Question about optics and Rail Cant
I am in the initial planning and budgeting phase of a 50 bmg rifle. I am looking to rifles, optics, and reloading equipment. Most of the scopes that I am looking at, that are in my budget have a 30mm tube. Some of the rifles I am looking at have the scope rail close to the center of bore (ie: Barrett m99) and some are raised up quite a bit (ie: Serbu BFG-50).
It looks like the rounds I mostly will be firing are m33 surplus and 750gr A-MAX reloads.
I have a few questions for you 50 shooters.
I would like this rifle scope set up to be capable of 200yards to 1760yrds (1 mile). I was wondering how much MOA of cant should I be looking for in the scope rail or mount?
Does a scope with a 30mm tube have enough adjustment?
I am seeing alot of scope rails with 20 or 30 moa of cant and a few scope mounts with the same. Would it be better to get the cant built into the rail on the gun and use a mount set up with no cant or would it be better to get a scope mount with the cant and no cant on the rail?
How far do you guys have your zeros?
Originally Posted By Panther1911:
I am in the initial planning and budgeting phase of a 50 bmg rifle. I am looking to rifles, optics, and reloading equipment. Most of the scopes that I am looking at, that are in my budget have a 30mm tube. Some of the rifles I am looking at have the scope rail close to the center of bore (ie: Barrett m99) and some are raised up quite a bit (ie: Serbu BFG-50).
It looks like the rounds I mostly will be firing are m33 surplus and 750gr A-MAX reloads.
I have a few questions for you 50 shooters.
I would like this rifle scope set up to be capable of 200yards to 1760yrds (1 mile). I was wondering how much MOA of cant should I be looking for in the scope rail or mount?
Does a scope with a 30mm tube have enough adjustment?
I am seeing alot of scope rails with 20 or 30 moa of cant and a few scope mounts with the same. Would it be better to get the cant built into the rail on the gun and use a mount set up with no cant or would it be better to get a scope mount with the cant and no cant on the rail?
How far do you guys have your zeros?
I have a Night Force 5.5-22X56 NXS it has a 30MM tube and I have a 20MOA base on a State Arms Rifle and I can shoot from 100 yards to a 1760 with this set up.
Ed
Ed,
Thank you for your reply.
What do you have your zero at?
When shooting at 1760, can you use your set up to dial the elevation or does it bottom out and you have to hold over?
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While a 30mm tube will give you more travel of the erector tube in the scope its important to look at the magnification numbers too. More magnification results in less elevation and windage travel. Typical numbers for Nightforce scopes;
5.5-22 power, 100MOA
8-32 power, 60MOA
12-42 power, 40MOA
One of the main reasons to put a cant on the scoperail is to have the erector tube looking through the center of the objective at long range. With 1000yd being a standard distance for competition the 30MOA rails are most popular.
Here is the elevation (MOA) requirements of:
Yardage-M33-Amax
1002.25--2.25
3007.507.25
60017.50-16.00
1000-36.75--30.25
1300-57.75--43.50
1500-78.50*-54.25
1700-100.25-66.50
1900-122.25-81.25*
2100-146.25-97.50
These figures are at sea level, so the numbers will be lower at higher altitude.
A 5.5-22x56mm scope has a total of 100MOA of elevation adjustment, 50MOA above and below center. On a 30MOA base we have 80MOA of available adjustment from a bore zero. According to the table above, we run out of elevation adjustment at a little past 1500yd with the M33, and just short of 1900yd with the Amax.
It is better to have the cant built into the rail.
Dave - Ferret50
Dave,
Thank you for your reply.
