Post by cootiekey on Mar 14, 2014 23:59:53 GMT -5
Warning – Long
first – the questions, Second – some data, Third – the story
Questions: Does IMR-700x drastically loose pressure when very cold? Do all shotgun powders perform worse in cold temperatures than pistol powders? How can you find out which pistol powders are temperature stable? What powder does the military use in 9mm ammunition? Is new commercial ammunition more temperature stable than reloads? What powder would you use for 115gr 9mm ammunition with a working temperature range of -10 F to +120 F?
Data: 9mm round, 115 gr FMJ bullet, WSP primer, 4.1 gr IMR-700x powder, - Pistol Taurus 24/7 OSS-DS large frame with 5.25” barrel. Temperature + 20 F.
Story: I was taking a concealed carry (CCW) class for Illinois (passed) and had to shoot 10 rounds each from three very short distances at a very large target. Any pistol could be used for the test (I brought my 9mm Taurus). The shooting test for the CCW class was early in the morning (just after sunrise) and the weather was cold (it got down to +10 F that night). The shooting test was early and I had to drive a while to get to their range - so - I decided to load up my car the night before. This means the ammunition and pistol had plenty of time to cool down to the outside temperature. The temperature reading on my car thermometer was +20 F when I arrived for the test.
Shooting the test was very frustrating because about every third round would stove pipe on ejection. The recoil (though never very much anyway) seemed less that morning. The shot placement was OK. Every round fired. They just didn't have enough energy to cycle the slide and eject the spent case reliably. The slide of the pistol moved as smooth and easy at this temperature as it does in warmer weather, so the firearm was not the problem. Then I remembered that temperature causes performance changes in the powder. ( I have some surplus 8x57 Mauser that is just too Hot so shoot in August). So it seems reasonable there would be some reduction of pressure when it is winter cold outside, but I was surprised how much it dropped off.
I have never shot outside with this pistol/reload in the cold of winter before. I use this combo outside Spring, Summer, Fall, to shoot USPSA. My 9mm Taurus has been consistent and dependable with the reloads I have been using for a few years now. I have gone through 2K rounds of this particular load with out any failures of any kind with consistent groupings (I'm happy with it). It knocks down the large steal targets with no problems (enough KE). I have never chronographed the load though.
I don't want separate loads with heavy powder charges to use only when it is cold outside. Here is one reason why. In my stupid state there are many – many – many places where a person can not carry concealed (no schools, no bars, no parks, on and on and on). If you drive into a parking lot of one of these locations you are required to store your firearm locked inside your vehicle. I assume while you are carrying the firearm close to your body, it will come close to your body temperature, but when it is locked in your car, It can either go through high temperature increases or very low temperature drops. Whatever load I use in that pistol has to shoot reliably over the big temperature swings because my life would be depending on it.
Thanks for any ideas.
first – the questions, Second – some data, Third – the story
Questions: Does IMR-700x drastically loose pressure when very cold? Do all shotgun powders perform worse in cold temperatures than pistol powders? How can you find out which pistol powders are temperature stable? What powder does the military use in 9mm ammunition? Is new commercial ammunition more temperature stable than reloads? What powder would you use for 115gr 9mm ammunition with a working temperature range of -10 F to +120 F?
Data: 9mm round, 115 gr FMJ bullet, WSP primer, 4.1 gr IMR-700x powder, - Pistol Taurus 24/7 OSS-DS large frame with 5.25” barrel. Temperature + 20 F.
Story: I was taking a concealed carry (CCW) class for Illinois (passed) and had to shoot 10 rounds each from three very short distances at a very large target. Any pistol could be used for the test (I brought my 9mm Taurus). The shooting test for the CCW class was early in the morning (just after sunrise) and the weather was cold (it got down to +10 F that night). The shooting test was early and I had to drive a while to get to their range - so - I decided to load up my car the night before. This means the ammunition and pistol had plenty of time to cool down to the outside temperature. The temperature reading on my car thermometer was +20 F when I arrived for the test.
Shooting the test was very frustrating because about every third round would stove pipe on ejection. The recoil (though never very much anyway) seemed less that morning. The shot placement was OK. Every round fired. They just didn't have enough energy to cycle the slide and eject the spent case reliably. The slide of the pistol moved as smooth and easy at this temperature as it does in warmer weather, so the firearm was not the problem. Then I remembered that temperature causes performance changes in the powder. ( I have some surplus 8x57 Mauser that is just too Hot so shoot in August). So it seems reasonable there would be some reduction of pressure when it is winter cold outside, but I was surprised how much it dropped off.
I have never shot outside with this pistol/reload in the cold of winter before. I use this combo outside Spring, Summer, Fall, to shoot USPSA. My 9mm Taurus has been consistent and dependable with the reloads I have been using for a few years now. I have gone through 2K rounds of this particular load with out any failures of any kind with consistent groupings (I'm happy with it). It knocks down the large steal targets with no problems (enough KE). I have never chronographed the load though.
I don't want separate loads with heavy powder charges to use only when it is cold outside. Here is one reason why. In my stupid state there are many – many – many places where a person can not carry concealed (no schools, no bars, no parks, on and on and on). If you drive into a parking lot of one of these locations you are required to store your firearm locked inside your vehicle. I assume while you are carrying the firearm close to your body, it will come close to your body temperature, but when it is locked in your car, It can either go through high temperature increases or very low temperature drops. Whatever load I use in that pistol has to shoot reliably over the big temperature swings because my life would be depending on it.
Thanks for any ideas.