13 round 45apc USP magazines?

[combat45acp]

Ok I ordered 7 FACTORY 12 rd magazines with the finger rest from CDNN Sports for my Tactical I just got, I have owned the full size USP 45 for years but bought it during the Brady Ban and only had 10 rounders for it. Anyway with the Tactical, I "HAD" to have hi-caps. All 7 of these magazines hold 13 rds not 12 They load very easily and feed and function good. My question is...is this normal?

[F1fanatic]

Hmmmmm. I have 4 - 12 round magazines and can only get 12 rounds in them. The 13th round won't fit.

[combat45acp]

Yeah every gun shop I call acts like I'm some kind of idiot and don't know what I'm talking about, like I must have some kind of after market magazine.
But I ordered factory mags!
The mags say specifically on them USP 45, and Made in Germany.

I emailed H&K and am waiting to hear back from them.

The 13th round loads easier than my Glock 21 mags do.

[jmikesteen]

It is not at all unusual, some here will say that you souldn't do it, I have never had a problem. Some of my mags cann't hold 13 without the use of my UpLULA but they all will. I have pre 2004 LEO marked as well as unmarked they all work. The 10 round HK45 will take 11 as well but the 8 round USP compact/ HK-45C will only take 8 no matter what.

By the way it is not just HK, my USP-45 15 round mags hold 16 rounds just as easily.

Mike

[ripley16]

Are they really HK mags or Promag? I know Midway often confuses factory with aftermarket.

[combat45acp]

Yes they are 100% Factory and not Pro Mags. The back has the dove tails where the metal is connected together. Did notice that the mag follower has an X stamped on it...don't know if that is normal. Plan to get more mags soon and will be bummed out if they only hold 12 rounds :-/

[WyDog]

Last Fall CDNN offered a factory 13 round mag for the USP45 for sale. Sounds like you may have gotten these instead of the 12 rounders. I don't know the story behind the 13 rounders, but I saw them advertised for sale.
WyDog

[combat45acp]

Wish I would have bought more than 7. I have only shot 91 rounds through this gun so far, (each mag once) and they ran fine lock slide open and all. Emailed H&K to see what they say, I will keep you posted. Thanks

[jmikesteen]

by the way I stand corrected the 8 rounders take 9 if you push.

Mike and yes theyt are HK gotta be new not to tell and I am a very old fart.

Mike

[GCS83]

Mine also fit 13 rounds, however I only load 12.

[heffa]

by the way I stand corrected the 8 rounders take 9 if you push.

Mike and yes theyt are HK gotta be new not to tell and I am a very old fart.

Mike

Can you send me your thumb workout video:) All I can get in the four of mine is 8, 8.5 with force. I have quite strong hands but not that strong!

[jmikesteen]

No way I could do it without the UpLULA, you will throw all your other loaders away, it's worth it. check out this part of an artical I just found on the 13 round USP

HK Universal Service Pistol
by Massad Ayoob
USP45 UTL. A combination of six letters and two numerals that stand for a lot: Universal Service Pistol, caliber .45 ACP, with Universal Tactical Light. Heckler & Koch's USP has been at the forefront of the plastic-framed handgun market in terms of functional technology since its introduction. The USP was designed to compete with the enormously popular Glock in terms of both construction materials and pricing.
Unlike the Glock, you can "have it your way" with a choice of USP fire control modes. Left hand or right hand operation. Double-action first shot, double-action every shot, or single-action "cocked and locked" for every shot. The standard model, called Variant One, can be carried in your choice of cocked and locked or double-action mode for the first round, with the same ergonomic, frame-mounted lever serving as both thumb safety and decocker.

The USP comes in two frame sizes: standard and large. The standard frame is available in 9mm or.40 S&W caliber, the large frame in .45 ACP. An even larger version of the latter in the same caliber won the SOCOM contract, and (except for the sound suppressor) you can buy the same gun as the Special Operations Command did, though why you'd want the extra size without the suppressor instead of the regular USP45 I can't imagine. Perhaps a collector would want a Mk. 23, as the "USP on steroids" is officially called.

Crime Bill Gun

The USP45 was introduced in 1995. The Crime Bill was already in effect, and the 13-round magazines for which it was designed would be sold only to police and military. A legal 10-round magazine was enough. I got a couple of USPs to test, wrote them up for both police and civilian magazines, and liked them so much that I bought one of them to keep.


The entire artical can be found here.

http://www.remtek.com/arms/hk/civ/usp/45/usp45.htm

[Gunschlinger]

Interesting that the article said it was designed to take 13 round mags.

