.357 Magnum Ammo

What is .357 Magnum?

Elmer Keith, Philip Sharpe, and D.B. Wesson (the Wesson of Smith & Wesson) developed .357 Magnum in 1934. The goal was straightforward: take the .38 Special case, lengthen it to prevent chambering in .38 Spl cylinders, and load it to significantly higher pressure. The result was the first commercially available Magnum cartridge and the dominant police and self-defense round for the next 50 years.

The Remington Model 8C police carbine chambered in .357 Mag could penetrate early car body panels that stopped .38 Spl — a real tactical consideration for Depression-era law enforcement dealing with heavily armed bank robbers. The S&W registered Magnum (later the Model 27) became the prestige police revolver. Virtually every major U.S. police agency carried .357 Magnum revolvers until semi-automatics displaced them in the 1980s.

Today .357 Magnum occupies a specific niche: it’s the best all-around revolver cartridge if you want one gun that handles home defense, hunting, and range use. The relationship with .38 Special makes it flexible in a way no other Magnum is.

The .357 / .38 Special relationship

Every .357 Magnum revolver also chambers .38 Special ammunition.

The .38 Spl case is shorter (.795” vs 1.290” for .357 Mag). It headspaces properly in the .357 cylinder and fires normally. This gives you two completely different performance envelopes in one gun:

• .38 Special standard: ~700–800 fps, ~170–200 ft-lbs — mild recoil, cheaper, adequate for defensive use
• .38 Special +P: ~900–950 fps, ~200–250 ft-lbs — more recoil, better performance
• .357 Magnum: ~1,200–1,450 fps, ~400–600 ft-lbs — sharp recoil and blast, maximum performance

Most owners shoot mostly .38 Spl for practice and carry .357 Mag defensive loads. This is the practical way to own a .357 — you’re not paying for the full-power round every time you go to the range.

One caution: shooting a lot of .38 Spl through a .357 cylinder leaves a carbon ring at the front of the cylinder throat. This ring can cause .357 Mag cases (which use the full cylinder length) to stick when chambering. Clean the cylinder throats periodically if you mix calibers.

Ballistics by barrel length

Barrel length has a large effect on .357 Magnum velocity — more than most handgun cartridges because the slow-burning powder keeps accelerating the bullet in longer barrels.

125gr JHP:

158gr JSP:

The lever-action rifle numbers are why .357 Mag in a Henry Big Boy or Marlin 1894C is a legitimate deer hunting setup inside 100 yards. It’s not a long-range cartridge — the ballistic coefficient of pistol bullets is poor — but inside 100 yards it carries serious energy.

Short-barrel defensive ammo: why it matters

Snub-nose .357 Magnums (2–2.5” barrels) produce far less velocity than the standard test barrel. A 125gr JHP at 1,450 fps from a 4” barrel drops to ~1,200 fps from a 2” snubby. Standard JHPs are designed to expand at the higher velocity — some won’t expand reliably at 1,200 fps.

The Speer Gold Dot Short Barrel line is specifically engineered for short-barrel revolvers. The 135gr version expands reliably at snubby velocities because the bullet construction is tuned for lower impact velocity. If you carry a J-frame or LCR in .357 Mag, use loads designed for the barrel length.

Also worth noting: .357 Magnum from a 2” barrel produces a significant muzzle blast and fireball. In a dark room, that’s a real issue. Some shooters carry .38 Special +P in snub-nose revolvers specifically to avoid the recoil, blast, and recovery time from .357 in a lightweight gun.

Gel testing data

From a 4-inch barrel, FBI protocol (10% gel, 4 denim layers):

The 125gr JHP from a 4” barrel is among the best-performing defensive pistol loads in gel testing across any caliber.

Brand guide

Speer Gold Dot 125gr GDHP — the law enforcement and defensive standard. Consistent expansion, high retained weight. ~$0.90–1.30/rd.

Federal Premium 125gr JHP (Classic) — the load that established .357’s reputation in the 1970s–80s. Still excellent. ~$0.80–1.20/rd.

Speer Gold Dot Short Barrel 135gr — buy this if you carry a snub-nose .357 Mag. Engineered specifically for 2–3” barrels. ~$1.00–1.40/rd.

Hornady LeverEvolution 140gr FTX — the lever-action load. Polymer tip is safe in tubular magazines (traditional pointed bullets aren’t), high BC for a pistol bullet. ~$0.90–1.30/rd.

Buffalo Bore 158gr JSP — full-power hunting and woods carry load. ~$0.80–1.20/rd.

Fiocchi 158gr FMJTC — affordable practice. Truncated cone FMJ, good feeding, consistent. ~$0.40–0.55/rd.

Magtech 158gr SJSP — Brazilian manufacture, reliable, competitive pricing for range use. ~$0.38–0.52/rd.

Price guide (2025–2026)

Note: .38 Special practice ammo for your .357 revolver runs $0.22–0.35/rd for FMJ — significantly cheaper than practicing with .357 Mag.

Firearms chambered in .357 Magnum

Revolvers:

• Smith & Wesson Model 686 (6”), 686+ (7-shot), 19, 27, 28 — the S&W service revolver lineage
• S&W Model 60, 640, 642 — J-frame snubbies (note: very light guns make .357 Mag brutal to shoot)
• Ruger GP100 — the most durable production .357 revolver; overbuilt for .357 loads
• Ruger Security-Six, Speed-Six — excellent older designs, now discontinued
• Ruger SP101 — compact, 5-shot, very strong for its size
• Colt Python — the premium option; excellent trigger, collector value
• Colt King Cobra — modern production, 6-shot, 3” and 4” barrel options
• Taurus Model 66 — 7-shot cylinder, budget option with mixed QC reputation

Lever-action rifles:

• Henry Big Boy .357 Mag/38 Spl — the most popular current lever-action in this chambering
• Marlin 1894C — 9+1 capacity, 18.5” barrel; discontinued by Remington, resumed under Ruger ownership
• Winchester Model 1894 .357 — classic design, still in production
• Rossi R92 — budget-friendly, Brazilian manufacture, good reliability record