Why different PF factor?

[shooterbenedetto]

Can someone explain? Thoughts and comments.

[Joe4d]

IPSC has two power factors, 160 for open 170 for everything else. When USPSA spun off we just split the difference.

[diehli]

Only in Open. Safety concerns f/ IPSC. Same reason they've got a minimum bullet weight.

[diehli]

Here's the relevant text under the Open Division requirements:

Ammunition which fails to meet the minimum bullet weight above, but which chronographs at Major power factor, will be treated as unsafe and must be withdrawn (see Rule 5.5.6). If the weight of the first of eight chronograph testing rounds drawn from a competitor under Rule 5.6.3.2 fails to meet the minimum bullet weight required for Major power factor, Rule 5.6.3.6 will apply, and a second round will be weighed as a final and definitive bullet weight test.

[wide45]

IPSC has two power factors, 160 for open 170 for everything else. When USPSA spun off we just split the difference.

Not so.

IPSC used to have the same power factors. They changed. USPSA chose not to.

[GrumpyOne]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

[redwoods]

IPSC has two power factors, 160 for open 170 for everything else. When USPSA spun off we just split the difference.

What about the production type division? They have to shoot at 170pf?

[jbullgpd]

IPSC has two power factors, 160 for open 170 for everything else. When USPSA spun off we just split the difference.

What about the production type division? They have to shoot at 170pf?

They are just talking about Major PF. production is minor, whole other ball of wax.

[wide45]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

There is some truth here.

[shooterbenedetto]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

Bingo! What I don't understand is why cant we both shoot at 160pf?

I think better for the gun, powder, bullets and better yet shooters!

[G-ManBart]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

Bingo! What I don't understand is why cant we both shoot at 160pf?

I think better for the gun, powder, bullets and better yet shooters!

Not really. You're talking 40fps difference (with a 125gr bullet). That really isn't going to make much difference in wear, safety or how the gun feels. In fact, most ammo has an extreme spread at least that big, so even someone flirting with just barely making 160PF (on average) is shooting many rounds that are really 165PF. R,

[G-ManBart]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

Yes, and there was also a time when USPSA had bullet weight restrictions for Major based upon barrel types (ramped or not) and bullet material (jacketed or lead). If your gun had a ramped barrel you could use a lighter, jacketed bullet than if it didn't. I'm sure someone will remember the specifics, but I think an unramped barrel required something like a 143gr minimum. That was some of the fallout of the first folks making Major with .38 Super. Somebody did pressure testing and found they could make Major with a heavy cast bullet (think it was 158gr) and Blue Dot powder while staying within SAAMI pressure limits. R,

[GrumpyOne]

Did not major used to be 175? USPSA dropped it to 165, IPSC dropped it to 160 (both for open, that is).

Bingo! What I don't understand is why cant we both shoot at 160pf?

I think better for the gun, powder, bullets and better yet shooters!

Not really. You're talking 40fps difference (with a 125gr bullet). That really isn't going to make much difference in wear, safety or how the gun feels. In fact, most ammo has an extreme spread at least that big, so even someone flirting with just barely making 160PF (on average) is shooting many rounds that are really 165PF. R,

Technically, yes, the difference is very small. But then again, we all load to a higher PF than what is required because of the variables. For a 165 PF, most load to 172, for a 160, I would think most would load to a 167 or so. And in some guns, the higher PF makes the gun comp work better, so even if they were to drop it, many would keep their old load.

Remember, IPSC has a minimum bullet weight for major, 120 grain I believe.

[pjb45]

The pressure testing on the 9mm was done a while ago. Many have felt it was not truly reflective of reality.

It is achievable to have 9 mm major and not have a safety problem.

The rationale that has been floated is if 9mm was deemed legal, there would be a rush to have 9mm guns built because the extra rounds in a magazine would be a competitive advantage. There would be an outcry of protest of having to buy another gun to be able to compete.

I agree with Bartman-PF has little effect on the gun - at the USPSA/IPSC levels.

[clintreich]

So do you have to meet both criteria to shoot major? Both a .40 caliber bullet and 165 PF or can you just meet one. I always here people sag they can shoot major with 38 super.

[G-ManBart]

So do you have to meet both criteria to shoot major? Both a .40 caliber bullet and 165 PF or can you just meet one. I always here people sag they can shoot major with 38 super.

For USPSA Limited, L-10, and Single Stack, to make Major, it has to be both .400" or larger, and 165PF+. For Open (and I think Revolver) it only has to be .354" or larger, and 165PF+. R,