Kimber Subalpine mountain rifle in .300 WSM

Con Kapralos

Hardcore hunters who pursue trophy animals all over the world are fussy when it comes to their gear. Hunting mountainous regions for premier game species demands kit 100 per cent reliable while being as light as possible. When you walk countless kilometres with a backpack and rifle, with all the load on your shoulders and back, any weight saved is a huge advantage.

Kimber of America create superb stalking rifles with the Mountain Ascent model having been in production for quite a few years and being an ultra-light stalking rifle it has many fans. In 2018 Kimber released a new variant of the Mountain Ascent – the Subalpine – offered in three action lengths in five popular hunting calibres: .308 Win, .280 Ackley Improved, .30-06 Springfield, .300 WSM and .300 Win Mag.

Nioa, Australian distributor for Kimber, forwarded a Subalpine rifle in the hard-hitting .300 WSM calibre to review, together with a Leupold VX-3i 3.5-10×40 riflescope, rings and bases. Additionally, Nioa supplied ammunition in four of Federal Premium’s .300 WSM hunting loads. I expected the Kimber Subalpine to be a quality rifle in fit, finish and aesthetics but shooting the potent .300 WSM calibre in such an ultra-light rifle would be a challenge. A benchrest rifle and calibre it certainly is not.

At a glance

The review rifle is of a turn-bolt repeating action designed on the Kimber 8400 platform with a full-length Mauser claw extractor with Controlled Round Feed (CRF) and extraction. The metalwork is stainless steel with a 610mm fluted barrel, threaded at the muzzle for use with accessories. The reinforced carbon-fibre stock in the soft-touch Gore Optifade Subalpine pattern gives the rifle its identity and it measures 1110mm and weighs 2.69kg bare.

The action

Three different actions lengths are used in the 84M (short), 84L (long) and in the review rifle the 8400 (Magnum), the cylindrical action made of high-quality stainless steel with a separate recoil lug between barrel and receiver.

The recoil lug sits flush with the sides of the barrel and in a recess in the receiver, so when the rifle is assembled the recoil lug can’t be seen. The bolt is a Control Round Feed design with a classic full-length rotating claw extractor which guarantees the cartridge case is held against the bolt face from the minute it leaves the magazine until it’s ejected from the action. Two solid lugs at the front of the bolt ensure a positive lock-up with the breech, and the overall action is very smooth with the bolt scaled accordingly to the Kimber 8400 Magnum action. The top of the action is drilled and tapped for scope mounting accessories and in the review rifle these were the excellent Leupold two-piece bases and corresponding scope rings.

The barrel

The light-profile stainless barrel measures 610mm (24^) , no doubt to assist the ballistics of the belted-Magnum chamberings. The diameter tapers from 28.9mm at the knox form to 14.4mm at the muzzle, which is also furnished with a 7/16×28 thread to accept a matching Kimber muzzle brake. It would have been useful for the brake to be supplied as shooting such a light rifle without some recoil management is not a wise choice.

The barrel also has a series of three flutes concentrically around its diameter, 200mm x 5mm. They start 290mm from the muzzle and terminate 60mm from the knox form and are there to lighten the barrel and assist with cooling. Internally the four-groove, one in 10^ right-hand twist is well suited to the .30-calibre projectiles users of a .300 WSM will hunt with.

Safety and trigger mechanism

The trigger safety is a three-position wing-type affair, easily operated with the thumb of the right hand as follows: forward to fire (red dot evident); fully rearward for safe, blocking the firing pin and locking the bolt; and middle position permitting the rifle to be loaded and unloaded while having the firing pin blocked.

This wing-type safety has merit and has been used on other popular rifle models but I prefer a linear-style safety lever rather one that rotates clockwise/anti-clockwise. The adjustable match-grade single stage trigger was excellent, set from the factory with a 900-gram let-off with absolutely no creep or over-travel. Added to that the lovely curved trigger shoe sat well in the index finger and allowed positive pressure to be applied to the trigger when firing.

