Questions on MOA and adjustments

Possum284 · #1 04-06-2008, 07:50 AM

I will apologize now for the long post but I have just started shooting long range and I am going to aquire a cheap bsa target scope for my rifle to start with my question is according to some calculators if I zero my rifle at 100yds and want to hit at 500yds I need to adjust 7.5moa now I'm assuming moa at 500 is 5in. so I need to adjust up about 37.5 inches now on the scope its 1/8moa adjustment so I'm assuming that every 8 clicks is 1moa but to go up 7.5moa that is like 300 clicks do you just sit there and count them or is there a quicker way of doing this I wanted to find out before I got the scope. I thought maybe there are some kind of marks on there that tell you that you went 1 full turn or something and that 1 turn is so many clicks or moa you know what I mean thanks for any help or advive.:o

britz · #2 04-06-2008, 08:36 AM

It is actually 60 clicks. but yes, it is too much to simply count. You should look to see how many inches per hundred your turret will do in one revolution. My Nikon Buckmaster (1/8 inch clicks) does 6 and my Monarch (1/4 inch clicks) does 12. On my Buckmaster If I need to move 7.5 I give the scope one full turn then start counting up the additional 12 clicks. BSA scopes are set at inches per hundred, not MOA and you will start to see the difference when you get out past 500 yards.

Possum284 · #3 04-06-2008, 04:32 PM

I guess I just don't get it how did you come up with 60 clicks and whats the difference between moa and inches per one hundred thats why I asked cause I haven't got any idea I didn't think it was going to be this confusing but thanks for responding

britz · #4 04-06-2008, 04:56 PM

Many people use the term MOA meaning IPHY because it is easior to say and many don't know the difference. The two are quite close - but not quite interchangable. 1 MOA is actually 1.047" at 100 yards and 2.094" at 200 yards and so on.

Your target is 500 yards away and you said that the drop is 37.5" (your bullet will hit 37.5 inches lower than your point of aim at that range). You take 37.5 devided by 5 to get to inches per hundred = 7.5. That means that you have to move your scope 7.5 IPHY to impact right on at 500 yards. 7.5 IPHY is 60 1/8th inch clicks or 30 1/4inch clicks (7.5 x 8 = 60).

7.5 MOA at 500 yards is actually 7.5 x 1.047 x 5 = 39.26 inches - a difference of only 1.75 inches. However, If my 300wsm is zeroed at 100 and I am shooting 800 yards. I need 19.2 MOA increase which equates to 161.2 inches at 800. If I turn my scope 19.2 IPHY I will only move the point of impact 153.6 inches missing the target by 7.6 inches. So as you can see it doesn't make that big of a difference until you get out there quite aways. I only realized the significance of it a last summer when shooting at 4 inch balloons at 550 yards away w/ my 300wsm.

Bravo 4 · #5 04-06-2008, 05:32 PM

Howdy Mr. Possum, I am not trying to be rude so don't take this the wrong way but here it goes.....I don't think you should be worrying about MOA/SMOA/IPHY. The reason I am saying this is because if you are gonna use a cheap BSA scope it more then likely won't have precise or repeatable turret adjustments. By all means take it out and test the thing and don't just take my word for it. If you are gonna just use the turrets for come-ups it needs to be pretty much dead on in terms of adjustments. I have owned several so called cheap scopes and most of my friends use them so I'm not trying to bash anything or anybody here, but I don't think I have ever messed with one that is spot on. I have seen lots of them that won't move every "click" or will make bigger jumps then what it should have. If it doesn't adjust correctly don't get discouraged as there are ways around it for the ranges you will be using it. First, if you can find one with a mildot, I don't know if the model you will use has the option, the mildot is pretty decent for hold over marks. Especially if you play with the power setting and mark it correctly for different ranges and different dots. You can also use the duplex part of the reticle for hold overs at different ranges at different power settings. These aren't as precise as dialing, but you could be surprised. If you have any questions about my rambling just send me a PM.

britz · #6 04-06-2008, 05:48 PM

+1 on bravo's remarks. The BSA's just arn't noted for their precise adjustments. But all that I've said will apply when you use it on a scope with consistant adjustment.

Eaglet · #7 04-07-2008, 03:08 AM

Possum284,

Don't get discouraged. At first it all seems complicated but it trully is not. In fact is very simple. Just keep on reading and getting info. from this website and it will all be there. Do searches on things you don't understand, you will find the answers. If you don't you may also PM me. We'll help you!