Husquvarna 7x57 surprises at range

MD

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I was trying out a new load yesterday (48.5 grains of h4350 behind a 140 grain Nosler partition) in my Husquvarna 7x57 and got a group at 100 metres about 1 1/2 inches high of the centre of the target.

I didn't have much more time as the range was closing so I tried three shots at my 200 yard target. Imagine my surprise when I found that the group was 7 inches low! It was a 1 1/2 inch group, can't complain about that, but I was shocked at how low it was.

I sight my 300 Win Mag and my 270 in for 2 inches high at 100 metres to get them close to right on at 200 metres.

The range closed before I could readjust the scope and shoot more, but how high am I going to have to sight this rifle in for at 100 to have it in the centre bull at 200?
 
I was trying out a new load yesterday (48.5 grains of h4350 behind a 140 grain Nosler partition) in my Husquvarna 7x57 and got a group at 100 metres about 1 1/2 inches high of the centre of the target.

I didn't have much more time as the range was closing so I tried three shots at my 200 yard target. Imagine my surprise when I found that the group was 7 inches low! It was a 1 1/2 inch group, can't complain about that, but I was shocked at how low it was.

I sight my 300 Win Mag and my 270 in for 2 inches high at 100 metres to get them close to right on at 200 metres.

The range closed before I could readjust the scope and shoot more, but how high am I going to have to sight this rifle in for at 100 to have it in the centre bull at 200?

If you sight in at 2.5" above zero at 100 m, you should be close to right on at 200 m.
I am using 1.0 grain above that with H4350 in mine, and if I sight in 1 3/4" high at 100 yds, she is zeroed at 200 yds.
Do you have a chronograph?

hf
 
I would think the twist nad barrel may affect this. I shoot 48 grains of IMR 4350 and sight in 2" high at 100 yards and I am just a little low at 200 yrds. 140 grn Accubond, 24" barrel and about 2790 fsp.

How fast is your load ? I could plot the trajectory for you of you want.
 
To get that trajectory with that bullet your muzzle velocity would have to be around 1900 fps?

Could you have mistakenly set your scale for 38grs?

48grs of H4350 should be close to 100% case capacity did you notice if the brass seemed full when loading.

Could you have inadvertly used another powder by mistake?
 
"How did the old loads work?"

My friend who gave me the rifle also provided the load recipe which he said was very accurate in that gun. The only difference was that he used a 139 grain Hornady SST bullet and I used a 140 grain Nosler Partition.
 
The load you give could not possibly have dropped that much at 200 yards, from a plus sighting at 100.
38 grains of powder, as mentioned, may be the answer.
Other than that, think of the scope.
A great many scopes malfunction, often not known to the shooter, causing no end of grief. I had a higher end scope that started to produce two groups, just 2 inches or so difference in elevation at 100. I blamed it on poor shooting, until the two groups went a foot difference in elevation at a 100! I then knew it was the scope, and proved it by changing scopes, but a group would have two or three high, and the others a foot lower, but each batch would form closely together.
 
"Did you shoot both ranges from the same bench supporting the rifle the same way? "

Yes sir.
 
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