Just got home from the range. I shot the following out of two P365XL 12rd mags with the magguts +2 springs and baseplates installed.

50rd Fiocchi 115gr FMJ
50rd Aguila 115gr FMJ
50rd Winchester White box 115gr FMJ
50rd Federal 124gr +P HST

Zero malfunctions. Will do one more range trip on another day this week and if all goes well one of the mags will go into my carry gun.

Since this thread popped back up, I've made 4 more range trips with a similar amount or rounds as before. I have almost 300 rounds through each of my 10 round +2 kit upgraded magazines, with no issues since installing them in January.

quote:

Originally posted by sigfreund:

quote:

Originally posted by sg:
I've seen many issues with these over the years being unreliable.

Where?
Seen them yourself or read about it?
"Unreliable" how?

So not SG but a recent (June 2021) report from a friend on issues with magguts kits in the 365:

quote:

First outing with the p365 magguts (one +2 for 10rd mag & one +2 for 12 rd mag)

I ran 75 rds of federal 115gr fmj through each mag.

25 rds of federal 124 gr +p hst through each

20 rds of Sierra 115 gr jhp through each

And 25 rds of 147 gr hst through each.

Total rd count 290.

I had 4 failure to feeds on the +2 10rd mag. 3 with 115 federal fmj, 1 with 124gr +p hst.

I had 3 failure to feeds with the +2 12 rd mag. 1 with federal 115 fmj and 2 with 124 +p hst.

The malfunctions happened about half way through the 290 rds shot. They ran flawlessly before that.

It could be a problem with the follower or maybe the spring isn't pushing the next round up soon enough so as to ensure proper cycling? Honestly I have no clue...

The 365 is already pushing the limits of its magazine, and adding after market pieces to get more rounds in seems like a poor risk reward proposition. YMMV

Just to follow up on this, I looked for videos posted about the P365 magguts kits. Somewhat interestingly, I found more on the XL then the base P365 kits. Here are a couple.



The guy below puts over 200 rounds through a few converted mags.

I've had 2 more range sessions with the +2 kits for my P365XL 12rd mags (14rd mags with the kits installed) and no malfunctions so far.

I've started carrying with one installed in my gun.

Giving this old thread a bump for any new experience with these. Has anyone installed one of these kits since the summer? How are they working out? Any updates from previous posters?

On specific question. Are there any issue after chambering a round and topping up? Any excessive string tension causing function problems?

As for others having feeding issues another SIG forum has posters with less than stellar reviews. Mostly ten kits IIRC.

I carry the finger grip in the pistol with the flat mag plate in the reload to lower it's carry profile. It's a Snagmag in the back pocket and is more visible in that location than otherwise. For the most part only other CCW bother to look as much as that is reported in forums.

Mag springs are one of those "value engineered" things. Most use a spiral spring and it doesn't collapse inside it's outer coils, which makes them stack tall when fully compressed. Those kinds of springs are also "additive," for every inch compressed they apply X amount of pressure, compress an inch more another X pounds. A mag spring needs to be able to lift a full stack of rounds in the heaviest bullets offered and to do it in the small time frame between the slide moving to the rear and then returning to pick up the next round. That timing issue is altered by interior magazine friction, slide speed with low or high powered rounds, slide rail friction, weight, and recoil spring tension light or heavy. Therefore, it's not always a bad mag, but it does lead the list. If modifying anything, try it one item at a time where you know it was the cause.

Now, how to stuff more bullets in requires a lower collapsed spring coil height, something that engine tuners watch carefully when changing cams and rocker arms. If the coil stack goes to full collapsed, it's dead solid. And something else has to give. This is seen in reports that a particular 365 mag seems impossible when new to fit all the bullets. It's approaching dead solid and the spring rate is rising substantially at that point. Magguts sidesteps a lot of the issue using the leaf spring, it has a lower collapsed height for the extra rounds and with careful guage and tempering will still meet the new required spring pressure to push the extra stack weight up.

If I found those kits being sold by a disgruntled owner for cheap, I'd switch out the spring, load +1 and call it good.

There is another spring type and it's used in Ruger 50 round and issue M9 mags - the clock spring. It's wound into a coil placed under the follower and it rises or descends pinned to it. The other end is fixed to the top of the mag tube, and as it unwinds it exerts a constant, not additive pressure. Again, the rated pressure is what it takes to lift the column up, that can't be altered much, but it's steady rate. Loading the first is almost the same as loading the last. Spiral stacked mags tend to over do it with the additive pressure, so a clock spring may feel weaker than the cheap stock mag. YMMV. Clock spring mags being expensive, they are rarely seen in the aftermarket but aren't uncommon with a few older models as only one or two mags was the norm in those days. A footlocker full, not so much.

Considering the coil spring won't have a tall height unwound, there may be another bullets worth of height available.

Here's where we are approaching the point of it being moot: A 6 shot with +1 gets you a seven shot, which is a 17% increase in ammo, goign to a ten shot magazine is a 66% increase. We are far beyond the need for just one more round, and the same for the +1 in a chamber routine commonly done with small single stack pistols. One more round was a notable increase. Four more is significant, and not to forget, every extra round is more carry weight. I "upgraded" from a poly .380 to the 365 and it's heavier, no doubt.

