F T/R Competition Scope base + optic elevation range OK?

[eracer]

7mm SAUM @ 1000 yards with 180 VLD.

My scope lists 50 MOA elevation travel. Is a 20 MOA base appropriate?

Seems like I might have an issue with getting a zero at 100 yards, since I'll only be 5 MOA off the stop when the bore and the scope axes are parallel.

Should I get a 15 MOA (or even 10 MOA) base instead? 10 MOA base would give me 35 MOA total elevation up, which should be plenty for this cartridge at that range.

Or do F-class Open shooters zero at 300 yards (or some other distance) and let their elevation calculations build off that?

 

[Denys]

Re: Scope base + optic elevation range OK?

I am not an F-Opener, I shoot only F-T/R. I could not care less if the scope on my LR rig cannot be zeroed at 100 yards or even 300 yards. What counts for me is that my 1000 yard zero is close to the middle of the travel; that's where the best glass is and that's what I want for shooting.

My NF-NXS has 45 MOA of travel and with my setup the 800/900 and 1000 yard zeroes are all near the center. The times when I take the rifle to 600 yards, I can live with being close to bottom.

 

[XTR]

Re: Scope base + optic elevation range OK?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eracer</div><div class="ubbcode-body">7mm SAUM @ 1000 yards with 180 VLD.

My scope lists 50 MOA elevation travel. Is a 20 MOA base appropriate?

Seems like I might have an issue with getting a zero at 100 yards, since I'll only be 5 MOA off the stop when the bore and the scope axes are parallel.

Should I get a 15 MOA (or even 10 MOA) base instead? 10 MOA base would give me 35 MOA total elevation up, which should be plenty for this cartridge at that range.

Or do F-class Open shooters zero at 300 yards (or some other distance) and let their elevation calculations build off that?

</div></div>


You need to find out where it zeros at 100 and get a base to fit.


My NF 32BR zeroed at 38MOA off the bottom at 100 yards. (When I first mounted it on a 20MOA rail it was at 18). Not all scopes will be centered in the erector at 100 from the factory. Mine is running on a 30MOA rail, and when I had my barrel replaced in January my first trip to the range the remounted scope was only off the 100 yard zero by 1/8 MOA, so it's not like the barrel was indexed funky.

My 32BR has 50MOA of travel. I zero at 8MOA from the bottom at 100 and it takes mid 30s, so say 34 to 36MOA to get to 1000 so I am at 42 to 44 or 8 to 6 off of the top.

Having a 100 or 200 yard zero is really nice for doing load development, for me it's mandatory.

 

[eracer]

Re: Scope base + optic elevation range OK?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: XTR</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eracer</div><div class="ubbcode-body">7mm SAUM @ 1000 yards with 180 VLD.

My scope lists 50 MOA elevation travel. Is a 20 MOA base appropriate?

Seems like I might have an issue with getting a zero at 100 yards, since I'll only be 5 MOA off the stop when the bore and the scope axes are parallel.

Should I get a 15 MOA (or even 10 MOA) base instead? 10 MOA base would give me 35 MOA total elevation up, which should be plenty for this cartridge at that range.

Or do F-class Open shooters zero at 300 yards (or some other distance) and let their elevation calculations build off that?

</div></div>


You need to find out where it zeros at 100 and get a base to fit.


My NF 32BR zeroed at 38MOA off the bottom at 100 yards. (When I first mounted it on a 20MOA rail it was at 18). Not all scopes will be centered in the erector at 100 from the factory. Mine is running on a 30MOA rail, and when I had my barrel replaced in January my first trip to the range the remounted scope was only off the 100 yard zero by 1/8 MOA, so it's not like the barrel was indexed funky.

My 32BR has 50MOA of travel. I zero at 8MOA from the bottom at 100 and it takes mid 30s, so say 34 to 36MOA to get to 1000 so I am at 42 to 44 or 8 to 6 off of the top.

Having a 100 or 200 yard zero is really nice for doing load development, for me it's mandatory.

</div></div>Excellent advice.

Can I use another rifle (with no cant) to check the scope erector's zero point? If I find a 100 yard zero on the scope when it's mounted on my Grendel it should be within one or two MOA of the 7mm SAUM's zero, which would allow me to find a reasonably close zero for the 7mm gun.

I really don't want to have Defiant build the action, then have to wait for chambering, inletting, etc. to provide the machined base.

Your thoughts make a great deal of sense, though.

 

[eracer]

Re: Scope base + optic elevation range OK?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Denys</div><div class="ubbcode-body">I am not an F-Opener, I shoot only F-T/R. I could not care less if the scope on my LR rig cannot be zeroed at 100 yards or even 300 yards. What counts for me is that my 1000 yard zero is close to the middle of the travel; that's where the best glass is and that's what I want for shooting.

My NF-NXS has 45 MOA of travel and with my setup the 800/900 and 1000 yard zeroes are all near the center. The times when I take the rifle to 600 yards, I can live with being close to bottom. </div></div>How do you handle load development if you can't zero at 100 or 300 yards?

 

[Denys]

Re: Scope base + optic elevation range OK?

Simple. I use a tall target board that looks like a thermometer. I put a small dot at the bottom, draw a vertical line from there and then I put in marks for every inch, and foot starting from the bottom.

Then I aim at the dot at the bottom and the groups grow at whatever elevation they shoould. The good thing with that is that I do not see the bullet holes as I shoot so I simply concentrate on the dot. It actually makes for tighter groups if I don't see the bullet holes as I aim.

To shoot over a chrono, I make sure the barrel is horizontal and in line with the chrono. The rifle is on a bipod and a rear rest, so I can see where I am supposed to aim to go over the chrono, and I do it.

Easy Peasy.

 

[XTR]

Re: Scope base + optic elevation range OK?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eracer</div><div class="ubbcode-body">Can I use another rifle (with no cant) to check the scope erector's zero point? If I find a 100 yard zero on the scope when it's mounted on my Grendel it should be within one or two MOA of the 7mm SAUM's zero, which would allow me to find a reasonably close zero for the 7mm gun.

I really don't want to have Defiant build the action, then have to wait for chambering, inletting, etc. to provide the machined base.

Your thoughts make a great deal of sense, though. </div></div>

I ordered my new Defiance action with a 30MOA rail for this scope, I hope it's right.

That said, I'd have never believed that the zero would be the same till I put the scope back on the rifle with a new barrel and it was dead on at 100.

Try it on another 308 and go with it, it will probably be close enough to tell them what rail you want.

 

[ivycool]

Re: Scope base + optic elevation range OK?

Mine is running on a 30MOA rail, and when I had my barrel replaced in January my first trip to the range the remounted scope was only off the 100 yard zero by 1/8 MOA, so it's not like the barrel was indexed funky.




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