Handloads for a Fast-Twist .220 Swift
Date: Jun 28 2022
I bought my .220 Swift in the middle of the raw fur spike of the early to late 1980s, when a prime mountain coyote averaged $65 and I would put 150-plus hides on stretchers every winter. That Swift, a Ruger M77 Varmint glass bedded into an early Boyd’s laminated hardwood stock, was shot frequently. It accounted for hundreds of furbearers and a multitude of predator-calling contest wins. I shot 50-grain Nosler Flat Base bullets mostly, predecessor to the modern Ballistic Tip, loaded hot with something approaching 38 grains of IMR-3031 in order to push 4,000 feet per second (fps). That speed caused the front of the bullet to vaporize, the solid base pushed through to poke a small hole on the opposite side. It reached out there, made lead margins on running coyotes manageable and, most importantly at the time, didn’t shred valuable hides.
Eventually, the fur market crashed, and without financial incentive I didn’t pursue predator calling with the gusto as I once had. I’d produce the Swift to belabor the occasional burrowing rodent, but began to notice it had lost its accuracy edge due to conspicuous throat erosion. The rifle was relegated to the dark recesses of a gun safe.
Decades later, on a rambling varmint-shooting road trip with my father, talking guns and ammunition to pass the time between shooting destinations, my forsaken Swift entered the conversation. We’d spent a somewhat frustrating morning shooting rockchucks across a 400- to 450-yard-wide canyon in a 10 mph crosswind with .22-250 Remington rifles spitting standard 50-grain bullets. We’d connected, maybe, one out of seven shots due to conspicuous wind drift. Bullets were landing 2 feet wide across that wide, rockchuck-infested canyon. I’d commented that I needed to re-barrel my old .220 Swift with a fast-twist tube to allow loading heavier bullets with superior ballistic coefficients.
My father went home and he did just that, adding a heavy 1:9 twist barrel to a FN Mauser action. That rifle served to test the theory and proved a hit. Shortly after, my old Swift received the same treatment.
As more shooters gain a firmer grasp on how ballistic coefficient (BC) directly effects things like long-range bullet drop and wind drift, it has become fashionable to equip .223 Remington rifles with faster twist rates. The last time I looked, nary a classic 1:12 twist .223 Remington could be found on the new-gun market. Savage (maybe others) now offer 1:9 twist .22-250 Remington rifles. For ages, the hotrod varmint cartridges – the .22-250 Remington and .220 Swift in particular – have been given 1:12- or even 1:14 twists allowing conventional bullets no heavier than 60 grains, and certainly not the sleek, “very low drag” or long-for-caliber lead-free bullets weighing even less that have become so popular. The slow twist rates are part tradition and part a fascination with high muzzle velocities via lighter bullets. A 40-grain bullet may leave the muzzle of a .220 Swift at a dazzling 4,300-plus fps, for example, but it bleeds momentum quickly.
If any varmint cartridge is truly capable of handling streamlined, heavy-for-caliber bullets, it is the Swift. It certainly owns the powder capacity. The Swift includes a higher powder capacity than the venerable .250 Savage, which handles 120-grain bullets and is considered an ideal deer cartridge. The Swift holds nearly as much powder as the .243 Winchester, which shoots a deer-ready 100-grain bullet. The Swift gains a new lease on life as a long-range/windy-day varmint cartridge by adding a faster barrel twist and loading heavier bullets. This is the ideal project for a tired Swift rifle – heavier bullets with higher BCs also promising longer barrel life. The 1:9 twist chosen for the test rifle seems ideal for bullet weights from 69 to 77 grains, and easily handles lighter lead-free bullets that will not stabilize in traditional 1:12 or 1:14 rifling twists. It’s something that can be accomplished for around $350, all in.
When we had our fast-twist Swifts built, load data was scanty, nearly all available
reference stopped at 60 grains. Berger and Sierra offered some tested loads and that was about it. When I did a load-development feature for Wolfe Publishing’s Rifle’s Varmint Rifles & Cartridges, Fall 2109, using my father’s fast-twist Swift, I essentially doubled available heavy-bullet data, much of it created on a Quick Loads program. In just the last five years, this has begun to improve slightly, as high BC is the latest rifle craze, driven by our obsession with going long. What I quickly learned is that instead of standard “varmint powders,” I enter the realm of “big-game” powders. In this test, this included IMR-4166 and Vihtavuori N140 at the fast end, and Vihtavuori N560, Alliant Reloder 26 and Hodgdon H-1000 at the slow end. In the middle were IMR-4451, Reloder 16, Hodgdon and Accurate 4350, Ramshot Hunter, Vihtavuori N160, Hodgdon 4831sc and Superformance and IMR-4955. Powders selected offer extreme temperature stability and clean-burning characteristics; Enduron Series also included de-coppering agents.