P239 Hold open last round fail

[Motega]

Sig Sauer P239.... I have 2 barrels/springs, 1 in .40 and the other 9mm- both on the same frame.

Only in .40 and only with certain ammo it doesn't hold open on last shot. I have a 9mm barrel/spring (Bar-sto) which seems to work fine with 115 and 124 9mm in several different brands. No problems in 9mm.

In .40, however, Using Golden Sabers and American Eagle 165 grain after the last round the slide closes though the hammer is back. Happens with 2 different mags too. Using the PMC Bronze it works OK- also 165 grain.

My guess is that the PMC is hotter allowing the frame to catch, does that sound right? Any other ideas?

.40 is new to me, I know some calibers are designed around certain rounds and I'm thinking maybe I should just try the heavier or lighter loads if .40 was kind of built around a specific load.

 

[9mmepiphany]

Sounds like you have placed your shooting hand's thumb in a position that rides on the slide release. There could be any number of reasons that it only occurs with certain ammo...something about your hold changes under certain recoil charcteristics.

You can confirm or disprove this by shooting the ammo, which causes the problem to occur, but using your left hand to shoot the gun.

The easiest cure is to lay the strong thumb atop the back of the support thumb

 

[MJ_ATL]

Three suggestions from experience with a P239...

1. Change the magazine springs in the mags that it won't hold open on. Every time I had that problem, changing the springs worked.
2. I noticed that Sig changed the follower on the P239 9mm magazines they may have done the same for .40SW as well, you might try new followers in addition to #1. The new followers look like they have more area to engage the slide release into a locking position.
3. How's your slide release doing for wear? and what about the associates spring? Not knowing how old the gun is these could be worn out.

I mention #3 since I was having trouble with a P226 with the slide locking back. Looked at the slide release and it had been worn down significantly and coupled with the old spring even a small amount of pressure would drop the slide. It could actually be a combo of 1-3. I'd try #1/2 first if you think its not your grip.

Or it could be your grip... like 9mmepiphany said.

 

[Motega]

Interesting thought, I just grabbed the pistol though and there is *no* way that's what is going on my thumb is a full inch and a half below the slide release.

 

[9mmepiphany]

What would it cost you to eliminate it as the cause...6 rounds?

If you'd feel more comfortable buying and replacing parts, it likely wouldn't hurt either

 

[Motega]

I am certainly going to try and fire it using the other hand, you are completely right it is only a few rounds, and it'd be a fun experiment since I am SEVERELY opposite eye dominant (right handed but left-eyed). As I said though this never happens with 9mm loads of any kind.

I think it's entirely reasonable to suggest the magazine may be part of the problem and for the cost of a follower and spring I probably should just buy another .40 mag. Again, in 9mm this hasn't happened at all and using the PMC .40 165 grain ammo it doesn't happen either.

Which leads me to believe the Federal and Golden Saber stuff is to blame - I would think that the Golden Saber is probably not that hot of a round due to its primary use as a home defense round?

 

[REJones]

I'm not sure it's an issue, but check to make sure the magazine springs are installed right side up. This was for the P226, but I had the slide fail to lock back after putting my mag spring in upside down. The follower didn't come all the way to the top. It should be easy to check . . . .

 

[MCMXI]

]I just grabbed the pistol though and there is *no* way that's what is going on my thumb is a full inch and a half below the slide release.

What kind of grip do you use such that your right thumb is so far below the slide release? Your thumb would have to be resting on the mag release i.e a very low grip . I think your problem is recoil related ... more specifically, the lack of control of the recoil from the .40 S&W. If the pistol is rotating in your hand(s) due to your grip, this could prevent the slide from locking back. I have a P239 chambered in 9mm Luger but my left thumb points downrange and rests on the frame just in front of the takedown lever. My right thumb pushes down on the base of my left thumb and resides about 1/4" off the slide to prevent the exact problem that 9mmepiphany mentioned.

Once I started shooting a lot of 1911 matches, when I shot my P220s, I found my right thumb creeping onto the slide release lever more than a couple of times. Now I make a conscious effort to apply downward pressure with my right thumb at the base of my left thumb to lock it in. Works great!

 

[Motega]

I put Hogue grips on it... I use a 2 handed grip with the heel of my shooting hand resting in the palm of my off hand.. guys like I said this is not happening with the PMC .40 EVER and never happened with 9mm ammo of any kind. It must be ammo related - or at least tied to the ammo somehow... as far as "lack of control" my tool of choice is a 1911 and I can hit bottle caps at 25 yards at will. It's not me, it's an equipment issue, just puzzling as to what is going on... the PMC and Federal (American Eagle) are both brass 165 grain ball and seem identical - except I am guessing one is hotter. Can anyone validate or invalidate my suspicions as to Golden Saber/A.E. being a little slower? I can't seem to find any data around.

 

[9mmepiphany]

I use a 2 handed grip with the heel of my shooting hand resting in the palm of my off hand

Now that you have described your grip...it sounds like a tea cup or tea-n-saucer hold...I'm starting to think that it is a matter of your grip not being secure enough. You're limp wristing the gun and not allowing the slide to travel back far enough

I'm not sure why you are so sure it is an ammo issue, while the American Eagle is a bulk ammo, like the PMC, the Remington Golden Sabre is considered a premium loading and wouldn't normally be considered underpowered...after all, it is the FBI choice, in .45ACP, for their SWAT and HRT teams.

Since the gun works with 9mm loads, it isn't likely that the problem is due to underpowered loads. The fact that it works with any .40 loading would mean it likely isn't the action of the gun at all. It is unlikely to be a magazine problem as it does work with the PMC loading. A incorrectly assembled magazine would have the same problem with all loadings.

 

[Motega]

Holy smokes, OK so maybe it is just that I don't want to hear "limp wristing" but please help me understand how with one type of ammo I have zero issues with my grip, with every other pistol I own I have zero issues like this, with this gun in 9mm I have zero issues but American Eagle and Golden Sabre turn me into a noodle-wristed Tinkerbell. Sarcasm aside, I am not processing this possibility. Maybe I am not understanding it right?

I took apart both mags, one was gunky the other looked unused and both have the same problem. Not the mags.

I'd think if it were my grip I would have experienced SOME kind of similar issue on the 100+ other autos I've owned and/or shot

I'll call Sig in the AM and see if there might be some kind of known FAQ about this-

And I have to question the Golden Sabre not because of the quality of the round but because it is specifically designed for LE and home defense it would make perfect sense that they WOULD in fact be purposely underpowered to avoid over penetration.

 

[9mmepiphany]

The grip you seem to use is borderline at the best for managing recoil...I thought it had passed from use back in the 50s. You might not even be limp wristing per sec, it might be simply the effect of the very low grip ( giving the recoiling mass more leverage) combined with the uneven pressure on the grip frame of your hand placement.

The .40 has a pressure spike which makes it's felt recoil sharper than other cartridges. This occurs at the same time that your grip is least able to resist it. While you grip might work with other guns, there is something about the two loads which combined with your grip (stacking tolerances) affects the slide travel just enough to not lock back.

because it is specifically designed for LE and home defense it would make perfect sense that they WOULD in fact be purposely underpowered to avoid over penetration.

I don't see the logic in this at all. Is this something that someone taught you in a class?

I don't think over penetration was ever a consideration in my former department's issue ammo selection. We usually issued +P or magnum loadings.

Common wisdom is that home defense ammo has different requirements than LE ammo