This project started in the fall / winter of 2023. We were working on a simple single shot plug-style insert for the Thompson Center Compass rifle so that single rounds could be loaded easily without needing to remove the magazine. While lamenting the lack of any companies manufacturing mags for the TC Compass an offhand remark was made by my father-in-law; “Hey! You can make mags for the rifle, can’t you?”… This seemingly innocent comment led to months of late nights staring at a monitor full of design files with a rare and precious factory magazine and calipers in hand. It took 63 different design versions, miles of filament for the 3d-printers to make prototypes, and 16 refills of the “swear jar” but now FINALLY magazines are once again available for the Thompson Center Compass rifles! We have named this new magazine the “NT-Mag” – Just about every other product name we could think of was taken so we just went with the first-name initials for my father-in-law and I. This is of course subject to change at a later date if we come up with something better!
Unlike the rotary style 5-round magazines that originally came with the rifle, our NT-Mags are a vertical feed box magazine design available in 10-round or 5-round capacities in addition to the single-shot plug that led us to start this endeavor in the first place. The top of our NT-Mag is shaped to fit the TC Compass magazine well with a built-in ramp to feed rounds into the barrel at the correct angle for reliable chambering. Best of all, these mags are designed and made by us in the USA! The first production version of NT-Mags are for TC Compass rifles chambered in the .308-based cartridges (.243, 6.5 creedmoor, 7mm-08, and .308) with plans for 5.56 / .300 blackout and long action (30-06, etc) versions at a later date once I get my paws on a rifle in each of these calibers.
The mag bodies are made from polyethylene terephthalate glycol (PETG) thermoplastic with embedded carbon fiber for added strength and rigidity. These magazine bodies have excellent chemical and oil resistance and can resist temperatures up to 160 degrees! The exterior is textured to closely match the finish and color on the TC Compass rifle. The follower and locking tab are a high-vis orange color while the dark gray release latch is a carbon fiber composite for strength and durability.
Below are some video demonstrations of the function of each magazine: 10-round, 5-round, and the single-shot plug:
