GTA

All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: UlteriorModem on October 15, 2018, 09:57:33 PM

Title: Explain to me why.. parallelax??
Post by: UlteriorModem on October 15, 2018, 09:57:33 PM
So I was putzing around with the Mayhem. Trying a couple of different 'holds', benched. Same distance, same pellets, same weather, same technique, trigger pull etc.

First I tried just resting the gun on the bag and a loose shouldering. It shot pretty well.

Then I tried the 'artillery hold' with the left hand resting on the bag and the gun resting on the open palm, not gripped, with a light shoulder hold.

Much to my surprise and bewilderment, the rounds with the 'artillery hold' were 2 to 3 inches lower than just resting on the bag. It was a good group but lower.

I was just wondering why or how that could actually be? How can raising the 'rest point' of the stock by the thickness of my palm cause that much difference?
Title: Re: Explain to me why.. parallelax??
Post by: Taso1000 on October 15, 2018, 10:06:42 PM
You are changing the harmonics of the system.  The system is the rifle, pellet, support, yourself and the environment.

Changing your hold on the rifle and even different pellets changes the harmonics of the rifle and thus the muzzle position as the pellet exits.

So basically you have to find the way the system will produce the best accuracy and repeat the process.

Some systems are more sensitive to changes than others.  The system is the rifle, pellet, support, yourself and the environment.

Taso

Title: Re: Explain to me why.. parallelax??
Post by: UlteriorModem on October 15, 2018, 10:57:47 PM
Quote
You are changing the harmonics of the system

Ah I almost understand. Wow springers are tough to tame.
Title: Re: Explain to me why.. parallelax??
Post by: Taso1000 on October 15, 2018, 11:15:14 PM
Here are a couple videos to get an idea on what is going on. 

https://www.youtube.com/watch?v=OksIysh0eTU (https://www.youtube.com/watch?v=OksIysh0eTU)

https://www.youtube.com/watch?v=OYm_tI7mbBw (https://www.youtube.com/watch?v=OYm_tI7mbBw)

https://www.youtube.com/watch?v=oo0W9hP3M5Y&app=desktop (https://www.youtube.com/watch?v=oo0W9hP3M5Y&app=desktop)

A barrel wags in 360 degrees, not just up or down.

Thanks,

Taso
Title: Re: Explain to me why.. parallelax??
Post by: xtred1 on October 15, 2018, 11:41:10 PM
These videos should be stickies. (maybe they are and I missed them)
Title: Re: Explain to me why.. parallelax??
Post by: Taso1000 on October 15, 2018, 11:57:12 PM
They aren't but they should be.  I just dug them up.

Thanks,

Taso
Title: Re: Explain to me why.. parallelax??
Post by: 19Sheridan57 on October 16, 2018, 08:11:01 AM
Yes, they should be !

   I don't have many "TWANGER " air rifles, but will buy/sell/trade one every once in awhile. I was shooting quite well with a Crosman I had, after many rounds of practice. I bought a higher powered .20 & could not hit a thing. I shot it, made notes, changed holds, changed pellets, & got terribly frustrated with it. One day, I picked it up & shot a good small group. I had to think of what I was doing differently. I was gripping & holding it like I was shooting a high powered rifle ! It is the only TWANGER that I hold like that & I have to remember that every time I shoot it.
Title: Re: Explain to me why.. parallelax??
Post by: north country gal on October 16, 2018, 12:05:43 PM
You are getting some bounce off the bag when you rest a springer directly on the bag and this will raise the POI, whereas placing your hand lightly between the bag and the gun will reduce some pressure and lower the POI. Even changing where you rest the gun on the bag can change POI. I have seen it many times with my springers. In fact, for my springers that see duty primarily as offhand guns, I make it a point not to sight them in off a rest. When I do, they always shoot too high when I switch to offhand. As always, the key to getting good performance with springers is consistency in all things.
Title: Re: Explain to me why.. parallelax??
Post by: xtred1 on October 16, 2018, 08:43:38 PM
I have seen the same barrel wag in a AK filmed in slowmo.
Title: Re: Explain to me why.. parallelax??
Post by: UlteriorModem on October 16, 2018, 09:38:49 PM
Thanks for the input one and all.

This is fascinating stuff to me!

I tried a little with the hand rested on the bag today and having some issues with consistency, even though I am trying to rest the rifle in the same spot on my hand every time.

Not 100% sure the new weaver 'extended' rail is holding firm. Might try the other rings tommorow.
Title: Re: Explain to me why.. parallelax??
Post by: Taso1000 on October 16, 2018, 11:51:12 PM
Thanks for the input one and all.

This is fascinating stuff to me!

I tried a little with the hand rested on the bag today and having some issues with consistency, even though I am trying to rest the rifle in the same spot on my hand every time.

Not 100% sure the new weaver 'extended' rail is holding firm. Might try the other rings tommorow.

Tom,

Make sure you are using a springer rated rifle scope.  Lesser scopes will break and become erratic in point of aim.

Thanks,

Taso
Title: Re: Explain to me why.. parallelax??
Post by: UlteriorModem on October 17, 2018, 10:33:28 AM
It is, a UTG 'Bug Buster' don't remember exactly which but it's the one with the 'easy tap' color illuminated reticle.

Anyhow I know it to be springer rated.

I am thinking the way the low profile extend weaver just kind of hangs off the end might be the current problem. It (the rail) was kind of cheapo Chinese I assume.