Nodes, Antinodes and Standing waves?

[gohring3006]

I have always worked my loads up at a bench with bipod and rear bag.
I have decided to switch to prone for all of my shooting. Do you guys think I should rework my loads? Or have you experienced the same load work up being "the one", regardless of being on the bench or prone. I understand I'll have to re zero, but I'm wondering if I should do a new work up. Thanks

Ps. Midway has thier competition shooting mat on sale for $24.99.

Edited to add.... I will be using the same set up, bipod and read bag in the prone position...

 

[Rich Coyle]

I understand I'll have to re zero, but I'm wondering if I should do a new work up. Thanks .

Why would you have to re-zero? I don't understand.

 

[gohring3006]

Why would you have to re-zero? I don't understand.

Well, I'm not really sure... But I have tried prone a few times before making this decision. And every time I tried it, my zero was shifted... I have only tried it with one of my rifles, and the zero shifted to high left, about 1.5 MOA in both directions. It could have been rifle or scope cant, not sure, but I did have a bubble level and everything seemed to be level. I haven't really shot enough to determine the culprit, or if it's just a change in position causing it. I wonder if the harmonics are different???

 

[RockyMtnMT]

Well, I'm not really sure... But I have tried prone a few times before making this decision. And every time I tried it, my zero was shifted... I have only tried it with one of my rifles, and the zero shifted to high left, about 1.5 MOA in both directions. It could have been rifle or scope cant, not sure, but I did have a bubble level and everything seemed to be level. I haven't really shot enough to determine the culprit, or if it's just a change in position causing it. I wonder if the harmonics are different???

I would say it has to do with how you influence the rifle differently in the two positions. Also head position. Does your scope have parallax adj?

Steve

 

[gohring3006]

I would say it has to do with how you influence the rifle differently in the two positions. Also head position. Does your scope have parallax adj?

Steve

Yes it does Steve, and that's a good point that I haven't thought of... Head position could be changing parallax... That's very good input...thanks

 

[MudRunner2005]

When I let one of my buddies shoot my rifles the groups are always the same, but shifted POI. The only thing I can come up with is that we line-up on the scope differently, which is causing the shift in POI.

I would guess that going from bench to prone, you are not lining up on the scope the exact same way, which is causing your POI shift.

I could be wrong, but just throwing it out there.

 

[gohring3006]

When I let one of my buddies shoot my rifles the groups are always the same, but shifted POI. The only thing I can come up with is that we line-up on the scope differently, which is causing the shift in POI.

I would guess that going from bench to prone, you are not lining up on the scope the exact same way, which is causing your POI shift.

I could be wrong, but just throwing it out there.

I would say you're probably right Mudd. My biggest concern is load work up. I wonder if the different position is changing harmonics enough to warrant a different work up. I'm going to have to shoot both ways and see. But being you and your buddies always seem to shoot the same groups just in a different location could mean I'm over thinking it... Two people holding the rifle different but shooting the same size groups is a good indicator there isn't much change in harmonics...

 

[MudRunner2005]

I would say you're probably right Mudd. My biggest concern is load work up. I wonder if the different position is changing harmonics enough to warrant a different work up. I'm going to have to shoot both ways and see. But being you and your buddies always seem to shoot the same groups just in a different location could mean I'm over thinking it... Two people holding the rifle different but shooting the same size groups is a good indicator there isn't much change in harmonics...

As long as nothing is touching the barrel, and your loads are the exact same, your harmonics should be the exact same...At least, I would think so. And you said you are still using a bag/bipod setup, so I would also think that harmonics should not be affected. But thats all conjecture. It's hard to diagnose over the interwebz.

 

[dsculley]

I shoot right hand, my son shoots left hand. If we shoot the same rifle, our zero is different but the groups remain the same. In the Carlos Hathcock biography, he stated there was one other sniper in his unit that he preferred as his spotter because they shot the same zero. As was said earlier, if you change your cheek weld or other little things your zero can change. If you change the position of the bipod on the rifle, the groups COULD change, but a change from bench to prone would not suggest a change in bipod mounts.

