Fudd Friday: The One-of-a-Kind Over & Under Thompson/Center Contender

For those unfamiliar, Thompson/Center has been making interchangeable handgun and rifle systems since 1967. The basic concept is elegant: one frame, multiple barrels in different calibers. Swap barrels, swap calibers. It's practical, it's economical, and it makes sense for people who like options. But apparently that wasn't enough for Sirois.

When "Why?" Becomes "Why Not?"

The inspiration came from an unlikely place—Savage Arms' old rimfire-over-.410 combination guns. Sirois had been thinking about that design when a customer called asking if he could do a .22 Long Rifle over a .410 shotgun on a Contender frame. The answer was no. But Sirois told him to call back in a week, because he thought he could do a rimfire-over-rimfire setup instead.

And he did. In less than a week, apparently.

The gun featured in Thompson/Center's recent video is chambered in .17 HMR on top and .17 Winchester Super Magnum (.17 WSM) on the bottom. That's two different rimfire cartridges in one pistol, with a selector switch that lets you choose which barrel to fire. No reloading between shots. You just flip the switch and pull the trigger again.

Let's be real—this isn't solving any pressing practical problem. Nobody wakes up in the morning thinking, "Man, if only I had two different .17 caliber rimfires in a single-shot pistol frame." But that's not really the point.

The Devil's in the Details

Here's where it gets interesting from a gunsmithing perspective. The selector switch on a standard Contender frame toggles between rimfire and centerfire firing pin positions. Sirois repurposed that mechanism to select between the top and bottom barrels instead. The rimfire position hits the bottom of the top chamber; the centerfire position hits the top of the bottom chamber. It's math, as he puts it—center lines and firing pin placement.

The barrels feature a regulator system that allows adjustment of the point of impact. Since you're dealing with two different calibers, you can set them to converge at whatever distance you want—50 yards, 100 yards, whatever makes sense for your intended use. The top barrel is your reference point; you adjust the bottom barrel to match.

The woodwork deserves mention, too. Sirois custom-shapes his grips, and they're genuinely well-designed. The featured pistol has a grip that wraps over for your thumb and contours nicely for your fingers. It's not just decorative—it's functional. The jeweling and decorative touches were handled by Ken Kelly at Magnaport, giving the gun a distinctly finished look.

Does It Actually Work?

According to the video, yes. The presenter put rounds downrange at 50 yards with both barrels and achieved touching groups—half an inch apart or less. That's impressive for any pistol, let alone one this unconventional. With the .17 caliber cartridges, there's minimal recoil, and the red dot sight reportedly stayed on target throughout.

Sirois is known for guaranteeing sub-MOA accuracy on his work, and he aims for half-inch groups or better. Given that he's built nearly a hundred wildcats and has extensive experience with custom chambering, those aren't empty claims.

The Bigger Picture

Sirois isn't limiting himself to over-and-under configurations. He's also built side-by-side versions, though those require different trigger and hammer mechanisms to work properly. The selector on a side-by-side literally slides back and forth to choose which barrel fires.

He's currently focused on finishing his bolt action projects and assembling more of his XPS (eXtreme Performance System) builds with various wildcat chamberings.

Why This Matters (Or Doesn't)

Let's be honest—you don't need an over-and-under rimfire Contender. Nobody does. But that's not a criticism. The firearms world would be a duller place if every project had to justify itself through tactical necessity or practical application.

This is craftsmanship for its own sake. It's answering "can it be done?" with "yes, and I'll show you how." It's taking a platform that's already versatile and pushing it into territory nobody else has explored.

Will this change the handgun market? No. Will you see these at every range? Absolutely not. But will someone see this and think, "That's incredible, and I want one"? Almost certainly. And that's enough.

The video is worth watching just to see Sirois's shop and hear him talk through the engineering. The man's clearly spent decades thinking about firearms design, and it shows. Whether you're interested in custom gunsmithing, wildcat cartridges, or just weird guns that work, there's something here to appreciate.

Thompson/Center posted the video on their YouTube channel, and it's garnered over 28,000 views since late October. For a 13-minute deep dive into a one-off custom pistol, that's respectable engagement. People are clearly interested in seeing what's possible when you combine technical skill with creative problem-solving.

The Bottom Line

Mike Sirois's over-and-under Contender is a solution in search of a problem, and I mean that as a compliment. Not everything needs to be mission-critical or tactically relevant. Sometimes it's enough to look at an established platform and ask, "What if I did this completely different thing with it?"

The fact that it works as well as it does—sub-MOA accuracy, reliable function, beautiful fit and finish—just makes it better. This is what gunsmithing looks like when someone's genuinely good at it and isn't constrained by what the market demands.

Would I buy one? Probably not. Do I appreciate that it exists? Absolutely. That's the thing about projects like this—they don't have to make perfect sense to make the firearms world more interesting.

If you want to see more, the full video is available on Thompson/Center Arms' YouTube channel. Fair warning: you'll probably come away wanting a custom Contender build, even if you can't quite justify it.