10MM Pistol Questions

[treillw]

Glock 20
KKM 5" barrel
200 Grain Hornady Hollowpoint
9.4 grains Blue Dot (Book Max)

Just started messing with loading some 10mm. Never saw these big scratches on the brass before. What are they from?

Also, I'm about 100 fps slower than the velocity published in the reloading manual. They use about the same 5" test barrel length for their data, Why am I so much slower? The barrel only has about 20 rounds though it. Do they speed up at all similar to rifle barrels? Any other reasons?

Thanks!

 

[kenhwind]

It looks as though the brass is hitting against the slide during ejection. the only 10mm pistol I'm familiar with is the Colt Delta Elite.
As for your velocity not being equal to the manual, everything is a variable.
Hornady used a Delta Elite for their test gun.

The Speer reloading manual has a chart where they tested the .357 magnum some of the revolvers where the same model, barrel length, etc, and the difference in results is more than we'd realize.

 

[Rsadams]

Correct , hitting the slide during ejection.... Remember not all 10mm is created equal.... Most cheap factory plinkers are on par with the .40 cal territory.... Real 10mm like from Norma or underwood and one other company I can't think of it are faster... Check your reloads with a crono.... Is the only way to know what you have.... Honestly I have found most loads are slower in real life then what manuals state... If it were me I would reload that brass with no problems or worries... If your going to shoot heavys fast alot I would look into a stronger mainspring....

 

[piie]

Yes, that is a common thing with Glock's it seem - although, my 23 in 40 does exactly that to my brass, while my 20 hardly makes any impressions on my casings - pretty sure any gunsmith familiar with Glock will be able to help you (perhaps the extractor just needs some TLC).

As stated with the difference in velocity, small things can make a change - powder lot variations, COAL, casings and primers - and the barrel itself - even if it is the same length - the bore diameters, or in the case of Glocks, the difference in the rifling - can have an effect on velocity. Those figures are not targets/goals...

 

[Lefty Trigger]

Those are being ejected really hard.

 

[6bra1k]

try some power pistol and get a set of tunnig springs

 

[rsbhunter]

Just curious, are those brass cases, color just looks funny? I have a Storm Lake 6" bbl that I load longshot and 800X in....awesome velocities, but wicked recoil...and yes, they are safe loads, I'm to old now to lose my fingers or sight because of hot rodding a load....rsbhunter

 

[db556]

My Glock 22 and 35 do that exact same thing.

 

[rsbhunter]

+1 on the spring...get a 22# spring if you go for "full" power 10MM loads....adds a little safety and lessens abuse on parts...rsbhunter

 

[Alaska Bush Man]

Don’t believe Reloading manuals velocities they have been watered down by lawyers since the 70’s.
Used 800x for years with 200 XTP at 9.4 in my 10mm and yes a 22 pound spring
Blue Dot in manual for 200gr XTP is the FBI load watered down almost the same as 40 SW

 

[Alaska Bush Man]

I settle on 10.0 of Blue Dot with 200 XTP
It seems the lower charges is not what my G20 wanted bent the brass and a lot of residue left …..it all cleaned / cleared up past 10.0 to 10.5 with 200 XTP.
The manuals are lawyer critique the max load is not the max load and most of the time grains away from max load.

 

[DocDoc]

Check over at Glock Talk for some more help. A chronograph is a great aid. To get a max load measure expansion just above the extractor cut with a micrometer for a full power load from Underwood, Double Tap, or Buffalo Bore, and compare with your handload. Those manufacturers are operating at a safe max, even pushing it, so do not go past.

And use good brass.

 

[Bat Rastard]

I load pretty warm, if I want HOT, I buy Underwood.

 

[Alaska Bush Man]

I load pretty warm, if I want HOT, I buy Underwood.

I just load warm too
I did go up too 10.5 of BD with 200 XTP the ship held together but I back off too 10.0 no need to stress a good G20.
But that load of 9.5 with the 220gr is a good load for Alaska Bush.