Bullet drop question

[Lonetour]

I'm stumped and can't seem to find an answer in any of the forums.

I'm shooting a Ruger 77 300 Win Mag built in 1985 1:10 twist
Berger 210 VLD hunting
71.1 gn R-22
OAL 3.35
chrono fps 2800 to 2830
elevation 800 ft
wind speed west 11 mph
shooting direction north

I sighted in 3" high at 100 yards when I went out to 200 yards my poi was consistantly 7" high shouldn't poi have dropped not risen?

Any ideas?

 

[Joe King]

whats your scope height above the bore?
at 200 it should be kinda close to your 100yrd zero higher or lower depends on your scope height, but 7" is wonky

 

[Broz]

I have found that peak bullet ark is closer to 200 yards. So giving that and if your rifle is capable of 1 moa, 2" of that could be within the rifles accuracy. 3" high at 100 I would expect to see it higher at 175 or so. So yes this could be possible, and also why sighting in too high at 100 is why many hunters shoot over the back at 200.

Jeff

 

[kcebcj]

Just ran your data through Exbal and sighted 3 inches high at 100 yards w/ the scope 1.75 above the bore shows you to be + 2.9 inches at 200 yards with a dead on at 263. You have a 3-4 inch error...that's a lot??

 

[Joe King]

Just ran your data through Exbal and sighted 3 inches high at 100 yards w/ the scope 1.75 above the bore shows you to be + 2.9 inches at 200 yards with a dead on at 263. You have a 3-4 inch error...that's a lot??

I did the same with JBM, but like broz said moa is multiplied by range, so if his load produces 2moa at 200, thats 4" + 2.9 = 6.9, can happen pretty quick it seems. damned details anyway lol

 

[Lonetour]

Thanks for the quick replies! Just so I can fully get this through my simple mind.

If according to ballistic tables/calculators my load should be 2" high at 200 yards I would multiply 2" times 2 (or 1" for every 100 yards of distance) then add the two for actual hight adjustment?

 

[Joe King]

No if for example your grouping at 200yrds is say 2moa/4" and your trajectory and zero put you say3" high at 200 then worst case you can hit 7" high, more likely you should see impacts at 5"high and 1" high at 200. I'm only using exaggerated examples to illustrate what can be happening, and reality is way more complex, but based on the info you've given us I think this is along the path your seeing. But sometimes really odd things happen for simple reasons and they can be frustrating to pin down.

What kind of grouping are you actually getting at 200yrds? maybe you might just want to get a hard zero at 200yrds or 300.

 

[Lonetour]

my worst group of three was 1.5" my best .75" I know I should have quit sooner as I was getting tired and frustrated.

I've hunted a long time and have never needed to shoot over 200 yards, at deer and moose. My elk hunting buds are telling me I need to be ready to shoot 600 or more so I either need to get this figured out or do what I'm most comfortable with ... shoot ethically within my comfort range.

Since it's to late to send my scope in to Leupold for custom turrets I ordered a turret from Stoney Point to see if this could help, any views on these?

 

[Joe King]

I've used em in the past, they are by no means the right tool for the job, but in a pinch and used with reason they can get you by. sort of like a bandaid