10mm Velocity Surprise

[CarJunkieLS1]

So recently I've purchased a Glock 40 10mm. I suppose it compliments my S&W 610 and my AR pistol all in 10mm.I yesterday shot the reloads for my 10's and well I didn't think I'd get the velocity I'm seeing.

My load data is 13.5gr AA9, once fired S&B Brass, 180gr Nosler JHP, and a Winchester LPP. COAL 1.260.

The Glock 40 is the OEM 6" barrel I am using an aftermarket RSA with a 22# spring. Otherwise unmodified. The AR pistol is as stock as it came with a 10.5" barrel. I see no pressure signs at all, case head expansion is .002 and the factory Glock barrel don't even have the smile that Glock 10mm's are known for.

Glock 40 5 shot average was 1295.
AR pistol 5 shot average was 1493.
Accuracy was very acceptable and function was flawless. Now to now to load up 500 more lol.

 

[dredd]

Thanks for the numbers.

I'm running AA#9 & 180/gr XTP's out of a G20 & G29

I haven't chrono'd them as of yet.

 

[TEXASJD]

I have been running blue dot with 200g cast in a G20 but will probably start looking for AA#9 as I am running out

 

[Mark_Mark]

So recently I've purchased a Glock 40 10mm. I suppose it compliments my S&W 610 and my AR pistol all in 10mm.I yesterday shot the reloads for my 10's and well I didn't think I'd get the velocity I'm seeing.

My load data is 13.5gr AA9, once fired S&B Brass, 180gr Nosler JHP, and a Winchester LPP. COAL 1.260.

The Glock 40 is the OEM 6" barrel I am using an aftermarket RSA with a 22# spring. Otherwise unmodified. The AR pistol is as stock as it came with a 10.5" barrel. I see no pressure signs at all, case head expansion is .002 and the factory Glock barrel don't even have the smile that Glock 10mm's are known for.

Glock 40 5 shot average was 1295.
AR pistol 5 shot average was 1493.
Accuracy was very acceptable and function was flawless. Now to now to load up 500 more lol.

180g going 1300 is nice!

 

[Lennyjoe]

Still have room to push a little faster if you wish,

 

[CarJunkieLS1]

I see that too but I really think the Nosler bullet builds pressure faster than the Hornady XTP's. Looking at that data I'm 1.4gr less powder and getting a faster velocity. I don't see a problem with more velocity and less powder . For comparison the Underwood 180 GDHP went 1340 from the same pistol.

When my KKM barrel for it gets here I'm looking to shoot 200's at 1300.

 

[jmr40]

It isn't unusual for some guns to shoot faster than another gun even with equal length barrels and some brands seem to do it fairly consistently. And sometimes by significant amounts. Glocks in all cartridges tend to shoot a little faster than other brands. I don't know why but some suspect the polygonal rifling. I've seen similar numbers when comparing Ruger revolvers with other brands.

Note the differences in velocity with various guns here. The 4" S&W 357 was faster than 3 other guns with longer barrels. Including a Python with a 6" barrel. Almost 100 fps faster with a 2" shorter barrel and 158 gr bullets.

BBTI - Ballistics by the Inch :: .357 Mag Results

 

[TTv2]

OP, how did you throw the charges or did you weigh each one?

Hodgdon lists a max charge of Longshot with one 180gr bullet at almost 1290 fps from a 5 inch barrel, so for a AA#9 to get that from a longer barrel and one that has the Glock rifling (that does seem to up velocity a bit) I can believe it.

Still, I'd get more load data to make sure it's safe. I've looked at differences in the Hornady manual and Lyman for certain calibers showing a difference of .3 grains for the max load.

 

[CarJunkieLS1]

OP, how did you throw the charges or did you weigh each one?

Hodgdon lists a max charge of Longshot with one 180gr bullet at almost 1290 fps from a 5 inch barrel, so for a AA#9 to get that from a longer barrel and one that has the Glock rifling (that does seem to up velocity a bit) I can believe it.

Still, I'd get more load data to make sure it's safe. I've looked at differences in the Hornady manual and Lyman for certain calibers showing a difference of .3 grains for the max load.

I let my Chargemaster dispense the powder for me. I set it one tenth under what I wanted and trickled the rest in to hit 13.5. I believe my load is safe in my pistol because case head expansion measured at .002 and the brass doesn't even have the classic "Glock smile" that is very common with hot loads and Glocks factory barrel. 1295fps with a 180jhp is plenty for anything I'll meet in the woods or the streets I don't live in bear country so I'm leaving it alone.

 

[BigBore44]

I mean, those are pretty good numbers. I chrono’d my 10mm loads a couple months ago at my buddies house. 180gr Noslers over 11gr BlueDot. My results were a little better. Would be nice if I could believe the numbers my chronograph gave me.

 

[Klaatu Barada Nikto]

I mean, those are pretty good numbers. I chrono’d my 10mm loads a couple months ago at my buddies house. 180gr Noslers over 11gr BlueDot. My results were a little better. View attachment 986597Would be nice if I could believe the numbers my chronograph gave me.

I have the same chrono, it once told me a 200g 45 Auto round went 2250. Seems highly doubtful since nothing blew up.

 

[Mr.Revolverguy]

OOOh A Thread on my favorite

Today September 9, 2018 I have decided to release my load data for others to enjoy. All data due to variances of reloading components and pistols the rounds would be fired in should start 10% below my published data. This data is not intended to replace the appropriate reloading manuals data and should not be used without verifying and double checking the loads between two different official published reference points — IE reloading manuals. If you elect to utilize any of this data it is at your own risk, you take full ownership and responsibility for your ammunition.

Check out the 10MM Load Depot http://www.dayattherange.com/?page_id=6173

 

[sparkyv]

I've done it and beyond satisfactorily in my M610, but check out Hornady errata.
https://press.hornady.com/assets/pc...Edition-Handbook-Updates-Errata1522702377.pdf

Still have room to push a little faster if you wish,

View attachment 986465

 

[CarJunkieLS1]

I've got a S&W 610 also and well I'll just say it eats up loads that my Glock or AR Pistol will never see. I plan to have the cylinder reamed out for 10mm Magnum too.

 

[sparkyv]

Mark over at Pinnacle High Performance will do it for $125. Great minds think alike.

I've got a S&W 610 also and well I'll just say it eats up loads that my Glock or AR Pistol will never see. I plan to have the cylinder reamed out for 10mm Magnum too.

 

[CarJunkieLS1]

Mark over at Pinnacle High Performance will do it for $125. Great minds think alike.

Funny you say that, that is the exact guy I have been talking to about doing it.