10mm vs 10mm FBI Load for Reliability in Glock 20

[DMW1116]

Does the reduced FBI 10mm load or its clones have trouble cycling a G20?

 

[Dan-O]

Negative. At least in a stock glizock. If you’re running a heavier recoil spring for nuclear 10mil rounds then possibly, but the factory spring weight should run watered down stuff.

 

[Lennyjoe]

No idea. I’ve never been interested in any 10MM watered down loads. I like the 10MM for its power and keep it for that reason.

I’d assume factory G20 spring would cycle lightweight 10Mm loads ok From the factory.

I go to a heavier recoil spring in G20/40 with full power loads to slow things down a bit and keep my brass in the same county.

 

[tominboise]

I have a G20 with a 20lb recoil spring. I often swap in a 40S&W barrel and it runs just fine with 40S&W ammo. You won't have any trouble with any factory 10mm ammo.

 

[DMW1116]

This is really a question for a friend that bought a Glock 20 and realized he didn’t much like full power 10 mm in a polymer framed pistol. He just got into shooting when he inherited several guns and began trading them off for different stuff he wanted. He’s firmly against 9mm for whatever reason, so went with 10mm.

 

[jmr40]

I shot 40 S&W loads directly in my G20 and G29 with the factory barrel and magazine. My Smith M&P 10mm does the same with no change in accuracy or reliability. Not something I'd want to do long term but it's nice to know it works in an emergency. Anymore 10mm ammo is priced about the same as 40 S&W and is just as available so there isn't much reason to do so.

he didn’t much like full power 10 mm in a polymer framed pistol.

Maybe with some more shooting experience he'll change his mind. Even with the hottest loads the large frame Glocks in 10mm and 45 ACP handle recoil better than most anything else. The wide grips spread out the recoil and the plastic frame flexes just enough in recoil to help.

 

[BreechFace]

On a stock Glock, no.

The watered down 10mm loads are probably a product of not wanting to change commercial reloading systems over from 40S&W manufacture other than setting bullet seating height for 10mm. I believe, this is some of the reason for the pathetic 10mm commercial loads we have today. Maybe as 40S&W declines and 10mm rises we will see some commercial reloading doing more than just change the presses for the longer 10mm cases.

In my Glock 20 that is my hunting sidearm protection (as well as in my Glock 40), I carry hot 10mm loads and only really shoot those through it. So they both have a 22lb. recoil spring in it to handle the loads and keep the components from excessive wear. I haven't had issues with watered down 10mm loads in it, but wouldn't trust it on the streets without changing back to the stock recoil spring.

 

[Rule3]

Does the reduced FBI 10mm load or its clones have trouble cycling a G20?

What is the FBI reduced 10mm load?

I have data for reduced "light" 40 SW loads.

 

[2ndtimer]

What is the FBI reduced 10mm load?

I have data for reduced "light" 40 SW loads.

According to various sources, the original “FBI Load” featured a 180 gr bullet at either 1,000 FPS (initially), and later 950 FPS to try to accommodate newer agents. Later they switched to pistols chambered for .40 S&W in smaller frame pistols with comparable ballistics to accommodate newer agents with smaller hands, i.e. women. Apparently DEI was alive and well even in the late ‘80’s.

 

[BreechFace]

The 10mm was never going to work out as a one size fits all in departments. Case length is too long for many in departments.

I have long fingers so it’s not an issue for me, but seeing others with shorter hands trying to handle the grip of a 10mm, it all makes sense why they stepped down to 40S&W, notwithstanding the extra recoil that was a complaint.

 

[Shawn Dodson]

According to various sources, the original “FBI Load” featured a 180 gr bullet at either 1,000 FPS (initially), and later 950 FPS to try to accommodate newer agents. Later they switched to pistols chambered for .40 S&W in smaller frame pistols with comparable ballistics to accommodate newer agents with smaller hands, i.e. women. Apparently DEI was alive and well even in the late ‘80’s.

No.

The reduced velocity FBI 10mm cartridge was loaded by Federal and used a Sierra 180gr JHP bullet propelled at 950 fps.

FBI switched to .40 S&W due to mechanical defects with its S&W 1076 pistol.

 

[21H40]

My G20 runs fine with every 10mm and 40 round I've tried. The 40 S&W "plinking" rounds should meet the same low recoil range that you're asking about, and they're shorter, too.

I'm curious what uncomfortable for your friend to shoot?
I've used Buffalo Bore and Under-roos (I don't remember their actual name tonight ) anti-bear, tank destroying, destructo-maximus rounds and found them to push heavily but not hurt like a 44 or 357 revolver can. The Glock seems to spread the recoil more comfortably across my hand.

 

[Robbins290]

My Glock 20 will run any ammo in spec, with no issues. I load some light 40 S&W loads for punching paper, for cheaper reloading. And my woods is load is a heavy, stout load. Never had and issue. Its a stock gen 3.

