floor 10mm loading for factory stock springs in G20 Gen4?

[rodregier]

Any experience on what are the lightest "power factor" loadings that will reliably cycle a 10mm Glock 20 Gen4 with factory springs?

I have some 135g 10mm Nosler HP projectiles to use up. Higher velocity loadings for them in 10mm produces poor accuracy and a lot of flash and blast.

So, I'm trying to figure out a lower speed loading that would have more accuracy, less flash and blast w/o changing springs.

An example of a lighter 10mm factory loading would be the Federal American Eagle Ammunition 10mm Auto 180 Grain Full Metal Jacket @ 1060 ft/sec published velocity for an IPSC power factor of 191.

I'm thinking something like 135g @ 1350 ft/sec (182 PF) assuming I can find published load data....

 

[PabloJ]

Having shot two Gen IVs I can tell you I had no problems with the following: PPU, Federal Hydrashok, American Eagle ball, Remington ball, PMC ball, PMC JHPs, Hornady JHPs (155gr, 180gr, 200gr), HPR JHPs. The PPU was the most anemic offering yet it posed no problems. The only ammo that had very few stoppages was Winchester Silvertip 175s.
The Gen IV 20 is excellent gun right out of the box you should have no problems.

 

[fxstchewy]

I shoot 40's with LW Conversation barrel and works fine.

 

[rodregier]

Typical lower-end Federal American Eagle Ammunition 40 S&W 155 Grain Full Metal Jacket with a published velocity of 1150 ft/sec. That works out to a 177 PF.

So it looks like if I stay above say 175 PF I can probably get proper function with factory springs.

Using a 135g projectile that works out to 1300 ft/sec.

Off to the reloading data references for 10mm

 

[ATLDave]

If PPU works, then the PF floor is pretty low!

 

[Dan-O]

I shoot .40 from a longslide 20 with a factory spring, and it cycles just fine. And these are 170 gr. lswc over 5 gr. of unique. Hardly barn burners.

 

[Robert101]

I reload so for me to find the bottom end it was easy and fun. I just kept reducing the charge wt. until it failed to cycle, then increased the charge wt. by .3 or .4 grains or so to make it reliable. For factory ammo, I don't know.

 

[Duvel]

I've run 135gr Sierras all the way down to 1,145, and coated 140s at 1,000, out of my G20.4

And that was with a 24lb spring

 

[rodregier]

Usual disclaimer on non-manufacturer load data applies.

I didn't have a chrongraph setup, but I did manage to test my loadings
using 135g Nosler HP and WSF powder in 10mm with Gen 4 G20 running factory springs
and an RM07 dot sight buried into the slide.

0.71cc of my lot of WSF is 8.14g which looks good.
My educated guess on velocity is 1350 ft/sec.
If that indeed the case that works out to an
IPSC power factor of 182. (Just to give a measure
of the relative force that would be available to operate the slide+spring).

Acceptable ejection, locks slide back on last round.
Also has pleasant recoil for 10mm, unremarkable blast and flash.
Looks promising for accuracy too.

Looks like a success.

The next increment down in the Lee Auto Disc was 0.66cc
That was marginal function, barely ejecting and didn't lock back on last round.
Still good accuracy

 

[PabloJ]

Shooting 135gr loads from 10x25 makes about as much sense as shooting 150gr out of .300 Weatherby Magnum.

 

[rodregier]

"Heavy for cartridge" projectiles are not always the right answer to all applications.

Originally I was experimenting with 135g as a fast-and-light 10mm loading like this commercial offering:

https://www.underwoodammo.com/10mm-auto-135-grain-jacketed-hollow-point/

So yes, there is a demand for such usage.

Alas, the powder I had onhand that delivers that level of performance (Longshot) has other unpleasant consequences - serious flash and blast.

So I decided I would come up was a nicer loading that would allow me to "use up" the rest of the 250 projectiles I had purchased.

Problem solved.

I think when I finish with the 135g projectiles I'll focus on my primary 10mm loading, 180g projectiles at 1200 ft/sec.

 

[lpsharp88]

I've had no issues with the 180gr Federal FMJ, or my powder puff range plinkers. For those, I use 175gr LSWC over 5.4gr of TiteGroup. Not sure what they chrono at, but they're very tame and have had zero issues.

 

[gotboostvr]

Can't blame you for trying either loading honestly.
I've got a box of 180gr XTP's In .430 I plan on using in 44mag just because it's something neat to play with.

 

[hAkron]

A few years ago, I had some great results with HP-38 and 165gr bullets in 10mm. I can't remember the exact recipie, but they were on the lower end of the velocity scale for sure. They cycled just fine in my S&W 1006.

 

[PO2Hammer]

My gen 3 G-20 cycled pretty low, 180's at roughly 900 fps was the floor. .40 ammo cycled just fine in a conversion barrel including slide lock.