The Fascinating .454 Casull
March 28, 2018
The .454 Casull had its big reveal when P.O. Ackley wrote about it in the November 1959 issue of Guns & Ammo magazine. Dick Casull had created the .454 first as a hot-loaded variant of the .45 Colt cartridge. Later it evolved into a proprietary cartridge with unique dimensions and ultimately became a standard industry cartridge. In 1983 Freedom Arms created a dedicated platform for the .454 Casull cartridge: the superb Model 83 single-action revolver. It was built from the concept stage forward as a durable vehicle for ultra-pressure handgun cartridges.
The history of this cartridge is well known, so I want to focus on technical points that developed as the cartridge journeyed toward SAAMI acceptance. If you want to brush up on its history, look to Layne Simpson's excellent overview article in the May 2009 issue of Shooting Times, which can be found at shootingtimes.com.
High-pressure loads in conventional .45 Colt cases could lead to great unpleasantness if fired in stock .45 Colt revolvers, so one of the first changes Casull made was to have custom cases built that were 0.098 inch longer to prevent chambering in conventional .45 Colt firearms. Freedom Arms sold ammo and component cases to complement its new revolver.
Early Freedom .454 cases had Large Pistol primer pockets. By the time we started work on Speer Reloading Manual #12 around 1990, Freedom Arms had switched to Small Rifle primer pockets. This allowed powerful priming plus thicker primer cups to minimize high-pressure flowback. At the same time, they beefed-up the case walls. This made stronger cases but reduced capacity. We reworked all loads for Speer Reloading Manual #12 to reflect the primer and capacity differences.
Pressures and Bullets
There are no published "standard" pressures for proprietary cartridges; their developers hold that information. We were fortunate that Freedom Arms gave us a crusher test barrel for .454 calibrated to the company's test equipment. In that barrel, the Freedom Arms factory ammo of the time produced in the range of 52,000 to 54,000 CUP. The .44 Magnum's limit on crusher was 40,000 CUP, and only the most powerful rifle cartridges ran at 54,000 CUP.
This raised a bullet problem. Conventional handgun bullets neither had nor required massively thick jacket walls to work without issue before the Casull appeared. Existing jacketed bullets could deform in a revolver's barrel-cylinder gap when pressures approached 50,000 CUP.
Those older jacketed bullets at full Casull pressures could swell into the gap. Shaved jacket material could cause premature wear of the barrel throat and/or the frame's topstrap. At over 0.030 inch thick, Freedom Arms's custom jackets overcame the problem.
Speer's .45-caliber revolver bullets designed prior to about 2002 did not have that jacket thickness. Bob Baker of Freedom Arms and I went through our 1994 Speer data line by line before we published. I wanted to be certain that the man who best knew the revolver was satisfied with our numbers. We agreed to hold pressures under 45,000 CUP to avoid jacket deformation.
Were these "mouse loads"? Judge for yourself. The fastest .44 Mag. maximum handload we had for Speer's No. 44-300 JSP posted 1,187 fps from our 7.5-inch-barreled Ruger revolver; the Speer No. 45-300 JSP held back to about 43,000 CUP posted an impressive 1,542 fps from Speer's 7.5-inch-barreled Freedom Arms Model 83, a velocity increase of 30 percent and a muzzle energy increase of 69 percent. Not bad for a "somewhat reduced" load and a pressure increase of less than 20 percent.
The Speer .45-caliber 300-grain DeepCurl bullet was designed expressly for the .454 Casull, but it's also at home loaded in the .460 S&W Magnum. It has a 0.030-inch-thick jacket to resist in-barrel deformation at massive pressures.
When the .454 Casull was standardized in 1997, everything changed. There were new firearms, and companies like Winchester and Starline replaced Freedom Arms as case suppliers. Our old crusher-type pressure barrel was obsolete, so we bought new test barrels, transducers, and calibration gear to comply with the new standards.
Although SAAMI set the maximum average pressure at 65,000 psi, we found no factory ammunition loaded higher than 55,000 psi. This allowed normal case extraction and ejection in double-action revolvers. For years, the finely fitted Freedom Arms Model 83 single action was the only production .454 firearm, and case ejection was never an issue with safe loads. Case removal from single actions is historically easier because you are pushing one case at a time, and the Model 83's interior chamber finish is impeccable.
At high pressures, extraction problems can appear in double-action revolvers. Like other ballistic test stations, we found that loading higher than about 55,000 psi created extraction issues in just about every mass-produced double-action revolver. When we did all-new Casull data for Speer Reloading Manual #14 in 2004, we used the stiffest cases at the time for top loads with the Casull DeepCurl and selected more conventional .454 cases for slightly reduced loads for bullets with "pre-Casull" jackets. The loads we published worked perfectly in our test revolvers.
Because .454 Casull factory loads can be punishing, we published some reduced-recoil plinking and practice loads. We used bullets cast from RCBS's No. 45-270-SAA 424 mold, a 270-grain Keith-style SWC developed for original Colt .45 single actions. We held these to under 36,000 psi, and velocities still ran from 875 fps to almost 1,200 fps.
Reduced loads in a big case can be ballistically challenging. Excessive pressure/velocity variations precluded developing mild loads in some of the new generation of "mega-Magnum" handgun cartridges. Not the Casull, at least not with that particular bullet. The shot-to-shot variation in both the pressure barrel and our Model 83 was some of the best we'd seen. Another bonus was that bullet loaded to less than 1,050 to 1,100 fps made the .454 Casull just plain fun to shoot! Not a lot of Casull owners think "fun" following an afternoon of shooting full-power loads.
One very important thing handloaders must observe: The changes over time in Casull case volume, bullets, and priming make it imperative that you use only the latest data and components. New components with old data- or vice-versa- will get you in a world of "ouch."