Sako S20 Hybrid Rifle Review

The Sako S20 hybrid rifle evolves with the owner, and it combines best-in-class versatility with superb accuracy.

September 04, 2020 By Joseph von Benedikt

Multiple fore-ends are available for the S20. The author used Hunter (top) and Precision (bottom) versions. Both feature side-mounted QD cups for attaching a sling, and the Precision stock has M-LOK slots for adding accessories like a bipod and a barrier stop.

Sako’s new S20 modular rifle is arguably the most user-adaptable bolt-action rifle. Designed to be ultimately configurable and capable across the full spectrum of potential uses, from hunting to precision/tactical competition, it’s a very intriguing firearm.

According to Sako literature, the S20 is designed to be a rifle that evolves with the owner, eliminating the need to purchase a new rifle every time your interest in a new shooting sport germinates. Here’s how Sako accomplished that.

Each rifle can be fitted with two sets of stocks composed of two different fore-ends and two different buttstocks. They can be mixed and matched to suit just about any need. Additionally, the trigger, scope-mounting setup, magazine, and other elements are user-configurable and adaptable. However, the stocks are the major players in this new system. More about them in a moment.

While S20 rifles will come configured as either the S20 Hunter or the S20 Precision, and alternate stock configurations will be available as optional accessories, the rifle I used arrived in a very nice hard case with a full bevy of parts and accessories. Included were the various stocks as well as four different sets of scope rings, a muzzle brake (the barrel is threaded 5/8x24), a monopod, two different thumbrests for the vertical-grip stock engineered for precision shooting, a five-round magazine (10-rounders are available), a barrier stop compatible with the M-LOK slots in the fore-end, a sling, tools, and other various accessories.

The action is a combination of excellent features from other Sako models. The S20 sports a three-lug bolt made of stainless steel, fitted with a classic Sako-type extractor and plunger ejector. A red-dot “cocked” indicator protrudes from beneath the rear of the composite bolt shroud. As for the bolt handle, it’s interchangeable. The one fitted to my rifle features a slightly extended tactical-type bolt knob that’s elegantly grooved around its radius, providing a no-slip grasping surface. A two-position safety resides just behind the bolt handle. It locks the bolt closed when in the “On” position, which I like, and there’s a small tab just forward of the safety lever that releases it so the chamber may be cleared without disengaging the safety. A sleek, striated bolt release button is located on the left rear side of the receiver.

Interestingly, the S20 action is intended to serve all short, standard, and magnum cartridges. Historically, Sako has designed size-appropriate variations for each. Not this time. The S20 magazine clearly shows that most cartridges will fit and function into one size.

Undoubtedly, the biggest departure from the Sako norm is the scope-mounting system. Sako is known for its proprietary scope ring system, which is excellent but difficult to find rings for in the United States. In a very savvy move, however, Sako chose to machine a 1913-spec Picatinny rail atop the S20’s receiver, making it compatible with all MIL-STD cross-slot rings. Being machined integral to the action, it offers unbeatable strength, too.

Beautiful Engineering

Important to the interchangeable stock system is the way the action mates with its bedding, which is a machined aluminum V-block. Rather than possessing a traditional recoil lug integral to or attached to the action, a slot machined across the bottom of the front receiver ring interfaces with a steel lug embedded in the aircraft-grade aluminum V-shaped bedding block.

While nearly seamless in appearance, the front and rear stocks are distinct, separate parts. Each has a composite exterior inhabited by an aircraft-grade chassis. This provides an excellent combination of accuracy- and consistency-enhancing rigidity, easy configurability, and robust strength.

Swapping the buttstocks is easy. Simply loosen the top receiver tang screw and the rear receiver screw just behind the trigger guard and pull the stock rearward. Insert the alternate stock into the machined-aluminum interface and snug those screws up to 7 Nm (Newton meters), which is about 62 inch-pounds on your American torque wrench.

Changing out the fore-end is a bit more complex. Loosen those same two rear action screws and remove the stock. Remove the front action screw or screws (one on the Hunter fore-end; two on the Precision fore-end). Remove the two side screws from inside the QD sling attachment cups, one on each side of the fore-end tip, and the traditional-looking sling swivel stud from the bottom of the fore-end tip. Give a gentle tug and the composite part of the fore-end will come free.

To this point, the barreled action is still firmly locked into the V-block chassis. Next, remove the action screws located at the bottom of the front receiver ring and just forward of the trigger assembly, as well as the rear tang screw, and lift the barreled action from the chassis.

While complex, it’s a beautifully engineered system. Because I couldn’t help myself, I fully disassembled the stock system and spent a happy 30 minutes playing with different stock/fore-end combinations and marveling at the ingenuity of the Finnish designers. Finally, I put the S20 together using the Precision stock and fore-end. I actually prefer the look and feel of the Hunter stock and fore-end, but I decided the Precision version would help me milk the best performance out of the rifle during accuracy testing.

In addition to the several M-LOK slots incorporated into the Precision fore-end that made mounting my favorite Spartan bipod easy, there’s an M-LOK slot just forward of the magazine and a compatible Sako-provided barrier stop, which helps shooters make the most of improvised rests in field-type shooting positions. Aft, the Precision stock comes with two thumbrests that help the shooter maintain a consistent, comfortable firing-hand grip; a quick-adjustable comb so you can finesse cheekweld to perfection; and a buttpad that’s adjustable for length of pull (LOP) via included spacers and for height by sliding the pad up or down in the screw slots. It’s worth noting that both stocks feature comb height, LOP, and buttpad position adjustments.

