30 rd 556 mag = 9 rd 458 Socom mag

[usp45ct]

Looking at a new upper for a lower I just picked up. Found out a standard 20-round 5.56mm NATO magazine can hold seven .458 SOCOM rounds and a standard 30-round 5.56mm NATO magazine can hold nine .458 SOCOM rounds. So would 30 rd post ban AR mags be fine when loaded with .458 SOCOM?

 

[shapiroeric]

It should be....IIRC a 30 round mag will hold 10 SOCOM rounds....and also something about grinding the notch out for feeding purposes....I may be wrong though

 

[pupchow]

I've read of issues with certain .458 SOCOM rounds hanging up in pmags.

You could just get some standard AR mags, and install .458 SOCOM stamped floorplates? Beyond the border, of course.

(I'm currently trying to decide between the .458 & .450, for an upper, so no firsthand experience)

 

[Terminator03]

Very interesting question. It seems as though it would be, but since those magazines you are referring to were originally designed for .223/5.56 rounds, it is definitely a gray area, unless the mags were somehow modified to no longer work with their originally intended rounds. Note, this is just my own thoughts, not stating as fact. Hopefully someone that knows more about the actual legality will chime in, but I suspect there isn't going to be anything in the MGL that clarifies this.

 

[LittleCalm]

Couldn't you just get pre-bans and then not worry?

 

[Shovelheddrew]

You can find the pre-ban ones but the required time machine is not cost effective.

 

[JayMcB]

I don't know that I'd want to have that argument with the statist DA/AG office, unless it was permanently modified to not allow 223/5.56 feeding

 

[Terminator03]

Couldn't you just get pre-bans and then not worry?

Of course, but he is asking specifically about post ban mags converted for a different round/count. Why would you want to utilize a $30 preban mag, when you might be able to use an $8 post ban one?

 

[jtnf]

The ultimate touchstone for "Gray areas in the law" was often repeated when I attended a "Gun Laws in Massachusetts" lecture class/lecture at Mass Firearms School...


Do you want, and can you afford, to be the precedent setting case?


No gray area at all in my mind. A 30 round post-ban mag is a 30 round post-ban mag, regardless of your intent. Possession = Bad day for you.

 

[exo]

Are there mags sold as specifically for the .458 socom, even though they might just happen to work with .223? I've never tried, but I suppose it might be possible to stuff 11 rounds of 9mm in a 10 rd Glock 22 magazine. There's got to be some "reasonable" (god I hate that word) interpretation of what the magazine was designed for, here.

 

[Golddiggie]

You could also get this 5 pack of base plates for the metal magazines to help eliminate worry... I know $5/plate is a bit much, but it could be seen as part of a 'perm modification' to the magazines to 10 rounds (which should be within MGL). Of course, I'm not a lawyer, or care about moronic MA laws.

In my quick google search, I did see how some polymer .458 SOCOM mag's had additional modifications to make them feed better. No idea if you need to, or should, modify metal body mags. I wonder if MagPul will release a dedicated .458 SOCOM magazine at some point...

- - - Updated - - -

Are there mags sold as specifically for the .458 socom, even though they might just happen to work with .223? I've never tried, but I suppose it might be possible to stuff 11 rounds of 9mm in a 10 rd Glock 22 magazine. There's got to be some "reasonable" (god I hate that word) interpretation of what the magazine was designed for, here.

Yes

It's a 7 round mag though...

 

[exo]

Yes

It's a 7 round mag though...

To me that looks like you could stuff 20 .223 rounds in there. The mag body even has a line for 20 on it. Is the follower different?

 

[mclina]

To me that looks like you could stuff 20 .223 rounds in there. The mag body even has a line for 20 on it. Is the follower different?

And why do they have to mention mag capacity restrictions on a page for a 7 round magazine?

 

[atilla]

Looking at a new upper for a lower I just picked up. Found out a standard 20-round 5.56mm NATO magazine can hold seven .458 SOCOM rounds and a standard 30-round 5.56mm NATO magazine can hold nine .458 SOCOM rounds. So would 30 rd post ban AR mags be fine when loaded with .458 SOCOM?

they are dedicated .458 socom mags, right?

right?

there's your answer right there. so what if .223 can fit? never tried, officer. these are .458 socom mags.

 

[warwickben]

50 and .410 are the same way. You can use normal ar mags with a little but of tweaking of the feed lips. I'd say just leav the mags loaded so if a cop starts to touch them you can say look there's on 10rds that fit in .

 

[Golddiggie]

To me that looks like you could stuff 20 .223 rounds in there. The mag body even has a line for 20 on it. Is the follower different?

Don't know why they left the '20' on it. They modified the feed lips, and some other areas to be optimized for the .458 SOCOM round. I suspect it would have issues with .223/5.56 now.

"These Lancer 5.56 AWM magazine feed lips have been carefully modified in our shop to hold the .458 SOCOM higher in the tube which allows the use of a wider variety of projectile shapes. We also cut a deeper clearance at the front of the magazine body to allow the big SOCOM case to better clear the magazine during the feeding cycle."

IMO, they should remove the '20' from it, since it's really not optimized for .223/5.56 now.

 

[RG617]

they are dedicated .458 socom mags, right?

right?

there's your answer right there. so what if .223 can fit? never tried, officer. these are .458 socom mags.

That's my train of thought. *scratching head* "30 rounds? What are you talking about? I couldn't get thirty rounds in there with a vise! Huh...? Why the hell would I want to put 5.56 in a .458 mag?! That's just asking for problems."

50 and .410 are the same way. You can use normal ar mags with a little but of tweaking of the feed lips. I'd say just leav the mags loaded so if a cop starts to touch them you can say look there's on 10rds that fit in .

This is exactly what I was thinking.

 

[usp45ct]

Thanks, that is what I was thinking.

 

[groundscrapers]

I could probably stuff 50 rounds of .22lr into a 10 rd 5.56 mag.

 

[dennism]

So what manufacturers make a completely unmarked for 223 4458 mag? Seems legit to me. Any input/opinions from the legal experts among us? Lens?

 

[warwickben]

So what manufacturers make a completely unmarked for 223 4458 mag? Seems legit to me. Any input/opinions from the legal experts among us? Lens?

You can get a basic gi mag unmarked . Blank floor plate. Brownells and midway.

 

[dennism]

You can get a basic gi mag unmarked . Blank floor plate. Brownells and midway.

Do they make snap caps that you can fill one with to demonstrate? I think this idea has some validity.

 

[warwickben]

Do they make snap caps that you can fill one with to demonstrate? I think this idea has some validity.

You can get snap caps in most sizes . Most rounds need the rights follower and spring .

 

[whatluck]

'permanantly modified to be unable to hold > 10 rds' in my non lawyer opinion means that your mag must have been modified in a way that it was no longer able to hold > 10 rounds.

Now post ban .458 socom mags are different. You could very easily argue that the mags and upper reciever are a matched pair, and that they're not interchangeable, provided you can make a reasonable argument that the mags were in fact designed for 458. So if you have wider feed lips, a different follower, and a marking that says .458, its unreasonable to say that's not a 10 round mag.

And yes, you can definately fit 11 rounds of 9mm into a glock 27 mag. It even feeds that way some time. Am I going to now argue that anyone with a 10 round G27 mag is a felon?

My advice? Use the mags that run best in your gun.