I am in agreement that your zero MAY be change but the load should still be good. With that said, "the proof is in the pudding" so now you have a good excuse to log some trigger time!

 

[RockyMtnMT]

If changing shooting position always changes your poi then we are in trouble for hunting. My shooting position in a hunting situation is rarely the same. I do not notice a wandering poi with different shooting positions. I think it is a head position change moving the cross hairs in the scope. If you do not have your scope set up properly and are using the parallax adjustment as a focus instead of using it to take the motion out of the cross hair then a difference in cheek weld will make a difference in poi. Correct me if I am wrong. I don't think Hathcock had parallax adjustment. So cheek weld from one guy to another would change poi. Even with parallax adjustment it is still important to get consistent cheek weld but not as important in order to get a consistent poa. Get down on your rifle and look through the scope. While looking move your head around slightly and see if your cross hair stays put or moves as your head does. If it moves then adj the parallax until it stays still while your head is moving. Adjust your eye piece to get the image in focus.

There used to be a sticky about how to set up a scope. I am sure it is still there. Worth looking at.

Steve

 

[gohring3006]

I really don't remember readjusting parallax prior to taking the prone shots, so that is most likely the problem. I'm going to test this further, I do believe going from a hard concrete bench to the softer loose dirt with the bipod legs is something I want to research further...

I think ther are numerous things that can influence the POI if they are not takin into account, and duplicated or at the least compensated for...


Interesting....lightbulb

 

[RockyMtnMT]

I really don't remember readjusting parallax prior to taking the prone shots, so that is most likely the problem. I'm going to test this further, I do believe going from a hard concrete bench to the softer loose dirt with the bipod legs is something I want to research further...

I think ther are numerous things that can influence the POI if they are not takin into account, and duplicated or at the least compensated for...


Interesting....lightbulb

I am one of the odd fellows that does not like to shoot off a bipod. I can not seem to get same poi all the time. I like to shoot off a bag or backpack or whatever so that the rifle can free recoil. Every now and then I stick a bipod on and give it a go because I think I should use one like everybody else. One session later it is off. I like to lay the rifle on something and get it aimed so that it stays on target without me. Then get behind it and influence it a little as possible and let er eat.

Steve

 

[ColoYooper]

Nodes, Antinodes and Standing waves are unchanged...so there is no need to further wear out your barrel in developing a new load. However, your cheek pressure, shoulder pressure, body alignment, grip, eye relief, trigger engagement, and bipod loading, may have all changed causing the rifle to recoil differently, causing a POI shift. In competing in Tactical Rifle competitions where you are guaranteed to be shooting in every possible, awkward position imaginable by the sadistic match director, I've become more aware than I previously was, to the above effects. I've found with attention to consistency to pressure in the above listed areas, that I can minimize the POI shift in different positions. ps if I were to pick two from above, I'd say cheek pressure and bipod loading.

 

[gohring3006]

Nodes, Antinodes and Standing waves are unchanged...so there is no need to further wear out your barrel in developing a new load. However, your cheek pressure, shoulder pressure, body alignment, grip, eye relief, trigger engagement, and bipod loading, may have all changed causing the rifle to recoil differently, causing a POI shift. In competing in Tactical Rifle competitions where you are guaranteed to be shooting in every possible, awkward position imaginable by the sadistic match director, I've become more aware than I previously was, to the above effects. I've found with attention to consistency to pressure in the above listed areas, that I can minimize the POI shift in different positions. ps if I were to pick two from above, I'd say cheek pressure and bipod loading.

Good info thanks...
I'm actually going to switch Bipods to a Atlas, it just seems easier to load the same every time. The Harris types are fine but can be finicky to load when trying different positions. I'm sure I can get better at loading with practice...