Makes me shake my Head

[Trapshooter12]

Not sure where to put this. So Mods if you want, move this.

It does deal with reloading.

I was at a Varmint Silhoutte shoot yesterday and toward the end of the shoot, this guy was having problems with some hot loads. He had been shooting fine up to this point. He was having sticky Bolt and blowing Primers. He had 5 shots left and told the scorer just to mark him a zero on the last five. When this Older shooter that has been around for awhile says wait a min and tells the guy to let him stick his Shells in the Ice Chest for a few min to bring the Temp down. It worked. The guy finished without any problems.

I'm not being Judgemental or Holier than though. But I have to ask who thinks up this stuff. Some of this stuff his wow thats a Hell of an Idea.

 

[ewoaf]

Re: Makes me shake my Head

which is why I do all my load workups in the heat of the summer.

 

[ChrisGarrett]

Re: Makes me shake my Head

Keeping ammo cool and out of the hot sun is common knowledge, especially for people a) already running hot loads and b) compete on a firing line, where they might be there for a while.

Also, don't leave a round in a hot chamber for 5 minutes, while you diddle with things, or keep it stored in your car or trunk.

I've put ammo in a cooler before, after taking it out of my hot truck, to cool it down and I've left a box of ammo on a bench, with the sun shining down on it for 20 minutes and it does get hot, spiking pressures.

Chris

 

[308sako]

Re: Makes me shake my Head

deleted in protest

 

[gcoulsey]

Re: Makes me shake my Head

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Humongo Spheres</div><div class="ubbcode-body">Our temps are running near 110 this week and when I go to the range the ammunition has been in the freezer overnight, and stays in a cooler till I am ready for it. I see alot less problems that way.</div></div>

you FREEZE your rounds??!! Wow!! I would have thought that would cause condensation/moisture issues internally?

 

[deadeye]

Re: Makes me shake my Head

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">Keeping ammo cool and out of the hot sun is common knowledge, especially for people a) already running hot loads and b) compete on a firing line, where they might be there for a while.

Also, don't leave a round in a hot chamber for 5 minutes, while you diddle with things, or keep it stored in your car or trunk.

I've put ammo in a cooler before, after taking it out of my hot truck, to cool it down and I've left a box of ammo on a bench, with the sun shining down on it for 20 minutes and it does get hot, spiking pressures.
</div></div>

+1 Learned this the hard way many years ago.

 

[The Mechanic]

Re: Makes me shake my Head

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gfunkUK</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Humongo Spheres</div><div class="ubbcode-body">Our temps are running near 110 this week and when I go to the range the ammunition has been in the freezer overnight, and stays in a cooler till I am ready for it. I see alot less problems that way.</div></div>

you FREEZE your rounds??!! Wow!! I would have thought that would cause condensation/moisture issues internally?
</div></div>
The humidity inside the round should not change from the humidity it was loaded in. Also the propellant will gas in the loaded rounds.
Basically freezer temps should not adversely effect the round.

 

[Clark]

Re: Makes me shake my Head

Bart Bobbitt post on rec.guns 2004

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">if you leave a round in the chamber
more than about 10 to 15 seconds, then its powder will be hotter and
burn faster pushing the bullet out faster causing that shot to strike
high - that's simple physics.

It's been my experience that when shooting the .308 Win. at 1000
yards, I have to come down 1/4 moa for each 15 seconds the round has
been chambered after the first 15 seconds. But the change is only
vertical, never horizontal.</div></div>


What does it all mean?
The chamber can be hotter than the weather.

 

[The Mechanic]

Re: Makes me shake my Head

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body"> Bart Bobbitt post on rec.guns 2004

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">if you leave a round in the chamber
more than about 10 to 15 seconds, then its powder will be hotter and
burn faster pushing the bullet out faster causing that shot to strike
high - that's simple physics.

It's been my experience that when shooting the .308 Win. at 1000
yards, I have to come down 1/4 moa for each 15 seconds the round has
been chambered after the first 15 seconds. But the change is only
vertical, never horizontal.</div></div>


What does it all mean?
The chamber can be hotter than the weather.

</div></div>

What he is saying is that in a shooting string, after firing the rifle the chamber and barrel heats up. This temp can be significantly higher than ambient temperature. As well as a bright sunny day can make a flat black barrel and receiver much hotter than ambient temps in a pocket or plastic ammo container. Much like a normal warm day out and you decide to not wear shoes and walk on pavement.

 

[sharac]

Re: Makes me shake my Head

It has to do with temperature of the powder (the higher it is the hotter the burn hence more velocity from the same load) and heat capacity of materials in fact assuming one is shooting cold weapon bigger factor than powder temperature becomes weapon(i.e. barrel) temperature as some of the energy from the powder burn goes to heating the surrounding metal. So for a first cold shot you'll usually get lower speed and this lower speed will still be present even if round is warmer (of course if you leave it in cold barrel it will get colder as well) upon insertion.

But still a lot depends on powder type, rifle and load (ocw or not hot wide the margin is etc...) so each must test it's own weapon and see...

Edit: And above all know your powder, for Vihtavouri 140 i can safely say for my rifle (tikka) a mild load will need .3gr deduction for 20°C difference so my summer 20+ load is .3gr lower than winter 0°C and below and i get same speeds (though in summer after a string of five i really have to wait for a barrel to cool down as it gets really hot and speeds start to increase).