Another thing happens - to carry an extra mag with ten round capacity, you equal 20, with a six shot mag, it takes three, to get up to 18 and you also get another mag change to do it. In a longer string of fire - say, even 12 rounds - you reload again to get another full mag. With a ten round system, you already reloaded and have 8 left over. One less mag change is one less opportunity to do it all wrong or be slide locked when you would rather be chambered. And that is a notable tactical advantage.

Hence my view - based on a long term perspective of single stack guns for self defense - we are already well ahead of the power curve in ammo supply just moving to ten round mags. Adding two to a ten round is only a 20% improvement, barely more than adding one to a six shot. We already got a 66% increase, good enough. Those that weigh the cost have remarked that a 14 round mag reload is relatively cheap compared to adding +2 to a twelve round, carry size is the offset.

Now, if we could just get the makers to use the leaf spring as their factory stock offering, we'd get not only more ammo but also the mass production of all those springs would reduce the cost instead of them being a proprietary aftermarket item. With the competition in the market place at all levels, its the price we don't pay that results in what we carry. If you decide to pass on the kits to increase capacity, you aren't wrong. It's not a moral or ethical failure. It might even be good common sense.

All the math and percentages don't mean much when you're bleeding out on the floor with a jammed pistol at your fingertips. Neither does the spare mag or two in your pocket.

You're making an assumption they're unreliable. What is this based on? Even up this thread, there've been a lot of positive reviews.

They now have a number of lines for a number of popular pistols. And the review I've seen are mostly good.

quote:

Originally posted by sns3guppy:
All the math and percentages don't mean much when you're bleeding out on the floor with a jammed pistol at your fingertips. Neither does the spare mag or two in your pocket.

quote:

Originally posted by BBMW:
You're making an assumption they're unreliable. What is this based on? Even up this thread, there've been a lot of positive reviews.

They now have a number of lines for a number of popular pistols. And the review I've seen are mostly good.

I don't assume. Ever.

I know how reliable my P365 with factory magazines has been for the past few thousand rounds, though I don't assume it will be in the future.

I'm not assuming the magguts modifications will fail. Nor do I care to find out.

The reviews have been mostly good?

That's mostly great. I'm mostly happy for those for whom it's mostly worked out.

I hope their handgun mostly works in a gunfight.

Or that their dentist mostly does a good job. Or that their next pilot puts mostly enough fuel on the flight. And that most of the oncoming drivers stay in their lane. Most of the time, anyway.

Mostly sounds like gambling. Which is a lot like assumption.

Or someone could buy them based on the reviews, then shoot the snot out of them before trusting them for carry. If they work they're good to go, if not, they just go away. The only gambling is with the money spent to buy and test them.

quote:

Originally posted by sns3guppy:

quote:

Originally posted by BBMW:
You're making an assumption they're unreliable. What is this based on? Even up this thread, there've been a lot of positive reviews.

They now have a number of lines for a number of popular pistols. And the review I've seen are mostly good.

I don't assume. Ever.

I know how reliable my P365 with factory magazines has been for the past few thousand rounds, though I don't assume it will be in the future.

I'm not assuming the magguts modifications will fail. Nor do I care to find out.

The reviews have been mostly good?

That's mostly great. I'm mostly happy for those for whom it's mostly worked out.

I hope their handgun mostly works in a gunfight.

Or that their dentist mostly does a good job. Or that their next pilot puts mostly enough fuel on the flight. And that most of the oncoming drivers stay in their lane. Most of the time, anyway.

Mostly sounds like gambling. Which is a lot like assumption.

This message has been edited. Last edited by: BBMW,

I bought 2 for the 10 rounders and 2 for the 12 rounders. Just a couple trips so far so certainly no high round counts yet but they work fine so far. If I go another couple hundred rounds I will call them gtg for anything.

quote:

Originally posted by BBMW:
Or someone could buy them based on the reviews, then shoot the snot out of them before trusting them for carry. If they work they're good to go, if not, they just go away. The only gambling is with the money spent to buy and test them.

It's all a matter of degrees. It seems that those complaining of issues haven't experienced the problms until they had a few hundred rounds through the magazines. No report on the number of mag spring cycles.

It may be that the problems don't occur until one has shot the snot out of them. That would make sense, given that springs tend to experience problems with increased cycles, not when new.

I haven't seen too many people complaining.

quote:

Originally posted by sns3guppy:

quote:

Originally posted by BBMW:
Or someone could buy them based on the reviews, then shoot the snot out of them before trusting them for carry. If they work they're good to go, if not, they just go away. The only gambling is with the money spent to buy and test them.

It's all a matter of degrees. It seems that those complaining of issues haven't experienced the problms until they had a few hundred rounds through the magazines. No report on the number of mag spring cycles.

It may be that the problems don't occur until one has shot the snot out of them. That would make sense, given that springs tend to experience problems with increased cycles, not when new.