10 mm loading question

[rope stretcher]

Good morning folks,

I’m looking for any input on this subject, Sorry if I’m long-winded here. I recently got a Glock 20 and started reloading 10mm.

I made 4 different loads, 2 of plated 180 grains bullets and 2 of Speer 165 gr GDHP.

Each of the loads tested higher on the chrony than I’d expected but the 165 grain loads were a good bit higher than published velocities and beat up the brass upon extraction/ejection (a little nick in the rim of some and dent in the case body). Spent primers looked fine. The much slower loaded plated brass looked fine.

Components were:
• new Starline brass
• Win LPP
• Speer GDHP 165 gr
• 9.0 and 9.5 grains of Power Pistol
• OAL for both loads were 1.255

Speer manual lists starting and max charges at 9.0 and 10.0 for Power Pistol. So I loaded the “start” load, 9.0 gr of PP and split the difference between “start” and “max” and loaded some at 9.5 gr of PP.

Velocities were: 9.0 gr Power Pistol 1,300 FPS (1204 in manual)
9.5 gr Power Pistol 1,340 FPS (estimate around 1,260, or so in manual)

I think my chrony is measuring OK because I shot some factory ammo and the measured velocity was within single digits of velocity listed on the box. It seems like 1,300 FPS and above for the 165 gr weight is pushing it a bit.

Anyone have any thoughts on this? I really like Power Pistol but maybe it’s not a good choice for 10mm?

Thank you.

 

[JRWhit]

Does your data list the used firearm per data listed? Are you using the same bullet or one similar? Keep in mind that the Glock has polygonal barrel, data my be from testing with a rifled barrel and may be a different length. I am not sure what differences to expect from a polygonal vs rifled, but these differences will effect outcomes.
Also keep in mind that Speer gold dots are platedand will expand to seal in barrel much easier than jacketed.

 

[Mr.Revolverguy]

Curious what were your Chrony results?

Though the Speer Manual is a good manual I always (rule must be followed in reloading at least for myself) I mean always cross check the load using another reloading manual. I have found some really hot loads in my speer manuals including the latest.

This is a perfect example of why I double check. In the latest Lyman manual #49 Power Pistol is listed

Speer 165gr TMJ 7.8 to 8.7gr of power pistol.
Speer JHP 180gr 7.2 to 8.0 of power pistol.

So your loads seem to be very hot to me which is what you experienced.

10MM happens to be one of my favorite rounds and I have shot over 30 loads I have developed and factory across a chronograph using a number of different 10MM firearms. Unfortunately I have not had the time to document this journey on my website but hope to get to it this week so stay tuned.

Real world experience for me looking at my spreadsheet. Power Pistol 8gr loaded under a 175gr Lead Bullet yields these kinds of numbers. Keep in mind this is set of data is from a Para LS Hunter with 6in Barrel.

 

[redneck2]

I just looked at Alliant's site. It lists 10.0 of Power Pistol with a 165 GD @ 1314 fps if I read it correctly

I'd probably stay towards the more moderate loads. Not sure that 40 fps extra is worth beating up your gun. And again, differences in brass/primer can make quie a bit of difference particularly in pistols

I have a G20 and like to get velocity but point of diminishing returns fits in here somewhere. FWIW I use Blue Dot

 

[Mr.Revolverguy]

The other thing what pressure signs were you seeing?

 

[MikieG]

The gun was designed just for 10mm. The only consideration when playing with these pressures is to be able to up the recoil spring rate. 10mm should be the global standard for pistols. It IS the perfect round.
Just put a stronger spring in and there will be no damage to the gun. You will see signs of primer or case failure long before there will be any damage to the gun.

 

[rope stretcher]

Thanks for the responses,

I'm using the same 165 gr bullet as listed in the Speer manual (GDHP). The test firearm in manual is a 5" barrel, S&W M1006. The Glock 20 that I used has a 4.6 inch barrel.

My chrony results were:

1,300 FPS for 9.0 gr of Power Pistol versus Speer published data of 1,204
1,340 FPS for 9.5 gr of Power Pistol versus Speer data (interpolated)of 1,260.

