MASTERPIECE ARMS MATRIX PRO RIMFIRE

Masterpiece Arms is well known for their PRS chassis systems in the centrefire world, but they also produce their own rimfire rifle. PRS shooters typically have highly specific and personalised requirements for a competition rifle, and will therefore adjust stock ergonomics to an extremely fine degree. This particular MPA rifle belongs to Josh Martin and serves as his personal competition rimfire, offering an interesting insight into what top-level shooters look for in their own equipment.

C2 Precision
Josh runs C2 Precision and sent me the rifle. It was all set up and ready to shoot with a Zero Compromise Optic on board, and the first thing that strikes you is the weight, as all up, this MPA indicated 8.3kg (18.26lbs) on the scales, with the rifle itself coming in at 6.8kg (15lbs).
The test rifle featured the 23” (584mm) option, one of several available barrel lengths, and the hand-lapped MPA/Spencer 416R stainless barrel comes with a 1:16” twist rate, although a 1:12” twist is also offered. An ATS barrel tuner came clamped around the external barrel profile rather than threaded to the muzzle, and I had to leave this alone. The gun was supplied meticulously tuned and batch-tested with Eley Tenex ammunition, also supplied by C2. The barrel diameter measured 30.4mm at the action with a straight taper down to 29.7mm at the muzzle. It is, of course, fully free-floating within the fore-end, and it shows a crisp 11-degree crown.

More than Voodoo
MPA’s Rimfire Elite action is also brightly polished stainless steel, and it conforms to the Remington 700 footprint. There is a recoil lug sandwiched between the barrel and the action face, with a Picatinny rail screwed in four places above. The rear left side of the action shows a black bolt release catch, with a familiar two-position safety catch opposing it on the right, with forward for fire and rear for safe (without bolt locking).
The bolt is 17.6mm in diameter and shows three lugs for a 60-degree lift. These are set just rear of the ejection port within the rear action bridge. The bolt face shows twin extractor claws, and like most rimfires, the manual ejection strength is reliant on bolt speed. The bolt handle is 70mm long with a serrated 24mm teardrop for grip. The action is designed exclusively for .22LR, so bolt travel is just 41.6mm, and operation is delightfully smooth.

Feeding the beast
A 10-round AICS-sized, rimfire-specific polymer magazine was supplied, feeding rounds from a single column to the bolt face. There is a manual slider to relieve spring pressure for fast loading, and the follower itself is red for visual contrast. The ambidextrous release lever is on the front of the spacious trigger guard.
The rifle features an interesting grip and trigger arrangement, with grips available in various sizes that typically include a right-side thumb rest. MPA’s Elite single-stage trigger is a unique design made by Bix’n’Andy. It’s adjustable from 4 to 32oz (275–2200g) and was exquisite, even at the lightest weights.

Show-off
Multiple colour options are available for the Matrix Pro II Competition Chassis, and in vivid yellow Cerakote, this one certainly stands out. The fore-end is 39mm tall, boasts a 14” (370mm) ARCA rail on its underside, and measures 71mm wide for ultimate stability when used with a rest bag. There is also a plethora of M-LOK slots on the underside and side walls.
The tip has a top guard fitting, allowing you to put downward pressure on the stock without affecting the barrel, and this is a modular component that interlocks, so it can be stacked in line to increase the covered area, which also adds additional weight. Grip panels are inlaid here.

Barricade stop?
The underside swoops down towards the magazine well without a specific square-faced barricade stop. The mag well is incorporated as part of the chassis and allows for smooth insertion and extraction of loaded magazines at speed.
Finger grooves visually break up the flat walls of the chassis, and there is a significant cutout in the base of the integral trigger guard to allow access to adjustment screws.
The vertical grip is heavily stippled and seems to be a proprietary MPA unit, available in several profiles to fit precisely on the stock and screw in place without any wobble. There is an inlaid anti-cant bubble behind the bolt shroud/tang area, and the chassis then splits above and below the thumbhole cutout, although it seems most PRS shooters now favour pinching their thumb onto the side of the stock anyway.
A similar finger groove/fluting style continues to the recoil pad, which shows an adjustable length of pull. This model has grub screws, but you can have thumbscrews as an option. The underside has a slender bag rider which is spring-loaded to pop out when the left-side button is pressed. It offers 25mm of vertical extension to stabilise the gun. There is also an adjustable cheekpiece on the top, and this is again a slender profile, so it fits neatly under your cheekbone without displacing your jaw laterally.

Infinite customisation
My main aim with this rifle was to assess the precision of the barrelled action, rather than to shoot PRS, where I knew I would be the weak link. The Voodoo 360 action used by MPA is exceptionally well made to the finest tolerances and is highly regarded for its smooth bolt operation, featuring a 60-degree lift that speeds up cycling and minimises positional disruption to the entire rifle.
Interestingly, as heavy as this gun is, you feel the recoil pulse through it more than other rimfires, which feels a little odd at first, but I think it’s because the weight of the gun maintains such a solid position, your personal influence is minimal, with only a very delicate grip required. This effect is likely enhanced by the fact that you are merely pinching the grip between your index finger and thumb, just behind the trigger, with only slight fingertip pressure needed to fire the shot.

On my belt buckle
I shot the rifle mostly from the prone position to maximise my precision potential, and found it very easy to shoot with near-perfect consistency. Your head position remains undisturbed on the stock as the bolt is cycled, as it is so light to lift.
MPA includes a steel ARCA rail extension, which is less prone to marking than Cerakote when a bipod is attached. It also provides increased linear extension from the bag rider to the bipod feet, helping to maximise the stability that is essential for precision shooting.
This rifle is chambered specifically for premium Tenex ammunition, and I shot at 100m, which is a serious starting point for a .22LR. Once I got used to the rifle, kept out of the crosswinds, and perfected the trigger, I averaged 28mm for all the groups, with one 5-rounder measuring 10.3mm. I won’t deny that the smallest error on my part could ruin a group, and the wind offered a constant test of my skills, but it was impressive to see such a small cartridge perform so well. Most importantly, its reliability makes it clear when you’ve let the team down, and with a rifle this heavy, it’s fascinating to see the reticle move slightly with nothing more than your heartbeat.
The MPA and ammunition outperformed me, but it was a pleasure to use and allowed me to see where I was getting things right or wrong.

Conclusion
The 23” barrel produced 1,083fps, equating to 104.9ft/lbs with this 40gr bullet, although the most significant figures are the 71fps extreme spread and 9.42 standard deviation. This data came from a 60-round string, shot outdoors in breezy conditions, rather than a five-round group in a tunnel range, making the figures all the more impressive in real-world terms. All the groups punched into paper displayed circular shot dispersion, indicating average elevation and windage variance from my point of aim and, realistically, the level of performance I would expect from a precision rimfire rifle, where single-figure extreme spreads—like those seen with centrefire benchrest rifles—are an unrealistic goal.
This rifle won’t suit everyone, and it’s an unusual test piece, as any purchaser is likely to modify it extensively to suit their needs. However, the fundamentals of the barrel, action and chassis are solid, providing a reliable foundation for success in the growing PRS market. GM