by Modular Rifle | Aug 29, 2015 | Modular Driven Technologies, Rifle Chassis System |
MDT TAC21 Chassis System

MDT TAC21 20 inch Suppressed Modular Rifle
MDT TAC21 Chassis System for Remington 700 Bolt Action Rifles
MDT TAC21 20 inch Suppressed – Project Complete
MDT TAC21 Chassis – As reflected on the page devoted to this project this rifle kicked off the rebirth of modularrifle.com and I’m quite pleased with how everything turned out.
Modular Driven Technologies – The entire project was a pleasure from the start thanks in large part to Maarten of MDT. He patiently answered each and every email in a timely and professional manner. Maarten is the single reason our second project will be a also be from MDT.
Packaging – The packaging was the first indication of the attention to detail and quality that MDT represents. So often these days gun parts are wrapped in paper paper, stuffed in a box and with a little luck arrive without to many dings and scuff marks. No chance of that with the TAC21. The unit ships in an ample box with a closed cell foam interior fitted for the individual chassis parts. Nicely done.
Construction – The MDT TAC21 Chassis is precision in and out. Flawless manufacturing, fit and finish. No interference from the Cerakote. Holes are cut clean and straight. Threads are cut clean. The pieces all go together precisely without forcing while retaining a tight fit. Make no mistake this is a piece of heavy duty gear which is not readily apparent in internet pictures.
Assembling the MDT TAC21 Chassis – The instruction manual is well done and written clearly. Installation was pretty straight forward if the directions are followed. (Remove the scope mount screws). As stated previously I suggest using the pdf instructions below as they are easier to read and view on a computer monitor.
Downloads
Note:We are going to call the MDT TAC21 20 inch Suppressed Modular Rifle project complete even though a keen eye might notice the images reflect a Larue Tactical Scope Mount and a Leupold Riflescope instead of the Vortex Viper PST 4-16×50 FFP Riflescope and Ameican Defense Manufacturing Scope Mount as listed on the project page. We will update the images once the new scope is in hand.
MDT CHASSIS MDT TAC21 CHASSIS

Atlas Bipods
by Modular Rifle | Aug 28, 2015 | Projects |
MDT TAC21 20 inch Built From a Remington 700 SPS

MDT TAC21 20 inch Suppressed Modular Rifle
MDT TAC21 RIFLE CHASSIS
MDT TAC21 20-inch Suppressed Modular Rifle – I decided to kick off the relaunch of this site with an entry-level project of readily available hardware, nothing custom. As a barreled action, I decided to use a Remington Model 700 SPS Tactical AAC-SD rifle at the cost of $650. The Remington Model 700 SPS Tactical AAC-SD has a threaded muzzle to accept an AAC-SD Sound Suppressor, and I just happen to have an AAC 762-SDN-6 on hand.

Remington Model 700 Tactical Chassis
The rifle will be based on the Remington Model 700 Tactical Chassis, with the key difference being a shorter 20″ threaded barrel.

Remington Model 700 SPS Tactical AAC-SD
Remington Model 700 SPS Tactical AAC-SD
Pillar bedded Ghillie Green Hogue over-molded stock. The heavy contour barrel has a 5/8-24 inch threaded muzzle to accept all AAC suppressors, flash hiders, muzzle brakes, and other manufacturers of similar accessories. It was shipped with a thread protector installed to shoot right out of the box or for the easy addition of accessories. The rate of twist, laser-etched on the barrel, is optimized at 1:10 inches to stabilize 168 to 220-grain bullets and sub-sonic loads. X-Mark Pro externally adjustable trigger is set at the factory at 3 1/2 pounds with a 2-pound range of adjustment.
The Model 700 SPS Tactical AAC SD Rifle, 308 (7.62×51 NATO), features a 20″ Heavy Barrel with 5/8-24 Threaded Muzzle. It ships with a thread protector installed. Accepts AAC and all 5/8-24 Threaded Flash Hider, Muzzle Brake, and Suppressor. 1 in 10″ Rate of Twist for 168 grain-220 grain Bullets and Sub-Sonic Loads. Hogue Overmolded Ghillie Green Pillar Bedded Stock. X-Mark Pro Externally Adjustable Trigger Set at 3 1/2 Pounds.
Note: Special thanks to the fine folks at Modular Driven Technologies for helping get this MDT TAC21 20-inch project off the ground by answering emails, a lot of them.
Modular Driven Technologies MDT TAC21 Rifle Chassis – Flat Dark Earth

Modular Driven Technologies TAC21 Chassis FDE
The chassis for this project is the Remington 700 version of the MDT TAC21 finished in FDE (Flat Dark Earth Cerakote)
Rifle Basix Remington Trigger Erv-3 K
We know we could always go with the safe bets of Timney Triggers and Jewell Triggers; however, the Rifle Basix Remington Trigger Erv-3 K was primarily selected because we have not previously tested this trigger, the price is fair, and it is readily available. We shall see how it performs.
Rifle Basix Remington Trigger Erv-3 K Remington after-market triggers feature state of the art CNC machined housings made from T6 6061 billet aluminum and are black anodized for a factory appearance. All internal levers are investment cast from A-2 tool steel, CNC machined and heat treated for excellent wear characteristics. The levers are now electro nickel plated for extra protection and bright appearance. Each Rifle Basix Remington trigger is hand assembled, mounted on a test action, adjusted within advertised specifications, tested for proper operation and safety function before packaging.
These triggers are guaranteed as long as they are in service, and may be repaired or replaced at no charge at any time (providing they have not been modified). Rifle Basix Remington triggers are designed for USER installation. No cutting, grinding, fitting or stock modification for adjustment screw clearance. These triggers feature wide (factory width) finger levers. Rifle Basix triggers are designed to utilize Remington’s original safety levers both right and left hand. New mounting pins are shipped with each trigger. Our new “K” kits are packaged with safety levers and bolt stop release to service the 2006 and later Remington rifles with their new trigger design. Right hand only.

Rifle Basix Remington Trigger Erv-3 K
Advanced Armament AR-15/M16/AR 308 Style Blackout 51T Muzzle Brake 102320
This Advanced Armament AR-15/M16/AR 308 Style Blackout 51T Muzzle Brake 102320 is the only option I can utilize with my rifle and suppressor combination.
XLR Industries Tactical Lite Butt Stock

XLR Industries Tactical Lite Butt Stock
One of the appeals of a modular rifle chassis like the MDT TAC21 is the ability to utilize an AR15 stock. I like that idea a lot. I had originally considered installing a Magpul PRS. I like the PRS except, for one thing, the weight. It comes in at nearly 2 pounds. Not set on a PRS, I began looking around and noticed that most of the TAC21 builds utilize a PRS. So in an interesting twist, I decided to go with the XLR Industries Tactical Lite Butt Stock. XLR Industries is also a manufacturer of modular rifle chassis. The Tactical Lite Butt Stock installed comes in about a half-pound lighter than the Magpul PRS. Now it’s important to note that MDT offers a stock specifically for the TAC21 Chassis. The MDT Skeleton Rifle Stock V2 stock is essentially what appears to be a skeletonized PRS designed only to fit the TAC21 and not AR15 or AR10 rifles.
Magpul MIAD Pistol Grip

Magpul MIAD Pistol Grip
The Magpul MIAD Pistol Grip was an easy selection. I like them and always have a few lying around.
Atlas BT46-LW17 Bipod

Atlas Bipod BT46 LW17 Bottom View
Read the Atlas BT46-LW17 BIPOD Specs here at our Atlas BT46-LW17 Bipod page
- Construction from T6061
- Type III Hard Anodized
- Stainless steel springs & fasteners
- 15 degrees +/- of preloaded Pan
- 15 degrees +/- of preloaded CANT
- Tool-less Optional 3″ leg extensions
- Tool-less Optional Ski, Cleat, and Spike feet
- The estimated range of elevation is 5-9″ Standard
- The estimated range of elevation is 7 – 13” Tall
- 5 Leg positions
- Novel 45-degree Leg position pioneered by B&T Industries L.L.C.
- Heat Treated Stainless Steel Leg components
- Fore and Aft pivot, limiting Bosses
- Non-Rotating Legs
- Strengthened Leg Boss
- Inner Leg constructed from T7075
- Standard height weight – 13 ounces
- Tall height weight – 15 ounces
Advanced Armament AAC 762 SDN-6 Sound Suppressor

