WOOX Superleggera .280 AI Custom Rifle Build

I had created a poll asking my viewers what hunting rifle content they wanted to see with a list of cartridges. To my great surprise, the forerunner, .280 AI, wasn’t even on the list. In this video, I’m putting together a custom .280 AI hunting rifle featuring the WOOX Superleggera and a Pristine long action.

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About the .280 AI

.280 Ackley Improved (AI) is a SAAMI-certified cartridge based on the .280 Remington. The .280 Remington is a .30-06 necked down to 7mm with the shoulder pushed forward 0.050” to prevent it from being accidentally chambered in a .270 Winchester. Typical twist rate is 1:10. The .280 AI is the 280 Remington with the shoulder bumped up to 40 degrees, requiring less trimming. This cartridge has a slightly larger case capacity with a standard .308 case rim and is typically paired with a 1:9 twist barrel.

The .280 AI provides much of the performance of a cartridge like 7mm PRC or 7mm Remington Magnum, but with a standard .308 bolt face.

Bill of Materials

This hunting build is based around the new Pristine long action and the new WOOX Superleggera hunting stock.

I added a Carbon Six 7mm 1:8 fast twist barrel, Hawkins Precision hunter bottom metal and magazine, Area 419 Hellfire muzzle brake, Bix’n Andy Dakota trigger, and an Element Nexus 4-25x50mm scope. (I used some similar components in my Pristine short action 6GT build.)

I initially planned to use the 7mm Carbon Six barrel for a 7mm PRC build, so it is a little faster than a conventional, SAAMI-spec .280 AI, but this means it will do well with bullets like the Hornady 7mm 175 grain ELD-X and 180 grain ELD Match.

Following the same path I took for the .280 AI F-Class build, I’m using the same Manson reamer and gauges with the Precision Matthews PM-1440HVT-2.

About the WOOX Superleggera

This lightweight stock, weighing 2.2 lbs., is specifically designed for hunters. It is a combination of carbon-reinforced nylon and American Walnut with an option for an adjustable cheek riser.

Use the ULTIMATERELOADER10 code to save 10% on everything at WOOX!

From WOOX:

The Superleggera, translating to “Super Light,” revolutionizes the standard for lightweight performance, tipping the scales at 35 oz. It harmoniously integrates the timeless beauty of American walnut with the robustness of modern, carbon-reinforced SLS material. The V-Block Bedding Mini Chassis fortifies this union, promising durability and precision. SuperLeggera has been tested .278 MOA improving more than .3 MOA the factory stock accuracy.

2x MORE ACCURATE, field tested!

SuperLeggera has been tested .278 MOA improving more than .3 compared to factory stock. Find the field test report here.

“Comparing the results in terms of precision, the groupings obtained with the Super Leggera stock (0.287 moa at 100m) compared to the Factory (0.599 moa at 100m) were significantly better.”

Specifications:

- Installation: Drop-in. Does not require pillars or extra bedding. No gunsmithing required.
- Grip: Ambidextrous
- Materials: Carbon-reinforced Nylon, American Walnut
- LOP: 13.5” – 14.5” adjustable (spacers also included)
- OAL: 31”
- Weight: 2.1 – 2.3 lbs *
- 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 Pristine Long Action

Pristine’s new long action has a 2-lug design instead of the short-action six-lug design. It is available as a repeater or single-shot and in right- and left-handed configurations.

CNC-machined from pre-hardened 416 stainless steel, the action is nitrided or polished (customer choice) and features a floating bolt head with swappable bolt faces.

From Pristine Actions:

A Pristine action is designed to be a direct Remington 700 replacement upgrade.

- CNC machined from one solid piece of pre-hardened 416 Stainless Steel
- Ultra-smooth bolt cycling – less than 4 pounds to lift the bolt
- 2-lug design, with light and quick 90° bolt lift
- Dual ejectors
- Bolt face diameters available for a variety of calibers (.480, .540, and .585)
- Floating bolt head allows for an exchangeable bolt head

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

Machining

The first step was to obtain a tenon print and receiver drawing from Pristine and create my own drawing with my intended specifications.

I also took the time to measure the action and verify that the dimensions matched the tenon print. I soon realized I had an issue.

The Pristine LA uses 1.125” – 20 barrel threads (Savage large shank spec). My Carbon Six barrel has a 1.200” shank. The minimum recommended shank diameter is 1.250” for 1.125” threads.

My solution was to slightly open the barrel channel for the 1.200” shank and to create a step-up ring with 1.125”-20 internal threads.

I then treated this step-up ring as my new shoulder for measurement and headspace purposes. I used the Precision Matthews PM-1440HVT-2 for all of my machining work.

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

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

Back to the chambering overview!

Machining Continued

I follow a strict checklist to make sure I don’t forget any steps.

I pre-drilled, then indicated the barrel to 0.001”, checking for radial and angular runout.

Next came single-point boring the chamber area and reaming off or boring off the lands in the neck area to neck-area length.

I turned the tenon and threaded it 1.125” – 20, verifying this with a threading micrometer and by screwing on the Pristine long action to check fit.

Everything fit perfectly.

With this complete, I cut the counterbore and checked fit with the action and bolt before cutting the bulk of the chamber with a Manson reamer.

When I finished with all of my work, I surveyed the throat area with a borescope.

Indicating the throat area of the breech end

I was thrilled with the results.

Putting It Together

I torqued down the barrel in the Short Action Customs Bravo Barrel vise and checked headspace again.

Checking headspace for Ackley Improved chamberings can be a bit tricky. You can either use dedicated AI gauges or use an Ackley go gauge and the appropriate standard go gauge (Ex. .280 Rem) as a no-go.I used dedicated Ackley gauges from Manson Precision.

