Elevation issue with viper hs-t 6-24x50

[jjones0926]

I am new to the long range gig and just recently finished my first long range build. Remington 700 with a shilen barrel, bedding block stock, and vortex scope.

This morning I went to the range and zeroed it at 100 yards, well my scope is in about the top 3/4 of elevation adjustment, I'm concerned that it will hinder my long range shooting. When a lot of adjustment is needed. I assumed with a 20 moa mount that it would have been in the bottom 3/4 of adjustment. Any ideas what this could be?

 

[jjones0926]

Anyone? No ideas?

 

[ksubuck]

Don't take offense with this. But is there any chance the base is installed backwards? My HST mounted on a 700 action using a 15MOA mount is in the bottom 1/4 of elevation adjustment.

 

[jjones0926]

No offense taken. That was my initial thought, but I double checked and its not. It can only mount one way, it has a built in recoil lug that buts up against on the back of the opening in the action.

 

[ksubuck]

Just checked mine again, MRAD version. Max travel is 19MRAD, I have 13+ MRAD up elevation adjustment on my setup. About 70% of adjustment range.

Maybe you could check the scope a bit. Center the turrets, ie count clicks for full adjustment range, divide by two, set turrets with equal amount of clicks for L/R and U/D adjustment. Then, loosen scope rings so scope can be rotated. Lock gun in vise. Aim crosshair on stationary object. Rotate scope left and right to see if crosshair stays on object. This should let you see if reticle is optically centered in relation to centered turret adjustment. If so, problem is in mounting system. If not, may need to contact Vortex for evaluation of the scope.

Don't know if this makes any sense. Maybe someone else can explain it better.

 

[jjones0926]

I just turned it all the way up, I get about 1.5 turns till maxed out. I dont even have enough shims to use the zero stop. I just took off the scope, mount, and rings and cleaned all the mating surfaces. Also made sure it was all pushed forward and retorqued it all. Going to range in the morning to evaluate it. Will update tomorrow. And if it still like this, I will do your recommendation and check to scopes center, because that could make a huge difference. It all made sence. Thanks!

 

[42769vette]

Its hard to tell from the pic, but is the scope touching the front of the base?

 

[jjones0926]

No, its extremely close, I actually had to file the edge of the base down just a little so it wouldn't. It has about the thickness of 2 index cards between it.

 

[bruce_ventura]

Rarely is the scope at fault when this problem occurs. Usually it's the barrel being installed crooked. I see this often on production rifles. It's obvious by inspection when the barrel is crooked left or right, but difficult to see when the barrel is crooked up or down, especially on a Rem 700. If so, the easy fix will be to swap out the base for a 40 MOA one.

What's the history of this rifle? Has the receiver been trued?

Also, don't expect the mechanical center (half way between limit stops) to be the same turret setting as the optical center (parallel to tube axis). Might be and might not. On a Vortex product, probably not. The two could differ by ~1 mil without it being a defect or warranty issue.

Use the rotation method described above: adjust the turrets so that the crosshair center no longer gyrates when the scope is rotated. Or, use the mirror method - place the objective against the bathroom mirror, look through the eyepiece and adjust the turrets until the reticle and its reflection overlap. Record both turret settings so that you can always get back to that reticle position.

 

[jjones0926]

Just got it back from the smith whose trued it, barreled it and parkerized it. From what I can tell he didna good job. Looking at the bolt lugs they are both making full contact, so as far as I can tell its a quality job.
He is a reputable smith.

 

[bruce_ventura]

Hmm. It's hard to screw up a truing job that bad - assuming he trued the receiver, and not just the bolt.

Better check the base fit too. Was it bedded to the receiver? If not, when you loosen the base screws, does it fit perfectly at the front and back (check for gaps on all sides with a .004" feeler gauge).

Diagnosing this problem is easy if you have a boresight collimator. Otherwise, you need to sight down the rifle bore to a distant target (100 yds is convenient) and compare the bore position with the riflescope crosshair position (with the turrets at the optical center). For a 0 MOA base the crosshair should position should be about 2" above the bore position. For a 20 MOA base, the crosshair will be about 18" below the bore position, if the target is at 100 yds.

 

[jjones0926]

Since I am checking this at my apartment. I am using 37 yards. Scope optically centered with mirror, my crosshairs are about 5.5 inches higher than looking through the bore.

Although it does look like the front is taller than the back based on the gap in the bolt opening.

 

[jjones0926]

I had to turn the scipe down 14.5 moa to get it to optical zero.

 

[bruce_ventura]

Confirmed - it's not the scope. Probably not the receiver if your smith trued it. That leaves the base. It should be sloping down toward the front. Remove it and check the fit on the receiver. Who made it?