Custom .300 WSM Build A-Z

My first .300 WSM ever on the channel features a Pristine Action and Carbon Six in a WOOX Exactus stock with a Bix’n Andy TacSport X trigger from Bullet Central. Watch and read on to see it all come together!

Disclaimer

Ultimate Reloader LLC / Making with Metal Disclaimer: (by reading this article and/or watching video content you accept these terms). The content on this website (including videos, articles, ammunition reloading data, technical articles, gunsmithing and other information) is for demonstration purposes only. Do not attempt any of the processes or procedures shown or described on this website. All gunsmithing procedures should be carried out by a qualified and licensed gunsmith at their own risk. Do not attempt to repair or modify any firearms based on information on this website. Ultimate Reloader, LLC and Making With Metal can not be held liable for property or personal damage due to viewers/readers of this website performing activities, procedures, techniques, or practices described in whole or part on this website. By accepting these terms, you agree that you alone are solely responsible for your own safety and property as it pertains to activities, procedures, techniques, or practices described in whole or part on this website.

About .300 WSM

This caliber approaches .300 Win Mag performance in a short action.

It was designed in 2001 and has a 0.535” case rim and 2.860” overall length. It is SAAMI-certified with a maximum pressure of 63,817 PSI.

Bill of Materials

I decided on the .300 WSM after Lapua released a new brass caliber last year, the .300 WSM. (This year Berger is producing .300 WSM ammunition!) I placed a Pristine Short Action Magnum Action in a WOOX Exactus stock with Hawkins Precision M5 DBM.

I also chambered a 1:9 Carbon Six barrel (22” finished) using a Manson Precision reamer and added the Bix’n Andy TacSport X Trigger from Bullet Central.

About the Pristine Short Action Magnum Action

This is my third Pristine Action build. My first build featured Pristine’s standard six-lug short action in a lightweight 6 GT build. Next came a long action .280 AI in a WOOX Superleggera stock.

Unlike my 6GT build, the Pristine Short Action Magnum action is two-lug and available in right and left-hand configurations, nitride or polished.

It has a 90 degree bolt lift, dual ejectors, and floating bolt head. Available boltfaces are 0.470” (.308) and 0.540” (Mag). MSRP ranges from $1,299 to $1,379.

From Pristine Actions:

- Accepts standard Savage Small Shank pre-fit barrels for super-simple installation. (1.062/1.055 x 20TPI)
- Accepts all standard Remington 700 triggers – no trigger hanger required.
- Sako Extractor – larger than standard means no failures to extract.
- Works with any Remington Stock/chassis system and most aftermarket chassis systems. * Please contact Customer Service for more details*
- Works with external magazine-fed and blind mag stocks.

Specifications:

- Double pinned precision recoil lug included
- 2 Lug floating bolt head for unmatched security and strength
- Interchangeable bolt heads for caliber selection
- Includes Pristine’s Frictionless Throw Technology – a roller cocking piece engineered for super light bolt lift that creates consistent and smooth bolt closing. No ‘cock-on-close’
- Cylindrical action designed to remove material stress
- Double ejection pins for more consistent and powerful ejection
- Isotropic surface finish for enhanced smoothness
- Replaceable bolt knob – standard 5/16-24 thread
- 90 degree bolt lift.

About the WOOX Exactus

First off, don’t forget to use code UltimateReloader10 to save 10% sitewide at WOOXstore.com!

The Exactus has a clean, straightforward design with an aluminum chassis core and Walnut stock and forend. (It is also available in Tiger Wood, Midnight Gray, and FDE.)

It has an adjustable cheek riser, rear Picatinny rail section, and QD sling swivel with M-LOK slots on the forend.

Checkering on the forend and grip provide a cool aesthetic in addition to better grip.

Out of the box the Exactus is a little short for me, so I had to add the included length of pull spacers.

From WOOX:

Precision-engineered for long-range shooting with a sophisticated wooden exterior and robust internal chassis core. Accuracy at a thousand yards is art and transferring the intentions of a shooter to a bullet destined for that distance requires an exacting platform. That’s why WOOX made the Exactus. Based on a forged aluminum monoblock chassis with precision-cut contact points of American walnut, the Exactus is a professional, tactical stock. Proudly made in Italy and USA.

