Effect of Various Error Factors on Accuracy

[Bwalton]

Nope... You shot.  The first time you showed up to check things out was before that....and I spoke to you on Doug Millers phone while you were there.

I said nothing about seven times....I don't know where you are getting that.....although I have been there six times since last September.

Mike

I shot one time in October thats it thats all...
here is your quote:  I have personally witnessed you shooting 50yds at Joes for many hours on several occasions with nothing decent to show for it......let alone sub MOA at 50 with any regularity.

And when I shot there in October I did not stay long cause the rifle was having problems...

[michaelthomas]

Yes....I acknowledge that is my quote.  What am I supposed to be looking at?  Are you confusing the word several with seven? 

Mike

[Bwalton]

Nope , several means more then two or 3 times...

[SpiralGroove]

Hey Guys,
This thread is starting to resemble the one Bob wrote about the Telephone booth in Coalmont being destroyed.  This is akin to "Reality TV ."  Pretty petty ..................... for two senior members

[michaelthomas]

I had this argument with my wife, once before.  I have spent most of my life thinking several meant more than one....like a few or a couple.  I suspect I erroneously learned that at a young age and it never got corrected because it may have never specifically mattered.   I will clarify and say two. 

I apologize for my misuse of the word several. 

I will also apologize for opening my big mouth......when I should have just kept it shut.  Sorry about that.

I will move on.

Mike

[shorty]

I am not sure about you guys but, this post was the most helpful on accuracy for me bar none. I believe a lot of what others say and what they can do but, I also always trust the math. Too me, there is no voodoo,magic, or personality of a mechanical device. If you have those things, it's because the mechanical device is not capable or the cause is not known and guessed at.

I do believe that Bob's graphical description of trajectory is correct. With that being said, actual mathematical POI and CTC can be calculated and those grouping should be a goal when "practicing".

What would be interesting though is what is an acceptable offset % of the true calculated trajectory of POI (acceptable error %) ?

For me, I can't use hold over for beans. Sometimes it takes at least 2 shots at 50 yards to walk my groups in "using range estimation with my scope" (on a pine cone- those little 1 inch ones).  This is one of those reasons why I do not hunt much. If I can not (or the gun)  perform at getting 5 shot grouping 1" or under at 25 yards, I will not hunt anything 30 yards and under. Forget 50 yards unless I feel I can track whatever I hit (Which is something I don't want to do).

Too me, I think my problem is plain ole ES%. Be it the tune or pellet weight.

Sometimes I will not shoot my full pressure range and put the gun down. The next day (without charging) I will shoot again forgetting what shot number I left off at or what charge I am at for hold over. This really messes me up using an un regulated gun. I can regulate to fix but for me I am constantly forever turning knobs for the best performance or type of shooting I am doing.

Heck, I only have one gun I like shooting (I only say that cause the boss won't let me buy anymore).

[Ribbonstone]

Kind of hoping this would settle down....too good a thread.

There is a kind-of solution to the last post:

Find where the rifle runs its best by testing.  IF it turns out to be (just picking numbers here) 2650psi to 1550psi, then only fill it to 2650 and refill it when it hits 1550.  Basically never go out of the rifle's "comfort zone"; if it has air in it (and hasn't leaked down in pressure) it's ready to shoot as well as it can.

Yeah...can get a lot more shots running from 3K to 1.2K, but you won't get any more or less of the best shots.


BUT, as Bob's post started, there is a whole lot more happening to the pellet on the way to the target than just small velocity variations.

[Tomg]

I wonder how much (chime in Bob) vertical difference headwind cause, even a little, since most pellet have poor BC.

[CptMoonlight]

So, I'm extremely new to the hobby and haven't had near as much trigger time as most of the guys here behind an air rifle. I've gone through a few tins of pellets and love to shoot. This post has been eye opening for me, because like a lot of guys, I got into the hobby because I watched some youtube videos. I'm grateful to some of those guys that have posted online because it has opened up a whole new realm of shooting for me. However, I'm old enough to realize that if it's too good to be true, then it generally is. I'm not talking down on anyone on this post. I appreciate that some guys have been entrepreneurial with airguns and have brought people into the hobby that never would have gotten there on their own.

That being said, I understand the frustration of those who truly know reality, with what is being perceived. I'm in a profession that suffers greatly from the delusion that a layman can understand the nuances of my day to day.

Thank you all for your addition to this post. It has ALL been helpful.

[SpiralGroove]

Well said Captain
You're right, when the numbers don't add up the Technical guy usually has issue with the Salesman .
But that Salesman fills an important role .

[rsterne]

Using the example given, a 2 mph headwind at 100 yards would only slow the pellet by just over 2 fps, and increase the drop by 0.07".... If you increase that to 10 mph, you lose about 12 fps, and the additional drop compared to no wind is 0.35".... On the other hand, a 10 mph crosswind would push the pellet 9.24" off course....

Bob

[HillGSA]

I'm in a profession that suffers greatly from the delusion that a layman can understand the nuances of my day to day.

You do sound like a very wise man... and you have elevated our curiosity to it's highest level, but do we dare ask ? what is your profession - sir ?
You do not have to answer, if you are not comfortable in doing so...


