I have been having issues with my EAA Witness moded magazines on my 10mm Beretta, so I have been looking to a new avenue. What caught my eye is the thread about 10mm ammo fitting in the HK USP .45ACP magazines. After investigating, I discovered that I can make the compatibility swap by only altering a few of the small parts in the gun, and only have to swap (or modify) the floorplate on the magazine.
In other words, I would not be legally modifying the magazine. However, there is one little problem. I live in California where it is illegal to ACQUIRE (not have) anything over 10 rounds. So the question is, would using a 10 round .45ACP magazine to hold more then 10 rounds of 10mm ammo, without modifying the magazine, be a legal infringement?

I would contact your local District Attorney's office and ask them, since they'd be the ones prosecuting a case like that. They may be able to give you a definitive answer.

Police department would be better... I worked briefly with a neighboring Prosecutor's Office. Anyone that would be prosecuting a case like that usually doesn't have the faintest idea, until they are given the list of charges and reports, then they still have to look up the current laws on it. Just for an example, one AP asked me and my supervisor if the bullets that go into a Tec-9 are the same as the ones that going into the pistols of some local departments. I'm sure that you could ask, but the chances that they have a statute on it aren't too high.

If it were me, I'd base it on the capacity of the rounds you insert, but I'd also mark on the magazine that you will be using those (I'd put it over the original caliber mark). If someone were to buy a 30 round AR15 magazine in NJ (max is 15 rounds), but use it with a .458 SOCOM, which only fits 10, I'd say you are fine unless you screwed the chief's daughter...

DO NOT TAKE ANY OF THAT AS RIGHT AND WRONG, BUT MY VIEW ON IT. I DO NOT EVEN LIVE IN CA. IF YOU DO GET AN ANSWER FROM SOMEONE IN AUTHORITY, WRITE DOWN THE NAME TO BE ON THE SAFE SIDE.

This post has been edited by Screwball: September 13th 2008 1:15 PM

I am talking about doing the exact opposite. Getting a 10 round HK USP .45ACP magazine and using 10mm auto in it without modifying the magazine.
You can have a 10 round magazine in CA. The magazine it's self is legal. The question is whether or not I am getting in to murky waters by using these magazines in a different gun with different ammo, that the magazine can hold more then 10 rounds of.

I prefer not to be talking with the government. Last time I called to ask if something was legal or not, they showed up on my doorstep the next morning wanting to search my house.

This post has been edited by brigadier: September 13th 2008 2:56 PM

brigadier, Legal is not in the eye of the beholder on this one. I am not a lawyer or a student of law but, California has some ways of misinterpeting what the intent of the law says even if they wrote it.
So even if your magazine is legal to own for the caliber it was designed for, using it for a different caliber which it would hold more than the allowed amount may actually void the intent of the law in their minds. Modified, "New & Improved" and homemade items are sure to change the rules by which they are judged.

It is a very interesting situation, sort of like the plug in a shot gun to limit the thing to 3 shells, removed it holds 5, hunt water foul without it makes the gun illegal to use and subject to penalties & fines.

Good luck getting a straight answer, ask the NRA (California area) for an interpetation and see if they could help!

What do they thing about barrel caliber conversions for instance like the Glocks.

This post has been edited by The_Shadow: September 13th 2008 8:47 PM

The only time caliber conversions are a legal issue is when you convert to a banned caliber (like .50BMG for instance) or make your gun a characteristic bases assault weapon by converting a rimfire gun with assault weapon characteristics to centerfire.

California is loose on customizations in a weird way. It is illegal to obtain but not illegal to have high cap magazines. Though converting low cap to high cap is illegal, there is no law forbidding you to make high caps from scratch.

Like I mentioned, I would consider the number of rounds inserted that would make it legal/illegal. I only used that example, being it was something I had in the back of my head. I'm not sure, but I do believe someone asking about filling a 10 round 96 magazine with 9mm rounds on BerettaForum... keeping a 10 round 96 magazine isn't illegal, but squeezing in the extra 9mm round in that same magazine is.

Modifying the magazine to not add the extra rounds world fix it.

There are lots of laws about circumvention though. Back during the ban a very gunny AG I knew warned me about that. Be careful.