I love innovation. One of the most interesting new designs I saw at Shot Show 2023 was from Senex Arms, with its lightweight and modular bullpup rifle that mostly uses standard AR-15 parts

The designer, Brandon Makowski, is a Recon Marine turned engineer. His combat experience and mechanical mind led him to create the Modular Bullpup Light Rifle (MBLR-15) using AR-15 parts. 



Senex Arms MBLR Bullpup Rifle
The MBLR-15 uses many of the same parts as the standard AR-15, making it a largely familiar platform for many modern shooters. (Photo: Dave Luu/Guns.com)

First, it uses the AR-15 barrel, gas block, gas tube, bolt, cam pin, gas key, pistol grip, and fire control system with a slightly modified trigger. It has a toolless quick-change barrel system that allows for 10-second barrel changes. 

This also means you can change to any caliber that works with the AR-15 barrel design. In the field, caliber changes take about 60 seconds. The speed of disassembly also means cleaning and maintenance are a snap, especially since many people are familiar with cleaning AR-15 parts. 

Senex Arms MBLR Bullpup Rifle
The bolt is modified to account for the length of the gun and its bullpup design. (Photo: Dave Luu/Guns.com)
Senex Arms MBLR Bullpup Rifle
The fire control system is also similar and should look familiar to any AR shooter. (Photo: Dave Luu/Guns.com)

Bullpup Benefits

The size benefits of bullpup designs are well-documented, as they allow a longer barrel in a shorter overall package. But even for bullpups, the MBLR-15 touts one of the shortest overall lengths available anywhere. Its smallest variant is 18.4 inches with a 10-inch barrel. That’s smaller than a SIG Rattler with a 6-inch barrel. 

Related - Ode to the Bullpup: Love & Hate for the Stubby Rifle Family

Senex Arms MBLR Bullpup Rifle,
When I say short, I mean short. Even with a generous 10-inch barrel, the gun only comes to 18.4 inches in length. (Photo: Dave Luu/Guns.com)
Senex Arms MBLR Bullpup Rifle
But it can be quickly modified to host a longer barrel or even to swap the caliber of the gun. (Photo: Dave Luu/Guns.com)



Additionally, the rifle is completely ambidextrous and includes left-hand ejection – not a common feature in standard AR-15 designs. There is also a quick-change handguard and multiple handguard lengths. This goes along well with the ease of changing barrel lengths for different applications. 

You can go from a sniper configuration with a long precision barrel and handguard in 6mm ARC to a short .300 Blackout-barreled CQB setup with matching short handguard in a matter of minutes. 

Traditional Problems

Senex Arms MBLR Bullpup Rifle
Solving two of my biggest complaints about most bullpup designs, the MBLR-15 basically has an AR trigger and still has a nice balance to the weight. (Photo: Dave Luu/Guns.com)

My common complaints with bullpups are with the weight/balance, trigger, and ability to clear malfunctions. The weight and balance of the MBLR-15 is better than any other centerfire bullpup I’ve felt. It is not only light but also has a nice balance point. 

The trigger is improved, as it’s basically an AR-15 trigger. As for the ease of clearing malfunctions, I had a long talk with Brandon, and he will be using some new ideas to address this issue in upcoming iterations of the rifle. This is why it’s helpful to solicit input in early stages of development. 


Now this is a gun that gets me excited, and it's definitely worth watching for in the future. (Photo: Dave Luu/Guns.com)

The MBLR-15 is still in the prototype phase, and there is no word on availability or pricing. But it is something to keep an eye on – remember, you heard about it here first. 

You can check out a video demonstrating the new design right here:

revolver barrel loading graphic