The magic here is it starts out a double stack magazine and the bullets are at 45 degree angle to each other. Fully loaded the pressure from the round above the round sitting on the follower keeps the follower in line in the mag. housing as it moves up the magazine. Here's the magic if that's what you want to call it. The slight taper at the top of the magazine keeps the follower in line to a single stack position. The round above the round touching the follower keeps the follower in line till the taper takes over- Simple just no one else thought of it. Actually all double stack magazines do this just in a shorter space at the top so the grip must be wide all the way to the top.

SPOILER : He concludes the mag spring is shorter. That's all. Just saved you 7 min.

I shot my Sig P365 for the first time today - looks like I’m lucky - we shot 200 error free shots today - I love this Gun

Been looking forward to this vid!!!

You missed the fact that the spring is spiral shaped so it kind of folds into it's self to make more room in the mag.

Really cool video Harry. That is a bada$$ holster also. Thanks for the video.

Thank for your this. Very informative, and done well to show there’s nothing really going on. So sig charging $50-60 for a mag was based on R&D recoup of...a spring?

The spring has narrow coils at the top and wide coils at the bottom. This allows the narrow coils to collapse inside of the wider coils. This allows the follower to get a little closer to the baseplate before the spring is fully stacked.

just what I was thinking, thanks

Thanks for pulling the the P365 mag apart. Was expecting not to see a spring, but instead to see some tiny little fairies in there holding up the follower. In all seriousness, I was wondering how you shape a follower for a mag that tapers from double to single. Wouldn't the follower need to be taller and tapered so it could match the width of the double stack section at the bottom and the single section at the top?. Or if it were narrow enough to fit high in the mag, then it could twist when fully loaded and down in the double stack section. Maybe that is the magic - the fairies are holding the skinny follower upright!

I personally am still going to have to wait at least 6 to 8 months after the rerelease of the 365 my understanding of some of the changes is they have milled a Groove into the slide in order to give more tolerance. I certainly am no engineer so I have no idea what effect this might have on the slide strength or function. I truly do hope they have solved all the problems because I really do want one of these guns if all proves well.. and that for me will be 6 to 8 months.

it's not a single stack, nor it's a double stack, it's a 1.5 stack.

That magazines spring has tighter coils up from the last two, those are obviously less tight by a big margine. I bet by loosening the last two and tightening all the coils above gave them extra round space. Probably some math and details of the SPRING involved, but the general idea. Magic

Nice Video, I just think Sig just used Voodoo to make the Mag! 😳 Carry On

Nice video Harry. I'm sure you get your hands on so many different guns. What are some of your midsize and range 9mm guns under $1000 . I have the Hk vp9 le 9mm, Glock 19 gen 4 and M&P M 2.0 9mm .Trying to think of my next purchase. The Shield 2.0 9mm is my carry, my 22lr is the Ruger Mark iv target stainless. I have also had the Canik tp9sf and the Ruger American Pistol 9mm. Any suggestions ?

Which one do you think will fit 9mm hellcat

I have the 10,12, and 15 round mags and none of them like hollow points. I even bought the sig 365 ammo and have frequent failures to feed. I have had no issues with cheap range ammo after 500 rds. I sent pictures to sig but have not received any reply about the issue. The round hangs up on the front edge of the mag.

Personally, I think the most fascinating thing about the mag/grip combo on the P365 is that it's the only part deemed to be "unique", yet it's not one of the things that seems to be part of the production issues. So *A)* Sig got the claimed "innovative" part correct, and *B)* Sig got several of the basics wrong. Go figure. Regardless, any attempt at true innovation (not just something to circumvent rules) is a good thing. I do hope they get the second batch 100%. -

Keltec has been doin this with the p11 since 1995

I've wondered myself.. there is no magic in the mag except shorter probably stiffer spring. So where does that leave us. They used a single stack slide and length. I'd be curious how thick the plastic is in the grip.

Will that p320 fit the p365

You are doing some of the best reviews and comparisons on this pistol of anyone.... Yeah it's definitely not rocket science I mean physics dictates 10 rounds of 9mm needs to take up a certain amount of space and there is no getting around that fact.... I would like to see the 365 magazine next to a Glock 26,, Smith & Wesson M&P 9 compact,, Ruger SR9 compact,, or CZ Rami.... if the magazines are the same width and they claim that the exterior grip dimention of the gun is narrower the only way to get that done is to make the wall thickness of the polymer itself thinner... I imagine the Glock 26 is wider in the grip because the Glock magazines being polymer over steel have to be thicker then just a standard All Steel magazine like the Sig.... the only way to make the magazine shorter than another 10 round is to have less spring length inside the magazine so it can compress a little bit farther which to me could cause functioning issues from the spring getting weaker prematurely.

I have the 9mm hellcat and the 380 ez m&p,, but I can't find a extended magazine I really get sick of the reloading

That was really interesting. Except for the Glock, all those mags were between 20.5mm and 21.5 mm. The Glock was 22.6

It’s the best gun ever took a bit to work it all out buts it’s by far the best gun ever

so the only difference is spring? hmm interesting, only time will tell if that hold up

And that is seven minutes of my life I’ll never get back and your point is

I cant believe so many people are suprised about the size of the p365 KelTec P11 has been that size wiyh 10 round capacity for at least a decade

I have about 1300 rounds through my 365 and I harry it every day. Very dependable or I would not carry it.

Funny how the Glock is the ONLY polymer mag on the table...

This is *exactly* the video I have been hoping for. Thanks! Would you care to speculate whether or not other producers will be able to duplicate this capacity without violating the supposed 3 'patents pending' on the Sig mag? I mean, if nothing here is revolutionary, how can they claim patentable tech?

Sorry Harry I meant to say your " favorite guns " mid and range size under $1000.

Are CZ75 mags about the same width?

Take a look at a Shield 9mm mag.

Please don't take this the wrong way, but the title of this clip borders on clickbait. Really, what did you expect? A genie to come out of that mag? Even without seeing it open it seems an obvious combination of a thin mag well, a slightly different mag geometry and that's all. Sig do what everyone does promoting their product, no one in his right mind would thing that there's anything extraordinary about that mag. They just did it first, and hopefully other gunmakers will follow suit. You could just name your clip: P365 mag measurements comparison, or whatever. But then you'd have less people watching your truly nice holster, right? It feels to me like you've been milking dry this specific cow (P365). No offense meant.

Too long, didn’t watch. 365 = sorcery