Comparison of QuickLOAD versus GRT simulations for an unusual 9mm pistol loading

[Zak Smith]

QL has a lot of parameters that you can tweak; many (not all) of them are right in the screen shots you posted. The most useful, IMO, is the case volume parameter. Different brass has different volume, and initial volume has a big impact on pressure and ultimate velocity (that's why seating a bullet out further -- which gives more initial volume -- gives you more velocity if you go back and adjust the charge for the same peak pressure).

In this case, I'd argue it's kind of pointless to attempt to make it match. What you create will be a true tautology and no new legitimate information will be created.

 

[JimGnitecki]

I'd STILL like to know the actual peak pressure . . .

Jim G

 

[Zak Smith]

You won't ever know the actual peak pressure unless you hook up pressure test equipment to your barrel.

 

[JimGnitecki]

You won't ever know the actual peak pressure unless you hook up pressure test equipment to your barrel.

Yes, I guess you are right. The consumer grade pressure test glue-ons won't work with a semi-auto pistol because the barrel is internal to the slide, and moves relative to the slide. No practical way to run the wires

Jim G

 

[twarr1]

GRT calibration;
https://www.grtools.de/doku.php?id=en:faq:faq-calibration

Concerning simulation accuracy;

GRT is able to predict rifle cartridges often below 3%. That is amazing enough when you look at the possible influencing factors and their variations (given reasonably good components):

• Powder lot-to-lot variation approx. 1-2%+
• Case volume approx. 1.5%+
• Reloading accuracy / tool variations 1.5%+
• Bullet length up to 3%
• Bullet mass approx. 1%+
• Special bullet constructions or materials: 1-10%+
• Environmental conditions such as temperature, humidity, etc.: up to 1-5%
• Barrel/weapon wear 1-2%+
• Chronometer accuracy: up to 5%
• Primer type, construction and components: 1-2%
• Physical effects such as projectile protrusion by primer before full powder ignition (mainly with cylinder cases or large calibers): up to 10%

 

[BW460]

I like GTR better than QL. When you are very careful with all of your measurements, you can calculate a very close velocity IN A RIFLE barrel. Both suck for pistol barrels. For pistols, I mostly just use them to keep an eye on the chamber pressure when I'm using a mixture of components that don't have published loads. I like the fact that GRT can factor in the air tempurature.