Sunday GunDay: Great .300 WSM F-Open Rifle from Down Under

Today’s featured rifle comes from the land Down Under — Australia. This impressive .300 WSM F-Open rig has top-tier components/accessories from multiple countries. From the USA comes the Borden BRMXD action, Krieger barrel, McMillan Kestros ZR stock, and R.A.D. 2 recoil system. The 10-60x56mm March scope comes from Japan. The Lenzi rear bag is from Italy, and the SEB front rest is from Indonesia, with a Rodzilla top from America. This rifle proved very accurate from the get-go, winning its first match, emerging with the top 600m Aggregate. This .300 WSM F-Open beast is definitely a winner.

Impressive .300 WSM F-Open Rifle from Australia

This rifle belongs to Kris Wilson, aka “Willow” on our AccurateShooter Forum. Just last week Kris posted in the Pride and Joy Rifle thread: “Got my latest build up and running — a .300 WSM F-Open rifle. Never shot a .300 WSM (Winchester Short Magnum) before today and I have to say that, while the recoil is on the sharp side, it’s entirely manageable thanks to the stock design and front rest.” Kris resides in Sydney, New South Wales, Australia and shoots at the Hornsby RSL Rifle Club. He has been his club’s F-Open Champion, even with some very tough competition — his club boasts two Australian F-Open championship-winning club members. Kris loves the F-Class game: “I started rifle shooting in 2015 when I was introduced to the world of F-class through shopping for a riflescope. Once I saw what F-class was all about, I was hooked.”

Kris produced this video on December 5, 2020. He reports: “Here is my first real outing with my new .300 WSM. I had previously sighted in at 50 meters at an indoor range to establish a wind zero. Had a rough idea of velocity so I threw together two loads to run at 600 meters. Our Aussie targets have a max numerical ring value of 6 (equivalent to “10” on USA targets). On Stage One I shot a 60.8X (60.10X max possible), grouping about 3.7 inches. On Stage Two, shown in this video, I shot a a 66.9X (66.11X max possible) with a 3-inch grouping. I took first place in both stages and won the overall Aggregate for the day. That earned me a Christmas ham and turkey for my trouble!”

.300 WSM Rifle Hardware, Cartridge Choice, and Reloading

Report by Kris Wilson, NSW, Australia

Stock: McMillan Kestros ZR with R.A.D. 2 system. 70% black, 15% grey, 15% red.
Action: Borden Rimrock BRMXD, left bolt, right port, left eject. The action is fully DLC coated and fitted with a +20 MOA rail
Trigger: TriggerTech Diamond
Barrel: Krieger 1:10″-twist, 4 groove finished at 31″ and fitted with an Ezell tuner.
Scope: March High Master 10-60x56mm with MTR-1 reticle, illuminated
Rings: ARC M10 High Rings
Front Rest: SEB Mini Rest, with Rodzilla Rest Top system
Rest Feet: Bryan Blake (F-Class Products) adjustable stainless feet
Rear Support: Lenzi (Italy) LR Rear bag, with custom metal base plate

Cartridge Selection — Why the .300 WSM Was Chosen over a 7mm Cartridge
I set out with the goal of building my ultimate F-Open rifle. Now “ultimate” is of course subjective, but I did not want to leave any stone unturned when it came to building a .300 WSM. When researching the equipment for my new build I had a couple of ideas in mind. I was already shooting a 7mm, in the form of a 280AI which had served me well, but I already had plans to switch to a .284 Shehane with the introduction of Peterson .284 Win brass, coupled with the fact Norma stopped making 280AI brass (Note: Peterson now makes 280AI brass). While I was reasonably well-covered with my .284 Shehane, I wanted something with a bit more horsepower to hold up at long range in choppy conditions. A lot of the top guys here shoot 7mm SAUMs but I wasn’t keen on going down that path. Why? For every accurate SAUM I’ve seen, I’ve seen others struggle and given that the 7mm SAUM seems to be particularly hard on barrels, I wanted something that could match the 7mm SAUM ballistically, but have better barrel life.

After plenty of research on AccurateShooter.com, and speaking with some shooters, both locally and in the USA, I decided to give the .300 WSM a go. This cartridge is not particularly popular in Australia for F-Open, primarily because most states enforce muzzle energy restrictions, so pushing the .300 WSM to its potential simply isn’t viable for many shooters here. It IS viable in my home state however, along with the ACT, so I can at least use it in major competitions in two Australian states without having to run at lower nodes where it would otherwise be trumped by the 7 SAUM shooters. I was also attracted to the cartridge through its general design, having a 35-degree shoulder angle similar to the inherently accurate .284 Winchester. I also think the .300 WSM resembles a super-sized Dasher, another devastatingly accurate cartridge. Most .300 WSM shooters report ease of tuning, another key factor I considered.

Choice of Stock, Action, and Barrel
My gunsmith, Matt Paroz (aka MattP on the AccurateShooter Forum) is one of Australia’s top gunsmiths as well as one of Australia’s top F-Open shooters. He knows what it takes to build match-winning rifles. Matt is also an agent for McMillan stocks and I was sold on the Kestros ZR after seeing how it well it tracked — the lower center of gravity it offers cannot be underestimated once you start stepping up in caliber size. I had previously seen a couple of rifles that Matt built for an Australian F-Open team member and I was blown away not only by the quality of the builds, but how well the components worked with one another. I already own a Barnard action, a match-winning action in its own right, but I was desperate to get my hands on a Borden. I liked the fact that Jim Borden times his actions as they leave his factory, so I ordered a BRMXD, left bolt, right port, left eject. I ordered my BRMXD fully DLC-coated, for both longevity and aesthetics.

