Cold vs warm ammunition

[Roe]

I've stressed that one needs to chronograph the loads all through the year and different temperatures if one wants to shoot properly longrange at unknown distances.
This data gathering takes some time. In this film I tried a little experiment too see if I could manipulate the ammunition temperature and match my already logged velocities.

I consider this a failed experiment as there was too much delay in the cartridge mass for me to say anything useful about the ammuninition temperature. I got ok velocities for the cold ammunition, the warm ammunition was a little harder to determine. It gave a maximum velocity indication but I could link it with sufficient accuracy to a temperature so this data could be of actual use.

The velocity variation between cold/ warm temperature is unavoidable, just make sure you don't get irregular performance at the higher and lower temperatures - accuracy must be the same through the temperature zone you shoot.

Here's the experiment Chronographing cold and warm ammunition

 

[dansig]

the ammo temp isn't the only thing that matters, air density changes when temperature rises as the air holds more humidity, and in cold weather things drop faster due to the fact that cold air goes down while warm air rises, and that is the main factor for difference in accuracy with the same load in different temperatures.

so trying to imitate different conditions to chronograph your loads just doesn't work except if you can get in to NASA wind tunnel to do your testing

 

[Roe]

Well that is exterior ballistics and I correct for that as well. You still need to start with temperature before going into DA as it gives both speed of sound and your V0. You need both to foresee your changed POI. If you look at the temperature corrections to pressure and humidity corrections to temperature youll see that you dont reach significant values for shooting and can use an ordinary DA figure for the air prloperties

 

[bheadboy]

one more thing you need to add to the equasion, the action/firing pin spring/ bbl tempreture, as all are influenced by temp.

cold slows springs, contracts metal, heat speeds springs, expands metal, chambers particularly become iceboxes or furnaces.

Bob

 

[Roe]

Ah the dangers of posting on a BR forum...

Do that ever reach significant values for practical shooting? What is the reference accuracy (not precision) standard?

 

[amlevin]

We have a couple of shooters at the "club" that have some cute methods for cold weather shooting.

One uses those "Toe Warmers" that heat up when you remove them from their sealed package. He puts one or two under his ammo box and covers it with a towel, taking each round from his little "oven" as needed.

Another uses a heating pad set on low. He always sits at a shooting position closest to an electrical outlet. :

Probably the next "trick" for cold weather will be to wrap the rifle's action in heat tape used for frost proofing pipes. Just set the thermostat for a little higher temp than used on the pipes. :-\

Pretty soon, winter shooting will look like Ice Fishing with little portable shacks for each shooting position with the muzzles pointed out a small "porthole". :'(

That way one would only need to develop his loads for Hot weather. 8) 8)

 

[K22]

Makes we wonder how my father managed to take 18 white tails over his hunting life time with an open sighted 30-30 Winchester.

 

[amlevin]

Makes we wonder how my father managed to take 18 white tails over his hunting life time with an open sighted 30-30 Winchester.

That's always the case for those that don't know something can't be done.

Just like the guy who held all kinds of records in Trap Shooting that only shot a Winchester Model 12 straight out of the box" while everyone else had all sorts of "customs" or imports selling for many thousands.

 

[Roe]

Just curious, what is the anomaly about shooting 18 deer with an open sighted 30-30?
Wouldn't that be quite normal, taking a few deer with a pet gun/ prefered challenge/ using what you got ?

 

[amlevin]

Just curious, what is the anomaly about shooting 18 deer with an open sighted 30-30?
Wouldn't that be quite normal, taking a few deer with a pet gun/ prefered challenge/ using what you got ?

In this day and age, using an old rifle, with a mundane caliber, and no fancy optics, is becoming an anomaly.

Almost gone are the days of someone going out for a day of hunting with 5 rounds either in the rifle or in a pocket, a wax paper wrapped sandwich in his pocket, and his trusty/favorite rifle sporting only Iron Sights.

 

[bheadboy]

Roe, hunting in Wy, Id, Ne, SD,Ga, British Columbia, Yukon and taking a goodly number of head in weather from -25f wind chill to +95f, from 5yd to 650yd, i have never worried about the temp. Snow to hot dusty bean field.

used everyting from mod 99 sav in 300sav with peep sights to 300wm with luepold

Size of animal makes up for lots of errors and point of impact change. precision target shooting is different.

Bob

 

[Roe]

Amlevin, yeah I suspected as much. It is even unusual to see a fixed power scope these days and lasers seems to be in a lot of pockets over here.

Bob, I know what you are saying. For short range and big targets there really is no need to worry about temperature. You are lucky to have hunted such a large span of terrain! Do you have any favorite forms? I'm weak for alpine hunting myself, absolutely love it.