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.357 Magnum Load Data

We gathered up propellants, bullets, and primers suitable for handloading the .357 Magnum cartridge.

.357 Magnum Load Data

The editor recently pointed out that my columns have been heavily biased toward loading rifle ammo. Taking the hint, I offered to remedy the deficiency by putting together some handloads for the ever-popular .357 Magnum. I suggested that I take a good look at the recently released Lyman, Nosler, and Barnes reloading manuals for the latest recipes with the newest components. He concurred, and the exercise afforded me the opportunity to revisit some of my favorite .357 handloads that I developed during the 35-plus years that I've been loading the cartridge.

For those who don't know, Smith & Wesson and Winchester co-developed the .357 Magnum revolver/cartridge package about 75 years ago. It was the first handgun round tagged with the "magnum" moniker. Prior to the .357, the old .45 Colt charged with up to 40 grains of blackpowder held the distinction as the "most powerful" handgun cartridge. Phil Sharpe and Elmer Keith contributed to the .357's development, and they experimented with S&W's .38-44 High Velocity cartridge, suggesting that its performance could be improved upon.

However, S&W decided not to simply introduce a further hopped-up .38 Magnum. Instead, the company redesigned and significantly improved the strength of the large-frame .38-44 Outdoorsman target model revolver to accommodate the nearly double chamber pressure generated by the .357 Magnum. S&W also increased the case length by 1/8 inch to prevent anyone from loading the then-new cartridge in either regular or heavy-duty .38 Special revolvers. Original .357 Magnum specs touted the muzzle velocity for a 158-grain, lead SWC bullet of more than 1,500 fps from an 8⅜-inch barrel. Since its introduction, the .357's ballistics have gradually diminished. Current factory ammo delivers substantially less performance, i.e., velocities are 150 to 200 fps lower.

Soon after my wife and I married, I purchased a .357 Magnum Ruger Blackhawk single-action. I reloaded using an RCBS single-stage press and die set with a steel sizer. Our budget would barely allow me to load a box or two of ammo occasionally. We met another newlywed couple, and I convinced Rod he needed a handgun to go shooting with me. He opted for one of the then-new Thompson/Center Contender single-shots fitted with a 10-inch barrel chambered in .357 Magnum. My shooting situation improved when we struck a deal where he bought the components; I provided the tooling, time, and effort to reload the empties; and we shared the ammo 50/50.

Since then, I've bought, sold, and traded lots of guns, and I no longer own my first Blackhawk. However, I still have several .357 handguns on hand, including a New Model Ruger Bisley single-action revolver. It seemed the most appropriate test bed for this review, especially since I had a machine rest set up for it. For serious handgun load development, I now depend on a machine rest simply because my arms are too short to hold a handgun far enough away to allow my eyes to clearly focus on the sights and target at the same time.

Because the .357 Magnum is actually the same caliber as the popular .38 Special, a huge selection of suitable bullets--both jacketed and cast--are readily available. Bullet weights typically range from 110 to 180 grains, and different nose shapes and types of bullet construction abound. Reviewing the latest editions of the reloading manuals noted earlier, I selected several component options suitable for .357 Magnum handloads.

.357 Mag Handload Data
Ruger Bisley and 30-year-old Remington factory ammo set the performance standard for Lane's .357 Magnum handloads.

The Ruger Bisley has a 7.5-inch barrel, so I expected to obtain top performance from the test loads. But first I had to prepare them. Checking my inventory, I had everything I needed except Ramshot Enforcer. According to the Barnes and Lyman manuals, Enforcer seemed to be a promising propellant to launch the heavier slugs. I also used different brands of Small Pistol Magnum primers and brass to duplicate the recommended recipes as closely as possible.

.357 Mag Case Prepping

This first step is probably the most important, especially for magnum handgun cartridges. The .357's maximum average pressure is specified at 35,000 psi. The relatively thin-walled cartridge cases must remain intact when a round is fired. I tumble them before loading so that I can easily inspect and weed out any cracked or otherwise damaged brass. You should also make sure there's no debris or other obstruction lodged inside the case.

