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UMC to Stock Installation Guide
Everything you need to know to install your rifle on your new stock.
Universal Mini Chassis -> Stock Installation
For Remington 700 & Remington 700–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Remington 700 footprint actions, including Remington 700, Defiance, Lone Peak, Terminus, Zermatt, Mack Bros, Bergara B-14, and other true R700 clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-Stock mounting screws with washers. For long actions, the short screw goes in the front and the long screw goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory bottom metal such as BDL or ADL systems is not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept CIP-length 3.850-inch magazines. Verify smooth bolt cycling and reliable feeding.
See Troubleshooting & FAQ section.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Adjustable Magazine Lever Upgrade
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
For Tikka T3/T3X & Tikka T3/T3X–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Tikka T3 and T3X footprint actions and other true Tikka T3 and T3X clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept CIP-length 3.850-inch magazines. Verify smooth bolt cycling and reliable feeding.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Adjustable Magazine Lever Upgrade
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For Savage 110 & Savage 110–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Savage 110 footprint actions and other true Savage 110 clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept CIP-length 3.850-inch magazines. Verify smooth bolt cycling and reliable feeding.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Adjustable Magazine Lever Upgrade
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For Howa 1500 & Howa 1500–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Howa 1500 footprint actions and other true Howa 1500 clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept standard length 3.715-inch magazines. Verify smooth bolt cycling and reliable feeding.
Adjusting the Magazine Lever
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For Weatherby Vanguard & Weatherby Vanguard–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Weatherby Vanguard footprint actions and other true Weatherby Vanguard clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept standard length 3.715-inch magazines. Verify smooth bolt cycling and reliable feeding.
Adjusting the Magazine Lever
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For Mossberg Patriot & Mossberg Patriot–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Mossberg Patriot footprint actions and other true Mossberg Patriot clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 2: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 3: Install the UMC Trigger Bow
To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
Step 4: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with the washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 5: Magazine Check
Insert an AICS-pattern magazine. Verify smooth bolt cycling and reliable feeding.
Optional Magazine Stop
If needed, install the supplied roll pin into the side hole of the UMC to limit upward magazine movement. Most AICS magazines do not require this.
Optional Adjustable Magazine Lever Upgrade
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For Ruger American & Ruger American–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true Ruger American footprint actions and other true Ruger American clones including the Ruger Glenfield.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory floorplate systems are not reused with the UMC.
Step 2: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 3: Install the UMC Trigger Bow
To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
Step 4: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-stock mounting screws. For long actions, the short screw goes in the front and the longer screw with the washer goes in the rear. Torque both screws to 60 inch-pounds.
Step 5: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept standard length 3.715-inch magazines. Verify smooth bolt cycling and reliable feeding.
Adjusting the Magazine Lever
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Magazine Stop
Install the supplied roll pin into the side hole of the UMC to limit upward magazine movement using a small hammer and 3/32” punch ensuring the pin sits flush to the outside of the UMC.
Optional Removal and Installation of the UMC Trigger Bow
Use 3/32” punch to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
For CVA Cascade and Cascade–Pattern Actions
Compatible Actions
The Grayboe Universal Mini Chassis is designed for true CVA Cascade footprint actions, including CVA Cascade and other true R700 clones.
What’s Included in the Box
Grayboe UMC Compatible Stock
Universal Mini Chassis (UMC)
UMC-to-Stock Mounting Screws
Action Screws (Barreled Action to UMC)
Optional Magazine Stop Roll Pin
Tools Required
5/32" Allen Key – UMC to stock installation
3/16” Allen Key – Action screws
5/64” Allen Key - Adjustable lever (if applicable)
Torque wrench (inch-pound capable, recommended)
1/8” Punch - Lever pin (for adjustable magazine lever upgrade)
3/32” Punch - Trigger Bow pin (only if necessary)
Small hammer for punch (for adjustable magazine lever upgrade)
Step 1: Install the Mini Chassis into the Stock
Place the Universal Mini Chassis into the stock inlet and ensure it sits fully flush. Install the UMC-to-Stock mounting screws with washers. For long actions, the short screw goes in the front and the long screw goes in the rear. Torque both screws to 60 inch-pounds.
Step 2: Prepare the Barreled Action
Remove the barreled action from its factory stock. Factory bottom metal such as BDL or ADL systems is not reused with the UMC.
Step 3: Install the Barreled Action into the UMC
Set the barreled action into the mini chassis. Install the two supplied action screws (same length front and rear). Torque both screws to 45 inch-pounds.
Step 4: Magazine Check
Insert an AICS-pattern magazine. Long action UMCs accept CIP-length 3.850-inch magazines. Verify smooth bolt cycling and reliable feeding.