Specifications:

- Installation: Drop-in. Does not require pillars or extra bedding.
- No gunsmithing required.
- Grip: Ambidextrous
- Chassis: AA 7075 aircraft-grade aluminum, hard anodized.
- Stocks: American Walnut, Beech
- LOP: 13.5” – 14” (spacers included)
- OAL: 31”
- Weight: 4.1 pounds
- Max Floating Barrel:
  - Remington 700 models: 1.17”
  - Savage LA models: 1.15”
  - Sauer 100 models: 1.10”
  - Tikka, Ruger, Howa, Weatherby, CZ, Savage SA models: 0.95”

About the Bix’n Andy TacSport X

Like all Bix’n Andy triggers, the TacSport X features a patented ball trigger design and is available directly from Bullet Central.

It is a single-stage trigger with right and left safety options. It is suitable for both competitive shooting and hunting with an adjustable sear and pull weight from 0.620 lbs. To 4.40 lbs.

I recently featured it in my Bix’n Andy trigger shootout and tested it on the TriggerScan TS-11. These graphs indicated a clean trigger pull with no grit.

About the PM-1440HVT-2

The Precision Matthews PM-1440HVT-2 is a great gunsmithing lathe, with the following stand-out features:

All Taiwanese built with Japanese spindle bearings
2.055″ thru-spindle capacity
Available cast iron ultra-rigid base
Variable Speed drive
14” Swing, 40” Between Centers
D1-5 Chuck Mount
MT3 Tailstock Taper

If you’d like to know more about the PM-1440HVT-2, check out our full overview HERE.

Machining

Every build starts with a preparation process including the tenon print and SAAMI diagram.

I input this information into a program that generates machining instructions.

I also follow a chambering checklist to ensure I stay on task if I get interrupted.

I decided to do my chambering work on the PM-1440HVT-2 lathe. It didn’t take long to realize that the 22” finished barrel blank was not long enough to get all the way through the chuck and outboard spider.

To resolve this issue, I cut the barrel to length and threaded the muzzle ⅝” x 24.

I faced the end of the barrel and cut the recessed flat crown.

Threading the muzzle allowed me to add a barrel extension to chamber the breech end.

I started with a rough dial-in and pre-drill.

This permits extended reach into the throat area to dial the barrel in to 0.010” or less.

Next is using a boring bar to bore the pre-drill area true and using a chucking reamer to ream off the lands in the neck area.

This prevents chatter and deflection when the reamer goes in.

I also had to turn down the tenon and cut thread reliefs, just as I did on the muzzle end.

Counterboring preceded threading, after which I test fit the action.

Finally, it was time to cut the chamber.

I employed a rigid reamer holder for perfect alignment, cut to depth, checked headspace and chamfered the chamber entrance.

Assembly

I used the SAC Bravo Barrel Vise to secure the action to the 1.2” barrel shank, torquing it to 75 ft.-lbs. and performing yet another headspace check.

I transferred the barreled action to my Arrow Products Precision Rock Vise and installed the Bix’n Andy TacSport X trigger.

The WOOX Exactus fit perfectly – I didn’t have to make any adjustments to the barrel channel.

As a finishing touch, I 3D-printed a cover for the rear Picatinny section for easier use with a rear bag.

I also added an ARCA rail to the M-LOK slots for better compatibility with all of my bipods and accessories.

I also made some adjustments to the .300 WSM accurate-mag feed lips for better feeding and added a Leupold Mark 5HD 5-25×56 scope.

Shooting

I experimented with several different loads, all set in Lapua .300 WSM cases with H4350.

I tested Sierra .30 Caliber 155 Grain SMK’s and a few others including Hornady 178 grain A-Max bullets, and the Hornady 208 grain ELD-M.

The ELD-M bullets yielded the best 100-yard results with five shots going into 0.488”.

The second group opened up as the suppressor came loose. (Don’t forget to tighten your suppressor!) The average velocity was 2701.4 fps with an 11.3 fps SD and 32.2 fps extreme spread. I braved the cold snow to engage a steel target at 706 yards.

The first shot was close, the second hit the T-post, causing the target to tumble to the ground.

Longshot’s Hawk spotting scope camera captured the whole event!

Needless to say, I will be doing more shooting in the future out to further distances as well as hiking out to replace the broken T-post.

Conclusion

In my view, this is a compact magnum hunting rifle capable of taking elk and black bear as well as deer.

Its quality components and accuracy also allow it to double as a long range rifle. Overall, I was very happy with this rifle and look forward to pushing it further with load development.