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McMillan Chassis
McMillan Chassis
A full-featured Micarta® F.A.S.T. chassis, built for your action. Configure it the way you want it — the simple steps below walk you through every option.
Build to order

CONFIGURE YOUR CHASSIS

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30-DAY RETURNS
Not satisfied with our chassis? Send it back for a full and prompt refund.
LIFETIME  LIMITED WARRANTY
Free repair or replacement for material or workmanship-related issues.
Description
CHassis sizes & Specifications
Supported Actions Chart
Pro vs standard
faq

Introducing the PRO line of Baby Orca chassis. Many PRO models are in stock, and many more are added every week. These are the PROs' salient features:

  • On average, 1.7 lbs lighter by weight (depending on action brand and model)
  • Larger barrel channel widths (ready for TACOM HQ structured barrels)
  • Refined Adjustable Rear Bag rider (finer and smoother adjustments)

These chassis are not just new products; they set new, higher standards. NEW MATERIAL: G10/FR4, a.k.a. Micarta. We are so confident in Micarta's characteristics that we will not create aluminum versions. Please see below for more about Micarta. These new chassis are presented in three different lines:

  • Makos - actions diameters up to 1.35"
  • Baby Orcas - actions diameters from 1.35" to 1.6"
  • Mama Orcas - actions diameters from 1.6" to 2"

Scoped and barreled actions maximum supported weights:

  • Mako F.A.S.T. Ready (no BipodeXt tubes) = 20 lbs.
  • Mako F.A.S.T. I (one BipodeXt tube) = 15 lbs.
  • Mako F.A.S.T. II (two BipodeXt tubes) = 12 lbs.
  • Baby Orca F.A.S.T. Ready (no BipodeXt tubes) = 40 lbs.
  • Baby Orca F.A.S.T. I (one BipodeXt tube) = 35 lbs.
  • Baby Orca F.A.S.T. II (two BipodeXt tubes) = 30 lbs.
  • Mama Orca F.A.S.T. Ready (no BipodeXt tubes) = 50 lbs.
  • Mama Orca F.A.S.T. I (one BipodeXt tube) = 45 lbs.
  • Mama Orca F.A.S.T. II (two BipodeXt tubes) = 40 lbs.
Action diameters up to 1.35" (3.43cm)
MAKO CHASSIS
CHassis Weight Specifications
Pro / Standard
Wt. w/no Tube
7.26Ibs (3.29kg) / 7.88Ibs (3.58kg)
Wt. w/1 Tube
8.07Ibs (3.66kg) / 8.69Ibs (3.95kg)
Wt. w/2 Tube
8.27Ibs (3.75kg) / 8.90Ibs (4.04kg)
Maximum supported RIFLe weights
Wt. w/no Tube
20Ibs (9.07kg)
Wt. w/1 Tube
15Ibs (6.80kg)
Wt. w/2 Tube
12Ibs (5.44kg)
Compatibility
Checking availability...
Action diameters from 1.35 to 1.6" (3.43CM-4.06cm )
BABY ORCA
CHassis Weight Specifications
Pro / Standard
Wt. w/no Tube
7.26Ibs (3.29kg) / 8.90Ibs (4.08kg)
Wt. w/1 Tube
8.46Ibs (3.84kg) / 10.08Ibs (4.61kg)
Wt. w/2 Tube
8.78Ibs (3.98kg) / 10.51Ibs (4.81kg)
Maximum supported RIFLe weights
Wt. w/no Tube
40Ibs (18.14kg)
Wt. w/1 Tube
35Ibs (15.88kg)
Wt. w/2 Tube
30Ibs (13.61kg)
Compatibility
Checking availability...
Action diameters > 1.6" to 2" (4.06cm - 5.08cm)
MAMA ORCA
CHassis Weight Specifications
Pro / Standard
Wt. w/no Tube
9.41Ibs (4.27kg) / 10.93Ibs (5.00kg)
Wt. w/1 Tube
10.61Ibs (4.81kg) / 12.11Ibs (5.53kg)
Wt. w/2 Tube
10.54Ibs (4.96kg) / 12.54Ibs (5.73kg)
Maximum supported RIFLe weights
Wt. w/no Tube
50Ibs (22.68kg)
Wt. w/1 Tube
45Ibs (20.41kg)
Wt. w/2 Tube
40Ibs (18.14kg)
Compatibility
Checking availability...
The difference between pro and standard versions are that PRO has been modeled for weight reduction. There are limited Standard editions of chassis at a discount that we will no longer make once they are out of stock 
Each chassis is built for a specific action brand and footprint, selectable in the configurator. If you don't see your action, contact us — we add models regularly and can often build yours.
Repeater chassis run AICS SSSF magazines and accept both 3.725" and 3.850" CIP lengths via our patent-pending Spacer — no need to remove the barreled action to swap.
Buttstock adjustments (length of pull, cheekpiece, bag rider, buttpad) are 100% toolless. Swapping modular feet uses the 5/32" hex key included in the box.
Can't find your action?
We add new action models regularly - tell us what you run and we'll confirm if it fits.
contact us
The Advantage of Micarta

