Im new to shooting and I had a question. I zero'd my rifle at 50 degrees (temp), I then shot today at 30 degrees and my POI was roughly 1.5" high. I thought a warmer outside temp increased muzzle velocity and would make my POI lower do to lower muzzle velocity. I did not log the humidity or barometer pressure the day I zero'd (my bad). Could it be higher humidity that caused a higher POI in the colder air? I zero'd my rifle roughly two weeks ago. I'm really curious so I can anticipate the shift next time more accurately. I'm shooting a .308 700P, another guy I shot with shoots a POF .308 and had the same thing happen. Both using 175s. I hope that's enough info. Forgive me if this is in the wrong section.
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Range Report Cold weather
- Thread starter crebrosseau
- Start date
Re: Cold weather
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swan</div><div class="ubbcode-body">I'd say "cold shooter" </div></div>
+1 on the cold shooter...having similar issues out here in the teens.
Only other thing I can think of is a colder barrel makes for a stiffer barrel, which could assist in the change of impact. I'm surprised to hear this about the POF though (a very stiff barrel)...I am shooting the same rifle and haven't had this happen. Get some shots off through a chronograph and when the weather warms up compare velocities and report back!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swan</div><div class="ubbcode-body">I'd say "cold shooter" </div></div>
+1 on the cold shooter...having similar issues out here in the teens.
Only other thing I can think of is a colder barrel makes for a stiffer barrel, which could assist in the change of impact. I'm surprised to hear this about the POF though (a very stiff barrel)...I am shooting the same rifle and haven't had this happen. Get some shots off through a chronograph and when the weather warms up compare velocities and report back!
Re: Cold weather
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">I wouldn't think 20 degrees would make 1.5" of difference. I have had some zero shifts due to temp, but I shoot from 0 deg to 90 deg F. </div></div>
I wouldn't either. Did you change ammo lots? I have had some hanky things happen between different lots of the same ammo.
(Yes, "hanky" is a technical term.)
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">I wouldn't think 20 degrees would make 1.5" of difference. I have had some zero shifts due to temp, but I shoot from 0 deg to 90 deg F. </div></div>
I wouldn't either. Did you change ammo lots? I have had some hanky things happen between different lots of the same ammo.
(Yes, "hanky" is a technical term.)
Re: Cold weather
"Cold shooter" may be it. Or like we'd say when I was deployed. "Gremlins", unexplainable flukes, "gremlins".
"Cold shooter" may be it. Or like we'd say when I was deployed. "Gremlins", unexplainable flukes, "gremlins".
Re: Cold weather
I'd say that's an interesting result.
I'd also say it's anecdotal (it happened this once...), and that the study needs more data before it becomes conclusive.
How a rifle performs is how <span style="font-style: italic">that</span> rifle performs, and sometimes no other rifle.
If it was mine, I'd reserve judgement until I'd done a thorough and repeated shakedown under a wide range of conditions. Usually, you just can't tell from a handful of instances.
Greg
I'd say that's an interesting result.
I'd also say it's anecdotal (it happened this once...), and that the study needs more data before it becomes conclusive.
How a rifle performs is how <span style="font-style: italic">that</span> rifle performs, and sometimes no other rifle.
If it was mine, I'd reserve judgement until I'd done a thorough and repeated shakedown under a wide range of conditions. Usually, you just can't tell from a handful of instances.
Greg
Re: Cold weather
I was out with my 5R this past Saturday. The temperature was 18 degree F, 45 degrees cooler than when I initially sighted it in. Impact point with 3 different factory ammo was the same as before at 100 & 200 yards. Not sure why 20 degrees would make that much difference unless it was extremely temp sensitive powder. I was shooting 168 FGM, 168 TAP, and 168 Remington match. I'd try it again and see the the results stay consistent. Did the results stay the say for the entire shoot?
I've put to rest a couple myths of my own on Saturday. My gun shot the same spot whether the gun was dirty or clean. The warm barrel shot the same as the cold. I thought both would cause some changes. If so, it was not enough to see at 100 or 200 yards. Unfortunately, I'm not close to a longer range.
Paul
Paul
I was out with my 5R this past Saturday. The temperature was 18 degree F, 45 degrees cooler than when I initially sighted it in. Impact point with 3 different factory ammo was the same as before at 100 & 200 yards. Not sure why 20 degrees would make that much difference unless it was extremely temp sensitive powder. I was shooting 168 FGM, 168 TAP, and 168 Remington match. I'd try it again and see the the results stay consistent. Did the results stay the say for the entire shoot?
I've put to rest a couple myths of my own on Saturday. My gun shot the same spot whether the gun was dirty or clean. The warm barrel shot the same as the cold. I thought both would cause some changes. If so, it was not enough to see at 100 or 200 yards. Unfortunately, I'm not close to a longer range.
Paul
Paul
Re: Cold weather
I shot a 3 shot group, 1.5" high. Adjusted accordingly on my elevation knob and hit dead on the rest of the day. So regardless of what caused it I adjusted by 6 clicks and fixed it. That's what's weird, nothing should make it hit that high and that short of range. In a couple days I'll shoot again, it's warming back up, and we'll see if I hit 1.5" low this time (going from 30 back to 50 degrees). I'm shooting 175gr Federal Gold Metal Match, all the same lot and fresh ammo.
I shot a 3 shot group, 1.5" high. Adjusted accordingly on my elevation knob and hit dead on the rest of the day. So regardless of what caused it I adjusted by 6 clicks and fixed it. That's what's weird, nothing should make it hit that high and that short of range. In a couple days I'll shoot again, it's warming back up, and we'll see if I hit 1.5" low this time (going from 30 back to 50 degrees). I'm shooting 175gr Federal Gold Metal Match, all the same lot and fresh ammo.
Re: Cold weather
My 700P is still under 50 rounds down the tube. That may have something to do with it. 34 I think, I'd have to check my log.
My 700P is still under 50 rounds down the tube. That may have something to do with it. 34 I think, I'd have to check my log.
Re: Cold weather
You and the rifle constitute a system. Ask yourself whether the temp difference had an effect on <span style="font-style: italic">you</span>, on how you dressed, relaxed, etc.
Barrel transit time affects recoil. Counterintuitively, a longer (slower) transit time recoils longer, increasing muzzle rise. Whether the temp difference is having this effect, or that much of the effect, is probably questionable. But I do think that somewhere in all of this, it's at least a small factor. The greater the distance, the greater the POI displacement.
You and the rifle constitute a system. Ask yourself whether the temp difference had an effect on <span style="font-style: italic">you</span>, on how you dressed, relaxed, etc.
Barrel transit time affects recoil. Counterintuitively, a longer (slower) transit time recoils longer, increasing muzzle rise. Whether the temp difference is having this effect, or that much of the effect, is probably questionable. But I do think that somewhere in all of this, it's at least a small factor. The greater the distance, the greater the POI displacement.
Re: Cold weather
I am about 50 rounds into the same issue. My current theory is the aluminum egw 20 minute base sandwiched between a steel receiver and steel rings. Delta is 1 minute from 30 to 50 degrees repeated over the course of several outings for my savage 308.
I have the exact same rifle in 223 (both shooting varget) except for a straight weaver base that does not have this issue at temp. If anyone has any input I am all ears.
I am about 50 rounds into the same issue. My current theory is the aluminum egw 20 minute base sandwiched between a steel receiver and steel rings. Delta is 1 minute from 30 to 50 degrees repeated over the course of several outings for my savage 308.
I have the exact same rifle in 223 (both shooting varget) except for a straight weaver base that does not have this issue at temp. If anyone has any input I am all ears.
