MT10mm, there are some trade-offs to using that heavy recoil springs which I'm sure you have noted.  That being it is tougher to rack your slide...if you are using this as a carry pistol for self defense it can pose issues clearing a jam, stovepipe or other.

Some of the recoil spring makers do preach about this as a warning.  Finding that balance of ammo performance and the correct spring combination make it worthwhile.

I must be lucky - I own 2 glocks 20sf gen 3 - 29sf gen 3 They have ingested every thing I have put in them - hungry devils Now I will say one thing, I have no interest in pushing the limits of my Glocks - I save that for my MC.  I also load my own to what I need for hunting and EDC. That being said - all pistols or semis have there own quirks and based on what you want and want to put up with is your decision - and belive me Glock have certain quirks. but I feel that their easier to deal with and correct - cheaper also - the gen4's not so good the gen3 seem to have most all the bugs taken care off - The Glocks where designed to be a field combat gun - just like the original 1911Colts wwII stile- from there with after market parts the sky is the limit for both of them. I'ed say go for the gen 3 just from what I've read about the gen4's. If Glock is your choice.

Doug 

Quote from: MT10mm on February 15 2014 09:40:12 AM MST
The gen4 I owned gave me problem after problem, started many posts about it.  I sold it and bought a 3rd gen SF. I am running 24lbs spring and things have been a lot better. I too have thought about after-market barrel but I do not reload so didn't feel there was much point to it.

Keep us posted!

What ammo did you have problems with? Was it only the Underwood nuclear loads?

Quote from: The_Shadow on February 15 2014 09:18:05 AM MST
Radiotom, let me apologize for the way things went down here.  I'm sure things will settle out between those two...
Sorry you were placed in the middle of that unneeded bickering.

Do you currently own the Glock 20 Gen 4 factory & KKM Barrel (4.6) barrels?  You mention about loading for it...

The Glock gen 4 is new and aftermarket RSA are far and few between, therefore tuning of the slide for the higher impulse ammo  has presented a challenge.  This will change I'm sure.  Many are still trying to dial in the system.
I am still studying the purchase of the RSA I want for my Glock Gen 3.

I feel that these captive recoil springs used on the Glocks while OK with most factory ammo, just doesn't apply enough pressure during lock up.  I change my Glock 29 to the Wolff Gun Springs brand of non-captive dual spring RSA with an assortment of recoil springs and it has performed fantastic with the 21lb set of springs, even at Underwood level ammo.

In studying the gen-4 situation it seems that they too are not getting enough lock-up pressure from the stock captive RSA to insure positive lockup for the duration of the higher impulse ammo.  These guns have a good deal of mass in their slides which is the main thing to their design.  The lower impulse commercial ammo will run OK with the factory RSA.

These guns work with the amount of dwell time the slide and barrel remain locked, the stronger non-captive RSA may help to control this to a point!  The semiautos are very dynamic with respect to their performance.  Tuning them takes time and experimentation, this can get costly with ammo cost and parts as you seek the solution to get things the way you want.

Good luck in your decisions and if you find solutions be sure to let those who seek answers know what works. 

Yessir, my apologies to radiotom and the others for knocking this thread off track. I thought of this earlier and should have apologized sooner.

At any rate, we can all agree on one thing....10mm is best! 

Quote from: radiotom on February 15 2014 10:12:03 AM MST

Quote from: MT10mm on February 15 2014 09:40:12 AM MST
The gen4 I owned gave me problem after problem, started many posts about it.  I sold it and bought a 3rd gen SF. I am running 24lbs spring and things have been a lot better. I too have thought about after-market barrel but I do not reload so didn't feel there was much point to it.

Keep us posted!

What ammo did you have problems with? Was it only the Underwood nuclear loads?

It was only with UW 220gr.

I have a Gen 3-G 20SF that has run all types of full power ammo with No problems, all hand loads but very top end with stock springs.

Sean

Quote from: radiotom on February 15 2014 07:36:02 AM MST
I decided to swap out the Underwood HP's for some Double Tap 200 Nosler HP's. We'll see how the Gen 4 likes that. I didn't realize that Underwood loads the nuclear stuff. I'm not interested in nuclear loads...I'll save those for my .44 Magnum Super Redhawk. Double Tap seems to load those 200's right under full power which sounds more like what I was going for with my 10mm setup (black bears and people, not grizzlies). I'll let ya'll know if I run into any issues.

Sometimes we concentrate on what something can't do, rather than what it can do.  If your loading your own, you will easily find very strong loads that run fine.  It seems that 650 ft-lbs works, 700+ can cause issues with my Gen4 w/ aftermarket springs.   I'm still messing with springs, and the jury is still out, but the stock spring/stock barrel might be as good as it gets. 

Besides, the G4 grip is nice in comparison to the G3.


Greg

HHMMMMM - I wonder if the Gen3 slide will fit the Gen4 bottom or use the adapter in the Gen4 and use the Gen3 springs - something to think about.

Doug

Quote from: ShadeTreeVTX on February 15 2014 07:48:28 PM MST
HHMMMMM - I wonder if the Gen3 slide will fit the Gen4 bottom or use the adapter in the Gen4 and use the Gen3 springs - something to think about.

Doug

I have G3 springs in 20, 22, and now 24#, as well as the adapter bushings to make them fit the G4.

The stock dual spring seems to keep the slide from slamming into the frame better that the heavier single G3 springs, but that's just my perception.  I will say that 135g Underwood works with the stock setup, but won't feed at all with the 22# spring. 

I wish the weather would allow more trigger time, but its been a nasty cold, snowy winter.  My theory is the slide rebounds under spring pressure, causing both a breaking of the wrist, as well as returning quick enough the next round in the magazine hasn't fully reached the proper position. 

Maybe a Springco recoil management system, else just live within the limitations.  I've already put enough money into an ugly black plastic pistol.

Greg

The gen 4 seems to have too many issues right now. I'd get the 20sf gen 3. You don't necessarily have to get an after market barrel especially right off. Maybe wait on that one, I wouldn't buy a 4.6 inch barrel to replace my 4.6 inch barrel. You may want a 6" later, who knows? Doubletap has always been really overpriced. Underwood is the hottest thing around but it is safe. I've never felt like I'm putting myself at risk or my gun is being badly abused. An upgrade for either DT or UW would be a 22 or 24 pound recoil spring. Enjoy your new gun whatever you choose. The 10 is king!

Quote from: ShadeTreeVTX on February 15 2014 07:48:28 PM MST
HHMMMMM - I wonder if the Gen3 slide will fit the Gen4 bottom or use the adapter in the Gen4 and use the Gen3 springs - something to think about.

Doug

Unfortunately the Gen 3 slide won't work with a Gen 4 receiver. Like Gman says, you would be best off getting the attachment for the Gen 3 springs.