So I have been working on a load with Longshot powder and 180 grain HP jacketed bullets (XTP like) with my new SR1911 10mm pistol. I prefer L/S because I have some and it works beautifully in my 40 S&W.
I made a series of loads all with an AOL of 1,260” and CCI large pistol primers.

I used the following grains of powder measurements, 8.5 – 8.7 – 8.9 – 9.0 – 9.1 and 9.3
these loadings all fall into the loading data of Hodgdon listing. What I’m seeing seems to be high pressure signs with the primers. The loads felt like true 10mm loads the 9.3 grain gave the best group but nothing to ride home about.
The primers are flat and the pin strike is also with a crater look.!

Is this normal in a 1911 pistol, its the first one I have owned?

But wait..... I found data by Hornady stating that their XTP 180 grain bullet lists 6.4 grains to 8.2 of Longshot, Wow that doesn't even reach Hodgdons minimum load of 8.5, What gives here?

So I loaded up the same AOL with the following: 7.3 – 7.5 – 7.7 – 7.9 – 8.1 grains and still the primers are flat! The 7.9 shot the best group. Notice where the pin hits it is flat with a very small dimples.
These felt light and more like 40S&W power. What do you guys think?

Uploaded some pics:
1st pic from left to right in twos are 7.3 - 7.5 – 7.7 – 7.9 – 8.1
2nd is 7.7 – 7.9 – 8.1 from left to right
3rd pic is the hodgdon load measurements (4 pcs brass).

I honestly don't get any useful information from reading primers so I can't help you there. I can confirm the obvious, each manufacturer's bullet varies in multiple ways so the powder charges need to be different in order to stay within SAAMI pressure specs.

My Hornady manual shows a 180 XTP with a max load of 8.2 grains of Longshot for a velocity of 1150 out of a 5 inch barrel. Hodgdon's load data shows a Sierra 180 with 9.5 grains of Longshot for a maximum velocity of 1287 fps out of a 5 inch barrel.

That's a pretty big difference both in powder charges and velocity. I load 180s at plinking velocity and do all my heavy work with 200 grain bullets at 1200 fps in my 6 inch 10mms so all I can tell you is to chronograph the loads as that will give you some idea of where you are in the pressure spectrum.

You may want to look at the velocities of some of the hotter 180 grain 10mm loads from manufacturers such as Underwood, Doubletap, Buffalo Bore, and Grizzly to see how fast they are pushing 180s.

You could also visit the http://www.10mm-firearms.com/ web site. There is an excellent factory pulldown section where many factory loads have been taken apart, powder charge weights identified and weighed etc. You could also just ask your question there in the reloading section as there is bound to be someone with more info.

I also find primer pressure signs a bit voodoo.

It could be a bit excessive headspace.

It could be a overly large firing pin hole or conversely issues with the firing pin and or pin protrusion.

It could be the metallurgy of the primers.

It could also be pressure issues.

Does the gun do this with all ammo? Including factory lighter loads? If so, its most likely a gun issue.

I have 3 diferant 45s a Ruger P90 a Springfeild XD and a Ruger SR1911.

Shooting the same load in all 3, the primers look fine in the casings from the P90 and the XD, the ones shot out of the SR1911.

Show some firing pin cratering I tend to believe it is SR1911 design.

I'm beginning to wonder if the extruded/ cratered primers are an artifact from the titanium firingpin Ruger uses in all the SR1911's. The primer itself is relatively round but the dent is extruded in any load much above the middle of the load range in mine.

FWIW Today I swapped out the OEM Ti firing pin in my SR1911 10mm for a steel one I had. Brass fired with upper end handloads now look normal without the extruded firing pin mark.
The 10mm uses the same size pin as 9mm and .38 Super in case you want to try this fix.

Good information to know thanks

quote:

Originally posted by crbutler:

Does the gun do this with all ammo? Including factory lighter loads? If so, its most likely a gun issue.

Thanks crbutler,
I only shot one box of American eagle ammo and the cratering was slight and was weak 10mm stuff that is really disappointing for the money.
I'm wondering if i should purchase a steel firing pin like (Rick R) just in case the factory Ti pin fails or has a short life cause I sure am not going to settle on light loads.
Also the CCI I used is harder than Federal primers and have never had a problem with either in other sizes.
Vin

quote:

just in case the factory Ti pin fails or has a short life

I really don't think that well be a problem I thinking of one if it does away with the cratering.