The primers looked normal as did the brass except for the dings and burrs on the rim and dents upon ejection.

The Hornady 8th manual doesn't list a 165 gr bullet but their "max" load for a 155 gr with PP powder is 10.0 gr, same as Speer's "max" on 165 gr GDHP. I've found that the Hornady load data sometimes seems conservative so I thought the Speer data would be OK, especially if I stayed low to mid range. But after looking at the brass and the velocities, it just doesn't feel right to me in my G20.

I loaded the 180 gr plated bullets at 7.0 and 7.5 gr of Power Pistol, the lower end of the table in the Hornady manual. These loads were fine, a little faster than published data, but no signs of over-pressure and brass looked normal upon ejection. The 7.0 load shot the most accurately.

I used Power Pistol because I really like it in 9mm & .40 and I have a bunch of it. I've always been told to never go below starting load data for a particular bullet & powder so I'm going to try some different powders.

 

[Mr.Revolverguy]

I would continue to use power pistol you have found your load. Again other manual list 7.2 as the starting load for your bullet so it is safe. I love power pistol in 10MM.

But if you are dead set on using something else I also like
BlueDot
and
AA#9

As a matter of fact I love the little manual Accurate Arms puts out for their powders they include plated bullets and I have found the data spot on my chronograph mirroring whats in their manual.

 

[rope stretcher]

I've never used AA pistol powder but AA-2230 has become my favorite for my ARs.

thanks, again, guys.

 

[bangswitch]

I'm using Blue Dot, 12.5 gr behind a 155 gr Rainier plated, COL 1.260, and 10.5 gr behind a 180 gr XTP. Those are just under the max loads in the Hornady 9th ed. I get no pressure signs, and have reloaded the brass 4 times. I have Gen 2 G20.

I've pretty much using just the 155's now, I also use them in a .40S&W for IDPA. You can load the lighter bullet at a heavier powder load and still get less felt recoil, and downrange energy will be higher to about 20 yards with a 155 at 1350 fps than a 180 at 1000 fps if you're doing it as a self-defense round. Power Pistol is a good powder, and I have used it for 9mm, .40 and 10mm, but Blue Dot will give better velocities in the larger caliber. I still use PP for 9mm.

 

[41 Mag]

I have a IAI Javeline which sports the 7" barrel in it. I found years ago it was real easy to stick with the Accurate powders. They meter like water and give good velocity and great accuracy. Granted I have a little more barrel to work with, but I would seriously be looking at AA5or 7 for those loads, then load for accuracy and not worry about the top end.

I have run every weight bullet from 135's up to 200's in it using AA5, 7 and 9. I like the #5 for 135-150'ish grain, then #7 for 155's up through 175's then switch to #9 for everything heavier. When I was loading a lot of different loads it was nice to only have to keep those three powders, which i also use in other calibers too.

My 180gr GD load easily hits 1350fps and usually holds right around 2" rested at 50yds. I tried real hard to keep some of the other weights, but since I hunt with it I decided to settle on one weight and stick with it. So far I haven't been let down. Light and fast works for some, but that 180gr GD slumbering out at 1350 really puts the smack down on a feral hog.

 

[ljnowell]

I love accurate brand powders but Power Pistol is one of the two that makes me cheat on my AA powders(the other is 2400).

Power pistol is a great powder for 10mm and will produce a really great fireball.

 

[SDGlock23]

I don't load for the 10mm anymore but when I did, looking back over my data 10.0gr of Power Pistol would get me around 1310 fps from a 4.6" G20 using 165gr Sierras, which aren't Gold Dots, but I can't imagine there would be a huge difference (8.0gr in a 6" G24 gets me 1250 fps with 165's).

If you're running one grain less (9.0gr) and getting essentially what I was getting using 10.0gr, maybe something is off. Always make sure your Chrony is in good light, is level and the rods aren't bent as that will cause inaccurate velocity readings. But Power Pistol is good powder I think, seems to always be nicely consistent in all the loads I've used with it in the .40, 10mm and .45 Super.