I opted for a TriggerTech Diamond trigger which has been timed to the action and offers a level of crispness the factory Barnard trigger cannot replicate. The synergy between action and trigger is just superb. I managed to get my hands on a 10-twist, 4-groove Krieger barrel that looks like a winner so far. Finished at 31″, this barrel has been super-easy to tune so far, with Berger 215gr hybrids showing very good promise. NOTE — Overall the rifle comes in 500 grams (1.1 lbs.) below F-Open max weight, so the next barrel will probably finish at 32″.

The barrel sports an Ezell tuner. I don’t touch the tuner until I’ve sorted my load and bullet seating depth. The tuner just affords me that extra flexibility in tightening up an already good grouping. At the end of the day, like any competitive shooter, I’m chasing tight vertical and horizontal, something which will run inside 1 MOA at 1000 yards. If I drop a shot, I want it to be my fault, not the rifle’s.

About my optics choice — when the chance to own a March High Master came up, I didn’t think twice. I have used March previously and got a sneak peek through an original High Master prototype which was doing the rounds in Australia. With superb image quality, it left a lasting impression. March has built up an excellent following and reputation in Australia, and so far I have to say it was money well spent. The March is held in place with a set of beefy ARC M10 rings.

The rest of my F-Open setup includes a modified SEB Mini up front, with a Rodzilla Rest top and Bryan Blake adjustable feet. I chose the SEB Mini because it has a wide, stable footprint but relatively light weight. That makes the Mini easier to transport. At the rear I use an extremely well-crafted Lenzi LR bag which sits on a custom rear plate. This heavy combination keeps things nice and planted. That aids in straight tracking.

Reloading for the .300 WSM — Process and Die Choice
When it comes to reloading, I keep it simple and don’t over-think things. I use Norma .300 WSM brass. I ensure case mouths are always deburred on the inside and out but I do not neck turn. I am set up to turn necks with a 21st Century unit, but after neck turning previously for a 6mm SLR, I just didn’t see a noticeable benefit in doing so. I always full length re-size after firing and prefer bushings, generally opting for .002″ of neck tension on anything I shoot. So far it seems to be working. With my .300 WSM I run a Redding Type-S full-length bushing die with a .335 bushing. A loaded round comes in at 0.337″ across the neck and I opted for a no-neck turn reamer which comes in at 0.343″, so there’s plenty of clearance. I use a Forster micrometer seating die. I prefer the feel of the Forster and I use Redding dry lube media to assist in smooth bullet seating.

Reloading room with MEC single-stage press on left and AutoTrickler with Force Restoration Scale on right. Note there are plenty of bullets — Kris got his supplies before the shortage.

I use an AMP Annealer and anneal after every firing. Powder charges are measured and dropped with a V3 AutoTrickler and A&D FZ500i scale. The 215gr Berger Hybrid seemed like a pretty good place to start as far as bullet selection. I point them with a Whidden bullet pointing die. Powder options can sometimes be a contentious choice and if you’re lucky you’ll get a couple of powders which will work well in any given barrel. For my .300 WSM I use Alliant Reloder 23. It is very temp-stable. My primer of choice is S&B Standard Large Rifle Primers. How does it all come together? The first nine shots through the barrel while zeroing the scope resulted in an ES of 17 and SD of 6 — promising signs for a light initial load of 63 grains.

Kris has been impressed with his .300 WSM beast: “Suffice to say I was very pleased with how things turned out! Despite the bigger bang this rifle makes, the Kestros ZR and R.A.D. 2 system made it remarkably compliant. The recoil is sharp but the R.A.D. system just takes all the sting out of it — it reminded me of shooting my old 280AI in terms of felt recoil. I was able to get back on target with a minimum of fuss and didn’t find the rifle fatiguing at all, so it gets a massive thumbs up from me.”

CONCLUSION — The .300 WSM is Very Effective for F-Open
With recent trends in F-Open equipment, such as rifle stock technology making a lower center of gravity possible, bigger F-Open options such as the .300 WSM are now quite manageable. That’s not to say this caliber is a pussy cat — it definitely kicks more than the .284s out there. But with my choice of components, the recoil is manageable and the R.A.D. 2 system takes the sting out, so I’m not left nursing a sore shoulder at the end of a stage. The rifle is off to a very positive start so far but I know it’s capable of more. The lead up to Christmas will keep me busy fine-tuning a load in time for the NSW State Title match to be held in late January 2021. With COVID-19 halting most competitive shooting in Australia in 2020, this 2021 NSW competition is sure to prove popular. I intend to have my .300 WSM rifle humming in time for it.

Kris Wilson (NSW, Australia) Talks About Competitive Shooting
When I was introduced to F-Class shooting, I was fascinated with the level of accuracy shooters were obtaining with their rifles and it was something that just drew me in. Since then it has been a gradual learning curve, not to mention the fact everyone I have met has been super friendly and willing to share their knowledge. The shooting fraternity is a great community to be part of…. Mixing it with Australia’s best is what drives me right now.

I’ve been working hard to maintain my skills and the new rifle is motivation. As reloading equipment and rifle components continue to improve, it’s a great sport which encourages learning and provides many opportunities to keep improving your shooting.