[combat45acp]

HK never emailed back, when I called HK the guy acted like of course they will hold 13 rounds but it's hard on the spring....ok I buy that? :-/

[jmikesteen]

Not me, with 13 the spring is more "at rest" than with 12:720:

[CPshooter]

This is interesting, to say the least. So was it designed for 12 rounds or 13? Someone who has knowledge on the subject, please chime in!

[AviatorDave]

Not me, with 13 the spring is more "at rest" than with 12:720:

Not really, the fewer rounds there are in the magazine, the less stress the spring is under. It may be just fine with a 13th round, or it may be over-compressing the spring.

But this is a very common situation - MP5 mags can all hold 31 rounds. You just can't get the mag locked in when the bolt is closed without REALLY smacking it hard, if at all. Most of my P7M13 mags will hold 14.

25 round UMP mags can easily hold 27 rounds, or 28 if you really cram the last one in there. You just run into the same difficulty of changing mags with a closed bolt however.

That extra room may be so that the springs aren't over-stressed.

[Rican Havoc]

Not really, the fewer rounds there are in the magazine, the less stress the spring is under. It may be just fine with a 13th round, or it may be over-compressing the spring.


I align myself with this camp. If the magazine has 12 witness holes, that's how many I load. Other wise, you're probably pushing the mags past their design and intended use, and don't be surprised when they fail to lock the slide on the last round, or even have a negative effect on the integrity of the mag body itself. I know for a fact that some of the SIG P226 zipper-back mags have had failures at the tack welds, making the magazine useless. By over-compressing the spring and stuffing more rounds in there, I wouldn't be surprised if you see both of these problems arise. It's one thing when it's a $25 P226 mag, but it's another issue when it's a $60 .45 USP mag. :(

[dcondiff]

If you can't get the job done with 12+1, I'd be willing to bet that 13+1 won't do the trick either ;)

Trust me, HK isn't going to advertise a lower capacity then what it was actually designed for -- the higher the capacity the better sales point it is.

Load 12 or run the risk of jamming or magazine damage. Considering you're probably just loading them up and popping them off at the range you really don't need to take the risk, do you?

[orfeo]

AviatorDave has it exactly right.

The fact that more rounds will fit than advertised, doesn't mean a thing about the intended capacity of the magazine. Overloading your mags beyond their specified capacity will compress your mag-spring beyond the limit it was designed for. When you do that, the pressure that the spring exerts on the last cartridges in the mag (when the spring is almost fully extended) is SIGNIFICANTLY less than it would have been otherwise.

In fact, a mag which has never been loaded to it's specified capacity, but downloaded by one round (as in a 12-round mag which has never been loaded past 11) will exert more pressure on the last cartridges in the mag than otherwise also. (Not to mention that it will be easier to seat on a closed slide with one less round in it too)

A magazine spring maintains pressure upon all the rounds in the mag up against the bottom of your slide. The top round in the mag is compressed down to about 3/16" below the magazine-feed-lips on a closed slide. As the slide cycles back the ejector pops the empty cartridge case out, and the top round in the mag is pushed up that last 3/16" (by the mag-spring) into the breachface area, and stops against the magazine-feed-lips. On the way forward again, the lower edge of the slide's breachface pushes the top live-round just past the feed-lips on the magazine where the mag-spring then pushes it up into the breach, sliding the case-rim of that round in behind the extractor, against the pressure of the extractor-spring, and the next round in the magazine up against the bottom of the slide. The slide continues forward, pushing the round into the chamber until the gun locks into battery and is ready to fire again.

**The strength of the magazine spring is critically important for pushing the cartridge up into the breach and into the grip of the spring-loaded extractor (at blinding speed no less).** This is WHY weak mag-springs will cause failures to feed. The pressure exerted by the mag-spring is highest when the mag is loaded to capacity, and gets progressively lower each time a round is stripped from the mag, since the spring is less and less compressed as the mag empties. The pressure exerted on the last rounds in the mag and on the empty follower against the slide-lock is FAR less than the pressure exerted on the first rounds, and this is WHERE you will first see symptoms of a mag-spring that is not strong enough for the job.

Overcompressing your mag-springs will significantly lower the pressure the mag-springs exert on the last rounds in the mag and on the empty follower against the slide-lock. . . Don't do it. :)

[combat45acp]

I have shot these a lot without any problems and they lock the slide back. No ftf or fte. The 13th round is really easy to load. Took my cousin shooting for the first time and he easily loaded 13 rounds in them not knowing what he was doing. The mag seats very easy with and without a round in the chamber with no force. I agree that the 13th round may compress the spring more, and with that gun being as accurate as it is only needing 12 + 1. However with them loading very easy I don't think they will cause any harm?? If you have ever loaded a Glock 21 magazine these are easier to load the last round than those and I have all generations of Glock mags.

