AutoComp Powder loads

[Waldog]

I did a search on this forum about 9mm loads with Win AutoComp powder. There are guys using from. 7.0 to 7.9 gr of AutoComp with 121 MG bullets. The Hogdon/Win load data website clearly show a MAX load of 5.2 gr of AutoComp with a 125gr SIE bullets and a MAX charge of 6.5 gr with a 90 gr bullet.

What gives? 7.0 to 7.9 is over 20% above MAX for a similar bullet according the the loading data. I know that AutoComp is new and really hasn't been scrutinized that much. Where are these guys getting their loading data? Or are they just overloading until the rupture a case or blow a primer and then back off .2gr?

Edited December 2, 2009 by Waldog

[shooterbenedetto]

Our load for 7.0g at 125g bullet is for 9mm OPEN race guns where we need a lot of gas to work our compensator.

load safely.

[Jeff686]

Although it isn't an exact science, you can also inspect the primers for flattening or cratering, sometimes an initial sign of high pressure.

Most of us running open guns exceed most of the 'book numbers'.

[runNgun]

Care must be taken when working up a Loads like this. While I have no pressure data with My loads I assume they may be over max pressure loads for a Stock Production Gun. The classic pressure signs (flattened primers, blown cases, etc.) are NOT there when fired in my equipment. I am also able to reload the cases (once fired ball ammo) another 4 times at over 1370 fps with a 125 gr bullet.

This ammo is fired in a pistol designed and built with a COMPENSATOR to handle these high pressures. A tight match chamber that FULLY SUPPORTS the case because it is NOT OVER-THROATED. Because we CORRECTLY FIT the barrel so the gun will UNLOCK at the CORRECT TIME, we are able to shoot loads like these.

Also note that the 125 gr load you noted has an OAL of 1.090", My load is at 1.150". The .060 shorter OAL would normally raise pressure greatly. So unless your Equipment is built correctly and you are competing in USPSA OPEN DIVISION and want to score Major Powerfactor. Don't work up a load similar to our Data.

[Pezco]

Heck, I exceed the book numbers just to make major in my Limited SV.

[Carl Provan]

More on this topic here

http://www.brianenos.com/forums/index.php?showtopic=83231

I have started using AutoComp. I am liking what I am seeing in recoil, cleanliness and loading benifits.

The powder is denser, there for it does not fill the case up at much. Also less spillage while reloading.

I am using 7.9gr on a 124CMJ MG at 1.145OAL in 38SC. I shoot an SV IMM with 4 ports in the barrel and the SV TI comp.

PF is 170.

Carl

[BigTinVA]

Is anyone using Auto Comp for minor loads in 9mm?

[Waldog]

OK, makes sense. Specially chambered barrels that have compensators. Still seems like an incredibly hot load. I just have production guns, I'll stick with loads that are much lighter. Thanks for the explanation.

[runNgun]

BigTinVa,

Loaded down, it did not work the comp as well. Faster powders seem to make more pressure-flatter shooting in my equipment.