Lubing handgun brass and resizing it with a steel sizer die is a not-so-pleasant memory of my past reloading experiences. For several years now, thankfully, we have carbide dies to resize most straight-walled revolver and tapered pistol brass. The super slick, hard insert eliminates the mess and bother of applying and removing the lube required to prevent a case from seizing in the old steel sizer die.

I always clean the primer pockets--in fact, I actually use an RCBS Case Prep powered unit to both clean and uniform the pockets each time I prepare a batch of brass. Then, I usually trim each one to a uniform length and deburr the case mouths--even if none of them are too long. Why? Because applying a uniform bullet crimp helps ensure consistent ignition. That, in turn, can make my handloads more reliable and deliver better performance.

.357 Mag Priming

After the dirty work is finished, you should wash up to remove any grit and grime from your hands. However, hospital-style sterile conditions are not required when priming. A friend of mine dons thin cotton gloves and carefully handles each primer with a pair of tweezers. I, on the other hand, dump the quantity needed into a primer tray, pick one up with my bare--but clean--fingers, place it in the priming tool I'm using, and firmly seat it just below flush.

If I'm loading more than just a few rounds, I use one of several priming tools available with an attached primer magazine. Either way works for me. Just use common sense to avoid potential contaminants when handling primers and always wear protective glasses.


.357 Mag Case Mouth Flaring

You must expand or flare the case mouth to facilitate bulletseating. The reason this operation wasn't included in the case-prep section above is simple: I don't usually do this until I revisit and finalize the bullet selection. The heel may be sharp or rounded or even tapered, i.e., like a boattail rifle bullet.

You should carefully adjust the expander plug position to expand the mouth just enough--but not too much--so the bullet is fully engaged and aligned with the case mouth prior to seating. Too little, and the case may score the bullet as it's inserted. This is especially true when loading cast bullets with or without gaschecks. Lead and lube will be scraped up the circumference of the bullet as it's seated and fill the crimping groove. This may interfere with crimping the bullet properly or even cause the case mouth to buckle.

Favorite .357 Magnum Handloads
Bullet Powder Type Powder Grs. Case Primer Velocity (fps) Extreme Spread (fps) Standard Deviation (fps) 25-Yard Accuracy (in.)
Case Bullets
Clements 155-gr. SWC H240* 13.5 R-PCCI 550 1479 64 16 2.40
Vaiant 160-gr. SWC Blue Dot 9.5 Fed. WSPM 1320 87 27 3.00
Cast Performance 180-gr. WFN-GC Enforcer 11.7 Win.WSPM 1178 49 13 2.00
Cast Performance 180-gr. WFN-GC H110 13.5 Front.WSPM 1205 51 13 1.70
Jacketed Bullets
Barnes 125-gr. XPB Enforcer 16.5 Win.WSPM 1578 49 12 1.90
Hornady 125-gr. JHP-XTP Power Pistol 10.0 Speer CCI 550 1448 71 20 3.00
Hornady 125-gr. JHP-XTP VV N110 16.5 Speer CCI 550 1520 75 26 1.90
Barnes 140-gr. XPB AA No.9 12.5 Win. WSPM 1330 92 27 2.00
Hornady 140-gr. JHP-XTB AA No.9 13.5 Win. Rem. 5 1/2 1368 65 25 2.50
Hornady 140-gr. JHP-XTB H110 18.4 Front. WSPM 1479 138 41 1.80
Hornady 140-gr. JHP-XTB H110 19.0 Fed. Fed. 200 1406 106 32 2.20
Speer 146-gr. JSWC-HP Unique 8.1 Speer CCI 550 1322 71 18 2.00
Sierra 150-gr. JHC W296 17.0 IMI Fed. 200 1311 88 26 1.90
Nosler 158-gr. JHP H110 15.8 Fed. WSPM 1251 116 30 2.20
Sierra 158-gr. JSP 2400 14.6 R-P Fed. 200 1306 87 25 2.90
Sierra 158-gr. JSP H110 14.0 R-P CCI 550 1160 42 17 2.50
Speer 158-gr. Gold Dot Unique 81 R-P CCI 550 1210 75 20 2.40
Speer 158-gr. Gold Dot VV N110 14.5 Fed. Fed. 200 1250 72 23 2.20
Speer 158-gr. Gold Dot VV N110 15.0 Fed. Fed. 200 1261 69 22 2.40
Winchester 158-gr HP AA No.9 14.6 R-P CCI 550 1393 69 18 2.20
Hornady 180-gr. JHP-XTP AA No.9 13.0 Norma Fed. 200 1188 80 25 2.10
Hornady 180-gr. JHP-XTP W296 13.0 R-P Fed. 200 1089 83 22 2.40
Nosler 180-gr. Partition HG 2400 12.5 Fed. Fed. 200 1221 92 23 1.40
Nosler 180-gr. Partition HG W296 12.5 Fed. WSPM 1022 72 23 1.90
* Handgun H240 in long obsolete.
.357 Mag Handload Data
Ramshot Enforcer and Accurate No. 9 delivered excellent performance with Barnes XPB copper bullets. The XPB bullet is a monolithic copper alloy formed to ensure rapid and controlled expansion and should not be substituted for any other bullet.

