View Full Version : P30, why only 15 rounds
I traded my M&P9 for a P30ls LEM this week and it is one of the best choices I have ever made. However I was wondering why they only have a 15 round capacity. The Mags appear to be the same dimensions as an M&P or G17 mag which both have 17 round Mags and in the case of the M&P are easily extendable to 22.
I am not exactly worried about losing 2 rounds but I am curious.
Also any idea if Hack sights will be available soon for these? It has Night sights that are pretty nice but I like what I am used too.
My guess, so the mags can be fully loaded for a longer time without issue than a Glock mag. There is more volume and the spring is no doubt operating at a lower stress level. People have reported shortening the follower to put 16 rounds in. That has to reduce the reliability.
My guess, so the mags can be fully loaded for a longer time without issue than a Glock mag. There is more volume and the spring is no doubt operating at a lower stress level. People have reported shortening the follower to put 16 rounds in. That has to reduce the reliability.
As I said. I am more interested in this on an intellectual level. I will take 15 reliable over 16 unknown any day.
F-Trooper05
02-29-12, 16:19
Why do Glocks only hold 17 when XDm's hold 19? Call the engineers and let us know.
XDM mags are bigger than Glock or M&P mags.
I am sure the engineers would be so interested to talk to me and answer this question. :dirol:
I asked here because of the overall depth of knowledge on the board. Hell around here there could be one of the designers for all I know.
F-Trooper05
02-29-12, 16:51
I've never measured, but my Glock mags seem noticeably fatter than my P30 mags. Plus they don't stick out of the bottom of the grip like Glock mags. I don't think you could add two more rounds without making the grip noticeably fatter and/or longer.
I don't know, but I assume it would be easier to insert a full mag on a closed slide, as well as aid in reliability on the first shot since there wouldn't be as much upward pressure on the slide to slow it down.
Chuck Taylor did a "torture test" on a Glock 17 that went to a few hundred thousand rounds last I heard. He stated that the mags springs would last longer on his 17rd mags when he would only load them to 15 rounds rather than to capacity. Unfortunately I am going by memory on this one as I can't seem to find the link to where he stated this, but post #12 on this thread states the same thing:
http://thefiringline.com/forums/showthread.php?p=4303665
There have also been a few reports of FNX-9 17rd mags going bad just by loading them to their 17 round capacity and keeping them inserted in the pistol.
http://fnforum.net/forums/fn-fnx/14984-magazine-issue.html
The most efficient mags that are also reliable seem to come from Mec-Gar. I believe the Beretta 92 and H&K P30 mags are about the same size, but Mec-Gar makes a flush fitting 17rd mag for the Beretta 92. I'd assume it all depends on the experience of the mag maker, as well as the quality of the springs that they use.
If H&K found out that reliability or service life would suffer by making them higher capacity, then I'd take reliability and durability over capacity. It is my understanding that H&K makes their own mags, right?
EDIT: I found the link to Chuck Taylor's comments on the mags here
http://www.tactical-life.com/online/combat-handguns/glock-17-9mm-torture-test/
That is very possible. The Outer dimensions of the P30 Mags are VERY close to the G17s. Same height and pretty much the same width. You can Almost get the G17 mag in the P30 but the plastic is a bit to thick and it won't fit when loaded.
However the P30 mags do have a couple ridges down the sides that would cut into the internal space. So it is very possible it was a conscious decision by HK to limit the capacity to 15 rounds and save the springs.
My Sig is not a Hk (Obviously) but my flush fitting 18rd mags are the same size as my 15rd which made me curious too. Upon minor investigation the follower in my 18rd mags had cut down anti-tilt "legs" or "stems" compared to the 15rd's to allow the follower to be pushed down farther. I still have complete confidence in my 18rd mags but odds are Hk will not compromise their perfectly enginered followers. Hell, they even feed rounds backwards :p.
HK are anal about their engineering so I'm going to assume that they have good reasons
The Dumb Gun Collector
02-29-12, 17:56
Probably what was required by the original contractor.
Probably what was required by the original contractor.
Possibly, but H&K didn't just do this with the P30.
The P2000/USPc are both about the size as a Glock 19, and while the Glock 19 uses 15rd mags, the P2000/USPc both use the same 13rd mags.
The reason is to reduce the stress level on the magazine springs. The rate of stress relaxation is not linear. It increases dramatically as the stress level goes up. Downloading by a couple of rounds or 10% or so will increase the useful life of the springs significantly on most magazines. This phenomena may not be as easily observed in some manufacturers guns/magazines due to more conservative design philosophies. HK would be one to come to mind.
If you hold a G17 magazine and an a P30 magazine side by side and then take them apart and compare springs, it is easy to see that there is a big difference. Even if you download a Glock magazine by several rounds, after a year of being loaded the spring will be a lot shorter, like between 1" and 2". That is spring force lost and functional margin lost. The same thing will happen over time to the HK magazines, it will just take a lot longer time to create a functional problem.
The phenomena of stress relaxation is analogous to creep. Stress relaxation is realignment of the grain structure of the spring in response to a fixed displacement, creep is realignment of the grain structure in response to a fixed load. Creep can eventually result in a fracture.
While I have not done any long term loaded condition comparisons, the same 5 P30 practice mags I have that have been used for more than 20K rounds have springs that are visually identical to new springs.
Great answer and description SP1!
You've also effectively debunked the internet wives tale that leaving magazines loaded doesn't wear out mag springs. Something anyone with even a little engineering or physics background knows is false!
Well done.
They do have 20 round P30 mags in Europe. ...anyone have a picture to compare?
They do have 20 round P30 mags in Europe. ...anyone have a picture to compare?