LIGHTER BY DESIGN. 
CALMER UNDER RECOIL.

Micarta weighs about 22% less than aluminum and its naturally low-resonance properties absorb vibration and eats recoil more effectively. Our Orca and Mako rifle stabilzers are a full-featured chassis with our patented BipodeXt technology engineered directly into it. It's nimble, resilient, and purpose-built for accuracy.
~22% LIGHTER
Micarta is about  22% lighter than aluminum while maintaining high strength properties.
DAMPENS RECOIL
The material naturally minimizes vibrations throughout the chassis.  Deadening recoil and improving shooting stability.
WIN AT THE RANGE
Micarta stocks have been used successfully by top competitive shooters since at least 2016 and continue to grow in popularity.
COMPATIBLE
Our chassis is currently compatible with 251 action models accross 26 leading action manufaturers and counting.

FEATURES

Three things that set the ORCA chassis apart from a bolt-together build.
Monolithic chassis & BipodeXt
Monolithic chassis & fore-end. The fore-end, which houses the telescoping carbon-fiber BipodeXt tubes and the action seat, is machined as a single piece of Micarta® billet, averaging 23.7" in length.
Adjustable magazine latch
Patented BipodeXt technology built in. Not an add-on but engineered with purpose. Move the rifle's resting point forward for dramatically improved stability.
Superior Material
Superior Material. G10/FR4, a.k.a. Micarta®. A highly stable, harmonically dead, recoil-absorbing material. To our knowledge, the only full-fledged, completely toolless adjustment chassis made from Micarta®
Tube Configurations

BIPODEXT - THE ARCHIMEDES LEVER

An integrated, telescoping rifle stabilizer that extends your rifle's fulcrum forward. 
UP TO
39"
MAX EXTENSION

SINGLE TUBE SETUP

FROM RIFLE TOE
UP TO
52"
MAX EXTENSION

DOUBLE TUBE SETUP

FROM RIFLE TOE
Toolless adjustment
Adjustable buttstock
Internally, we refer to our flagship buttstocks as "Rear 2.1" and "Rear 2.1 PRO". These buttstocks adjust without tools in six (6) different ways. A seventh adjustment is swapping the modular ABR feet. Swapping feet requires a 5/32” Hex key, which is included with the provided tool set.
Length of pull
13.5"–15.5"
Buttpad vertical elevation
4.2"
Cheekpiece elevation
2"
Cheekpiece fore & aft
2"
Rear bag-rider elevation
1"
Cheekpieces
0.8" · 1” · 1.5" · 2"
Feet:
5" · 6" · 5" tilted (180 MOA)
Behind the rifle

WHAT IT MEANS ON THE GUN

Calmer Crosshairs
Extending the bipod forward mathematically reduces the effect of shooter movements.
Better Recoil Control
Placing the bipod farther forward helps tame the rifle’s tendency to jump. The Micarta material noticeably mitigates recoil.
Spot Your Own Shots
Reduced rifle movement makes it easier to maintain your sight picture and see where your shots land.
Faster Follow-ups
Less recoil means less correction is needed before your  next shot.
Adjustable Buttstock
Our adjustable buttstock helps you adjust your rifle the way you want.
Bipodext Built-in
BipodeXt is integrated directly into the chassis, creating a purpose-built platform rather than an add-on.
PROVEN BY SHOOTERS

TRUSTED BY SHOOTERS

"There isn't a single item in the marketplace that makes you shoot this much better immediately out of the box." 
- Derek R., Warren, OR 
“"Great chassis, tremendous finish with areas and features that show an obvious attention to details in both functionality and user use."”

