The Ultimate 6×47 Precision Rifle Build A-Z: Woox Furiosa Ultra & BAT Hammerhead

I’ve built a lot of rifles over the years but this is one I think will make my favorite’s list: 6mm x 47 Lapua in a WOOX Furiosa Ultra chassis around BAT Machine’s brand-new Hammerhead action!

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Bill of Materials

This build is full of new products. A 6mm 1:7.5 Krieger barrel blank from OTM Tactical (UR5 to save 5%) is set in a WOOX Furiosa Ultra chassis (ULTIMATERELOADER10 to save 10%) with a BAT Hammerhead action.

I also have the Timney Calvin Elite Custom Rem700 trigger, Leupold Mark 4HD 6-24×52, and Hawkins Precision M5 DBM.

I used Triebel reamers and gauges with the Precision Matthews 1440HVT-2 lathe. If you are interested in building your own precision rifles, be sure to check out the Colorado School of Trades!

About the WOOX Furiosa Ultra

The WOOX Furiosa Ultra is a chassis designed for PRS shooters that builds on the features and functionality of the original Furiosa.

The Ultra has a vertical rather than slanted grip and longer forend than the Furiosa.

Hybrid construction of American Walnut and 7075 CNC-machined aluminum provide a distinctive appearance and feel, combining tradition and innovation.

Both the cheek riser and length of pull are micro-adjustable. The Furiosa Ultra has a full-length ARCA rail and side M-LOK slots as well as an integrated bag rider.

WOOX Furiosa Ultra Barrel Channel and Internal Weights

It does not come with bottom metal, but is cut for M5, which you can order directly from WOOX ($249).

The Furiosa Ultra retails for $1399. The ULTIMATERELOADER10 discount saves you 10% on everything at WOOX!

From WOOX:

Furiosa Ultra is the answer to requests from PRS shooters wanting the ultimate classical wood stock and chassis system from WOOX.

A full 3” longer than the flagship Furiosa, Furiosa Ultra widens the barrel channel to accommodate barrels up to 1.20” in diameter, adds a full-length Arca rail, and incorporates the WOOX Suspense™ weight system.

Integrated into the fore end of the Furiosa Ultra, the Suspense System allows for up to six 2.5-ounce weights to be arranged to achieve proper balance. Two weights are included (additional weights sold separately).

The vented fore end includes port and starboard M-LOK™ panels for maximizing accessorizing capability.

The striking shoulder stock of the Furiosa has been remodeled in the Furiosa Ultra for competition with a vertical grip and matching bag rider. Thumb rests are molded into the chassis, milled from aircraft-grade aluminum. Micro-adjustable cheek riser and LOP, microcell 2-way adjustable butt pad and a 3.5″ bag rider create custom fit and stable platform delivering exceptional accuracy.

Specs:

- Installation: Drop-in. Does not require pillars or extra bedding. No gunsmithing required.
- Grip: Vertical w/thumb rests
- Chassis: AA 7075 aircraft-grade aluminum, hard anodized.
- Stocks: American walnut
- LOP: 13.5” – 15” adjustable
- OAL: 34”
- Weight: 4.5 lbs.
- Max Floating Barrel:
  - Remington 700 models: 1.20”
  - Savage LA models: 1.15”
  - Sauer 100 models: 1.10”
  - Tikka, Ruger, Howa, Weatherby, CZ, Savage SA models: 0.95”
- Colors: Walnut
- Mounting Systems:
  - 10″ M-LOK™ (x2)
  - Full-length Arca rail
- Ideal for: PRS Pro Series, PRS .22LR, NRL, Benchrest, F-Class

About the BAT Hammerhead Action

The new Hammerhead action from BAT Machine features a shorter 75 degree bolt throw with different bolt stop options for different throw lengths.

It shares the same tenon print as the BAT Igniter and BAT Bumblebee which I have already chambered for, none of which have counterbore. (Bruce Thom and I proved counterbore is not necessary in this video, but do NOT try this at home.) This allows me to swap barrels between all three actions.

From BAT Machine:

Our Newest purpose built competition action. Faster operating than ever before with our renowned BAT Precision. Featuring a shorter 75 degree bolt lift that doesn’t compromise action strength or feel. The Hammerhead includes a standard length bolt stop or a short travel bolt stop for BR/Dasher length cartridges. The shorter position reduces travel by .350″ thus improving cycling speed. An adjustable and removable screw is fitted to the magazine port to allow for the use of AICS magazines without the feed-lips contacting the bolt. Our new Hammerhead action is designed to handle Magnum cartridges. Available from Unknown Munitions.

