7 RM help please?

HTDUCK · Sep 27, 2010

:roll: A couple of months ago I traded for a Savage 110 Tactical in 7Rem Mag.
Topped it off with a Vortex 6x24x50 in Leupold rings and bases.
Worked up to a 160 AB topping 65 grs of RL 22.Safe load,shoots tiny, little ( Pop would smile :mrgreen: ) bughole size groups at 100 yards.
Tested and tested and tested them again.
Chrono shows 3170 ten feet from the muzzle.
Same groups. Looks like lighting in a bottle as a long range deer load.

Sunday It finally cooled off. About 65 degrees Sunday morning.
Decided to get serious about zeroing the rifle as I have only six weeks until I spend a week deer hunting.

Got the zero 2.5 inches high at 100 off the bench using bags.
Scope was set at 12 or 14 power.
Dry patched the barrel,let her cool for an hour while I was "playing" with some other load development on a buddy's rifles.
Shot another group.Same point of aim, same point of impact.2.5 inches high, dead center windage wise.

Moved to the 200 yard line and set her on the bags again.
Shot a five round group that was well under MOA,about an inch to be exact.

Only problem,this first group was 4 inches above point of aim at 200 yards.

Stumped, I shot my 280 at the 200 yard line while the Savage cooled.
It's zeroed 1.5 inches high at 100.
Load is a 139 BTSP on top of 58 grs H4831SC@ 3000 fps
Three 139 Hornady's that I could cover with a quarter.
Group was just a tad low,right at six o'clock on the bull.

Walked downrange,hung new paper and then bagged the Savage again.
3 rounds later,another sub one inch group.Problem is,they were 4 inches higher than point of aim once again.

The only thing that I had changed was the scope's magnification.
At the 100 yard line I had it set to 14 power,at the 200 yard line I dialed it up to 24 power.
I adjusted the objective lens,never touched the turrets.

What went wrong?
Why is this 7 Mag shooting so much higher at 200 when it should be headed the the other way?
I would think that at that zero it should be at the top of a one inch bull rather than still climbing?

I'm thinking I need some new glass.
I can't think it's the rifle or the load.

JD338 · Sep 27, 2010

Sounds like a scope issue to me, the rifle is shooting very well.

Try changing out the scope, if you have a spare. Make sure the bases are tight.

JD338

Guy Miner · Sep 27, 2010

Agree. Swapping to a different scope might be a real good idea. Easy to try at any rate!

Guy

DrMike · Sep 27, 2010

The fact that you are getting good groups despite a shifting zero is indicative of a scope failure. Even the finest scopes give out on occasion. The great thing is that most reputable manufacturers stand behind their product. Vortex hit the market with a strong promise to stand behind their product. Test with another scope. If it is the scope, as the evidence seems to suggest, I have no doubt that Vortex will make good of their product.

SJB358 · Sep 27, 2010

HT, I don't think it is a scope issue at all. Looking at your velocity and the BC, and your zero of 2.5" high at 100 yards, you are looking at a 270 yard zero. You are a little high, but not too out of line. That is a smoking load. I ran the ballistics, just to see and it should be about the same height or a touch more at 200 than what you are at 100.

7mm 160 gr., .531 B.C
Range (yards) Muzzle 50 100 200 300 400 500
Velocity (fps) 3170 3076 2984 2805 2634 2469 2310
Energy (ft.-lb.) 3570 3361 3163 2796 2465 2165 1895
Trajectory (270 yd. zero) -1.5 0.9 2.5 2.5 -1.8 -11.1 -26.1
Come Up in MOA -1.5 -1.8 -2.4 -1.2 0.6 2.7 5.0

I think you are in great shape, your midrange looks decent, and the extra 1.5 could be because of the scope power, or just aiming a little different, it all still looks in line to me. My 270WSM is exactly the same deal. I zero it 3" high at 100 and it is about 4" high at 200 and zero at 300. Scotty

baltz526 · Sep 28, 2010

Sounds exactly how i sight in my open country rifles for 300yds. 2.5" high at 100yds is 4" above bore. 5.5 at 200yds above bore, zero is 300, -9" at 400, -24" at 500. This is not how i site in all rifles just ones i use on the high desert

SJB358 · Sep 28, 2010

Same here, I have found the 3" high zero at 100 gives between a 225 and 300 yards zero depending on caliber. I have used this zero for all my rifles, except the ones with a ballistic reticle, that require a 200 yard zero to make the other stadia wires work. Scotty

HTDUCK · Sep 28, 2010

I think it may be as Scotty said.

I didn't realize it at the time but my shooting partner was working on loads for his 270,setting right next to me.

His 130 ABs were right at two inches high at 100 but at 200 were close to three inches above point of aim.
I didn't know he took some elevation out when I looked at his last target,it looked good.Right at the top of a 2inch bull at 200.Took him several ( I think he said six) clicks to get it there.

He sent me an e-mail this morning with a link to a ballistics program where he had plugged in my numbers.It showed my rifle to be zeroed at somewhere in the 325 yard area........

Back to the bench,gonna load some more 160s on top of that RL22 and go back to the two hundred yard line to start with.
I think from now on I'm gonna use the 100 range for load development and then go to two hundred to set zero.

One thing most of ya'll ain't gonna be able to believe, but here in N Tx where we live there isn't a range that we go shoot more than 200 yards; unless we wanna drive 140 miles.

I sure as hell appreciate the input you fellas always give me.

Thanks for the help.
Howard