Muzzel Velocity???

Remington country

Remington country

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Hey guys

Been doing a bunch of long range shooting with my new 300 RUM. Ive only had a chance to run it threw a Crono one shooting. I came out with a load 210 gr berger VLD 92 gr Retumbo that shot 3065fps that was at 1265 ft elevation and around 22 degrees C. Just wondering how much colder weather and higher elevation will effect my velocity I will be going on an elk hunt very soon and just want to make sure I'm ready

Thanks Guys...
 
There are a few online ballistics calculators that will allow you to play with temp and elevation. I would give them a shot and see what it says.

Tdc
 
Elevation won't affect muzzle velocity one bit. How does the round know what elevation it is at during the firing sequence?

Temp may affect muzzle velocity only because some powders burn a bit slower when cold.

The real thing that elevation and temp will affect is air density which will change how easily the bullet slips through the air. In reality this will only be relevant for longer range shots, say more than 200 yds. Otherwise don't worry about it, none of it will make any difference to your shot.
 
Suputin said:
The real thing that elevation and temp will affect is air density which will change how easily the bullet slips through the air. In reality this will only be relevant for longer range shots, say more than 200 yds. Otherwise don't worry about it, none of it will make any difference to your shot.
Click to expand...

X2 here
 
If you are getting speed X at sea level , for exsample. Then you go to 7000ft , the air is going to be much thinner actually increasing your speeds. However this is where barometric presure comes in, Because its all about " air density " Although the air could be thinner from altitude it could be canceled out because the air is colder... colder air is typically more dence than warm air ... slowing your round down.

So here's where you get fked ... Say your sighting in on the coast of B.C at sea level where is very humid and the air is very dence. Then you head to Alberta where its 2500 - 3000 ft above sea level and very dry and the air is a little thinner, early in the year the temps could be the same. At long range you could see a very big diffrence in your ballistic performance. close ranges ... 200 - 300 maybe , probably dont have to worry. 1000 yards ... gonna wanna put a kestrel weather station and a ballistic calulator on that and dial your minutes.

I like to run Hodgson powderes ... Speciffically Retumbo because its not as sensitive to tempature. I find specifically for me the Reloader powders ... R19 and R22 are the 2 ive used can be very sensitive to tempature. Sighting my gun in early september then shooting in november and seeing my velocities drop 100fps. That is a big difference at 500 - 1000 yards.
 
Ya sorry thats right , " at the muzzle" but you will carry your energy farther in lower air density. Thus having higher speeds at longer range than you might have previously had.
 
THanks for the great info guys I do use a Kestler wind Meter and I snipe for my ballistic calulator all i was worried about was getting in tot he cold weather currently i'm usuing the Value 3065 with the wind meter i can put in all th evalues but it wont change my FPS I really like shooting Retumbo it seems to be a very good shooting round. I recently finally broke the 1000 yrd mark with a shot at 1100 yards at our local range couldnt be happier.

Thanks again
 
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