Well I decided to try a test and see what effect ammo temp has on accuracy with "match" 22LR. I was using Lapua Center X for the test which has proven to be very consistant for me out of my Sauer 200 TR. I have only had the rifle for 6 months or so therefore I have not had a chance to shoot it in the cold weather. I know that 22LR can be frustrating at best in sub 40F temps. So here we go with my very unscientific test.
The rifle and ammo as stated have proven to be very accurate and consistant for me in warmer temps. With this combo I can expect 1/2 MOA at 50 yds and 100 yds with ease. I have seen much better than that more than occasionally, but we will leave it at 1/2 MOA as the control.
I took a box of Lapua Center X that was room temp and put it into my lunch box also room temp and put my Kestrel and a chemical heater (the kind in the pouch that you shake up). It road in the floor board of my car with the heat on it to the range. I then took a second box and left it in the trunk on the way to the range.
At the range I left the rifle in the case and in the car to stay warm as I set up my targets. I then quickly set up the rifle and had my lunch box next to me. I removed 5 rounds at a time working as fast as I could to keep the temp up for the "warm ammo" and quickly loaded them. I shot 4 groups of 5 rounds at 50 yards tring to shoot quick enough as to not let the ammo cool in the mag.
Here is the rifle with the "warm ammo"
Kestrel showing the temp of the warm ammo. It started out at 63F and quickly dropped to 58F just in the time it took me to pull it out and snap a pic. The air temp was right at 20F. So during this test the warm ammo was between 63F and 52F.
As I shot the warm ammo and whial I shot my TRG I let the other box set out and "cold soak" I kept my Suunto next to it. The cold ammo and rifle set out for about 2 hours. So by the time I was ready to shot this round it was pretty cool. My watch read 23F, my phone read 17F, and my car read 20F. So we will go with 20F for the cold ammo.
BM11 shot this round for me (b/c he enjoys showing me up with my own rifle). Again it was the same 4 groups of 5 rounds. I was not worried about having a different shooter do this round as we both are about the same for the most part. Here is the target, cold ammo in on the green targets (disreguard the group to the top of the green targets) and warm is on the pinkish targets:
So as you can see there was not a big difference in accuracy. The warm ammo agged out at 0.488" and the cold ammo agged out to 0.502". I was a bit shocked by the results, I would have thought the warm ammo would of done better. As I said this rifle and ammo is usually very consistant. There was a little wind blowing but nothing major. I know this dosnt prove anything but it just makes me think, could rimfire accuracy have more to do with the density of the cold air than actual ammo temp? I know when I was shooting the warm ammo it felt warm and the lube was slick as it usually is. The cold ammo was well cold and the lube was thicker. Maybe it has to do with bore temps and its impact on lube and bullet? Hell I dont know, I just felt like screwing around. One thing is for sure I am going to keep looking into this b/c it is intresting!
I would appreciate any thoughts or test that others may have ran in these conditions. I would also like any suggestions as to other things to try with cold rimfire. I am going to buy some biathlon ammo to try if I can find any...
Also a side note my POI was the same as it has been all along (no major impact shift). And the other thing which is just cool to mention each group the first shot with the warm ammo went into the center of the target (the 3rd group was slightly left) but it was close.
The rifle and ammo as stated have proven to be very accurate and consistant for me in warmer temps. With this combo I can expect 1/2 MOA at 50 yds and 100 yds with ease. I have seen much better than that more than occasionally, but we will leave it at 1/2 MOA as the control.
I took a box of Lapua Center X that was room temp and put it into my lunch box also room temp and put my Kestrel and a chemical heater (the kind in the pouch that you shake up). It road in the floor board of my car with the heat on it to the range. I then took a second box and left it in the trunk on the way to the range.
At the range I left the rifle in the case and in the car to stay warm as I set up my targets. I then quickly set up the rifle and had my lunch box next to me. I removed 5 rounds at a time working as fast as I could to keep the temp up for the "warm ammo" and quickly loaded them. I shot 4 groups of 5 rounds at 50 yards tring to shoot quick enough as to not let the ammo cool in the mag.
Here is the rifle with the "warm ammo"
Kestrel showing the temp of the warm ammo. It started out at 63F and quickly dropped to 58F just in the time it took me to pull it out and snap a pic. The air temp was right at 20F. So during this test the warm ammo was between 63F and 52F.
As I shot the warm ammo and whial I shot my TRG I let the other box set out and "cold soak" I kept my Suunto next to it. The cold ammo and rifle set out for about 2 hours. So by the time I was ready to shot this round it was pretty cool. My watch read 23F, my phone read 17F, and my car read 20F. So we will go with 20F for the cold ammo.
BM11 shot this round for me (b/c he enjoys showing me up with my own rifle). Again it was the same 4 groups of 5 rounds. I was not worried about having a different shooter do this round as we both are about the same for the most part. Here is the target, cold ammo in on the green targets (disreguard the group to the top of the green targets) and warm is on the pinkish targets:
So as you can see there was not a big difference in accuracy. The warm ammo agged out at 0.488" and the cold ammo agged out to 0.502". I was a bit shocked by the results, I would have thought the warm ammo would of done better. As I said this rifle and ammo is usually very consistant. There was a little wind blowing but nothing major. I know this dosnt prove anything but it just makes me think, could rimfire accuracy have more to do with the density of the cold air than actual ammo temp? I know when I was shooting the warm ammo it felt warm and the lube was slick as it usually is. The cold ammo was well cold and the lube was thicker. Maybe it has to do with bore temps and its impact on lube and bullet? Hell I dont know, I just felt like screwing around. One thing is for sure I am going to keep looking into this b/c it is intresting!
I would appreciate any thoughts or test that others may have ran in these conditions. I would also like any suggestions as to other things to try with cold rimfire. I am going to buy some biathlon ammo to try if I can find any...
Also a side note my POI was the same as it has been all along (no major impact shift). And the other thing which is just cool to mention each group the first shot with the warm ammo went into the center of the target (the 3rd group was slightly left) but it was close.
