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?

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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.

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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.

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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.

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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.