Effects of elevation on PF

toxic

toxic

CGN frequent flyer
Rating - 100%
22   0   0
Wasn't sure if I should post this in the reloading section or this one. But since the IPSC shooters are here....

I'm going to the nationals in Pitt Meadows this year and I'm wondering how the change in elevation will affect my PF. Should I be loading more powder than I do here in Winnipeg? I usually load to 135pf to shoot production. Will that be enough at higher elevation?:confused:

When I place poorly I want to be from lack of ability and practice not because I didn't make PF...:D
 
The last Nationals in BC I went to, I didn't notice any change in velocities for my .40 cal ammo. One thing to remember, the chrony is only going to be 10 or 15 feet from the muzzle. Over such a short distance, I wouldn't expect much change at any elevation.

Now shooting over a longer distance, say 30 or 40 yards, there could be some effect. I have no idea how much, but I know there is a difference in how much bullet drop you get for different altitudes.

If the chrony is all you're really concerned about, with a 135 PF here in Winnipeg, I'd be confident that you will make the minimum of 125 PF.

By the way, if you don't make PF in Production, you don't place at all.:runaway:
 
Last edited:
Um..... Pitt Meadows is within spitting distance of sea level. And don't let the fact that the event is at Thompson MOUNTAIN confuse you. The range is MAYBE 600 feet above sea level. The use of the term "mountain" being largely a matter of charity.... :D
 
My load in Prince Rupert chrono's at around 172PF, sea level + maybe 50' and wet, 12 degrees temp approx.
Same load in Terrace (100 miles inland, drier and warm- hi teens, don't know the altitude) came in at 182.5 PF
I'm thinking the make of the chrono has more than a bit to do with it...
 
toxic said:
Wasn't sure if I should post this in the reloading section or this one. But since the IPSC shooters are here....

I'm going to the nationals in Pitt Meadows this year and I'm wondering how the change in elevation will affect my PF. Should I be loading more powder than I do here in Winnipeg? I usually load to 135pf to shoot production. Will that be enough at higher elevation?:confused:

When I place poorly I want to be from lack of ability and practice not because I didn't make PF...:D
Click to expand...
You're a wise man to think about this at this time - :cheers:
I've seen it happen; someone go from Edmonton (2000 ft) to Florida (0) and not make PF.

Lots of good comments above, but I'll toss in my 2 cents too. Of course, Elevation is a factor.
Winnipeg is at 700 ft. so it looks like you're pretty close to the same (as per BC Riders helpful info) If you're 7-10 points above PF on decent equipment that you can trust, you'll be good to go.

One of the advantages of living on the coast is that your bullets only get faster as you travel, whereas those mountain types have to be much more careful...
 
I've certainly noticed a difference between shooting outdoors on a cold day compared to shooting indoors, that's for sure, chronoed it to make sure. Cold weather usually makes MV go down, and BC is warmer, so you may well find the drop in sea level is countered by warmer weather. The temperature difference is usually more of a factor than elevation imx.
 
cybershooters said:
I've certainly noticed a difference between shooting outdoors on a cold day compared to shooting indoors, that's for sure, chronoed it to make sure. Cold weather usually makes MV go down, and BC is warmer, so you may well find the drop in sea level is countered by warmer weather. The temperature difference is usually more of a factor than elevation imx.
Click to expand...
Many powders are very temperature sensive - some get faster some get slower. It depends on the powder.
 
Elevation can make a difference, but I doubt that you will notice it over a 700 ft elevation change.

I develop all of my loads at an elevation of 2,900 to 3,900 ft (depending on which range I am using). Let's call it an average of 3,500 ft of elevation. On AVERAGE I expect to lose about 35 fps of velocity when I go to a range at sea level. Sometime the velocity is the same at sea level as at my local ranges; other times the velocity is less at sea level. Generally the worst case is a loss of about 30-40 fps.

This fairly consistent whether I am using 9mm, .40 or .45.

I do not know if it is air density, humidity, bad karma or just being closer to the centre of the earth (and it does not matter), I just expect and prepare to lose abut 35 fps of velocity. So being over the power factor by 10 points here means that I may only be over the power factor by 3 points at sea level. Good enough.

Assuming that the velocity loss is linear; then my 35 fps loss over 3,500 ft of elevation works out to 1 fps of velocity per 100 ft of elevation. With you being at 700 ft of elevation, than you could expect to lose 7 fps of velocity. The differences in reloading components, chronographs, wear on your barrel and standard deviation of any load will exceed the 7 fps that you might lose from change in elevation.
 
PF stands for Power Factor. VelocityXBullet weight/1000

Thanks for the input guys. Sounds like I should be good to go with what I have now. :rockOn:

Now I go on to worry about something else like my total lack of time to practice...
 
toxic said:
PF stands for Power Factor. VelocityXBullet weight/1000

Thanks for the input guys. Sounds like I should be good to go with what I have now. :rockOn:

Now I go on to worry about something else like my total lack of time to practice...
Click to expand...

Last Saturday was practice, sort of.
 
I don't know where in the standings you are but I'll ask you this:
Will 140PF (where you are now) keep you from winning the match?
I'm guessing that you would barely notice the difference (and ultimately not affect your standing) but it would make minor for sure.
Travelling all that way for no score, that would peg the "all things that suck" meter big time.
 
I usually shoot around 178 PF here in Winnipeg. For the Nationals in 2007, just to be safe, I added 0.2 grains to my load, and chronied at 183 PF:eek:. I'm not planning to change my load this time.
 
You must log in or register to reply here.
Back
Top Bottom