POI shift ?

[JimNM]

MOA and MRAD (aka:MIL) have ZERO to do with accuracy. Accuracy is in the ballistics.

MOA and MRAD are measures of resolution. An accurate gun with a crappy scope is still an accurate gun. A crappy gun with a great scope is still a crappy gun. The two variables do not correlate.

Sorry to drag the topic away from the OP. I will go quietly back to my corner.

 

[CoyoteGod]

It also depends on what scope you have. In example a 1/4 MOA scope might not show a POI change at 100 yards as much as what a 1/10th MOA scope would.

This is a very common misconception that MIL is more accurate than MOA and it simply isn’t. MOA in the clock face is a smaller unit of measurement over distance, even though MIL has more clicks. MIL is used and adopted by the military and competition because it’s the most used worldwide, that is the best benefit, over than mathematically MIL is often easier for dial rotation calculations for long distance in your head.

 

[CoyoteGod]

MOA and MRAD (aka:MIL) have ZERO to do with accuracy. Accuracy is in the ballistics.

MOA and MRAD are measures of resolution. An accurate gun with a crappy scope is still an accurate gun. A crappy gun with a great scope is still a crappy gun. The two variables do not correlate.

Sorry to drag the topic away from the OP. I will go quietly back to my corner.

Seriously. This has been beatin lmao! Back to POI!

 

[Vetmx]

When you have guns on one side of the safe that never experience it, some for 7+ years, and guns on the other side that do, that kinda rules out excuses blaming everything except your favorite toy. Especially when you’re using the same optics. When you physically fix the issue and understand what caused it, there’s no need to debate it. Fixing a pellet POI shifter can be different than fixing a slug POI shifter. Different factors to consider.

 

[Vetmx]

MOA and MRAD (aka:MIL) have ZERO to do with accuracy. Accuracy is in the ballistics.

MOA and MRAD are measures of resolution. An accurate gun with a crappy scope is still an accurate gun. A crappy gun with a great scope is still a crappy gun. The two variables do not correlate.

Sorry to drag the topic away from the OP. I will go quietly back to my corner.

This is funny and true. I’m currently dealing with a crappy shooter. After tons of testing and then some machining, still crap. So I tossed a $2k optic on just to be sure. If it wound up being the scope, it would give me an excuse to beat myself up for a week. Nope, still a crappy shooter.

 

[Gerry52]

The most I've ever had poi shift is MAYBE a click or two but most times NONE. My FX Boss, Royale 500 & Bobcat .22 are amazing that way. I traded my Bobcat for an Edgun r3 long, .22 & it doesn't seem to suffer poi shift either! Is it LUCK or the platforms I choose?

 

[ocdairgunner]

I experienced POI shift from both of my PCP’s. Do keep in mind that I shoot from my room where temperature is rather consistent (within 68-72F). Outside temperature however is always changing and so is wind speed and direction. The target I zero my PCP’s is 45 yards from my room window. Every time I have had a POI shift, it has been horizontal, thus making me turn the scope adjustment knobs 3-5 clicks to get back to zero. Could it be my scope? Most likely, but I think wind plays a part too. At 45 yards - 2-5 mph breeze can cause drift. Sometimes I get frustrated because it’s hard to tell if it’s me, the gun or scope, projectile (slugs in Taipan and pellets in the FX) or other factors. I have just accepted it and chalk it up to the quirks of this hobby.

I would really like to have access to an indoor range where I can test both my PCP’s. Taking away the wind and temperature as variables. This way I could test zero at 50,75 and 100 yards on a day to day basis and see of its the gun, scope, or me.

 

[ThE PuNiShEr]

I experienced POI shift from both of my PCP’s. Do keep in mind that I shoot from my room where temperature is rather consistent (within 68-72F). Outside temperature however is always changing and so is wind speed and direction. The target I zero my PCP’s is 45 yards from my room window. Every time I have had a POI shift, it has been horizontal, thus making me turn the scope adjustment knobs 3-5 clicks to get back to zero. Could it be my scope? Most likely, but I think wind plays a part too. At 45 yards - 2-5 mph breeze can cause drift. Sometimes I get frustrated because it’s hard to tell if it’s me, the gun or scope, projectile (slugs in Taipan and pellets in the FX) or other factors. I have just accepted it and chalk it up to the quirks of this hobby.

I would really like to have access to an indoor range where I can test both my PCP’s. Taking away the wind and temperature as variables. This way I could test zero at 50,75 and 100 yards on a day to day basis and see of its the gun, scope, or me.