Step 5: Magazine Stop
Install the supplied roll pin into the side hole of the UMC to limit upward magazine movement.
Optional Adjustable Magazine Lever Upgrade
Remove the pin holding the magazine lever with 1/8” punch making sure to capture the spring. Replace with adjustable magazine lever, placing spring back in its place and punching the pin through both the trigger bow and magazine lever pin holes.
To adjust the adjustable lever, use the 5/64” Allen key to loosen the lever. Move the lever in the position that places your magazine position to feed rounds consistently and tighten.
Optional Removal and Installation of the UMC Trigger Bow
Use punch 3/32” to remove the two pins holding on the trigger bow located on the side of the UMC. Remove the trigger bow. To install, place the trigger bow in place and punch the two pins flush using a 3/32” punch and a small hammer.
See Troubleshooting & FAQ section for more information.
Troubleshooting & FAQs
Find solutions to common installation challenges and compatibility questions. Expand each section for detailed answers.
The most common cause is mixing up screws within the hardware set.
All screws are labeled—verify you are using the correct ones for your setup
Always start screws by hand to ensure proper alignment
Do not force screws into place
Once installed correctly, torque screws to the specifications listed above.
If screws will not thread smoothly by hand, stop immediately and contact support at support@grayboe.com.
For proper installation and performance, use the following torque specifications:
UMC mounting screws: 45 in-lb
Action screws: 45–65 in-lb
Action screw torque can vary depending on the rifle and may affect accuracy. We recommend starting at 45 in-lb and increasing in small increments to find what produces the best results for your specific setup.
Always tighten screws evenly and alternate between front and rear to ensure the action seats properly.
We recommend using a calibrated inch-pound torque wrench for best results.
If you are unsure or experience inconsistent performance, stop and contact support at support@grayboe.com.
Polymer magazines can vary significantly between manufacturers—and even between batches from the same manufacturer. Because polymer can flex and warp due to environmental conditions, fitment may not always be consistent.
Start by testing multiple magazines to determine whether the issue is magazine-specific.
If you are using polymer magazines and experiencing a tight fit:
Lightly sand the binding areas on the magazine body
Do not remove material from the magazine catch interface
For the most consistent fit, steel magazines are recommended, though they are typically more expensive.
If the magazine still will not seat after trying multiple mags and confirming proper installation, stop and contact support at support@grayboe.com.
With AICS-pattern magazine systems, it is possible to push the magazine higher than intended. This can cause interference with the bolt.
To correct this:
Ensure the magazine is pulled downward slightly so the mag lever is properly resting on the mag catch
Avoid applying upward pressure on the magazine (such as resting it on a surface while shooting)
To address tolerance variation across rifles and magazines, many UMC systems are compatible with an adjustable magazine lever, which allows you to fine-tune magazine height for proper feeding.
If your UMC is not equipped with one, it can be purchased and installed
This ensures the magazine sits at the correct height in the magwell
Some UMC models also include a mag stop pin, which helps limit upward travel of the magazine.
If interference continues after confirming proper magazine position, stop and contact support.
This is typically caused by the magazine sitting too low.
First, verify:
The magazine is fully seated
The mag lever is properly engaged and resting on the mag catch
If the issue persists while everything appears correctly seated, the magazine may still be sitting slightly low due to tolerance differences.
In this case, an adjustable magazine lever may be required to fine-tune magazine height and ensure reliable feeding.
See the installation section for instructions on installing the adjustable lever.
If the issue persists after adjustment, stop and contact support.
First, verify proper installation:
The top line of the mini chassis should sit flush with the top line of the stock
Ensure the action is fully seated in the UMC
Check both the tang and recoil lug areas for any gaps
If everything is installed correctly and the barrel still appears high:
This can be normal with thinner barrel profiles, especially in models like the Flagstaff and Halo
This is a cosmetic condition only and does not affect performance
If the barrel is contacting the stock at any point, stop and contact support.
Start with installation checks:
Ensure the UMC is seated squarely in the stock
Confirm there are no obstructions between:
Action and UMC
UMC and stock
To reseat the system:
Loosen the action screws
Lightly tap the butt of the rifle on a solid surface
Ensure the recoil lug is properly seated
Retighten screws evenly to the recommended torque
If alignment still appears off:
Variations in barrel or action manufacturing can affect visual alignment
Compare fitment in another stock if possible
If the barrel is contacting one side of the channel or alignment appears excessive, stop and contact support.
The bolt notch is intentionally oversized on many models to accommodate a wide range of action clones.
This is not a functional issue and does not affect performance. It is purely cosmetic.