[orfeo]

I have shot these a lot without any problems and they lock the slide back. No ftf or fte. The 13th round is really easy to load. Took my cousin shooting for the first time and he easily loaded 13 rounds in them not knowing what he was doing. The mag seats very easy with and without a round in the chamber with no force. I agree that the 13th round may compress the spring more, and with that gun being as accurate as it is only needing 12 + 1. However with them loading very easy I don't think they will cause any harm?? If you have ever loaded a Glock 21 magazine these are easier to load the last round than those and I have all generations of Glock mags.

Like HK told ya. . . "of course they will hold 13 rounds but it's hard on the spring. . ." :)

[gunut45]

I have shot these a lot without any problems and they lock the slide back. No ftf or fte. The 13th round is really easy to load. Took my cousin shooting for the first time and he easily loaded 13 rounds in them not knowing what he was doing. The mag seats very easy with and without a round in the chamber with no force. I agree that the 13th round may compress the spring more, and with that gun being as accurate as it is only needing 12 + 1. However with them loading very easy I don't think they will cause any harm?? If you have ever loaded a Glock 21 magazine these are easier to load the last round than those and I have all generations of Glock mags.

Do it all you want, but you are wearing out the spring. Leave it loaded for a couple months and you will know what I mean.

I have worn out the spring on a USP .45 mag by keeping it loaded in the gun 12+1 in the pipe. Only time my pistol has ever had an issue.

Bottom line, factory springs suck = don't load 13 if you keep the gun around for and kind of self defense.

[jmikesteen]

Nuff Said,

http://findarticles.com/p/articles/mi_m0BTT/is_163_27/ai_99130369/


then the oniy real question is, was it designed to be 12 or 13 not the "current line" from HK, Does anyone here know Mr. Ayoob and can ask him what was it that made him think it was a 13 round mag. I have read him for years and he is not the type to miss much.

[combat45acp]

so my next question is...the magazine spring on the USP mags I have, have four small coils at the top and seven at the bottom end. Which looks like it is to let the top part of the spring go into the center of the spring. Is that how everyone else's mag springs are? Also there is a small (x) on the follower front anti tilt lip visible when looking down at the top of the follower...is that normal or mean anything.

I understand everyones point but every gun shop and dealer I have spoken with says they can only squeeze 12 and these take 13 with no effort.

I will get a pic of it soon.

Thanks.

[combat45acp]

I will get a pic of it soon.


Here's the pic:

http://i133.photobucket.com/albums/q55/eph28savedbygrace/100_0680-1.jpg

[AviatorDave]

Those 4 smaller coils at the top are probably to allow the spring to fit into the upper part of the magazine where it tapers from the double-stack section to the single cartridge feed at the top of the mag.

If it was the larger circumference the full length, the spring would bind where the mag tapers at the top. If it was the smaller circumference, the spring would tend to curve to one side in the middle and drag against the mag body.

[orfeo]

. . .the oniy real question is, was it designed to be 12 or 13 . . .

It was designed to hold 12. . .

[orfeo]

. . . Does anyone here know Mr. Ayoob and can ask him what was it that made him think it was a 13 round mag. I have read him for years and he is not the type to miss much.

You and Mr. Ayoob have special authorization to load 13 rounds if you want

[Rican Havoc]

then the oniy real question is, was it designed to be 12 or 13 not the "current line" from HK, Does anyone here know Mr. Ayoob and can ask him what was it that made him think it was a 13 round mag. I have read him for years and he is not the type to miss much.

I'd say it was a simle typo and/or misprint. Later on in the article, under the heading "Bottom Line" he writes the following:

The new versions will make a fine gun even better, and the only possible icing on the cake would be if the magazine ban could be repealed, bringing its magazine capacity up from an admittedly-adequate "10+1" rounds of .45 ACP to the even more reassuring "12+1" rounds that this fine pistol was designed to hold - the better to protect the decent people HK designed this system to serve.

This could be a mistake by the person who transcribed this for the web, or it could have actually been misprinted in Guns Magazine. It is not uncommon to find these errors in gun magazines, and they will often correct them in the next issue if they are brought to their attention.

[combat45acp]

Orfeo...Thanks, I was fishing for a green light! ;-) I'm good now. lol

[jmikesteen]

see that is what we have been waiting on orfeo, someone who was there on the dev team. thanks for settleing this.

[orfeo]

see that is what we have been waiting on orfeo, someone who was there on the dev team. thanks for settleing this.

Glad I could help! ;)

[orfeo]

Orfeo...Thanks, I was fishing for a green light! ;-) I'm good now. lol

Anytime! lol ;)

[combat45acp]

plan to order some Wolf 10% springs to see if that changes things too.