Unexpected .22lr bullet drop

[sterling]

Hi all,

 

I've been getting slightly erratic results with winchester subs recently, so I've given the barrel a good clean and gone back to eley subs. So I zeroed at 50yds and after a dozen fouling shots, I was getting consistent 15mm groups... so far, so good.

 

As I tend to limit shots on rabbits to headshots at an estimated 75(ish) yards, I took the target back to 75yds to see what to expect. Now my hold-over technique is basically instinctive after studying ballistic charts and a lot of practise. I'd expect about a 2.5" drop at 75yds with a 50yd zero but to my surprise a nice tight group appeared a full 7" low!? Tried a different box of ammo, same thing. I can only guess current eley subs are shooting a lot slower than the advertised 1065fps?

 

Any bright ideas before I go back to the winchesters again?

[dadioles]

I agree with your guess of a couple of inches drop at 75 yards, give or take a bit, with "normal" subs at around 1000fps but a drop of 7" does sound a bit dramatic.

 

Without a chronometer you are a bit stuck. To get such a big drop at that distance suggests that you are shooting something like 600fps instead of 1000fps.

 

Is it possible that the ammunition is not quite what you think it is?

[1066]

I have found Eley subs to well down of the stated 1065 fps - More like 990-1020 fps, that's with my 16" and my 20" barrel rifles. However there does seem to be something wrong to give you your excessive drop. If the rifle has a moderator I would remove it and shoot another group and try and shoot a few of your rounds through a chronograph.

[Redgum]

why zero at 50yds if your head shooting at 75yds?

[telf]

i started a thread on here a while back on winchester subs shooting high,which semed to me to have come about since the packaging had changed as i had no problems before they were reboxed if thats the right word,and there were quite a few replys saying that they were having the same problem,it would seem now that its not just problems with winnies

are eley made by the same manufacturers as winchesters,which i am led to believe is cci

[wymberley]

Think you must have problem other than velocity. In my barrel, the only round that shoots to speed is SK. All other shoot slower than the SK advertised figure of c1033. You'd need an MV of c675 to produce the drop you're getting - assuming a 2" sight height.

 

[cooter]

If you want to test your groups/setup with a known constant I would try a box of RWS.

[kent]

why zero at 50yds if your head shooting at 75yds?

I do as do many its a case of not shooting over the top peak trajectory as you will zeroed at 75.

If you want to test your groups/setup with a known constant I would try a box of RWS.

Rws although very accurate are about the slowest and loopiest you can get in subs. If you looking for flatter that is

[kent]

Think you must have problem other than velocity. In my barrel, the only round that shoots to speed is SK. All other shoot slower than the SK advertised figure of c1033. You'd need an MV of c675 to produce the drop you're getting - assuming a 2" sight height.

I am a big fan of SK, yet when I shot some Eley subs this spring I was seriously impressed out to 130yds they were every bit as flat as SK and others ( I think its a duff batch maybe badly stored even?)

[Whitebridges]

 

...................but to my surprise a nice tight group appeared a full 7" low!? ..............

 

Surely the solution is to re-zero your scope? Check the POI's at say 40, 50, 60, 70 yards and note the drop. I use Eley subs and at these ranges there isn't much to compensate. Isn't a "nice tight group" precisely what you are after?

Edited September 30, 2013 by Whitebridges

[sterling]

why zero at 50yds if your head shooting at 75yds?

 

 

I do as do many its a case of not shooting over the top peak trajectory as you will zeroed at 75.

 

Yeah, what Kent said. I don't strictly shoot only at 75yds, I mean I don't tend to exceed it very often.

 

Well thanks for all the replies chaps, I've tried a couple of the recommendations. My buddy shot quite a few of my eleys through his ruger 10/22 and found they shoot as you'd expect any .22 sub to shoot. Through my rifle though, he was shooting them way low too, so it's thankfully not my shooting that's to blame. Next I took the moderator off and even though it was now shooting a couple of inches high at 50yds, the round was dropping as you'd expect at 60, 70, 80, 90 and 100yds. So I took the parker hale mod apart and low and behold; clear signs of baffle strikes. Doesn't explain how it was still shooting tight groups but it goes some way to explain the recent eratic results.

 

So, I'll pick up a new moderator and I'll get the muzzle thread checked for alignment for peace of mind. Still not case closed, but at least I'm not going mad.