308 Marlin Express. Scope is maxxed out to lower POI. It's 3" high at 100, which I wanted, but prints almost 6" at 220. It should only print inch or two high at 220 with 3" print at 100. I've removed the scope multible times, checked the mounts, counted turns on the turrets to reset in the middle, even shimmed the rear mount. Nothing changes. The 308 MX doesnt have the ballistics to do what it's doing at these ranges. Any thoughts??
Hitting high, scope bottomed out
- Thread starter recurve60#
- Start date
Wire reticle possibly broken inside the scope?
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pressfit
Well-Known Member
That's crazy.. zero at 200 should be 3 inches high at 100...?? Do you have another scope you can try?
280longshot
Well-Known Member
If you look through the scope and adjust the elevation turret, can you notice any changes in you sight picture? Try that first by moving your adjustment all the way up and all the way down while looking through the scope with your rifle on a solid rest.
280longshot
Well-Known Member
If your sight picture is indeed moving meaning you notice your crosshairs moving up and down, then you need to shim the front mount not the rear mount.
You need to chase your point of impact with your crosshairs.
This will at least give you some adjustment in your elevation turret, then adjust your point of impact to zero at 100 yds, then shoot 200 yds and see what happens.
You need to chase your point of impact with your crosshairs.
This will at least give you some adjustment in your elevation turret, then adjust your point of impact to zero at 100 yds, then shoot 200 yds and see what happens.
Take the shim out of the back and move it to the front mount. This will raise the front of the scope and lower where the barrel is pointing.
Hunter 257W
Well-Known Member
Is it possible that the scope bases have been installed in the wrong place? If they were different thickness this would leave the scope offset from it's proper alignment and account for having to use up all your adjustment to Zero. I don't know if this is even possible with this rifle/mount combination or not - just a thought.
Surely when you put the shim under the rear base, it changed the POI?? It would have to. As the others said though you need the shim under the front base as that would tilt the gun downward and lower the POI.
The real puzzle here is how you are getting such a flat trajectory out of a 308 Marlin Express?!? That bullet should not still be rising at 200 yards like that. There is no way you can get high enough velocity to do that. Are you sure you've fired enough shots at both ranges to be sure of where it's hitting???
Surely when you put the shim under the rear base, it changed the POI?? It would have to. As the others said though you need the shim under the front base as that would tilt the gun downward and lower the POI.
The real puzzle here is how you are getting such a flat trajectory out of a 308 Marlin Express?!? That bullet should not still be rising at 200 yards like that. There is no way you can get high enough velocity to do that. Are you sure you've fired enough shots at both ranges to be sure of where it's hitting???
That is my dilemma. How in the world can it be almost six inches high at 220 when three inches high at 100? If I can get it three inches high at 220 heck I'll have a 300 yrd gun with zero hold over or under !!!!!! My rings are kwik site see thru for marlin 336. I've fired 5-6 boxes thru it working on this issue. At the moment there are no shims in it. I'm honestly thinking my barrel is uphill a couple thousanths. It is very consistent with sub 3" groups at 220.Hunter 257W":2tdf790g said:
Hunter 257W
Well-Known Member
Even if the receiver were bored out of spec so that the barrel were mounted with an upward tilt, that would be no different than adjusting the scope elevation downward or shiming the rear scope mount to tilt the scope downward. Any of these situations would cause the problem of running out of adjustment before getting Zeroed. But the impossible trajectory...........I don't know what to say. Maybe I could get you to bless my 257 Weatherby? If you can enhance it to the degree of your 308 Marlin, I'll have a laser beam and will never have to consider range again! 
Seriously, I don't know what to say to explain how the POI is 6"at 220 yards and only 3" at 100.
Seriously, I don't know what to say to explain how the POI is 6"at 220 yards and only 3" at 100. Hunter 257W
Well-Known Member
Have you tried putting the shim under the front base? That's what I'd do next and see if I could get it down closer to dead on at 100 yards then go from there.
I will shim the front and see what happens. There was a run of this gun in 2009 that had barrel droop. A machine went out of spec that wasn't caught. Barrels were pointed down so much that it could not be corrected without a new reciever installed at marlin. Mine is a 09 rifle. I wonder
I shimmed the front with three layers of aluminum from a coke can. It got dark on me, so I dont know about 220 yards, but at 100 I'm in the bull now. I'll shoot 200 in the next couple days to see what happens.
280longshot
Well-Known Member
Great, looks as though the shims are working, hopefully it's enough that you have some adjustment in your turret.recurve60#":d0uxsl9g said:
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451LRML":1w6w7x0y said:
This.
Thanks guys. I've got some lee room now with elevation adjustment. My fields are flooded , so may be a few days till I can shoot longer range to see how it turns out.
Don't know if it matters, but see through rings move the line of sight quite a bit above the line of bore.
Hunter 257W
Well-Known Member
jetwrnch":csw3m2v0 said:
That is a good point. Just to see what effect it would have on the point of impact to change the sight height relative to the bore line I've been playing around with the Hornady Bullets website Ballistic Calculator using 308 Marlin Express numbers. Specifically the Leverevolution ammo with the 160 grain bullet (Bc = .395) at 2,660 ft/sec.
I experimented with the zero range until I got a 100 yard point of impact close to what Recurve started with, which is 3 " high at 100 yards. I got 3.5" high at 100 with a 275 yard Zero. Surprisingly it does show that load at 4.1" High still at 200 yards. Not quite as extreme as what he got but the fact that it is higher at 200 than it was at 100 with this cartridge surprised me.
Now if you drop the scope back down to a more common 1.5" above the bore, and Zero so that you hit about 3" high at 100 yards, it is just 1.4" high at 200 yards. Also the Zero range changes to 225 yards.
Sight Height makes quite a difference.
