Okay, answering questions one at a time:
Let me ask you, do the malfunctions happen at the end of the magazine? Say the last or next to last round?
Happens all throughout the magazines. Has happened on 2nd round, next to last round, and everything in between.
Fix, call Brownells and order a pack of wolff extra power magazine springs. The +10% ones. They're the same as the extra power springs that fit the model g19.
The 9-round magazines hold 8, but I can jam another one in there if I put my weight on the magazine while pushing it down onto a cartridge and slide the magazine over onto it. With the +1 extension that magazine holds 9 comfortably. The 22 mag holds 14 easily and the 15th goes in with difficulty. I am fairly certain that they do not require extra power magazine springs.
Glocks don't need to be "broken in," so the 500 rounds that you spent "breaking in" the G27 also don't relate to the problems you're experiencing. I'd try several fixes before I'd pay $50 to send it to Glock to have them tell you that there's nothing wrong with it.
I had heard that, but others had said otherwise. Didn't know who to believe, so I gave it a chance to fix itself. It didn't.
Could be, but we are both experienced shooters and haven't had problems with anything else. She put 200 rounds through a rental Glock 27 with no problems either. I put about 1000 rounds through a Kel-Tec P11 with no limpwristing problems, and I haven't loosened up since then, and I would doubt the Glock would be more sensitive than the Kel-Tec. However, I have not ruled out this possibility. I will make a conscious effort to not limpwrist the next time I shoot it.
I had heard exactly the opposite. I thought the Glock was supposed to run nearly dry. I left the factory copper-colored grease on the slide rails, and gave everything else a light film of Hoppes Elite.
3.take mag extensions off
There is only one magazine extension, on one of the factory 9 round magazines. All three magazines malfunction equally, with and without the extension.
4.try 165gr and above ammo
Have been using both 165 and 180 grain ammo. Haven't tried anything lighter.
5.make sure ejector is not broke or bent
It's perfect. It has had no problems ejecting or extracting, only feeding. Nose down in the magazine or nose up onto the top of the barrel.
6.take to gun smith that is certified with glock so warranty is not voided
Definitely thinking about that one, but most gunsmiths around here are more into blued double barrel shotguns and bolt rifles.
That's one of my last options.
Did the pistol work fine when new?
Nope.
If all else is as it should be, the major causes of pistol malfunctions are either "dirt", ammo, or magazines.
No dirt. I clean my pistols religiously (even my wife's pistols). The ammo has varied from WWB to Blazer Brass to Remington UMC to a few Gold Dots. Nothing has fed reliably. The magazines are all three factory stock magazines, and one has a +1 Pearce extension on it - all three have experienced jams. The chances of all three new magazines being problematic is practically zero.
Use stock factory magazines for the 27.
One of them is stock, still jams.
Using 22 mags may let them rock enough to cause a feed jam. The Pearce +1 extension may be a problem, it's another possible cause due to it letting the spring out farther plus the extra pressure on the bottom of the magazine pulling to the rear with the little finger.
Could be, but like I said the stock 27 mags would jam too. They both jammed before I put the +1 extension on one of them.
Take your magazines apart and clean them.
Did.
You may try downloading them by 1 rd to see if it makes a difference - do not stretch the springs when you have them out for cleaning, this will weaken them.
Tried that. In fact, the magazine springs are so stiff it takes a herculean effort to get that 9th round in. And I know better than to mess with springs - I do have a degree in mechanical engineering. Good idea to mention that though, I know folks will do a lot of stupid stuff.
Make sure the pistol is properly clean and lubricated. Detail strip and clean the slide - specifically, around the extractor to make sure that there isn't any "trash" keeping it from opening as the base of the brass slides up behind it.
Been there, done that. No extraction or ejection problems anyway. Only feeding.
Use american made factory ammunition. 165 and 180 grain should work fine.
All I've used so far. Mostly WWB, Blazer Brass, and Remington UMC. All fail to feed.
The 40s do have snappy recoil but should still function fine if all is as it should be and your not letting it "jump" out of your hand in recoil....a proper grip is all that is needed - no death grips required ! You should be able to fire it weak hand only without problem...if not...you may want to consider a model 26.
She rented one along with the 27. She said it felt wimpy. She put 200 rounds through the rental 27 with no problems.
if its doing it with all three mags I would have to say its either a problem with the gun (highly unlikly unless someone tried to do something internally, or it is a one in a million factory screw up) or a problem with the shooter( higher probabilty- have other shooters try it).
It does indeed jam will all three mags. I have had other shooters shoot it and it does jam with them too. Granted, both others were long-time revolver shooters, but .357 snubs aren't exactly pansy-guns. The rented Glock 27 worked perfectly for both of us through 200 rounds each, which is one reason she decided to buy it.
Set aside the G22 magazine (use it in a G22), restore the stock G27 magazine floor plate to the magazine which has the Pearce +1, and check the feed lips of the stock G27 magazine to see if they exhibit any signs of being pinched or damaged.
Only recently bought the 22 mag, the gun was jamming with the stock floor plates before we put on the Pearce +1, and I already checked the feed lips - they are perfect.
Now, while another forum has had a surfeit of threads discussing the 'best' follower for a .40 S&W chambered Glock, and Glock has revised their followers a number of times (for more than just the .40 S&W models, FWIW) ... it may not be necessary to replace older revisions of .40 followers & magazines with new ones ( and newer followers don’t all work in older magazine bodies, anyway). If they work for one person and their ammunition selection, then they work ...
These are all three brand spanking new factory magazines (new from the factory from our local dealer in February and the 22 mag in May), the newest drop-free version. All of them have the number 6 stamped or molded into the area which engages the slide stop.
She tried one - hated it. I tried one - it was okay.
Sorry for such a long reply. Thanks to everyone for your suggestions, it's been very helpful.