Home Forums Hunting & Shooting Long Range Hunting took my lightweight 308 to 1000 and have a couple questions

Hey I have a rem 700 stainless mtn rifle in 308 with an ultralight leupold 3-9 with m1s. It shoots 175 smks at 2622 into great groups at 100. I printed out the ballistic info for it with drops and holdovers. The numbers don't match up though. I've done the same with several other rifles and been very close. I would think there would be a well known ballistic coefficient for the 175 smk. I will get the numbers and some better range results when I get home. I'm just bored at work now. Here is a pic of a 200 and 500 yd group but what is going on is that it doesn't require nearly the amount of holdover as my chart. Figured with it being such a popular combo somebody else might have some similar drop data

What BC are you using on your charts? I'd think somewhere around .480 would be close.

Guessing it is the scope adjustments...

This is what I was using

Yeah I was thinking the turrets might be off too.
It took me 22.5 moa to get to 800 and that's a pretty solid # I shot it quite a few times on two days and its very repeatable just weird bc my calc said 27 moa.

My 500 is 11.5 moa chart says 12.5. I thought maybe it was a difference in moa and inches but that's not enough. When I shot 1000 the chart says 39.9 and mine was more like 33.5. I think getting a 175 smk at 2622 to 1000 with 33.5 moa isn't right but correct me if I'm wrong.

Not complaining too much about the 6lb 5oz launcher

What altitudes and temps are you shooting at? Does your Ballistics program allow you to input that? Makes a difference�

John

Thanks aalf for the pic flip I have no idea how you did that...I'm computer retarded.

Could be some vertical parallax in there too.

Yeah I know it does but I didn't know how much and figured it couldn't be that much. I do use a generic calculator but was just comparing data from my other 308s. I'm shooting near sea level maybe 500' and prob about 70 degrees

Yeah I can see some but I try to keep it consistent

Predmaster,


You are getting way ahead of yourself. The first order of business with any scope is to map tracking. Get a big piece of cardboard and put a dot at the bottom. Then mark out every 5 MOA (not 5 inches) up from center of bottom dot and place another dot all the way until you've hit 40 MOA. While you're at it do the same for windage, though I don't go out as far. Ensure that the target is exactly 100 yards from the shooting position.

Get a solid zero, and I don't mean 2 or 3 rounds (in both your 200 and 500 yard groups you are .5moa low). You have to shoot enough rounds to know where the true center of "cone" is. Once you have a good zero go to the marker cardboard and fire a group at the bottom dot. Dial up 5 MOA and fire another. Up 5 MOA and fire another. So on until you reach 40 MOA or bottom out the elevation. Then work your way back down. Check the windage. Then note where your groups land and do some math to find out what the true adjustment increment is.


Until you do the above you are just wasting bullets.

I'm not talking about inconsistency really. You can be quite consistently off center, inducing a consistent parallax error.

I notice the "sight height" in the program is 1.3 inches, and I sincerely doubt the scope's center is only 1.3 inches over the center of the bore.

Ok thanks for the help. Maybe I posted this in the wrong section since it is just a hunting rifle. Without worrying about increments and calculations would it be ok for me just to shoot all the yardages tape my data on it and go hunting. Everything I've seen so far out of it shows great accuracy (for a 5 1/2 lb rifle) and repeatable turrets. I have other more dedicated long range guns and that's basically what I've always done with them with no real complaints. I just use some sort of calculations to get in the ballpark and then shoot to verify. I guess my question was why this one is so far off. Maybe I've just been kinda lucky before. It's no real problem.

Here it is with sight height of 1.5 and mine is about 1.4" with ex low talleys

Running your numbers gives me 9.7moa at 500 with a 200 yard zero and 35.3moa at 1000.

I'd check the tracking of the scope first.