 

[jmorris]

The watered down 10mm loads are probably a product of not wanting to change commercial reloading systems over from 40S&W manufacture other than setting bullet seating height for 10mm.

I doubt that. Would be closer to loading 45 gap using 45 acp equipment. Shorter case, different primer size, powder charge, seating depth, crimp depth. Different enough that everything would be different, even if you altered bullet weights between the two, to allow for the same powder charge, it's not going to be a game changer.

 

[sqlbullet]

While I don't make a practice of it, I have shot actual 40 S&W light loads in my G20 Gen3 SF with full reliability. As a full fledged 10mm nerd I felt I should have first hand experience with the practice.

For that matter I can't remember ever having a stoppage in my Glock 20. It is used as the unloading machine for all the ammo that won't feed in my 10mm 1911's, which can be a bit picky about COAL. When I have a round stop a 1911 it goes in the pile and gets shot in the Glock as a wrap up to the shooting session.

Additionally, the "common" lore is that the 10mm FBI load was created to accommodate recoil averse agents. This is incorrect. The lite load was created by the FBI ballistics lab tech who was using his personal Delta Elite in the testing. He was concerned about abuse to his gun with full power loads as Colt was dealing with cracked frames. So he personally created the reduced power load - Sierra 180 grain at 980 fps in December 1988 for use in the testing in Jan 1989.

 

[Show Me]

Quite a history concerning the 10mm. I bought a G40 simply because I had no autos left and because it's the biggest glock. Glocks are super familiar to me.
Heavy or lighter just like .357 . Versatile

 

[WisBorn]

I have shot Federal American Eagle 180 FMJs rated at 1040 fps in my G20 and Underwood hardcast coated 200 grain rated at 1250. No problems with either load.

 

[DMW1116]

If I were to get into 10mm, I think the G40 would be my choice, or a 610 from S&W. My friend wanted a carry gun in a more modern form than his 1911 Commander. The handful of 10 mm I’ve shot doesn’t seem too bad but I’m not running more than a half dozen at a time.

 

[Jim Watson]

A friend chose a Glock 20 for his GSSF prize gun.
I would have gotten a 21 or 41 for common ammo with my 1911.

 

[Shawn Dodson]

Additionally, the "common" lore is that the 10mm FBI load was created to accommodate recoil averse agents. This is incorrect. The lite load was created by the FBI ballistics lab tech who was using his personal Delta Elite in the testing. He was concerned about abuse to his gun with full power loads as Colt was dealing with cracked frames. So he personally created the reduced power load - Sierra 180 grain at 980 fps in December 1988 for use in the testing in Jan 1989.

No.

FBI FTU recognized a 10mm 180gr bullet has the same sectional density (.161) as a .45 ACP 230gr bullet (.162).

FBI FTU Chief John Hall brought in his personally owned Colt Delta Elite to test 10mm loads.

They decided to experiment by handloading a 10mm 180gr JHP bullet about 100 fps faster than the standard .45 ACP 230gr load (850 fps).

The "reduced velocity" 180gr 10mm load out performed all 9mm and .45 ACP loads that the FBI had tested.

Many folks complained at the time that the FBI had simply reinvented the .45 ACP 185gr load. It did not.

Instead, in the context of sectional density, FBI developed a souped-up .45 ACP 230gr load.

 

[sqlbullet]

Yeah. I think we are in violent agreement. I was not aware of the methodology that the FTU used to create the reduced power loads, only that the desire to use something "less" than the Norma loads was driven, at least in part, by the use of a personal firearm.

Thanks for that added clarity.

 

[Show Me]

Yeah. I think we are in violent agreement. I was not aware of the methodology that the FTU used to create the reduced power loads, only that the desire to use something "less" than the Norma loads was driven, at least in part, by the use of a personal firearm.

Thanks for that added clarity.

"Quite a history" right

 

[.38 Special]

My 29, with factory spring, has been perfectly reliable with every load I've tried, from full power barn-burners to .40-equivalent powder puffs. I can't imagine the 20 would be any different.

Too bad about those triggers, though.

 

[DMW1116]

I tried the trigger on his Glock. It was a pretty good one. Not even as far as Glocks go. It was not difficult to dry fire while keeping the sights steady.

 

[JTQ]

They decided to experiment by handloading a 10mm 180gr JHP bullet about 100 fps faster than the standard .45 ACP 230gr load (850 fps).

The "reduced velocity" 180gr 10mm load out performed all 9mm and .45 ACP loads that the FBI had tested.

Just another data point, but Elmer Keith's "Police Load" .41 Magnum is right in that range. https://en.wikipedia.org/wiki/.41_Remington_Magnum

Keith's original vision called for dual power levels in the .41, a heavy magnum load pushing a 210-grain (14 g) JHP at a muzzle velocity of 1,300–1,400 ft/s (400–430 m/s), and a milder police loading which was to send a 200-grain (13 g) semiwadcutterdownrange at around 900 ft/s (270 m/s).[3][5]