Hi mate, here's something I think I can help with. The fact that the outside temperature is different from that of the room you're shooting from and the rifle is tempered to it, does not affect the velocity, for those 45 yards to the target, the projectile cannot be affected by this temperature difference. Play with the wind completely and check the speed of the shots again. I think it's unnecessary to fill your head with nonsense like barrel indexing and so on Today, my hobby friends and I spent 3-4 hours shooting 250-300 shots at a distance of 100 m in the Extreme Benchrest discipline. I would say that I am satisfied with the day, I again scored 210+ points for a non-professional like me

 

[ocdairgunner]

Hi mate, here's something I think I can help with. The fact that the outside temperature is different from that of the room you're shooting from and the rifle is tempered to it, does not affect the velocity, for those 45 yards to the target, the projectile cannot be affected by this temperature difference. Play with the wind completely and check the speed of the shots again. I think it's unnecessary to fill your head with nonsense like barrel indexing and so on Today, my hobby friends and I spent 3-4 hours shooting 250-300 shots at a distance of 100 m in the Extreme Benchrest discipline. I would say that I am satisfied with the day, I again scored 210+ points for a non-professional like me View attachment 572462View attachment 572463View attachment 572461

Thanks friend. I will keep that in mind the next time I set-up my targets. I have tested my first shot velocity from both by PCP's and I am very lucky to have them tuned really well. The Taipan shoots the H&N 25 grain slugs at 940fps and the FX Wildcat shoots the 44.75 grain JSB's at 895 fps. Through my various tests, the first shot after the guns have sat overnight or for multiple days have been within 5 fps of their average. My issues I believe is from my trigger pull and wind causing the POI shift. I will have to be mindful next time I shoot and perhaps use a gun rest to shoot so it takes out the trigger pull issue/variance from the equation.

 

[jjwoody03]

Ive had a classic FX rifle for several years and the first thing I noticed was the barrel, which is basically free floated from the breech was not very rigid and I was always checking the zero every time I took it out of the cabinet. Once I installed a barrel band to increase the stiffness of the barrel the re-zeroing problem went away...

 

[Solo1]

You claimed a MRAD scope would "show" POI drift more clearly than a MOA scope.

Poppycock says I. All too common for people to confuse POI (ballistics) and POA (optics) - however, that is a topic for another thread.

POI drift in center-fire and rimfire has much more to do with heating and cooling. My PCP collection (no FX in my bunch) does not suffer from POI shift from (gun) internal sources.

What are you quoting me for i said nothing about the scope?

 

[JEFFPPC]

It also depends on what scope you have. In example a 1/4 MOA scope might not show a POI change at 100 yards as much as what a 1/10th MOA scope would.

What does the click value have to do with POI change. Nothing!

 

[JimD]

I changed my tune (HS) for my Caiman X because of velocity inconsistencies and target shooting significant POI shifting for the first 5-10 shots. It was tuned for about 875 with 18 grain H&Ns and is now tuned for about 910 fps with the same pellet. First shot goes where the rest go now and velocity is much more consistent. My 30 yard challenge score at 875 was decent but I've done better over 900 and hope to do so again. I think generally accurate pellets and tunes give better ES but I don't always see that.

But more to the POI point, when shooting a 30 yard challenge target I often seem to experience small, like 1/4 inch shifts in POI. Only for a shot or two. It may be wind but sometimes I cannot see a shift in my wind flags that matches. But I am not looking at the wind flags right when I squeeze the trigger. I am also sure that when I don't concentrate on my trigger pull I can pull or push the POI. So I work on that. The Caiman barrel seems to be free floated and the trigger is the lightest of my PCPs at about 2 ounces (and it's consistent). There is lead fouling in the barrel I have not been able to remove so that is another possibility. I've shot one 200 with the Caiman but more typically it is in the 190s. Plenty good enough for pesting but it can be a little frustrating on targets.

I traced unusual inaccuracy in my P35-22 to loose stock attachment bolts. That gun is less fussy than the Caiman and just as accurate. The trigger is not as good but decent. But the POI seems to move a little with it too. It may all be unseen shifts in the wind. A chance to shoot at 30 yards indoors would be very useful.

 

[JimNM]

What are you quoting me for i said nothing about the scope?

The post I quoted had been removed, and the system picked up your post Instead. I have had it edited to remove the confusion.

 

[Troy Bakel]

Using a Targetshooting.com 1 piece rest, my 30 cal M3 is zeroed at 20 yards indoors and tuned for 45 grain diabolo pellets.

I took the average edge to edge measurement for ten 5 pellet groups, divided that average measurement by 2 and calculated via "rise over run" what my dispersion area size would be at 100 yards.

The dispersion area was slightly less than the area of a diamond being 2 inches from top tip to bottom tip and 2 inches from left tip to right tip.

I left the rifle zeroed at 20 yards and outdoors I shoot that 2" diamond at 20, 30, 40, 50, and 60 yards. I shoot sitting at a bench using a bipod and my right shoulder and left hand, no rear rest.

