I know it sounds weird but let me explain.
Maybe wrong forum even but whatever!
I have posted before about my POI changing from Warm Temps to Cold temps. I eliminated ammo by conducting a field experiment.
Zero @ 40* F and Up POA = POI. When temps dip below 40* F the POI needs to be raised 3/4 MOA Up to hit POA. It seems to be consistent.
Started to think about the dynamics of the rifle.
Decided to get the Bore Sighter out. I put the rifle outside in 35* weather and place the bore sighter in place and left it for a while.
I then adjusted the turrets to match up with one of the grid lines and left it a little longer.
After a while I brought it in being careful not to bump or move the bore sighter. I recorded the location of the reticle and left it all set inside (69* F) for several hours. I then looked through the scope to see the location of the reticle.
I found that it moved with out touching a thing. I made a turret adjustment to put it back where it was outside. 6 clicks (IPHY) down to get it back to the same spot. Which means POI would have gone up about 1 1/2 IPHY from 35* to 69*.
I have never actually experienced this much change but I am seeing 3/4 change consistently. And yes, I know this it not a precise method of testing this but none the less, it is moving.
A while back I was having POI shifts when the rifle was impacted on the ground. I had the front lug bedded by a very talented local Smith (in other words I trust him completely). I then found that the torques specs had changed for AI from approximately 53 in/lbs to a little over 88 in/lbs. When I torqued it to these specs the rifle shot POA = POI even when impacting the rifle on the ground pretty hard.
But, it seems now that I am getting this 3/4 moa change that was not there before.
It should be noted that I did not have the rear part of the receiver bedded. Only the area around the front lug back to the magazine well. There does not seem to be any movement in the rear of the receiver when torquing it down but could the whole thing be "warping" in the different climates?
I am in stage two of the test right now. I loosened the torque on the chassis to where it is just holding the barreled action. Not even finger tight. I adjusted the ret. to coincide with a grid line and put it all back outside. I am now waiting for the results of that. I am surmising that if the ret. doesn't move then the torque/chassis/bedding may be the issue. If it does, then well, Scope/Base/Rings combination may be it.
FYI - USO SN3 Tpal 3.2x17 - Seekins Precision (6x4 Ring Set) - Factory AI AE Rail mounted with 8-40 Screws
Thought about posting this in the Gun Smith Forum so I could get some input from them, but, range report and exterior ballistics (even though this is not a direct bullet parameter) seemed to make more sense.
Thanks for looking!
Maybe wrong forum even but whatever!
I have posted before about my POI changing from Warm Temps to Cold temps. I eliminated ammo by conducting a field experiment.
Zero @ 40* F and Up POA = POI. When temps dip below 40* F the POI needs to be raised 3/4 MOA Up to hit POA. It seems to be consistent.
Started to think about the dynamics of the rifle.
Decided to get the Bore Sighter out. I put the rifle outside in 35* weather and place the bore sighter in place and left it for a while.
I then adjusted the turrets to match up with one of the grid lines and left it a little longer.
After a while I brought it in being careful not to bump or move the bore sighter. I recorded the location of the reticle and left it all set inside (69* F) for several hours. I then looked through the scope to see the location of the reticle.
I found that it moved with out touching a thing. I made a turret adjustment to put it back where it was outside. 6 clicks (IPHY) down to get it back to the same spot. Which means POI would have gone up about 1 1/2 IPHY from 35* to 69*.
I have never actually experienced this much change but I am seeing 3/4 change consistently. And yes, I know this it not a precise method of testing this but none the less, it is moving.
A while back I was having POI shifts when the rifle was impacted on the ground. I had the front lug bedded by a very talented local Smith (in other words I trust him completely). I then found that the torques specs had changed for AI from approximately 53 in/lbs to a little over 88 in/lbs. When I torqued it to these specs the rifle shot POA = POI even when impacting the rifle on the ground pretty hard.
But, it seems now that I am getting this 3/4 moa change that was not there before.
It should be noted that I did not have the rear part of the receiver bedded. Only the area around the front lug back to the magazine well. There does not seem to be any movement in the rear of the receiver when torquing it down but could the whole thing be "warping" in the different climates?
I am in stage two of the test right now. I loosened the torque on the chassis to where it is just holding the barreled action. Not even finger tight. I adjusted the ret. to coincide with a grid line and put it all back outside. I am now waiting for the results of that. I am surmising that if the ret. doesn't move then the torque/chassis/bedding may be the issue. If it does, then well, Scope/Base/Rings combination may be it.
FYI - USO SN3 Tpal 3.2x17 - Seekins Precision (6x4 Ring Set) - Factory AI AE Rail mounted with 8-40 Screws
Thought about posting this in the Gun Smith Forum so I could get some input from them, but, range report and exterior ballistics (even though this is not a direct bullet parameter) seemed to make more sense.
Thanks for looking!
