One of the important advances in precision rifle shooting has been the development of high quality stocks and chassis. If you aren’t familiar with the difference between the two, let me clear it up for you; a stock is usually made of wood, polymer or other material (fiberglass, carbon fiber), while a chassis uses a more rigid material like aluminum.
Think of it like this; you can bolt an outboard motor to either a wooden boat or an aluminum boat. Over time, and with use and water involved, the transom of the wooden boat could deteriorate and allow some wiggle room. The aluminum transomed boat, however, is likely to continue to work until a weld breaks or something similar.
Modern rifle stocks have greatly improved, but the more modern chassis have taken it to the next level. Grayboe’s Universal Mini Chassis and Stock System illustrates perhaps the best of both worlds.
Grayboe makes stocks and chassis here in America. Their mission is to build high quality, innovative rifle stocks that are affordable. Their Universal Mini Chassis system blurs the line between stock and chassis.
You might ask what makes a good rifle stock. A good stock is rigid and unchanging. Accuracy is all about repeatability and a stock therefore needs to be an unchanging and rigid platform for your rifle to launch projectiles. The best stocks are often made of synthetic materials that are unaffected by weather, water, and temperature.
So what makes a chassis better, you ask? A chassis is usually made of metal and polymer, allowing the rifle action to be bolted to an immovable structure. The idea behind a chassis is the same, with such a robust structure to support the rifle action that you’ll see the least amount of variation from shot to shot.
The Universal Mini Chassis is essentially a minimalist chassis that’s small enough to bolt into a stock. The UMC incorporates everything needed to mount and operate the rifle action. It has a built-in magazine well, trigger guard, and enough support for the action, while providing solid engagement with their compatible selection of stocks.
Grayboe has a variety of rifle stocks that are interchangeable and compatible with the UMC while the UMC’s themselves are available for a wide variety of popular rifle actions. I expect as popularity grows, this list of supported actions will expand . . .
- Remington 700 and R700 clones
- Tikka T3/T3x and clones
- Savage 110 and clones
- Howa 1500 and clones
- Weatherby Vanguard and clones
- Ruger American Gen 1 & Gen 2
- Mossberg Patriot
- CVA Cascade
To clarify, you can put any UMC into any of Grayboe’s various UMC-compatible stocks. So you can add a UMC to your CVA Cascade hunting rifle action, for example. Then pick one of Grayboe’s UMC stocks.
Then in just a minute or two, you can swap that very same stock to your Remington varmint rifle equipped with its own mini chassis. Gone are the days of picking a chassis for a specific rifle action footprint. Now you can use the same UMC stock on a variety of UMC chassis-equipped actions.
Like every other good chassis out there, the UMC is precisely machined to fit your rifle’s action perfectly. It incorporates a cut for recoil lugs, triggers, safeties and other action elements. It also incorporates an AICS magazine well and catch, even for rifles that didn’t use them in their factory configuration. That eliminates the need to come up with typical bottom metal or floorplates when making a custom rifle.
Grayboe makes several different stock models for various purposes, and they are available in different color patterns to fit your preference. And any of them can be used with one or more Universal Mini Chassis-equipped action.
Some of the stocks are made of carbon fiber, others from fiberglass, and still others made are impact-resistant polymers. The UMC chassis itself is machined from 6061 aluminum. The materials offer both high quality and durability without losing sight of affordability for those who aren’t paid to fly from one match to the next.
For my testing purposes, I used the Grayboe Flagstaff and Core stocks, the latter being a heavy competition-focused stock incorporating features for that purpose. The Flagstaff on the other hand is meant for hunters and folks looking for a quality rigid stock that won’t burn their budget for hunting season.
I used two different UMC chassis made for both CVA Cascade actions as well as the Remington 700 since I have several of both rifles.
Over the course of several months, I mounted several rifles in various combinations on both stocks to see how the interchangeability works IRL. I also wanted to evaluate the quality and performance of the sum of all the parts and configurations.
My two CVA Cascade rifles are short-actions. One is a 24-inch 25 Creedmoor model while the other is a Cascade SB 18-inch 6.5 Creedmoor. Both shoot great, and were only improved with the Grayboe UMC system.
I also used them with a couple of my custom Remingtons, the first being my son’s 16-inch .260 Remington and the other a custom heavy .223 Remington. Both of them were built over a decade ago and they still hammer.
Installing the UMC is pretty easy. They come with all the fasteners you will need to attach them, so the original action screws can stay with your original stock. After bolting the rifle into the UMC chassis with a touch of Loctite, it was a piece of cake to then drop them into the different Grayboe UMC stocks.
The UMC chassis is secured to the stock using two screws that also ought to get a dab of blue Loctite. Once installed, the whole ensemble feels fantastically rigid and sturdy.
Then it was time for the rest of the kit, like attaching a bipod to the M-LOK rail that runs the centerline of the forend of both stocks. Being a hunting configuration, I added a simple sling-stud for my Harris bipod to the Flagstaff. On the heavy-built Core competition stock, I installed an ARCA rail so I could slide my Atlas bipod back and forth. A sling can be attached in various ways using the different QD cups that come in the Grayboe stocks.
Adjusting the stocks to fit me was pretty straightforward as well. The Core is fully adjustable, allowing you to customize length of pull with spacers. The comb height can be raised or lowered by loosening a thumb-screw on the side of the stock.
On the Flagstaff it’s a little simpler. No comb height adjustment, so instead I installed one of my Triad Tactical stock packs that give me both the right comb height and a soft place to rest my cheek.
With all that done, the rifles were ready to shoot. There was no need to re-zero the rifles, as the scopes had never left the actions during the stock swap.
First off: the Flagstaff. It’s a no-nonsense hunting stock with everything you need and nothing you don’t. It has low profile features that wont snag on your gear and isn’t too cumbersome to carry through the mountains.
Finger grooves along the length of the forend give good purchase for the inevitable carry changes during long hikes. The grip area has a nice texture to it for controlling the rifle one-handedly and despite being made from impact-resistant polymers (which makes it affordable), it’s still very rigid.
The Core competition stock, on the other hand, is whole lot more. It’s built from either carbon fiber or fiberglass (3 CF options, 4 fiberglass), but not to save weight. The Core has the competitive shooter in mind and those folks worry more about features and stability than anything else. Heavy is you friend when it comes to stability.
Many PRS/NRL comp guns weigh-in at well over fifteen pounds, and some over twenty, so the Core has no reason to skimp on features or strength.
Aside from its extremely rigid structure, the Core has many nice features like a huge barrel channel for those fat competition bull barrels. The full-length M-LOK rail under the forend gives lots of real estate to mount accessories. You can also mount Hoptic USA aluminum cartridge quivers to the side of the stock just below the ejection port for quick reloads.
I already mentioned the adjustable buttstock, which makes it easy to comfortably fit you. The grip is very comfortable and keeps your hand properly positioned to pull the trigger straight back.
There are other Grayboe UMC stocks as well, and any one of them can now be quickly installed on either of my chassis-equipped rifles. I love the ability to switch back and forth and configure my different rifles for different purposes as needed. While Grayboe offers some very affordable options, they also have some more expensive choices so there’s a something for everyone.
If you are looking to get addicted to rifles like I am or improve your current rifles, you should give these a try. They give you incredible modularity and options in a quality, rigid rifle platform that will improve your shooting whether it’s on a range or in the alpine slopes.