When I thought I had a POI shift I would check the rifle indoors at 20 yards using an NRA AR 5/10 target and the 1 piece rest. 1st round of each group always smashed the center dot ( expected for a 30 cal diabolo being thrown at a .177 target) and the average dispersion size of the 10 groups always remained the same.

I found that my POI shifts outdoors were due to:

1. Trigger pull
2. Grip
3. Cheek weld
4. Breathing
4. Bipod Torque
5. Not loading the bipod forward
6. Too much shoulder
7. Too much left hand on the butt stock

 

[Vetmx]

Using a Targetshooting.com 1 piece rest, my 30 cal M3 is zeroed at 20 yards indoors and tuned for 45 grain diabolo pellets.

I took the average edge to edge measurement for ten 5 pellet groups, divided that average measurement by 2 and calculated via "rise over run" what my dispersion area size would be at 100 yards.

The dispersion area was slightly less than the area of a diamond being 2 inches from top tip to bottom tip and 2 inches from left tip to right tip.

I left the rifle zeroed at 20 yards and outdoors I shoot that 2" diamond at 20, 30, 40, 50, and 60 yards. I shoot sitting at a bench using a bipod and my right shoulder and left hand, no rear rest.

When I thought I had a POI shift I would check the rifle indoors at 20 yards using an NRA AR 5/10 target and the 1 piece rest. 1st round of each group always smashed the center dot ( expected for a 30 cal diabolo being thrown at a .177 target) and the average dispersion size of the 10 groups always remained the same.

I found that my POI shifts outdoors were due to:

1. Trigger pull
2. Grip
3. Cheek weld
4. Breathing
4. Bipod Torque
5. Not loading the bipod forward
6. Too much shoulder
7. Too much left hand on the butt stock

Having a default test that almost can’t be screwed up is very smart. It saves time chasing ghosts. But if it fails, then it’s almost definitive and then it’s time to get to work figuring out why.

 

[Revoman]

I believe that much of the POI changes are from not adjusting the parallax properly. There are plenty of videos out there showing those minute changes, all due to parallax error.
Just my 2¢.

mike

 

[CoyoteGod]

The most I've ever had poi shift is MAYBE a click or two but most times NONE. My FX Boss, Royale 500 & Bobcat .22 are amazing that way. I traded my Bobcat for an Edgun r3 long, .22 & it doesn't seem to suffer poi shift either! Is it LUCK or the platforms I choose?

OR is it your tuning? I don’t know, I am not the greatest tuner, but maybe a better tune means a better harmonic Airgun and subsequent less POI? Seems reasonable.

 

[Vana2]

IMHO, people don't shoot enough shots to get a statically relevant zero and again not enough to determine if that zero has really shifted.

I shoot a 50 shot "report card" to test the accuracy of the system (gun, optics, projectiles and the shooter) under the current conditions. I use five 5-shot groups to check the zero and 25 single-shot targets to get a clear view of where each shot is going. I measure group size and the delta (POA to POI) to come up with a number to compare how well we did.

As mentioned above, there's lots of variables that can affect the accuracy from session to session. In shooting multiple 50 shot report cards and comparing them I get to know the capabilities of the system. Being perfectly honest, shooter input and focus (or the lack of focus) seems to be the biggest variable, it's just very easy to shift the blame elsewhere.

Cheers!

 

[JEFFPPC]

IMHO, people don't shoot enough shots to get a statically relevant zero and again not enough to determine if that zero has really shifted.

I shoot a 50 shot "report card" to test the accuracy of the system (gun, optics, projectiles and the shooter) under the current conditions. I use five 5-shot groups to check the zero and 25 single-shot targets to get a clear view of where each shot is going. I measure group size and the delta (POA to POI) to come up with a number to compare how well we did.

As mentioned above, there's lots of variables that can affect the accuracy from session to session. In shooting multiple 50 shot report cards and comparing them I get to know the capabilities of the system. Being perfectly honest, shooter input and focus (or the lack of focus) seems to be the biggest variable, it's just very easy to shift the blame elsewhere.

Cheers!

View attachment 572668

Well it's not practical in real life which to me would be either a match or a hunting situation to shoot a 50 shot warm up. But given you have a 50 shot warm up target to me you obviously need a click or so down. Windage looks pretty good although shot with no flags is suspect. What would be interesting would be to shoot the same format several days in a row with no scope changes and see if the results are parallel. Even better if you did it with at least one flag do you don't shoot in any reverses but in similar conditions. Shooting your individual dots shows more pertinent information than shooting groups. Good thread. The information you have with your target needs to be gathered with maybe 10 shots or less at a timed competition.