Advanced Armament AAC 762 SDN-6 Sound Suppressor
The Advanced Armament AAC 762 SDN-6 Sound Suppressor is the only .308/7.62 Nato I presently own.
Modular Driven Technologies MDT AICS Style 10RD 308/7.62 Polymer Magazine
Modular Driven Technologies provided us with this magazine. If all the reviews turn out to be accurate, the MDT AICS Style 10RD 308 Polymer Magazines at $39.99 will be an absolute bargain for folks shooting an AICS compatible platform.

MDT AICS Style 10RD 308 Polymer Magazine
Vortex Viper PST 4-16×50 FFP Riflescope with EBR-1 MOA PST-416F1-A

Vortex Viper PST 4-16×50 Riflescopes with EBR-1 MOA PST-416S1-A
Vortex Optics has become tremendously popular in recent years. Performance at a given price point is said to be comparable to the more expensive competition. I have zero experience with the brand, so I figure what the heck. The Vortex Viper PST 4-16×50 Riflescopes with EBR-1 MOA PST-416S1 should suit my needs perfectly.
Scope Mount
The scope mount is turning out to be a difficult choice for this MDT TAC21 20-inch rifle project. There are many excellent mounts on the market. The AERO Precision Ultralight 30mm, Scope Mount is both economy of weight and cost. Looks nice, clean, and straightforward. Moving up in cost and weight is the American Defense Recon No Offset. The American Defense Recon No Offset is a robust mount with dual locking levers and substantial surface contact. Next up is the BOBRO Standard Precision Optic Mount. BOBRO, without question, makes some of the finest gear available.
While the current line of mounts is no longer as sleek and sexy as the earlier generations, they still retain BOBRO’s patented QD system, which in my opinion, is unrivaled at this time. Last but not least, the ugliest, most substantial, and most expensive is the SPUHR. The SPUHR is a square mount. The rings are cut cleverly at 45 degrees, there is a level built-in which is a big attraction, and the mount accepts bolt-on accessories for adding another Picatinny for a secondary sight. The SPUHR is not QD.
MDT Chassis Accessory Rails – 5.0 Rail with QD Sling Point

MDT Chassis Accessory Rail – 5 Inch
We need the MDT Chassis Accessory Rails – 5.0 Rail with QD Sling Point to utilize our Atlas Bipod.
MDT CHASSIS MDT TAC21 20 inch Suppressed Modular Rifle

MDT CHASSIS
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by Modular Rifle | Aug 26, 2015 | Buttstocks, Gear, Modular Driven Technologies |

PRS Adjustable Butt Plate
The Modular Driven Technologies PRS Adjustable Butt Plate is three-way adjustable for drop pitch and offset as well as length of pull. It further enhances the MAGPUL PRS® stock by adding the adjustability and the comfort of a soft rubber recoil pad. This is a complete module. It replaces the existing MAGPUL PRS® recoil pad, mechanism and all. Visit Modular Driven Technologies for ordering information
PRS Adjustable Butt Plate Features:
- Allows for PRS stocks to be perfectly fit to your position and/or clothing
- Adjustable vertically and for cant/rotation
- PRS butt plate retains the LOP adjustment that comes standard with PRS stocks
- Includes soft, rubber, recoil pad
- Adjustments are easily accessed through the rear of the recoil pad
- Over 3 inches of vertical adjustment
- Easily replace existing PRS hardware
- Aluminum construction with matte black anodizing and steel hardware with a matte black finish
MDT Magpul PRS Adjustable Butt Plate Installation Video by Modular Driven Technologies