The magazine

The absence of a magazine floorplate or detachable box magazine reflects the purpose of this rifle. Being a serious ultra-light mountain rifle, at best the user will deploy one or two shots maximum on their quarry, so why engineer a magazine with higher capacity when it’s not needed? Saving a few grams here and there is what makes the Subalpine appeal. The steel magazine box sits in the floor of the riflestock and a multi-fold leaf spring and polymer follower manages the 3-shot magazine capacity found in the Magnum chamberings. Rounds are loaded through the top of the action and for removal must be cycled through the action and ejected. The short and long action chamberings in the Subalpine come with 4-shot magazine capacity.

The stock

This is one major component which makes the Subalpine tick, being made of a reinforced carbon-fibre composite its strength and light weight is its greatest ally. The stock is covered with the Gore Optifade Subalpine camouflage pattern which enhances the aesthetics and is of a pleasing American profile with straight comb and clean lines without chequering panels.

Grip is provided by a well-engineered surface coating which feels a tad ‘tacky’ but offers excellent hold with wet or dry hands. The trigger length of pull comes in at 345mm and is finished with an excellent one-inch Pachmayr Decelerator recoil pad and stainless QD sling swivel studs. A separate aluminum triggerguard is fixed to the stock with two small screws, one external and the other internal. Bedding-wise, aluminium pillars provide a super stable platform which the barrelled action mates up to, and a recess in the floor of the stock just forward of the front aluminium pillar mates with the recoil lug. The entire barrel length is free-floating.

Range testing

From the outset I knew I wouldn’t be able to defy physics with the Subalpine and .300 WSM chambering – without the matching Kimber muzzle brake, testing would be slow and methodical. The pencil-thin 610mm barrel would heat up quickly and this would have to be factored in. Normally for standard short or long action calibres I’d fire five 3-shot groups at 100m with a barrel clean between changes in ammunition, but for the Subalpine in .300 WSM, three 3-shot groups would be the maximum with each ammunition brand.

Kimber Subalpine rifle .300 WSM at 100m


Best group (mm)

Worst group (mm)

Average group ** (mm)

Federal Premium Trophy Bonded Tip 180gr




Federal Premium Power●Shok 180gr




Federal Premium Trophy Copper 180gr




Federal Premium Edge TLR 200gr








** Average calculated from three 3-shot groups at 100m

It can be seen that the ultra-light weight of the Subalpine and .300 WSM cartridge was a real trial to shoot accurately and no doubt having the Kimber muzzle brake would have helped tame recoil, muzzle jump and resulted in improved group sizes. Shooting in warm weather meant the barrel heated up quickly and my Barrel-Cool fan was kept busy. The smallest groups were always the first three shots fired and as the barrel warmed up shots would string out as you’d expect from an ultra-light mountain rifle.


The Kimber Subalpine is a specialist rifle for the hunter who treks on foot. Backpacking hunts where everything you need is carried on your shoulders demand a rifle that contributes minimally to the weight. When crossing steep country, being able to use both hands and not have a 4kg-plus rifle hanging off your back is preferable. The Subalpine is offered in five calibres and is bound to appeal to the hunter who walks long and hard in daunting terrain for their trophy quarry. It’s a premium grade rifle and retails for around $3000. More at


Manufacturer: Kimber of America, Yonkers, NY

Model: Subalpine

Action: Control Round Feed (CRF) bolt-action, stainless steel, front locking repeater

Trigger: Adjustable match-grade, single stage (set at 0.9kg on review rifle)

Safety: Three-position, Model 70 wing safety with bolt-release button

Barrel: Ultra-light weight, fluted, 610mm (24^) in length, one in 10^ right-hand twist (on test rifle in .300 WSM), recessed target style crown. 7/16×28 thread on muzzle for applicable recoil devices. Barrel length ranges from 560-610mm (22-24^)

Sights: None fitted. Action top drilled and tapped for scope mounting hardware

Calibres: .300 WSM (tested), also available in .308 Win, .280 Ackley Impr, .30-06 Sprg, .300 Win Mag

Magazine: Internal box magazine, 3-shot capacity (Magnum calibres) 4-shot capacity (short and long action calibres)

Stock: Reinforced carbon-fibre material with soft-touch Gore Optifade Subalpine pattern,

aluminium pillar bedded, 1^ Pachmayr Decelerator recoil pad

Distributor: Nioa

RRP: $3000 (approx)

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