Checklist:
- check stock screws to make sure nothing has come loose
- check your scope mount screws for same purpose / also check your scope to make sure it is NOT canted left or right of center of the bore and that your eye relief is set correctly for you.
- KNOW if your scope has 1/4 min clicks (most common), 1/2 min clicks (on a lot of 1.5X4, 1.5X5X32 type shotgun scopes) or 1/8 min clicks
- When is the last time you thouroughly cleaned your gun?
First what do I mean by 1/4 minute clicks on your elevation and windage adjustments? GOOD question and over the years, I am absolutely amazed the number of people I meet at the local gun range who do not have a clue what I am talking about.
Definition: What does the term minute of angle mean in regards to sighting in your rifle?
ans: A circle contains 360 degrees and each degree has 60 minutes in it. At 100 yards, one minute then = exactly 1.047 inches. Growing up as a kid, we had an old saying around the farm when working on equipment and other chores that when finished with a job, "It is close enough for government work".
If one fires 3 shots into one inch or less at 100 yards, the rifle is commonly called a "Minute of angle rifle" (AT LEAST with that particular load. In other words it may put 3 shots of 150 grain fodder into 3/4 of an inch and put the same brand of 180 grain bullets into 2.5 inches.
OK then, how does that relate to the 1/4 min, 1/2 min and 1/8 min clicks on my scope adjustments? BRAVO, another GOOD question.
Let's suppose for a min that you are getting a 1 inch group at 100 yards, the center of which is 4 inches to the RIGHT of your point of aim, and 2 inches higher than your point of aim. Let's futher imagine that you are shooting a quality .308 Win rifle with a decent scope on board.
What changes would I make with a 1/4 min click scope? The 1/4 min scope by definition means that every click on that scope whether windage or elevation would move the point of impact 1/4 inch at 100 yards. If it were my rifle, I would then TURN the windage 1/4 min dial exactly (16 clicks to the LEFT) or 4 clicks per inch, moving the point of impact DEAD center on the target for (left to right/windage) puposes. I would leave the elevation adjustment alone as is, since 2 inches high at 100 yards with let's say a 150 grain Federal Power Shok (WHICH is what I am using for deer hunting this fall) is about perfect to allow me to hold dead on a deer's chest out to around 250 yards which accounts for 99.9% of all deer hunting almost everywhere.
So FAR, So Good, but I am getting the cart ahead of the horse. Let's further suppose you haven't shot your rifle since last season, or that perhaps it is a NEW rifle to you and has not yet had a round through it. Your sporting goods store sold you the rifle and mounted your scope and bore sighted it for you before you left. Let's keep it simple and imagine it is a Savage Weather Warrior .308 Win with the accu-trigger and your purchased two boxes of ammo. One was 150 grain Win Power Points and the other was 150 grain Remington core Lokts. (WE do not know what your rifle likes to eat yet, so we will try both rounds to see which shoot best).
So where do you take your FIRST shot? The range is set up with markers at 25, 50, 75, 100, 150 and 200 yards. You have a 1 in 6 chance of being right. IF you guessed 25 yards you are correct. Beflore you load up and take that first shot, make sure you go through steps 1-4 listed above. Make sure the eye relief is set so that when you throw the rifle to your shoulder with the scope set at its lowest power, you have a FULL FIELD of view through the scope. IF not, then it is probably too close to your eye, so gently loosen the rings until with just a little pressure you can slide your scope forward till your have a full field of view when quickly mounting the gun. While your at it, make sure your scope is level and NOT canted to the left or the right. Snug those ring screws back down, Don't put a 4 foot length of pipe on the end of your allen wrench. Snug them down.................don't try to twist them off or crush the scope.
Okay, having done all that, make sure your rifle is set up on sand bags, or a quality range bag, or aCaldwell lead sled, or a bipod etc. so you have a steady rest. By the way, do NOT rest your rifle on the barrel/ rest the forearm of the stock on the bags. Do not grip the gun like it is going to fly backwards over the bench. Give it a firm grip, but not too firm. In our imaginery gun with the accutrigger, I suggest getting a sight picture and DRY FIRING it a few times to get used to the trigger.
Moving forward, you have fired 2 shots at 25 yards. The good news is the shots cut one ragged hole, The bad news is that point of impact is 3 inches to the left and 2 inches low of the center of the target. This is where the MATH comes into play. A 1/4 min scope moves the point of impact 1/4 inch at 100 yards, and therefore 4 clicks move point of impact 1 inch either up and down or left and right. At 25 yards (it is a multiple of 4X)................in other words it takes 16 (SIXTEEN CLICKS) to move the point of impact (1) inch at 25 yards. In this case we are 3 full inches to the left of our point of aim so we need to move the windage adjustment to the RIGHT a full FORTY EIGHT CLICKS to center our target.
I have found over the years, that if you put your point of impact dead center left to right (windage adjustment) at 25 yards, and approximately 1/2 inch LOW at the range, you will end up being right where you want to be at 100 yards and beyond. That being the case, I would then move the elevation adjustment UP 24 CLICKS. That should put your group 1/2 inch low and dead center of the target at 25 yards. You will find that you ill be in good shape when you get to 100, 150 and 200 yards with this setting. Different rifles, scopes and bullet weights can cause that equation to vary somewhat, however you will be darn close to where you want to be. Part of the reason I say that is unfortunately all scopes with 1/4 min clicks do not move point of impact exactly 1/4 inch at 100 yards. This is primarily due to manufacturing tolerences and often the PRICE of the scope itself.
UPDATE 10/20/2011: Took my .308 Savage Weather Warrior to the gun club yesterday to check it out before hunting season. My first shot at 25 yards was dead center in the bullseye. My next two shots at 100 yards were 1.25 inches center to center and 2.25 inches high. Lastly I fired a three shot group at 200 yards and results were a 1.5 inch group dead center on the bullseye. Different guns and loads will print slightly different at extended ranges, however you can't go wrong by getting dead center on the bull or depending on rilfe and load up to 1/4" or 1/2" low at 25 yards and then do your find tuning out at 100 yards. Again this was with Federal's 150 grain power shok load. This rifle wears a 3X10X40 Bushnell Elite 3200 scope with rainguard and duplex reticle. I am very confident with a decent makeshift rest and 8 seconds or more to get into position to take a whitetail out to 200 yards and beyond.
I would be a rich man if I had a dollar for everyone I have watched try to sight in a brand new rifle by starting out at 100, 150 and even 200 yards while having no clue of where that particular rifle hits at 25 yards.Trust me you will save a LOT of ammo by starting at 25 yards and getting it right than watching the dust fly at 100 yards and beyond the try guessing how much to adjust your scope. I also normally fire two shots at each range, to verify group center.
HOPE THIS HELPS. Good hunting., Dan
1 comment:
Great tips. Some them I really don't know untill read this article. Thanks to you.
Post a Comment