Rifle Scopes Mounted scope, now only 6.6 mils of UP left

[Nightflight]

Just wondering if this is normal... Got a new Leupold Mark 4 8.5-25x M5 TMR FFP scope today, drove straight to the range from work, mounted and zeroed the scope at 100 yards. It took only .2 mils windage adjustment, but a lot of elevation up clicks to zero the scope.

After zeroing, the remaining UP adjustment totals 6.6 mils, the available DOWN adjustment is 17.5 mils.

The scope is mounted on a JP CTR-02 .223 rifle using Leupold Mark 4 steel rings.

Not that I plan to shoot this rifle so far that I need more than 6.6 mils of UP, but it would be nice to have the scope somewhere in the middle of the adjustment range at zero.

Is this normal? If not, where should I look for problems - the rings, receiver rail, or the scope?

 

[CSTactical]

Re: Mounted scope, now only 6.6 mils of UP left

The higher the power (magnification) the less travel up you will have. How much MOA do you have in the base? I tend to recommend 30moa bases for a scope like this.

Mike @ CST

 

[Nightflight]

Re: Mounted scope, now only 6.6 mils of UP left

Mike, the 6.6 mils of up adjustment is consistent for the entire zoom range.

With the scope's available 85 MOA, I figured that I'd have about 12 mils each of up/down adjustments. While I did not expect everything to mount perfectly level, I did not think that I'd crank the scope 2/3 up just to zero at 100 yards, either.

It seems to me that either the scope, rings, or the rifle's upper reciever is pointing down. Or maybe this is to be expected of ARs for some reason?

The rings are mounted right on the upper receiver's picatinny rail.

 

[nfoley]

Re: Mounted scope, now only 6.6 mils of UP left

I had an AR that had the same issue. Had to get the Badger 22 MOA base. Worked great, and didn't look bad either. I was told it was the AR's rail that was the problem.

 

[taseal]

Re: Mounted scope, now only 6.6 mils of UP left

I think something is def off. 2/3 is alot. Have you mounted another scope on this rifle before? Maybe you should try that to see if it's the rifle or the scope.

What moa base again? I didn't see it if you mentioned it

 

[GasLight]

Re: Mounted scope, now only 6.6 mils of UP left

Could be runout in the bore of the barrel. It is common practice to 'time' the bore runnout to the 12:00 position, which will result in the opposite situation as you are encountering. If the smith that chambered your barrel didn't do this, and the runout ended up timed toward the 6:00 area, it could result in the exact situation that you are encountering. You can check everything else, but if it is runout, the only way to correct without a setback and touching up the chamber is to get enough cant in your base to overcome the difference. I have seen this in the windage area as well as the elevation area. Last .308 my brother in law owned required 15 MOA base just to get the zero close to the scope's mechanical zero. Not the end of the world, if it shoots well, get a canted mount or base.

Dave

 

[Nightflight]

Re: Mounted scope, now only 6.6 mils of UP left

GasLight, that is a great theory!!! I just sent an email to JP Enterprises to ask about this possibility.

To answer a few questions above: there is no base, the rings are mounted on the upper reciever's integrated picatinny rail (this is an AR-type rifle). I never tried this test with my old scope, so I can't say for sure that the problem is not within the new scope itself.

 

[sobrbiker883]

Re: Mounted scope, now only 6.6 mils of UP left

Badger 22moa base and whatever wings you want, needing a canted base is a common issue with AR's.

Good luck telling JP that they timed your barrel wrong......

 

[JByrd]

Re: Mounted scope, now only 6.6 mils of UP left

They don't call it a FLAT top for nuthin.

 

[taseal]

Re: Mounted scope, now only 6.6 mils of UP left

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">
Good luck telling JP that they timed your barrel wrong...... </div></div>

That's what I was thinking lol

 

[Nightflight]

Re: Mounted scope, now only 6.6 mils of UP left

Well, it appears to be a problem with the rifle and not the scope. I put levels on the receiver rail, the railed gas block, and on the flat top of the muzzle break. When the reciever is level, the gas block and the muzzle break levels both indicate a down slope.

JP Precision will fix the rifle, but it'll take them "about a month" to do so. Apparently, they don't have a range and taking a rifle out to test shoot it to confirm my observations is something that is scheduled a few weeks in advance.

Gaslight - JP does not time barrel installation to address bore runout. Actually, my technnical contact at JP seemed unaware of this practice.

 

[lazy21]

Re: Mounted scope, now only 6.6 mils of UP left

Buy a us optics and problem solved.