Features:

- Remington 700 Short Action Footprint
- Integral 20 MOA Picatinny Rail and Recoil Lug
- 75 Degree Lift 2 Lug Bolt
- Comes with Two Bolt Stops: (Standard & .35″ reduced travel for BR/Dasher)
- Modular Bolt with Spiral Fluting and a Flat Face
- Action Weight is 34.6 oz
- Large (3.03″) Magazine Opening Cut for the Accuracy International AW (double stack double feed) Boxes.
- Adjustable stop to optimize use of AICS magazines
- Ejector Port Length is 2.55″ at Stock Level Tapers Back to 2.76″ Long at the Top.
- DLC Coated M-16 Style Extractor.
- Black Nitride Coated Body, Bolt, and Firing Pin
- Custom anodized aluminum knob with 5/16-24 thread.
- Barrel Tenon is 1.0625 x 18 tpi

Machining

I started with a 6mm 1:7.5 Krieger barrel blank from OTM Tactical and finished it at 26”.

This time I used a Triebel body/neck reamer and a throater rather than a rougher and a finisher.

This allows me to provide exact freebore for a specific load, bullet, magazine, cartridge OAL, etc. I used this technique before with Triebel tools on my 6.5x47mm BR build and my .50 BMG build.

The basic chambering process is the same as with an all-in-one reamer and I still used the shoulder as a datum point for the go and no-go gauges.

After I completed the primary chambering process, I went in with the throater.

Throater alignment is a little less critical because it is a long and flexible reamer, so I chucked it in a drill chuck rather than using a rigid reamer holder.

12mm Rigid Reamer Holder for PM-1440HVT-2

Separate throating does require one more tool: a freebore gauge.

This gauge mimics the case rim and ogive area of the bullet, allowing you to do headspace and other relevant checks.

Measuring Headspace Depth With Triebel Freebore Gauge

Considering the tones of the Walnut and steel, I decided to polish the Krieger barrel rather than Cerakote it.

I chucked it up in the lathe using a barrel extension and live center and I proceeded to go up to 2000 grit. I used some oil to prevent the sandpaper from clogging up and went over the areas until I was happy with the result.

Putting It Together

This rifle was incredibly easy to put together. Using a SAC Bravo barrel vise secured on an SAC vise stand with multi-base, I torqued the barrel to the action.

The Hawkins M5 DBM fit perfectly with the included action screws and everything lined up perfectly.

The design of the WOOX Furiosa Ultra also allows me to remove the bolt without having to move the cheek riser.

With the rifle assembled, I mounted the new Leupold Mark 4HD in Leupold 34mm rings.

Loading and Shooting

I am waiting on some custom 6mm x 47 Lapua Triebel dies, so I got creative. DO NOT TRY THIS. I used 6mm Dasher dies and 6.5mm x 47 Lapua brass from my EVH tribute rifle build to try to engineer some cases that would work. The range results were very unimpressive.

Digging into this issue further, I took the fired cases back to my shop and checked the headspace. All seemed in order. Next, I necked down more cases and measured them with the Short Action Customs modular headspace comparator. I quickly learned that I was knocking back the shoulder over 0.11”. This was barely even safe! I threw those cases away and backed the die even further up until the brass would chamber without bumping the shoulder. The next five shots at 100 yards measured 0.395”!

I’m very happy with this result, especially since I’m only fire-forming brass. I expect even better after load development with the right equipment. For this session, I loaded 36.0 grains of H4350 with Berger 6mm 105 grain hybrid target bullets. (Be sure to always reference several reliable sources of reloading data.)

Having solved my problem, I loaded 30 rounds and proceeded to the Ultimate Reloader ridgeline. I started on the tank trap to get a better idea of how the rifle balanced. It did so well we easily balanced it on a bag on a tip of the tank trap for photos!

After this, I engaged D-M rock chuck steel targets from the prone position at 336 yards. The wind was a bit sporty, as shown through the Longshot Hawk spotting scope camera.

After warming up, I moved to 660 yards, then 706 yards, then 1,390.

My estimated dope was a little light, so I’ll be going back through and running calculations in Hornady 4DOF when I get my full loading setup. Even so, I managed several successive hits confirmed by the Caldwell Flash Bang at 660 and 706 yards.

The wind at 1,390 was especially tricky, but I still had consistent impacts.

Conclusion

I’ll talk more about the 6mm x 47 Lapua cartridge in future videos, but I really like it. It gives you more than a 6mm Dasher, but better barrel life than a 6mm Creedmoor.

There is some contention over how finicky it is, but I already have a great starting load. The rifle performed flawlessly and balanced well. I especially appreciated the beauty of the WOOX Furiosa Ultra in the sunlight and the ease of the BAT Hammerhead 75 degree bolt throw.