We do? Never saw it. Maybe I must look at HK booth at IWA next week (if I manage to came).
However I had 16rd P2000 mags - those had just longer bodies and "elephant foot" baseplates. Similar design as 10rd mags for HK45C.
BTW As experiment I was fitting Gramms STI springs and followers to HK mags for competition use. Usual capacity gain for .40 and 9mm mags was about 2 or 3 rounds (for example 3 rounds in 10rd P2000SK 9mm mags).
The answer is obvious. Being that NJ has a 15rnd mag limit, they were catering to the civilian pistol buyers of NJ :sarcastic:
In all serious, I don't know, but I'm glad they did do a 15rnd mag. As a NJ resident, I appreciate that it's 15rnds. I wish Glock would come out w/ a 15rnd G17 mag, as it's one of my favorite shooting pistols.
Why do Glocks only hold 17 when XDm's hold 19? Call the engineers and let us know.
Because the grip and the mags are larger. To my eyes, goofy big on the XD (probably more for marketing reasons to claim 79 rnds per mag...) which makes it impractical for CCW to me, in addition to other reasons to avoid XDs, but that's another thread. :cool:
Look at a loaded P30 mag vs a loaded glock mag. In the p30 mag, the top 3 rounds are single stacked on top of each other. I have seen others say this is to ensure feeding reliability.
May just be marketing/gunstore BS.
Look at a loaded P30 mag vs a loaded glock mag. In the p30 mag, the top 3 rounds are single stacked on top of each other. I have seen others say this is to ensure feeding reliability.
May just be marketing/gunstore BS.
I heard that engineers at HK believe that squeezing too many rounds in so much space mags offer may hurt pistol reliability and long term mags durability. HK main customers seem to stress this features over magazine capacity or do not care about capacity or just accept enlarged magazines (like 16rd P2000 GPM magazine for uniformed carry or 10rd MK24 Mod 0 magazine) when capacity is an issue.
Also any idea if Hack sights will be available soon for these? It has Night sights that are pretty nice but I like what I am used too.
A variety of options, including those, will supposedly be available Fall 2012
As I said. I am more interested in this on an intellectual level. I will take 15 reliable over 16 unknown any day.
I agree, 15 for sure vs something else is infinitely for desirable. Also, the Glock grip angle is shallower, in other words, a longer line fits in the same vertical space.
I'm more interested in where Mel Gibson and Bruce Willis get their Beretta pistol mags! Those buggers hold hundreds of rounds! ;)
In all seriousness, if the capacity is related to the longevity, give me the extra ammunition. I was always taught magazines are disposable items with a finite life span.
Army Chief
03-02-12, 13:13
There could be any number of reasons for this, but I would be more interested in comparing views of the interior of these two mags than with cursory examinations of the exterior. HK has tended to incorporate some very subtle features into their magazines to enhance reliability, and there is usually more than meets the eye to a typical HK mag. (This is also one reason why they tend to be more costly, as well.) It could be that subtle internal ribs or geometric variances (especially where the two columns of cartriges converge as they approach the feed lips) reduce the interior volume just enough to where 15-rounds is the physical limit.
Either way, nice pistol!
AC
The plastic detent plate at the bottom of a P30 mag has a raised pyramid built into it, presumably for spring relief. It measures 0.315 inches thick from the bottom of the plate to the top of the pyramid, excluding the detent button. The detent plate in my M&P was a thin, flat piece of metal. I interpret this to mean that HK mags can be fully loaded, while M&P mags should be downloaded at least one round for optimum spring life and function. It also suggests that a P30 detent plate could be modified to get at least one more round, at the expense of spring life.
I would guess it has to do with reliable feeding, durability, or other quality that is to be highly desired. The way I see it they may be able to squeeze a round or two extra by doing certain things although maybe not due to the difference in the grip and general design of the P30 vs Glocks and other pistols with a little higher capacity but I will say at the more extreme there is the XDM which demonstrates issues with going to far, have one of them and pretty much all malfunctions are magazine or ammo and even under normal loading the XDM just seems off.
If its the case then I appreciate the balls to stick with something less flashy that is better.
The Dumb Gun Collector
03-03-12, 17:49
Ken Hackathorn told me that HK's approach to engineering was to tell the engineer to give it twice what it needed and S&W's approach was to tell the engineer that they worry too much.
The plastic detent plate at the bottom of a P30 mag has a raised pyramid built into it, presumably for spring relief. It measures 0.315 inches thick from the bottom of the plate to the top of the pyramid, excluding the detent button. The detent plate in my M&P was a thin, flat piece of metal. I interpret this to mean that HK mags can be fully loaded, while M&P mags should be downloaded at least one round for optimum spring life and function. It also suggests that a P30 detent plate could be modified to get at least one more round, at the expense of spring life.
I modified my HK USP 16rd .40SW mags (white transparent mags) for competition use by trimming HK follower and lockplate. I got +2 rounds capacity with stock spring. Mag was working flawless, but I would not use it outside of competition anyway.
Removing lockplate and using very flat Grams STI follower (with 9 coils spring) gave even +3 capacity (with original basepad). So there is capacity potential inside HK mag bodies. But followers and lock plates are engineered for reliability and durability. My P30 mags feed good even when dropped in sand or mud and then put back in pistol. Also I do not see need to download HK mags - they are designed to be loaded to capacity. My P2000SK mags are kept loaded to capacity for last 10 years and they work flawless every time I go for the range or to IDPA match. I recently got new mags for P2000SK and by "finger-feely" test springs on old mags are as stiff as in new ones. In new mags I extended capacity by 1 round using Pearce Grip Glock extensions (PG-2733), that allow me better grip on pistol as well.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.