Signed layman     

[HunterOne]

No idea what the BC is, but assuming the bullet loses no velocity at all, 82 yards is 246 ft., so at 1050 fps that would take 0.234 sec.... Maybe 1/4 second?....

I'm thinking anyone watching a video could probably notice a quarter second difference between the shot and the impact???  Longer ranges more noticeable lag...

Of course videos are shot at some number of frames a second, so if someone were so inclined, they could establish the number of actual frames between the shot being fired and the impact of the shot, if someone were so inclined...

Or they could just do it the ez way....trust
 I do not see the benefit to deceive?

I just happened to run upon this post. I have to admit that I have shot with Baxter on several occasions.  I have even had the fortune of  almost beating him in a 97 yard AT44 .22 cal shootout until he grouped five shots at .5 inch ctc which completely blew me away.  On the same day, he hit a 117 yard squirrel shot with the BT65 .25 on the first shot  .  I'm far from an expert on any of this but felt I had to chime in on this conversation. 

The dude is a perfectionist when it comes to shooting.  He puts in more practice time than I could even attempt to.  Practice pays off.

[moorepower]

Wind is a bite in the rear. My varmint shooting is mostly prairie dogs. If you hit them in the head or chest you do not need a moa gun. If you can put a pellet in a 3 inch circle, at 100yds. The pooch will rapidly expire. That being said, if the wind is blowing much, I go to the .17 Hornet or .204, and keep my shots within 200 yds. And still am not embarrassed to miss. The V-Max is a little more forgiving of shot placement than a pellet.

[jvanschoonhoven]

I Love this whole thread even the arguments. Let me try and shed a little light on this from my perspective. I was a professional trials rider on bicycles you ride over obsticl courses and try not to put your foot on the ground. We bunny hop up things  4 to 5 feet tall without a ramp. Anyway I won 5 national championships the north american championship and was in the top 10 in the world.. my first international competition  I went to I was scared to death cause I had seen videos of these guys ride and been on the forums and read. How big of things they could  jump up. I knew I didn't  have a chance against these guys..  end of the day I walked away with the championship.  Moral of the story is doing something till you get it right a few times is one thing.. doing it till you hardly ever get it wrong is completely another.
To be honest anyone claming moa accuracy out to 100 yards with any gun 100% of the time I call BS. I have competed with some of the best pb shooters in the world and none of them would guarantee this level of accuracy. We need to start living in reality! 

Bob back to the orignal post. For hunting knowing your kill zone size and range are huge. For me if it is a long shot I will wait for the gs to stand up so my vertical kill zone is much bigger. I am shooting a .25 at 940fps so the kill zone is a lot bigger then with my .177
Reading the wind is what seprates the men from the boys. Rangefinding can be done very accurately with a quality rangefinder down to 1 yard at 100 yard getting your vertical drop close... one thing that has not even been mentioned is altitude and humidity. Both have an effect on your pellet flight path so thats one more variable  for 1st rd hits.
For the record my longest ground squirrl kill was 110 yards firs shot was "4 low cause I guessed on the range rather then taking time to use my rangefinder. 2nd shot hit the mark.  I am nowhere near shooting Moa consistently at 100 with my pellet gun. Im close with my my competition pb but even then it doesn't happen all the time.

[michaelthomas]

Here is an interesting (and easily provable) fact on air rifle accuracy. 

Indoor 25y benchrest is mostly about the equipment.  It's a worldwide platform that outdoor benchrest shooters use to evaluate their stuff without the influence of the wind.

Basically.....if you drop one point, you have shot outside the MOA "zone"....as the 9 ring is .315" in diameter.  The number of rifles used by the best competitors worldwide that can consistently shoot without dropping one point during a match at 25y indoors is zero.

Mike

[moorepower]

Even if it was a railgun locked in a vice, pellets guns will still have fliers. To "ME" E.S. is the most important thing to try to control, because it is about the only thing I really have any control over! At 100 yds. or even 50 yds. the wind can be blowing 2 different directions and have different values/speed. The shape of the terrain where you are shooting will have a great influence on the wind. What is growing, around the area will have an effect on the density altitude, and the list goes on. The more you shoot the better you "can" get.

[Sfttailrdr46]

  I have seen the effects of wind and once you are skilled with the rifle you are shooting and leaning how it will shoot at distance the deflection of the pellet will be greater as the pellet leaves the rifle than when it is closer to the target.

[rsterne]

Very true, as once the pellet is deflected by a wind near the muzzle, it continues on that new (angled) course all the way to the target.... Thanks to Michael for that initial insight, something obvious I never really thought about until he mentioned it in another thread....

Bob

[jvanschoonhoven]

Bob,
From my understanding of shooting long range rifles 800 to 1,000 yards the wind pushes the bullet more the farther out it is because the bullet is going slower so the wind has more time over the same distance to move the bullet.
Also momentum is less so it is easier to move it. So if there was a 5mph wind left to right for the first 50 yards then it switchs to a 5mph right to left your bullet would go left by quite a bit.

Does this make sense?