is a great compromise that produces more than adequate performance in either short or long barrels. In .357 Mag., you can load softpoints in the 165- to 180-grain range.
Propellant choice becomes a factor for the handloader. A light propellant charge may not produce enough gas volume to keep a jacketed revolver bullet moving down a long barrel. You will see the best performance by sticking with the slowest burning revolver propellants that don't overfill the case. Consider Hodgdon H110, Alliant 2400, Winchester 296, Ramshot Enforcer, VihtaVuori N110, and Accurate Arms No. 9.
If you wish to load practice/plinking ammo in the 1,100- to 1,300-fps range, hard-cast lead bullets work if properly loaded. With those, don't use handgun propellants faster burning than propellants like AA No. 7, Alliant Power Pistol, Ramshot True Blue, and VV N350. Stay close to the maximum charge to keep pressures up.
However, loading "light" to reduce recoil is seldom necessary with carbines and rifles chambered for revolver cartridges; a magnum cartridge that delivers punishing recoil in a revolver is often a pussycat in a long gun. Dear Daughter #2 is rather petite, yet she had no problems when she first shot a centerfire rifle — my old Ruger semiauto carbine with full-power, 240-grain .44 Magnum loads.
There are long guns — either factory or custom — chambered for some of the "mega-magnum" revolver cartridges like the .454 Casull, .460 S&W Magnum, .475 Linebaugh, and .500 S&W Magnum. The same rules apply to these.
Semiauto Pistol Cartridges in Long Guns
You won't get the same velocity increase from a 9mm Luger, .40 S&W, or .45 ACP carbine that you experience with the magnum revolver cartridges. The reason is not pressure — the 9mm and the .40 have the same peak pressure as the .357 Mag. — but rather case capacity. A short, semiauto cartridge case simply cannot hold the volumes of slow-burning propellants that are so important to the velocity boost we see in a magnum revolver cartridge.
Velocity increases are seldom more than 100 to 200 fps in a 16.5-inch barrel. I worked with some 9mm Luger 124-grain ammo Speer developed for a "special" customer. It posted about 1,150 fps from a Browning Hi-Power and just under 1,300 fps from the 9.8-inch barrel of an H&K MP-5. Adding barrel length beyond that didn't add much speed.
First and foremost, you have to consider bullet shape. Today's factory-loaded bullets are shaped for reliable feeding in either a handgun or a carbine. Most of the modern hollowpoint offerings should feed fine, and, of course, FMJ bullets nearly always work. However, in the infancy of the expanding handgun bullet, there were some designs that loaded close to the 9mm Luger's industry minimum COAL. Most were 90- to 100-grain bullets, and they should be avoided for carbine reliability.
Best overall performance comes with the "standard-weight" bullets: 115 to 124 grains in 9mm Luger; 180 grains in .40 S&W; and 230 grains in .45 ACP. Lighter bullets may work but can be factory-loaded with rather quick-burning propellants that can't push very long in a 16.5-inch barrel. The 147-grain bullet used in 9mm ammo generates under 1,000 fps from a 4-inch pistol barrel; reliable function depends on the brand of ammo and rifle. Before settling on 147-grain ammo in a 9mm carbine, test thoroughly to ensure it works for you.
Handloaders should never go "off book" to get better velocities in carbines that shoot small-capacity, semiauto pistol cartridges. You'll do best sticking with data for standard-weight bullets (see above) and choosing the slowest burning propellant — usually the one with the highest charge weight — shown in trusted handgun load data. That gives you the best opportunity for a decent velocity increase while maintaining safety and reliability.