M*CARBO Brotherhood

Magazines Part 2: Big Bore

My experience is limited. I’m still learning what works and what hasn’t yet.
Standard mags will work. Somewhat. I’ve had issues on the last round.
The damned bullets are so big, they just go where they are meant to.

Proper followers are the best solution I’ve found for flawless feeding.
The price per magazine really goes up with each part you have to add.
For example, Lancer L5AWM with Tromix followers, about $40 each.
Then add the +6 floor plates to increase capacity, another $25 each.

I found a cheaper fix for PMags, basically just grinding down the follower.
Making it flat, so the last round isn’t being pushed to one side.

These seem to work fine, but you may need to remove the front rib.
I only had to remove the little stop at the top to run flat nose 450 BM.

There’s plenty of info about how to modify PMags, so I won’t go deeper into that.

This morning as I was organizing my mags, I may have discovered the best trick yet.
I grabbed one of my 10 round IFC .410 mags and loaded it down with .450 BM rounds.
These are by far the easiest mags to load and hold 10 rounds, actually 11 rounds.
I have not tested these to see if they feed and cycle yet. I’m gonna try later today.

I also want to see if the followers will fit in PMags. But I don’t want to get ahead of myself.
I’ll post back with my results. And if anyone has better methods, please share.


Bummer, the .410 mags don’t feed at all. Still want to try the followers in PMags.


@ValorSolo How will you identify them for caliber? I’d be likely to grab my .223/5.56 mags when heading out the door with, say .300 Hamer carbine. (maybe a bad example, but you get the idea)


Don’t know if it will work for you but I use color code stickers on mine for different loads. All are 5.56 but yellow sticker is hollow point, red is ballistic tip, blue is soft point, green is, well green tip, orange is the GMX (Guilding metal lead free) and black is FMJ. I keep lots of loaded mags around and this is the system that works for me.


This is an issue that everyone out there is going to have to “fix” themselves.
Me, I use specific colored mags for each build I make. Or each set of builds.
You are gonna have to come up with a system that works best for you.

I really like to come up with a color scheme or type of magazine for each rifle.
Stick with it and make it work for whatever build I’m doing.

I’m kinda glad the .410 mags didn’t work. Now I’ll try the followers in the PMags.
Zombie green PMags, for my Zombie green 450 BM rifle.


Lancer is making their metal lipped AR mags for big bores that hold 4 rounds for 13.99. I had thought about ordering a few of these just for the follower and placing inside the larger magazine bodies. This would be a lot cheaper than just buying the Tromix follower. Also the 4 rounder would be good for shooting off of a bench.
I have also found it easy to buy a Silver Sharpie pen, and marked on the bottom of my black Polymer mags, exactly what the caliber is. Especially .300 blackout since I don’t want any chances of a mishap. I have bought the larger 20 round Lancer .223/5.56 mags and run my .450 BM with those. It hold around 10 rounds, but I have never needed to shoot this gun until the mag was empty. I use it for hunting, and the factory steel magazine destroy the brass and doesn’t want to feed correctly. My 2 cents only.