The trigger is adjustable, too. A hex-head screw accessible through the magazine well allows the shooter to adjust weight of pull between 2 and 4 pounds. I adjusted the trigger on my rifle all the way down, encountered a hard stop (which I like), and shot, happy with the 2-pound precision trigger feel. In addition to pull weight, the trigger blade is adjustable for position by a few millimeters in each direction. This enables the owner to position it perfectly for reach, benefitting feel and control.

Sako touts increased barrel life and excellent accuracy from its cold-hammer-forged (CHF) barrels. In creating a CHF barrel, the blank is first drilled and then inner-surface-honed to a very smooth surface. Then a mandrel is inserted, and the barrel is hammered from all sides. The hammering transfers the reverse image of the rifling from the mandrel and work-hardens the steel, which provides the increased resistance to erosion and the resulting longer barrel life. As for accuracy, although some detractors claim a hammer-forged barrel cannot be as accurate as a button- or cut-rifled barrel, consider this: Unlike most of its competitors in the production-rifle world, Sako offers a sub-MOA guarantee for five-round groups, not just the three-round groups most companies guarantee.

Each S20 comes with a five-round magazine (three rounds in magnum cartridges), and 10-rounders are available. Made of a high-impact composite, the double-stack, center-feed magazines are designed to accept cartridges loaded longer than usual, enabling handloaders to finesse bulletseating depth for maximum performance. This is the first factory rifle I’ve seen that not only provides this feature but also advertises it. Kudos to Sako.

For those wondering, in order to prevent cartridges from moving forward and back in the magazine during recoil, the company designed internal contouring that interfaces with the cartridge’s shoulders, holding them rearward and preventing projectile tips from contacting the inside front of the magazine. It’s a nice touch that minimizes potential accuracy-inhibiting damage to bullets.

As I mentioned, Sako provides a beautifully engineered bridge-type scope base that clamps atop the Picatinny rails machined into the front and rear receiver rings. My rifle came with four different ring sets, including rings for 1 inch, 30mm, 34mm, and 36mm scope tubes. Each ring’s flat base features four small posts that are machined integral to the ring and mate with corresponding holes in the flat top of the bridge-type scope base. The attaching screws are inserted from the bottom, so ring bottom halves must be installed prior to the base being mounted to the receiver.

Superb as the new S20 system is, I can’t love everything engineered for it. Although the Sako scope-mounting accessory bridge mount and system are beautifully thought out and executed, I think it’s unnecessary unless you order a version with built-in MOA so you can dial a scope for extreme distances. My sample is marked 0 MOA, so it’s not an improvement. Also, because of the cross-slot bases machined into the top of the S20’s action, the bridge elevates any given scope’s position above the axis of the bore by more than a quarter-inch.

I don’t like high-riding scopes, and I don’t like fiddling with unnecessary bits of hardware, so I went the simple route and just installed a Leupold VX-5HD scope in 30mm Nightforce rings directly to the Picatinny rail machined into the action. The result is lovely, the optic sitting tight to the barrel, with just a whisker of clearance between the barrel and the objective lens housing.

Admirable Accuracy

At the range, I bore-sighted the Leupold scope and began firing test groups. From the very first three-shot test, the S20 clustered bullets in admirably tiny groups. My rifle is chambered for 6.5 Creedmoor, and the 24-inch barrel has a twist rate of 1:8. The magazine loads easily, the action feeds cartridges smoothly into the chamber, and the rifle feels great in shooting positions and through recoil. Having an icicle-crisp 2-pound trigger doesn’t hurt, either.

Two of the four loads tested averaged well under 0.75 MOA. Of the two, the S20’s favorite was Hornady’s 147-grain ELD Match ammo, which turned in an impressive 0.64-inch average. Federal’s 135-grain Hybrid Hunting ammo wasn’t far behind, averaging 0.68-inch groups.

I’m guessing the S20 has a minimum-dimension, match-type chamber because Federal’s Hybrid Hunting match-grade ammo with the Berger bullet was snug. Two cartridges out of the box were tight enough that the bolt wouldn’t close on them. Tight chambers are both good and bad. Without a tight chamber, you usually can’t achieve the sort of accuracy the S20 is capable of. On the flip side, you’ll want to chamber-check all ammo at the range before hunting or competing with it.

Aside from those two rounds of Federal ammo, the S20 functioned perfectly, feeding, firing, extracting, and ejecting smoothly and reliably. In addition to the 6.5 Creedmoor chambering I tested, the S20 is offered in .243 Winchester, 6.5 PRC, .270 Winchester, 7mm Remington Magnum, .308 Winchester, .30-06, and .300 Winchester Magnum.

The S20 is a very innovative rifle, offering features that few others, if any, can compete with. It has the rigidity, stability, and accuracy of a machined-aluminum chassis paired with the comfortable handling feel of good composite material. In my opinion, it has the best scope compatibility of any rifle Sako has ever produced. It’s ergonomic and smooth to function and fire. Without qualms, I can say the S20 is one of the most interesting new rifles on the market.