autoloader Archives -
March 29th, 2020 by AmSJ Staff

The Magnum Lite Autoloader

Review and photographs by Oleg Volk

Magnum Lite 22WMR Rotary Magazine

The rifle uses a rotary magazine common to the discontinued Ruger 22WMR model. Each cartridge is contained between two pawls and thus protected from interference by the rims of other rounds. With the heavy return spring, an oversized bolt handle comes in handy.

The creation of an accurate .22 Magnum autoloader has long been plagued by cycling challenges caused by the cartridge shape and construction. The long, skinny case has a lot of surface area and resists extraction. Extracting it while the gas pressure is high runs the risk of blowing out the thin case head typical of rimfire ammunition. Balancing these conflicting requirements was a huge technical challenge to overcome – until the Magnum Lite.

Magnum LIte 22WMR

The rail is elevated enough to permit scopes with objectives up to 50mm – quite useful for varmint hunting.

Magnum Research calls the action “gas-assisted blowback,” but it is not. Gas assistance uses a muzzle booster to move the whole barrel (as on a Maxim machine gun), or diverts a small amount of gas that is tapped off just in front of the chamber and uses it to move a piston impinging on the bolt. The gas is then diffused and vented into the forend.
DEAD FOOT ARMS


The Magnum Lite uses neither, and the mechanism is more simply described as blowback with a gas pressure regulator. According to the manual, it keeps the pressure curve consistent for reliable and safe cycling. The manual sternly warns about using ammunition under 30 grains. My best guess is that the pressure curve spikes sooner in the cycle, leading to ejection failures and possibly blown-out brass.

 

The heart of the Magnum Lite is the graphite-wrapped barrel, which is 19 inches long and tipped with a stainless-steel cap. While the extra 3 inches over the minimum non-NFA (National Firearms Act of 1934) length gives no more than a 100-feet-per-second advantage with some loads and none at all with others, it does reduce the muzzle blast a bit and moves it further away from the shooter.

Magnum Lite .22

The Magnum Lite 22WMR, complete with a thick graphite-wrapped barrel and integral Picatinny rail machined onto the receiver, is under 4.5 pounds. Between the ergonomically sculpted thumbhole stock and light, crisp trigger, the Magnum Lite is quite accurate off hand.

The optic that I installed for testing is the Nightforce 3.5-15x, with an adjustable parallax. Off-hand shots were done with it set to minimum magnification, and supported set to medium. The top setting is reserved for use with a bipod or a sandbag. Given the small size of rodent targets and the relatively modest kill zones for 22WMR on larger creatures, the higher magnification comes in handy. The glass is quite heavy, almost 2 pounds counting the rings, which is why the weight saved by the use of a graphite-fiber barrel is so helpful.

 

Magnum Lite 22WMR

Since 22WMR chamber pressures vary from minimal, with Winchester Dynapoint, to high, with defense ammunition meant for shorter barrels, the Magnum Lite vents into a diffuser block, which in turn lets the excess gas into the stock.

While no ammunition maker markets 22WMR-match ammunition, it’s been my impression that the consistency of most US loads is quite good. Further, .22 Magnum bullets have a longer bearing area than heeled 22LR bullets, therefore have the potential for decent accuracy.


The old standby, CCI Maxi Mags make a ½-inch group at 25 yards, and the Gold Dots closer to a third of an inch. With the high initial velocity, they don’t go transonic until they’ve reach 150 yards or more, and give consistent accuracy for at least that distance. Given the mechanical and ergonomic capability for excellent accuracy, this Magnum Research design has amply deserved its popularity. I only wish for one upgrade – a muzzle threaded for a sound suppressor. That option exists on the 22LR model but not on the 22WMR. AmSJ



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