Max amount of cant in scope base

[jonaddis84]

Well I finally got some range under my totally redone 110BA 338LM today. Of course something has to change after the first serious range day, for me its probably going to be the scope base.

I got a 40moa SS base made by Cameron at Murphy Precision for the gun thinking that would be plenty. Unfortunately for some reason with my setup that still leaves me with ~11 mils below my zero, so only 25.5 mils up remaining in my Razor.

I checked the math on the base, its definitely 40, I had started thinking he accidentally milled a 20moa. Doing the math to get closer to the bottom of my turrets at 100yd zero I need an additional roughly 36moa of cant!

Has anyone seen or used something anywhere near 75moa in a base before?

I already have an issue at max dialed where the can/mirage cover are slightly obscuring the sight picture, and its even worse when its hot. Im definitely going to get a higher set of rings to help this problem a bit, and theyll be required if I put more cant in the base anyway.

Im thinking just going 60moa, I think Ive heard of people running that much before, what do you think?

ETA: I know youre going to ask wtf I need all that elevation for, well the 25.5 dialed only gets me to about 1950yd, +9mil hold gets me to 2250 so I should be happy...but Id rather the turrets get me to 2300 or so so I can be more precise with my aiming point.

 

[Goin'Hot]

Re: Max amount of cant in scope base

If your scope will handle it, run it. I had Cameron make me a couple 45moa bases for my Premiers. As I calculate it, I can dial up to 2200 and use hold overs from there. When I store my rifles, I just turn the scope up 14 mils and let them sit. You don't want to store them bottomed out.

 

[jonaddis84]

Re: Max amount of cant in scope base

I guess I dont have any doubts on mechanically being able to do it, just whether its going to be pointless because Ill be looking into the suppressor so bad. I suppose if its bad I just dial out the magnification a bit and that cures the blurred picture problem.

Well 11 mils is almost another 40moa on top of 40 already, so technically I should be able to zero at 100 with a 75 moa base. I only worry that the math doesnt work out perfectly and I end up too far, so Ill likely try a 60

 

[jonaddis84]

Re: Max amount of cant in scope base

My other concern is why Im so far off the bottom to begin with...

Although doing the math on this, Razor has 36 mils total adjustment (~130moa). Half of that is 18 mils. I am 11 off the bottom so Ive gone down 9 mils from the scopes true center. 9 mils = 32.4moa. Im sure the other 7.6moa is a combination of rifle variable and the drop from muzzle to 100yd.

 

[gstaylorg]

Re: Max amount of cant in scope base

You could get another 20 MOA without doing anything other than purchasing one of the NF Unimounts, which has 20 MOA cant built in, and using it on your existing base.


http://nightforceoptics.com/RINGS__BASES___MOUNTS/mountsUnimountL.jpg

 

[jrob300]

Re: Max amount of cant in scope base

Jon.

The other thing you're gonna run into at some point is scope ring height issues. I had a Razor in Vortex rings on a 45 moa base on my Tikka 300WM. IIRC, we got 25 mil up with a 100yd zero and made 2300 with some holdover (I dial 1 mil over and use the aiming dots in the Christmas tree for better precision), but the front of the scope nearly hits the barrel. Any more cant and I'd have to get taller rings and that will only work so long.

We're going to have to go back down this road again soon as my son is getting a 30" WM chambered specifically for the high BC 225's and 230's and hopes to get out to 2500 with it.

Glad you brought this up... going to have to start thinking about this again soon.

John

 

[MontanaMarine]

Re: Max amount of cant in scope base

If you need more than a 40-45 moa base, you might be interested in something like this:

http://vgmount.com/

 

[MontanaMarine]

Re: Max amount of cant in scope base

But then again, you probably need some of that extra scope height on that VGM. Without it, you might have the objective bell hitting the barrel when you jack up the ass end of that puppy.

 

[ranger1183]

Re: Max amount of cant in scope base

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MontanaMarine</div><div class="ubbcode-body">If you need more than a 40-45 moa base, you might be interested in something like this:

http://vgmount.com/ </div></div>

These also work on that same principle.

http://www.iveyshooting.com/

 

[jonaddis84]

Re: Max amount of cant in scope base

I definitely plan on getting higher rings, more to alleviate the blurred sight picture from the can/mirage cover issue than to keep the bell from hitting barrel.

Those adjustable mounts are just way too high for me, and I dont need that really, Im fine with a fixed amount as long as it gets me where I want to be.

 

[jonaddis84]

Re: Max amount of cant in scope base

Called up Cameron Murphy today. He's making me a stainless 65moa base out of some 3/4" stock. His bases normally measure 0.420 tall in the rear no matter the cant, with the 3/4" stock he can make one 0.670" tall. Hopefully this will solve two of my problems at once without needing a new set of rings.

Will update when I get it.

 

[clayne_b]

Re: Max amount of cant in scope base

I have a Variable Gantry Mount, it works very well and is perfectly repeatable

 

[cali_tz]

Re: Max amount of cant in scope base

I just went thru the same thing with my 338LM... and went from 20MOA base to 65MOA. That finally allowed me to zero at 100 yards, and have available all 26MIL of the S&B scopes capability.

 

[Inline6]

Re: Max amount of cant in scope base

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">I just went thru the same thing with my 338LM... and went from 20MOA base to 65MOA. That finally allowed me to zero at 100 yards, and have available all 26MIL of the S&B scopes capability. </div></div>

That really makes me think what are the SB capable of... I am zeroed at a 100 with my 6.5 creed have a 20 moa base and 20 moa rings and I still have my full 26 mils. I guess a lot more adjustment is available in the scope, you only have 26 mils on tap at a given time.

 

[cali_tz]

Re: Max amount of cant in scope base

Inline, yes it's interesting. The documentation implies that 45MOA base is what's needed to optimally mount the S&B PMIIs. So you are practically there with your 40MOA base. I don't understand why I needed 65MOA. I tend to think my Steyr rifle under the Pic rail isn't exactly level and so my 20MOA Pic rail maybe wasn't a full 20MOA with respect to level.

 

[jonaddis84]

Re: Max amount of cant in scope base

Got the base, what a tank!

Was still able to zero at 100 yards and have around 3 mils still below that. Now I have just over 33 mils available up from my zero, should be good for around 2250 or so according to shooter.

You just cant beat Murphy Precision for work like this, I ordered it on a Monday, I had a custom one off scope base the next monday!

If I wouldve thought of it at the time I couldve had him add the two extra screw holes. But I had some time the other day and decided to add them myself being a solid top action. Im sure they arent necessary, but they also cant hurt.

 

[MontanaMarine]

Re: Max amount of cant in scope base

Nice!