The "magical" 17 rounds...

I see it as sort of a chicken-and egg issue. My guess is that most pistols designs are finalized before the engineers figure out how many rounds they can shove into a mag that can subsequently fit into the mag well they've created.

Or, perhaps the pistol is designed around a particular capacity. If the marketing department says, "this pistol must have at least a 17 round mag," then the pistol would be designed around the mag to some extent.

Just spitballing here.

I also can squeeze in 2 more rounds with a flush fitting aftermarket mag (over a factory 15 rounder) in my Ruger P95DC. It is interesting what the different designs can do with the same amount of space. I was considering buying another newer 9mm with more capacity, since my P95 came with 10 round mags. I saved myself a few hundred dollars when I realized it could hold 17 round mags without an extended mag. Sweet.

Shooting more than a string of 10 at the range and My accuracy suffers. For a carry gun I have no problem with having five shots on tap. I don't expect to be repelling the "hordes" before I can get to a bigger gun. The grip size and shape is more important to me than the maximum amount of ammo on board. You can't miss fast enough. The capacity wars have more to do with marketing than reality.

Jmhu, Cheers,

ts

scramasax said:

Shooting more than a string of 10 at the range and My accuracy suffers. For a carry gun I have no problem with having five shots on tap. I don't expect to be repelling the "hordes" before I can get to a bigger gun. The grip size and shape is more important to me than the maximum amount of ammo on board. You can't miss fast enough. The capacity wars have more to do with marketing than reality.

Jmhu, Cheers,

ts

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When carrying, how will you get to a bigger gun?

The 18 + 1 capacity of the CZ SP-01 was one of the selling point for the gun for me. . . . . . . as was the 20 + 1 for the FNH Five Seven pistol. Of course, neither of those are very good for conceal carry. As I see it, the best one for capacity and carry ability would be a Glock 19.

Orion, I conceal an SP-01 every day. Good holster and good belt will do it.

What constitutes an over-compressed spring? How is it determined? Who do you believe uses an 'over-compressed spring'?

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There were reports of mag springs failing on FN's FNX-9 pistols simply by leaving the mags loaded and inserted in the pistol for a period of a few weeks. I'm not sure if this has been resolved as of yet, as I sold my FNX a little while back.

http://fnforum.net/forums/fn-fnx/14984-magazine-issue.html

I also remember a Chuck Taylor Glock torture test, where he stated that his Glock 17 mags would last much longer when he loaded them to just 15 rounds rather than 17. I believe Glock has redesigned their mags since then.

http://www.tactical-life.com/online/combat-handguns/glock-17-9mm-torture-test/

During this initial phase, I also wore out several sets of magazines, noting that the follower springs tended to get soft after a month or so if the magazines were left fully loaded with 17 rounds. As a result, after replacing the springs, I decided to experiment a bit, loading them with only 15 rounds instead of the usual 17.

Within a short period of time, it became obvious that the remedy worked. The magazines functioned perfectly even after extended time periods when so loaded. In fact, though they’re the old type that didn’t drop freely from the weapon, I still have four of them and even after thousands and thousands of rounds, and they still work reliably.

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Other companies like H&K seem to be going the other direction and seem to be putting less rounds in their mags when compared to mags of similar size from other manufacturers.

An H&K USPc has about the same grip length (if not longer) as a Glock 19, though the Glock holds 2 more rounds.

An H&K P30 has about the same grip length (if not longer) as a Glock 17, though the Glock holds 2 more rounds.

I've heard that this was to increase reliability and spring life.

I think from a historical perspective, 17 rounds became desirable for service pistols (Ie; police departments).
I read that NATO chose the 5.7 as their new service pistol because they were able to stuff 30 rounds in a mag so that does indicate 17 is about the max the mfg's feel comfortable stuffing into a pistol.

I think 15+1 is magical. Of course it's heavy and an FNP-45 USG.

18 total or so probably became a/the magic number because back in the old revolver days, that's what cops carried on duty.. six in the cylinder with two loaded speedloaders on the belt. So then of course it was logical and way more better and or an easy sell to go the way things have gone.. to carry two extra loaded mags.. everyone was and is happier?

An interesting point is the Browning P35 High-Power only had a 13 round capacity.
That was done so the magazines could be left loaded indefinitely with no risk of over-compression weakening the spring.

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The Hi Power mags were notorious for crapping out when filled to capacity. The British military loaded their Hi Powers with 12 rounds, which they learned from experience. Perhaps the springs are better these days. As others have noted, reliable 17 rd mags can be had for the M9, which originally held only 15.

The number 17 isn't magic. It's just the approximate number that fits in a full size grip.

GLOOB said:

The Hi Power was notorious for jamming when filled to capacity..

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Never heard that one nor has that been my personal experience. Mags stuffed and cocked for almost 35 years.

I don't have firsthand knowledge, but it's something I've seen cited by several sources who claim to have served. Forgive me if it's wrong, but I've read it so many times, I thought it was not only factual, but in the realm of common knowledge.

Again, perhaps the springs weren't as good back then. Or maybe they downloaded to avoid replacing old mag springs when needed.

It well could have been superstition.. I've actually seen, first-hand, some odd stuff.

rcmodel said:

Hmmm?

Just off the top of my head, it is because the mags have steel body's.

The Glock and others use plastic with a steel liner for stiffness.

And they are thicker walled, so take up more room which could have been used for cartridges in a thinner wall steel mag.

But thats just a WAG.

An interesting point is the Browning P35 High-Power only had a 13 round capacity.
That was done so the magazines could be left loaded indefinitely with no risk of over-compression weakening the spring.

The same cannot be said of the 17 & higher capacity mags that use over-compressed springs.

rc

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What constitutes an over-compressed spring?

What are some example guns/magazines that you believe use an over-compressed spring?

I mentioned Glock as one.

Even the Glock annual published by Glock every year had an ongoing "torture test" by a fellow named Chuck Taylor who said mags fully loaded with 17 rounds had weak springs that would not operate the slide stop after about 5,000 rounds.

He went on to say that mag spring life could be increased dramatically, or almost indefinitely by downloading by 2 rounds.

That has been my experience with a Glock 23 I have owned for going on 17 years.
All my mags still have the original springs in them and are still going, and going, and going.

As for what other guns?
I really don't have an answer to that, as I have no experience with every new hi-cap gun that has come out over the last several years.

But my feeling is probably all of them that hold half a box of ammo would benefit from downloading a couple rounds.

rc

Interesting. 5,000 rounds through one single magazine is a metric crapload. I personally would MUCH rather have the full capacity and simply change out the mag spring when the slide stop doesn't get activated after putting 5,000 rounds through the one mag.

I wouldn't call that over compressed, either. 5,000 rounds on one single mag/spring is more than plenty