Open class caliber question

[TheyCallMePo]

Is the division mostly 9mm and 38 super? I was perusing the interwebs and looks like 40sw died out a while ago? Or does it more have to do with 40sw not working with a compensator well?

[Mazdaspeed Jon]

9mm and 38 super are the dominant calibers because of magazine capacity. I believe with a 9/38 170mm mag you can get 27 or 28 rounds. A .40 cal of the same length would only be able to fit around 23 or so. As for whether to go 9 major or 38 super? The big difference really comes down to the availability of the brass. 38sc brass is hard to find and can be expensive while 9mm is plentiful and cheap. The other big difference is powder availability as there are only a few powders that are good for 9major (Autocomp, Hogdon CFE, etc). So really, it comes down to cost of brass vs availability of powder.

[ScottyXbones]

I'm sure other members will have more expertise than myself, but I heard that any serious competitor in USPSA/IPSC shoots .40 or .38 super for the point advantage. .38 super provides enough gas to work a comp properly, I'd think that .40 with a lighter bullet would do the same.

I've heard most standard 9mm pistols will beat themselves to death/failure with the pressure requirements to meet major pf.

[yoshidaex]

To score major in open, the minimum bullet diameter is .355 and it has to travel the appropriate velocity.

Gas volume is important to work the comp on any open gun to reduce recoil. The more powder, the more gas volume when a bullet is shot. With a 40, you don't need much powder to make major since the weight of the projectile will compensate for the slower speeds.
Less powder = less gas volume = less effect on comp.
You can increase the amount of powder to get more gas but there is a point of diminishing returns with the 40.

No serious competitor will shoot 40. You give up capacity versus someone shooting 9/38. The 40 shooter may argue you can always throw a reload in somewhere when moving to another position but it still takes some time to do a reload and time is important in the open division race.

A properly built gun will last thru many rounds regardless of bullet selection. I have about 50k rounds thru one of my open guns and it's still going strong and accurate.

[JTROKS]

Back in the days when the power factor to score major was 175 open gun shooters wanted more gas. There were 9x25 Dillon and 40-9er (40S&W necked down to 9mm). As if the 38SC with 115 grain bullet at 1550 FPS wasn't loud enough. You just knew when TGO-Rob Leatham and some of his teammates were shooting, the combination of multi port comp with 9x25 was loud and sharp. With the major power factor set down to a saner 165 level I knew right away there will be many USPSA members Switching to 9mm major. 40 S&W is popular in Limited Division,but I did see a couple of open guns in 40.