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Got a chance to shoot some reloads through a chrono today. It is my first time doing this. My guestion is,would temperature have a noticeable effect on velocity? I shot some 9mm,115g,Berrys plated rn over 4.5 tg through my p89. Primers were cci,oal was 1.145. These were just some rounds I made up to see how they worked in my guy but got a chance to shoot them through a buddies chrono. They were all in the 1100 fps range. Just wondering about if the temp would effect it much. It was about 19 degrees out with about 15 mph winds. Any info would be greatly appreciated. Not worried about making any power factor yet but will be in the future.
 

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Titegroup is fairly temperature stable. Not a real problem. I would be more concerned with plated heads over 1100 FPS. Nearing the upper limit there.
 

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Powders like Titegroup are fine. Some powders are not. I used to shoot BLC-2 in my Model 70 in .222 Rem. Wonderful powder in warm weather, lost a LOT of energy when it got cold. If I were still shooting .222, I'd use a modern powder that's less temperature sensitive, maybe Benchmark or Varget.
 

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Back in the 80's there was talk that Blue Dot would result in higher pressure in extremely cold weather. :(
First of all I never understood why "cold" would cause higher pressure. :confused:
Secondly, I had fired a substantial number of 3 inch 12 gauge reloads with 1 1/2 ounce and 1 7/8 ounce of #4 shot over max loads of Blue Dot in the 70's with no problems. Sometimes we were duck hunting in single digit temperatures sometimes zero or slightly below. :)
This came from gun and hunting magazines, maybe letters from subscribers. :rolleyes:
Apparently that was not true. Anybody ever heard of this?
 

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Even if you have non-temperature sensitive powder you will still experience slightly lower velocities due to the denser air in cold temps.
Not sure how noticeable it would be with handguns but long range rifle might be a different story.
I'm thinking that folks like Iowegan can shed more light on this subject.
 

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Thanks for the input so far guys. I don't have any reason to push them any harder so I don't see any reason to make up any more of them. I was just trying to research this issue so if I do want to get into building a round to make power factor for idpa,if I should wait till it warms up. I don't have access to a chrono all the time yet.
 

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Shootin357, The Speer reloading manual actually has a temperature versus velocity chart that applies to powders that are not temperature compensated (extreme rated) but the slowest velocity in the chart is 2600 fps. Using a velocity of 3300 fps (three times your velocity), the chart shows a loss of 64 fps at 20 deg. If you divide that by 3 to correlate with 1100 fps, you should be in the ball park at about 21 fps loss. That said, it will only affect the first couple rounds fired because heat transfers quickly from the chamber, through the brass case and into the powder .... so follow up shots should be the same as in warm weather. Unless you are an exceptional match grade loader, chances are your chronographed velocities will vary considerably more than 21 fps so the real answer is .... I doubt if you will see a lick of difference on a 19 deg day versus a 70 deg day.

Piedpiper46, The issue with Blue Dot being higher pressure in cold weather is totally bogus. All smokeless gun powder ... single base or double base, will burn faster as temperature increases and will burn slower when temperature decreases.
 

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Got a chance to shoot some reloads through a chrono today. It is my first time doing this. My guestion is,would temperature have a noticeable effect on velocity? I shot some 9mm,115g,Berrys plated rn over 4.5 tg through my p89. Primers were cci,oal was 1.145. These were just some rounds I made up to see how they worked in my guy but got a chance to shoot them through a buddies chrono. They were all in the 1100 fps range. Just wondering about if the temp would effect it much. It was about 19 degrees out with about 15 mph winds. Any info would be greatly appreciated. Not worried about making any power factor yet but will be in the future.
Morning Shootin357

You have a brave friend-- No way would I let anybody shoot Berry's plated through my chronograph at 1100fps (+/-) UNTIL they put 10 rounds or so into a virgin cardboard or paper target at about 20 feet to make darn sure that the bullet plating was staying intact & on the bullet all the way to target impact.

As mentioned above the ambient temperature probably didn't have a lot of effect on the velocity of pistol rounds using TightGroup. Ball rifle powders are usually the worst as far as temperature sensitivity goes.

Even then, outside temperatures aside-- (19°f isn't even that cold)-- What was the temperature of the powder inside the rounds? That is the important thing not outside temperatures.