.357 Mag Powder Charging

I typically use a volumetric measure to dispense powder charges after I've calibrated it by weighing several charges on an electronic scale. Propellants like H110, Accurate No. 9, and Enforcer flow like water, so charge weights vary only 1/10 grain at most. Blue Dot, Unique, or other flake-type propellants are not as compatible with volumetric measures, so thrown charges can vary up to 1/2 grain. That's a lot if you're loading 15 grains or less of propellant. Never use these for maximum loads unless you weigh each powder charge. For non-maximum charges, I typically weigh every tenth charge, but I always visually inspect each case in the loading tray to make sure I've properly charged each one before seating the bullets.

.357 Mag Bulletseating

Most seater dies, if properly adjusted, will both seat and crimp the bullet. Place a sized and trimmed case in the shellholder, raise the ram, and screw the die in until it touches the case mouth. Then back off the die a half-turn, replace the empty case with one that's flared and charged, and position the bullet squarely on the case mouth. Guide the case/bullet combo into the seater die with your fingers, and incrementally raise and lower the ram while adjusting the seating stem position as needed so the top of the cannelure or crimping groove is almost aligned with the case mouth. Be sure to use a seating stem that closely matches the nose shape to avoid damaging the bullet.

When the bullet is seated deep enough, back up the seating stem several turns. Screw the die in incrementally--a quarter-turn at a time--until you achieve the desired crimp with the ram in the full-up position. Screw the seating stem down until it firmly engages the bullet nose and tighten both jam nuts on the die body and stem. Remove that round and seat another bullet carefully to verify that the die and seating stem are properly adjusted to seat the bullet and crimp the case mouth correctly.

.357 Mag Handload Data

You may have to tweak one or both slightly to achieve the correct seating depth and amount of crimp. Remember, you can always seat the bullet a little deeper and crimp the case mouth a little more, but you'll surely damage the case and/or the bullet if you seat it too deeply or force the round into the die too far.

.357 Mag Loading & Shooting

Like I said, I revisited some of my old favorite .357 handloads. When I checked my stash of ammo, I found several boxes dated as far back as the mid-1980s. I assembled several fresh batches using proven propellants like H110, 2400, W296, AA No. 9, and Unique. I also experimented with some newer propellants, including Ramshot Enforcer and VihtaVouri N110.

As you can see in the chart on page 19, I eventually tested quite a few different .357 Mag. recipes. When I started this project, I figured I'd load four or five boxes of handloads to complement the ones I had on hand. However, the more I loaded and shot, the more I wanted to load and shoot. I eventually fired 925 rounds at 150-plus targets. I guess I was just having too much fun loading and shooting. And as it turned out, I found some new favorite loads for my trusty .357.

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