170 mm vs 171.25 mm mags

[glock-hoser]

Good afternoon! Does anybody know why the mag length for Open is different between USPSA and IPSC? For IPSC it's 170 mm and for USPSA it's 171.25 mm (though still being called 170 mm). I assume most shooters use 171.25 mm mags, except for when travelling to international competitions, but how is this done for the US IPSC Nationals, which I guess is run under IPSC rules? Is there a rule exeption made so everyone can compete with their 171.25 mm mags?

[Bkreutz]

In USPSA, the allowable measurement includes the tolerance, in Limited, the max is 141.25 but I've never seen them referred to as anything but a 140, same thing with Open (or single stack Limited) I don't have an IPSC rulebook but it might read 170mm with a 1.25mm tolerance. Personally I think the reason they don't agree is they are both trying to piss the other organization off.

[Schutzenmeister]

IPSC rule is 170mm ... Period.  USPSA added 1.25mm as a more or less manufacturing tolerance, or something.  

 

The US IPSC Nationals are run under IPSC rules.  There is no waiver.  Show up and use 171.25mm mags and you will be shooting for no score.

[ChuckS]

IPSC.org has the rulebook available for your enjoyment...

[Bkreutz]

10 hours ago, ChuckS said:

IPSC.org has the rulebook available for your enjoyment...

I looked at it, interesting that the format is exactly like the USPSA book, right down to the chapter and appendix numbers. It's also just as vague as the USPSA book (example: Appendix D1, #4, Minimum caliber/case length: 9mm/19mm. #5, Minimum caliber for major: No (WTF does that mean?) Looks like the author/s of both books are/is related They do have a +1mm tolerance on the size of the box though.

[ChuckS]

5 hours ago, Bkreutz said:

I looked at it, interesting that the format is exactly like the USPSA book, right down to the chapter and appendix numbers. It's also just as vague as the USPSA book (example: Appendix D1, #4, Minimum caliber/case length: 9mm/19mm. #5, Minimum caliber for major: No (WTF does that mean?) Looks like the author/s of both books are/is related They do have a +1mm tolerance on the size of the box though.

Go over to the Global Village and get some condescending info from Vince..

[BeerBaron]

honestly I think adding the extra 1.25mm was a mistake. we had 170 and 140 rules. that was fine. now if you want to shoot IPSC matches in open you need to stick to 170mm or run 2 sets of base pads. 

 

oh and the ipsc appendix says min for major = no as for standard division there is a min for major (in addition to the min general caliber) being 40/10mm.

 

I have NFI why USPSA added extra 1.25mm for tolerance. STI 170s and SVI 170s sold at the time made the 170mm rule no problem.  SPS tubes are even shorter so you could add a 6mm pad. 

[George Jones]

What I was told (many moons ago) was that when the mag length rules were created, most of the existing mags were a bit oversize.  Rather than render them illegal, the dimension was purposely increased to allow their continued use.

[bret]

On 5/12/2017 at 6:25 PM, glock-hoser said:

Good afternoon! Does anybody know why the mag length for Open is different between USPSA and IPSC? For IPSC it's 170 mm and for USPSA it's 171.25 mm (though still being called 170 mm). I assume most shooters use 171.25 mm mags, except for when travelling to international competitions, but how is this done for the US IPSC Nationals, which I guess is run under IPSC rules? Is there a rule exeption made so everyone can compete with their 171.25 mm mags?

Merica!!! thats why, we do things how we want.

If a mag is gauged and exceeds 170 mm at IPSC, you shoot for no score.

I never saw a mag gauged at IPSC Nationals.

 

[Schutzenmeister]

1 hour ago, bret said:

I never saw a mag gauged at IPSC Nationals.

 

I have ... Also seen it at Continental (Lv 4) and World (Lv 5) Championships.

 

Edit to add:  If you are measured at a USPSA match and your mag exceeds 171.25 mm, same thing:  You shoot for no score.  (Same rule, different length for the standard.)

Edited May 20, 2017 by Schutzenmeister

[bret]

14 minutes ago, Schutzenmeister said:

 

I have ... Also seen it at Continental (Lv 4) and World (Lv 5) Championships.

 

Edit to add:  If you are measured at a USPSA match and your mag exceeds 171.25 mm, same thing:  You shoot for no score.  (Same rule, different length for the standard.)

I never seen any mags gauged but at the NC Blue Bullets a buddy was bumped to Open for his limited mags being over 141.25 MM, Todd Jarret was bumped to Open too in that match for mags too long.

 

[Schutzenmeister]

It happens ...