Power factor and the road.

[joelogic]

Do all national level multigun matches chrono your ammo?
How much do temp, elevation, and humidity effect fps?
Do you load for the range or create one load that works everywhere?
What's you comfort level over the minimum?
I load to about 125pf but here in the bay area that's at 60F and near sea level.
Would you adjust your load for superstition, ironman, nationals?

Yes, I know there is a reloading forum but I find competitors answer more relevant.

[SuperSet]

IME, USPSA MG Nationals is the only major match that chronos. Virtually all other major 3-gun matches are using IMG scoring so no major/minor wierdness. Which ones are you doing next year? I plan on only SMM3G, LaRue, FNH USA, and Houghton at West Point (not a big match but I want to support the Army).

[joelogic]

So many things to learn.

Next year will be Ironman and maybe Nationals if I can find some money.

Ok, then what about for large pistol only matches?

[Religious Shooter]

What division are you shooting in? For pistol only matches is it an IDPA, USPSA, etc. match?

[joelogic]

Uspsa, limited.

[gun fu]

Uspsa, limited.

You pose very good questions and the variables indicated are indeed there.

Almost all larger USPSA matches; Sectional, Area, Nationals do have a dedicated "Chronograph" stage where the CRO will ask for 5-8 rounds from your mag and save it in a ziplock bag and will await you when your squad is up. Then based on your declared power factor they will measure PF for you.

For these larger matches I create a cushion for my 9 major.

My minimum is 165, and through my chronograph I load to approx 170 PF for variance. So far, i have yet to fail Major!

My production , minor load, 9mm I load to 133+- Powerfactor. Again for variance and preference.

My Limited 40 S&W load is loaded to approx 171 PF also.

Hope it helps!

[Voo]

Do all national level multigun matches chrono your ammo?
How much do temp, elevation, and humidity effect fps?
Do you load for the range or create one load that works everywhere?
What's you comfort level over the minimum?
I load to about 125pf but here in the bay area that's at 60F and near sea level.
Would you adjust your load for superstition, ironman, nationals?

Yes, I know there is a reloading forum but I find competitors answer more relevant.

Hey JL,

I think it's much safer to give yourself a margin when reloading. Trying to load at 125PF is too borderline. Getting bumped down to minor is one thing, but not making minor just says you've spent all that time/money on training, food, gas, lodging, match fees to shoot for fun.

I've chrono'ed my load in the morning (cold) and in the afternoon (warm/hot) and the velocities do change.. I can't for the life of me find my excel sheet with the data so I dont want to say a "specific" delta on the velocity, but there is a difference.

A buddy who traveled the country shooting matches (sponsored by the navy) definitely said it makes a difference. You need to know how your powder behaves at temperature. Stuff like W231 is temperature sensitive. You're going to get slower velocities if things get frosty.

Another thing I saw last year is the potential for the chrono to be off. How you calibrate these things is beyond to me. I've yet to see how anyone has determined if there chrono is actually correct. The only thing I've done is stack them one behind another and shoot through both. If the readings are very similar then your chances of the chrono being correct are good. But don't assume that the chrono is going to be accurate. Your chrono could say 1020 fps while theres says 1000. Using a 124 grain bullet could mean a bad day for you.. Better to add more powder and give yourself a cushion.

To combat this issue, my buddy recommended a powder that wasn't temperature sensitive. He also said to up the PF to ensure that it wouldnt' be an issue. That's pretty much it.

[hammer]

Voo,

That is interesting. I didn't know W231 was temperature sensitive. I've been using it for about six months now. Does your buddy know where I can get more information about which powders are temp sensitive, etc? A chart would be awesome.
Thanks.

[gose]

I chronoed my ammo the week before the multigun Nats and considered lowering my load a tad, since I was at 173.
Ended up at 165.1 after 6 shots fired...