r/canadaguns • u/JerkyMan360 • Aug 04 '26
Misc MRX mag question
Hypothetically if a person were to modify a pump action rifle receiver that uses an AR magwell to fit MRX mags would that be legal? If so would modifying the magazine to have only one set of fins and modifying the rifles’ magwell to fit the one set of fins be legal?
10
u/jmz-jmz Aug 04 '26
My understanding is that you can work on / add to / change a mag well, modifying magazines is a big no no. Do more research and don’t take my word for it.
6
u/Iokua_CDN Aug 04 '26
My understanding of it is that you cannot modify the magazine. So you'd have to exclusively modify the magwell
7
u/ExplosiveFetusActual Aug 05 '26
You can modify a magazine all you want, as long as you're not making one to fit in a centerfire semi auto. Shaving off the side ridges on the MRX mags would probably be considered manufacturing an AR15 magazine. Adding ridges to the side (what the MRX mags have) is manufacturing something new, because it won't fit in an AR magwell.
I hand filed slots in my Ruger American's magwell to fit MRX mags. Completely legal. You would have to do something like that.
9
4
u/BrotherLefthand Aug 04 '26
Can't modify the magazine to fit a rifle. Can modify the rifle to fit a magazine.
Here's the problem though. The MRX magazines don't have a proud follower. You would lose LRBHO or would have to modify the magazine to get the correct follower height.
1
u/JerkyMan360 Aug 04 '26
I see, so a combination of both mag and magwell mods is a no no then?
3
u/BrotherLefthand Aug 05 '26
You might get away with it if the mag can't fit into an AR, but the legal headache isn't worth it even a little bit.
Just modify the mag well.
1
0
u/Murray3-Dvideos Aug 05 '26
My non professional understanding in laymans terms: You cant modify a semi autos magwell to accept manual arm magazines and you cant modify manual arm magazines to fit semi auto PATTERN magwells. For ex, grinding the ribs off a manual arm MRX mag to fit in a Taipan manual arm which has an AR15 pattern magwell would be turning that 20rnd MRX mag into a prohibited device, amoung other illegal acts. BUT modifying a manual arms magwell to accept a different manual arm magazine doesn't strike me as being any different then buying a ACIS chassis for your Tikka to ditch Tikka mags.
2
u/MostEnergeticSloth Aug 05 '26
There is no distinction in the law between different magazines apart from "rifle" or "pistol". AKA no such thing as a "manual arm" magazine. You can modify any firearm you want to fit any magazine you want.
0
u/Murray3-Dvideos Aug 05 '26
Magazines designed for manual actions. I did say "Layman's Terms". Although I could very well be wrong about the legalities of modifying a semi autos magwell to accept magazines designed for manual actions. If it is legal, its odd that ive never seen anyone do it in the 20 years ive been shooting, but then again maybe good manual arm magazines with a capacity greater then 10 were pretty much non existent anyways.
3
u/BrotherLefthand Aug 05 '26
The only legal distinction between the magazines used for firearms is between long guns and pistols.
You don't see it often because it's a pain in the butt. The types of magazines for manual action firearms, such as the MRX 20rnd, aren't designed to quickly feed ammo and allow for a bolt catch.
There's a write-up on CGN about making an MRX magazine work in a semi-auto and the final conclusion was that the juice isn't worth the squeeze. You may as well just buy crossmags or LAR mags.
2
u/MostEnergeticSloth Aug 05 '26 edited Aug 05 '26
Hunting gear guy had a video with his 180 where he was shooting an MRX magazine. It was just never explicitly mentioned and editing was cut such that it never fired 20 rounds. People just don't talk about it because
1) It's not necessarily fast to do
3) It involves cutting up a gun which usually cost people a lot of money (semi-autos these days) and some people aren't keen on that.
And you're also correct; "manual action" magazines that would hold more than 10 and theoretically could work in modern semi-autos didn't exist even 10 years ago. It's one thing to cut up a rifle, but with feed geometry and retention method, there really weren't any options.
3
u/Murray3-Dvideos Aug 05 '26
Well I learned something today, thanks fellas
2
u/MostEnergeticSloth Aug 06 '26
Also just a quick fyi since I went to double check to make sure I wasn't losing my mind/memory, it was actually the SBI Lynx 180 video not a WK one.
1
2
2
u/ivanlarav Aug 04 '26
Modifying the magazine in a way that might make it fit or be compatible with a semi-auto rifle is illegal.
As long as those modifications do not make the magazine compatible with a semi-auto rifle, you should be okay.
At least, that’s the advice on CGN coming from the creators of the Renegade.
1
11
u/MostEnergeticSloth Aug 04 '26
Modifying a rifle to fit a legally-existing magazine is a legal act. You could do the same to a semi-auto rifle magwell. Some cops might take issue with it due to not knowing the law, and I'm not saying you wouldn't end up defending yourself from a charge due to prosecutors also not knowing the law (or not caring and just wanting to charge someone even if they know it's wrong), but it is legal.
Modifying the magazine (cutting off the ridges) would be creating a prohibited device.