Point-of-entry shift when changing pellets

[-=ed]

Question:

First you have zeroed you gun with Crosman wadcutters at, say, 20 yards, and are getting dime-sized 10-shot groups, or at least are proud of what you're getting.

Now you change to superdomes, or whatever... what kind ofpoint-of-entry shift might you get? The "common", and the" pretty bad."

I hear about re-zeroing all the time, but I was wondering just how pronounced the change can be.

It varies widely, the most extreme examples are, in my experience, maybe 1 inch groups from 35 yards with .22 14.6 gr Beeman FTS then switching to 17.10 gr Silver Arrows.

My guess is that it has something to do with the rifle. I notice with heavier pellets my rifle kicks left a bit and has to be adjusted for.

The Silver Arrows will literally be off the paper, a good 4-5 inches left of target until I sight it back in. Logun Penetrators (20.5 gr), Beeman Kodiaks (21.10 gr) and Beeman Crow-Magnums (18.20 gr) all kicked left until sighted back in.

I didn't do a precise progression so I cannot say for sure if it's a linear relationship between the amount off center and the weight of the pellet, but I strongly suspect there is one.

Either that or I just lean to my left when I shoot =D

[rabbit]

-=ed,

     If I was getting " dime - size " 10 shot groups at 20 yds., I would be pretty happy. Best of luck...

                                       Rabbit    

[vinceb]

You never know until you try it. One gun might shoot two pellets very similarly, while another might shoot them several inches apart. And both could group very well with both pellets.

My Gamo Shadow, for instance, at that kind of range would shoot Gamo Match and CPL's very close to each other, while my B20 would shoot the CPL's several inches to the left.

[Gene_SC]

OK, Ed, I use mostly RWS Superdomes. Example: If I switch to lets say CP's, I usually have to re sight. CP's tend to go higher and to the right a bit after my rifle is set for RWS Superdomes. Now the weight difference probably plays a big part to this. I never really checked the weight difference between lets say RWS Superdomes in a .177 compared to CP's in a .177.

I do know this that I am very happy with the RWS Superdomes and probably am in a rut.. using them..

Yes the main thing I have learned in the last 8 months is finding the right pellet for the right air rifle and sticking with them.. When I first started out I bought probably $200.00 worth of pellets and did not know what I was doing...

Then the light went on. First I got adjusted to shooting a springer and would generally group at around 5 inches at 40 yards. Then I started methodically going through each tin of pellets un till I found the one that had the tightest groups. It took me 5 months to finally find out what pellet to use with which air rifle.

And of course every time I move the target in or out using RWS Superdomes or any other pellet. I have to re-adjust 0.

One other thing. I was talking to CDT tonight and we were talking about pellets. How easy the scirts get damaged. After a while  you will notice which pellets are damaged if you shoot one and it goes low or astray. Just in the shipping process pellets get damaged because of the movement. Lead is soft and damages easily.

This is just my own experience.

Good luck Ed

Gene

[-=ed]

rabbit - 8/22/2006 8:10 PM -=ed, If I was getting " dime - size " 10 shot groups at 20 yds., I would be pretty happy. Best of luck... Rabbit

:p :p I guess I should have been more obvious in my humor there :p :p :p

[-=ed]

I like superdomes a lot myself, and premiers.

What I was looking for, info-wise, was how far the point of impact would shift.

I can get 4-6 inches at 25 yards, and I just wondered if this is near what others get when they change pellets.

[ribbonstone]

Think some of that shift depends on the type of gun being used.  A whole lot of rather violent things going on inside a springer, and woul expect any significant delay time of one type of pellet over another in getting ut of the barrel would give a larger shift...somthing like a single stroke pneumatic would proably give the least.

So there is stuff going out independent of the pellet's flight through the air that can change it's point of impact.

If you test enough pellets, will find at least a couple of types that have nearly the same POI (at least at some given range).  

But usually, we'll find a pellet that the gun really likes and just buy a bunch of them....worry about finding another batch of pellets when they run out (which is a good reason to buy a LOT of pellets once you settle on one).
-- ------

Kind of hard to give solid numbers...the ones that shot so far off from the others pretty well got dropped from any testing (wasn't looking for the ones that landed far way, was looking for the nes that landed close to the others...the opposite of what you are asking about).

Some times the results are surpriszing...two pellets that look so different can actually shoot  to the same spot.

I often see large (3/4"" or more at 30 feet) changes in poi when changing pellets with springers.(center group to center group,ignoring group sizes) up,down,sideways...No pattern that I can figure out,except that pumpers and co2 guns tend to shoot to closer poi's with different pellets than springers,and heavier tends to go higher,but not always.Has to do with recoil and pellet exit timing, I'd guess.