My headspace was a little bit on the tighter side with the extra crush from the step-up ring, but it still passed the go-gauge test. I then added the stock and bottom metal.

The Hawkins Precision DBM bottom metal and hunter magazine keep this build compact. The magazine just barely extends beyond the stock, giving you a detachable box magazine capability with an almost flush feel.

Having a detachable magazine means you can load it ahead of time without safety concerns. It is also simple to unload the rifle without having to run the bolt several times with an internal magazine.

I decided to mount the Element Nexus Gen 2 4-25×50 FFP with ACCU-LITE rings on this rifle.

Just like the Theos, I’ve been incredibly impressed by this Japanese scope, featuring tool-free resettable turrets, a zero stop, and revolution indicators.

The scope added approximately another 30 ounces to the set-up. Though I could have chosen a lighter optic, I typically run heavier optics as I prefer having the extra tactical features.

Loading and Shooting

I got a rough zero with a bipod and a rear bag before moving to the mid-mountain 100-yard bench.

I didn’t have any factory .280 AI so I loaded some. (.280 AI loading video coming soon!)

I couldn’t find any specific load data with my 1:8 twist barrel (all was for 1:9), so I started off conservatively, loading 57.0 grains and slowly working up to 60.0 grains of Hodgdon H1000 with Hornady 180 grain ELD-M bullets. (60.0 grains is slightly over maximum load. Do NOT try this at home.)

60.0 grains had the best chronograph results with a 2784.20 fps average velocity, 5.5 fps standard deviation, and 13.2 fps extreme spread. We did observe slight pressure signs.

While the velocity numbers were good, the accuracy suffered. I switched to the Berger 180 grain Hybrid Target bullet and my first five shots tore one ragged hole measuring 0.520” at 100 yards.

I also tested Hornady 190 grain A-Tips and they performed similarly to the 180 Grain ELD-M bullets.

Neither matched the accuracy of the Berger bullets.

TriggerScan — About the Bix’n Andy Dakota Trigger

Bix’n Andy’s single-stage Dakota trigger comes in a number of configurations for different rifles with both top left and top right safety options. We have the Rem 700 top right safety model.

The Dakota is designed for hunters but also has a place in long range shooting; it is adjustable between 450 grams (0.99 lbs.) and 2000 grams (4.41 lbs.).

I like light target triggers, but prefer an approximate one pound pull on a hunting gun.

From Bullet Central:

The Bix’n Andy Dakota Trigger for the Remington 700 series is a high-performance, affordable upgrade for your rifle. Renowned for its precision and reliability, this trigger offers a host of features designed to enhance your shooting experience, whether you’re hunting, participating in sports shooting, or engaging in long-range competitions.

Adjustable Trigger Pull Weight

The Bix’n Andy Dakota Trigger allows for precise customization with an adjustable trigger pull weight ranging from 450 grams (0.99 lbs) to 2000 grams (4.41 lbs). This single-screw adjustment makes it easy to fine-tune your trigger to your specific needs, providing optimal control and comfort.

No-Latch Trigger Mechanism

The innovative no-latch trigger mechanism increases reliability by reducing the number of moving parts. This design ensures a smoother, more consistent trigger pull, which is crucial for achieving high accuracy and precision in shooting.

Weatherproof Construction

The Dakota Trigger is built to perform in all weather conditions. Its weatherproof construction ensures that you can maintain peak performance even in adverse environments, making it a dependable choice for any shooting scenario.

Searless Design

The searless design of the Dakota Trigger guarantees simplicity and absolute reliability. This single-stage trigger mechanism maintains dry trigger characteristics across the entire adjustment range, providing a crisp and clean break every time.

Patented Ball Trigger

Bix’n Andy’s patented ball trigger design minimizes friction, ensuring a smooth and consistent trigger pull. This feature enhances the overall shooting experience, making it easier to achieve precise and accurate shots.

Ideal Trigger Shoe

The Dakota Trigger is equipped with an ideal trigger shoe designed to minimize the impact on the rifle’s position during the shot. This feature is essential for maintaining accuracy and consistency, particularly in long-range shooting scenarios.

Precision Manufactured Parts

Each component of the Dakota Trigger is precision-manufactured to the highest standards. This meticulous attention to detail ensures that every trigger performs flawlessly, giving shooters confidence in their equipment.

Specifications:

- Trigger Pull Weight: Adjustable between 450 grams (0.99 lbs) and 2000 grams (4.41 lbs)
- Weight: 50 grams (1.76 oz)
- Measurements: 50 x 50 mm (1.97 x 1.97 inches)
- Brand: Bix’n Andy
- Model Series: Dakota Trigger
- Target Use: Hunting, Sports, Long Range
- Trigger Rifle Model: Remington 700
- Trigger Characteristic: Single Stage
- Safety Position: Top Right
- Height of Top Sears: High (4.0 mm / 0.157 inches), Low (3.6 mm / 0.142 inches), Medium (3.8 mm / 0.150 inches)

I decided to run some profiles using the TriggerScan TS-11 to fully quantify the Dakota’s performance.

Travel to actuate is approximately 0.014”. This is very tight and ideal.

Shooting the gun at 100 yards, I always knew when it would go off. It was also very crisp.

The TriggerScan data confirmed what I observed on the range. Overtravel was approximately 0.086” with peak force about 0.920 lbs.

Conclusion

I was very happy with this rifle and its performance.

While the Hornady bullets may perform better with further load development, the Berger 180 grain Hybrid Target bullets performed so well that I’ve decided to focus on different powders, seating depths, and other specifics with that bullet.

The step-up ring solution worked well and the combination of WOOX Superleggera with the nitrided Pristine Long Action resulted in an old-school look with contemporary feel. Watch for an upcoming video on reloading .280 AI with Forster equipment!