Jonathon W.

Aylesbury, UK

“"I finally got to shoot a few 33XC rounds today. Folks came down to see what I was shooting and then asked me a bunch of questions about the chassis. Love this thing so far!"”

Richard F.

San Diego, CA

“" [...] Utilizing the BipodeXt to stabilize my rifle platform has greatly increased my accuracy. Not only does it help with the stability, but it also has helped me manage the recoil of the rifle. I have been able to spot my own shots and been able to regain the target immediately and send another down range. I will continue to use the BipodeXt and recommend it to any of my friends and students.””

Brian Hyman

5th Degree Black Belt Martial Arts Instructor, CA

““I was shooting unsupported…as in a hunting situation…the difference between shooting just on the bipod and shooting with this extension unit was noticeable, holding those crosshairs on was a lot easier. The real design of this system is very flexible actually, able to be used in lots of different formats. I think it’s a good idea. It is something that will be happy to live in our shooting kit.””
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Mark Else

Mark and Sam AfterWork, YouTube ELR shooting channel

““I was witnessed shooting a 1/3 minute group at 735 yards with a .308 rifle, and I have to admit, it is the best group I have ever shot! If it looks right, It’s probably going to work right.””
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Robin Ireland

CSA Great Britain .50 Cal shooting team – shooter

“"A fantastic piece of kit that we are all sold on and pretty much blown away [by]. It [BipodeXt] solves many problems of stability, from moving the bipod so far forward, the system becomes massively stable. ALL twitching is removed and follow on shots and target acquisition is pretty much instantaneous.””
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Chris Buckley

FCSA Great Britain .50 Cal shooting team – Captain

“"I have never felt such recoil reduction. The comfort level has definitely increased my odds of winning tremendously — it won't be long before it happens again."”
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Jay Monych

ELRSO Founder · 🥇 1st place, Conquer the Castle Match 2026

“"That thing [BipodeXt] is incredible! Definitely going to be a product I’m going to start using on all my long range stuff."”
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Charlie Melton

Retired Navy SEAL Sniper / instructor, Owner / Founder Charlie Mike Precision, Normangee, TX

““Because of my job, my throwing / shooting arm can get the shakes from time to time. With BipodeXt, I went ten for ten in the x ring right out of the drag bag! It has become a necessity, and I use it on all my rifles now whether I am banging steel or out in the field hunting, I never leave home without it.””
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Nash Walters

Major League Baseball Player (pitcher), Milwaukee, WI

Good to know
Frequently asked questionS
Each chassis is built for a specific action brand and footprint, selectable in the configurator. If you don't see your action, contact us — we add models regularly and can often build yours.
Repeater chassis run AICS SSSF magazines and accept both 3.725" and 3.850" CIP lengths via our patent-pending Spacer — no need to remove the barreled action to swap.
Buttstock adjustments (length of pull, cheekpiece, bag rider, buttpad) are 100% toolless. Swapping modular feet uses the 5/32" hex key included in the box.
Micarta is ~20% lighter yet dampens recoil better — it's a "dead" material with almost no resonance. We're confident enough in it that we don't make aluminum versions.
Can't find your action?
We add new action models regularly - tell us what you run and we'll confirm if it fits.
contact us
NOT SURE WHAT YOU NEED?

WE CAN RECOMMEND YOU A SETUP.

We'll point you towards the right Accuracy Solutions product for your rifle, shooting style, and weight needs.
Contact us
Accuracy Solutions, bringing innovative concepts to the firearm industry to increase precision and accuracy potential of today's shooters.