Was the gun left out in the cold overnight? Or was the gun in a warm place until just before the chronograph testing? Or was the gun kept holstered under a coat until just before shooting? If the gun was in a warm car or truck, or under a coat, until just before the shooting (or the gun was shot some on the range just before the chronograph work) then the powder inside the rounds was nowhere near the outside ambient temperatures.

Bottom line here-- I haven't ever noticed cold temps effecting my pistol rounds much as far as speed or accuracy goes but sure can see the effects of very cold temps on my long range rifle (especially 500+ meters).

The biggest effect I find on my pistol rounds in cold ambient temperatures is when shooting suppressed & trying to keep the bullet speed under the speed of sound. The colder it gets the more likely I am to have a bullet creep into the supersonic or high transonic when shooting suppressed.
 

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Discussion Starter #9
Thanks gentleman, I didn't think it would have a dramatic effect on speed and using your calculations Iowegan I can see that. When I do make some rounds to make power factor I planned on giving myself a pretty reasonable margin of error. I see your point too Gunner. It wasn't a very controlled test. The guns and ammo were sitting outside on the bench with us after leaving my friends shop. We drove to the range,about two minutes down the road. One thing we did notice was that all of our first shoots through the chrono seemed to be slower than the other nine. Usually by 150 fps or more. I left the numbers at my buddies unfortunately. Thanks again!
 

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Back in the 80's there was talk that Blue Dot would result in higher pressure in extremely cold weather. :(
First of all I never understood why "cold" would cause higher pressure. :confused:
I know nothing of the details of pistol/shotgun powders in this area.

In rifle powders, it's actually fairly common these days to see _peak_ pressure increase a bit at lower temperature. Note that "lower" is a relative term. It is also very common to see a slight hump or hole/depression in the middle of a curve describing peak pressure vs temperature. That's a consequence of the temperature-compensation characteristics of modern rifle powders.

It is very important to understand that the details and degree of temperature resistance of any powder is different depending upon the cartridge-bullet combination it is used in.

It is also very important to note that barrel temp has a bigger influencer than air/ammo/powder temp, but NOBODY does their testing with both rifle _and_ ammo at 0, 70, and 125F.

There was excellent data available from DuPont decades ago for their single-base IMR powders regarding temperature vs pressure and velocity. Unfortunately, DuPont got rid of their smokeless powder business a long time ago, and General Dynamics (the current manufacturer of most of the IMR powders) is not so forthcoming with that kind of info. Too, GD has completely revamped the IMR manufacturing line/process, so even though we still see powders with the same names as our parents and grandparents used, they are not the same powders chemically or physically. Neither do they have the exact same burning characteristics.

Anyway, there's some good pressure and velocity data in the first post in this thread:
http://65creedmoor.com/index.php?topic=4040.0

Again, I know nothing of pistol/shotgun powders in this realm.
 

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I think there was an article in the "American Rifleman" discussing this in relation to the military and long range shooting. Don't know if this helps?
 

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In response to the previous:

http://www.shootingsoftware.com/ftp/Pressure%20Factors.pdf

of interest barrel temperatures, powder temperatures, and heating cartridges in hot chambers -- heat transfer measurements

with factual data measurements

the math is at about statistics 101 level

references are provided

the February 2015 issue of Handloader magazine is also of interest - especially how the same powder can act differently in different cartridges - a good read but with no actual pressure measurements

lots of stuff on the internet is of no or little value and is undocumented and speculative
 

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Most of my shooting is with home cast bullets, however, I have used quite a few copper plated bullets. I know the manufacturers recommend holding the velocity down to "cast bullet" levels. I've pushed them to 1200 fps. many times and had no problems, other than the fact that they have no crimp groove.

I seriously doubt that a plated bullet would "come apart" any more than a cast bullet does. Leading....maybe, strip the rifling.....maybe, but not come apart.
 

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BassMan, I found the tests in your reference interesting, however; I didn't see any reference to velocity versus temperature ... only chamber pressure. I hope you know, chamber pressure can increase and velocity can chronograph slower so the tests really didn't apply to the OP's question nor did they address handguns at all.

I think Varminterror had the best idea .... just put a loaded magazine in your pants pocket for a few minutes prior to testing for power factor ... not too technical, no charts, graphs, pressure sensors, or thermometers required. Just chronograph your loads and it will work just fine.
 
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