mid range rifle shooting questions

[thomis]

I'm gearing up to do some mid range rifle shooting in a couple weeks. I'll be using a .243 Winchester and .308 Winchester and shooting out to 300 yards (which is actually long range to me). The purpose of this is partly for fun but also to get some practice if ever I get a shot on a whitetail out across the bean fields.
I've been handloading, checking ballistics tables, using software, etc. to have an "idea" of the trajectory of each of my handloads for both rifles. Both rifles have Leupold Vari X II 3x9 one is the 40 objective, the other is the Ultralight 33 objective. Both scopes have the standard wide duplex reticles.
Each rifle is zeroed at roughly 30 yards to maintain a couple inches above and below line of sight out to about 250 yards, where the bullet hits zero again. If I'm trying to get the best groups and test loads at 300, do I aim the same way at the bullseye and just measure the group size way down on the target? I guess what I'm asking is, if I don't have one of the nicer scopes with the "accurange" or other such hold-over reticles, then how do you try and hit the bullseye? I guess I could do the calculation, i.e. 1 click at 100 yards = 1/4" so one click at 300 yards = 3/4", determine the drop from ballistics table, then adjust scope, theoretically, when I'm finished shooting at 300 yards, do as many clicks back down to where it was and I'm good at 25 and 250 again?
I've just never shot targets out to these distances and I want to make the most of this rare opportunity I have to check my loads. Any tips and tricks are appreciated.

 

[sage5907]

thomis, the trick to long range shooting out to 300 yards is to set your scope so it shoots dead on at 200 yards and then learn the arch of the bullet so you know where it hits all the way along it's travel out to 300 yards. Some people set their scope so it hits 2 inches high at 100 yards and think it will be dead on at 200 but that's not always the case. You must actually set the scope to hit dead on a 200 yards and then look at the point of impact at 100, 150, 250 and 300 to learn the arch of the bullet for the 243 and the 308. When you hunt you won't have time to adjust your scope elevation with the scopes you have so at 300 yards you use a high shoulder shot on the animal to account for the distance.

Also, if you shoot from a bench and then hunt by shooting from a rest from a sitting position the point of impact may be different because you hold the rifle different. When you hunt you must sight the rifle to shoot in the position that you will be using when you hunt. This may not be important at 100 yards but it is important at 300 yards. I'll say it again to be clear, when you sight in from a bench and plan to hunt with the rifle you must tweek your zero to the position you will be using when you hunt.

 

[sage5907]

thomis, I had a friend that every time he changed ammo brand he would change the zero of his rifle to accomodate the change in point of impact. I finally told him to pick one brand and weight of bullet to hunt will, sight his rifle in for that particular bullet for hunting and leave the zero alone. When he used another brand for practice it wasn't important if the bullet was hitting a little low, high, left or right, the only thing important was the size of the group he was shooting. Practice is to learn how to maintain or improve your shooting skills.

 

[jr_roosa]

You may also get weird windage changes at different ranges with different ammo, and certainly with different shooting positions, and maybe even with different clothes.

I'm not certain who originally came up with the whole "13/16ths of an inch high at 42 yards will get you dead on at 300" thing, but it's worthless other than to get on paper, and only then with a particular system that has been worked out, for example an M16 with GI sights and issue ball ammo. Once you change ballistics, sight height, and how you shoot individually, it can be all over the place.

There is no substitute for putting holes in paper. The ballistic program come-ups should be pretty good, but I bet you don't have a chronograph to verify muzzle velocity. Take your most accurate shooting position (I like prone, most people like benched) and shoot groups at 50, 100, 200, 300 yards and do the actual measurements. Then get your hunting gear on and see how your point of impact changes with different positions in your actual hunting coat. Pick a scope setting that works best for your most common shot and then write down how much you have to adjust holdover for various ranges.

Good luck!

-J.

 

[sixgunner455]

Maximum point blank range (MPBR) is what I use if I'm using a scope w/o ballistic markings of some kind or other. Sometimes even if I am. It's very simple, and requires no adjustments when shooting at big game.

How big is the kill zone on your game? If you're aiming at the heart and lungs of a regular sized deer, it might be 8" top to bottom. If you can keep your hits in a 6" circle from field positions, you'll kill that deer.

The way MPBR uses that circle theory is, if the bullet is, at the height of its trajectory, 3" above line of sight/point of aim, the spot at which it drops to 3" below line of sight/point of aim is your maximum point blank range. When your rifle is zeroed this way, you make no adjustments for range all the way out to what you have calculated and verified as your maximum. If it's a .243 shooting 100gr bullets, it'll probably have a MPBR of ~300yds, with the bullet passing POA at ~260yds. .308 will be 20 or 30 yds less. Those are really rough estimates, btw. You have to calculate the trajectory for your rifle and actual load (muzzle velocity, bullet and BC, etc), and then go to the range and confirm at each distance that your hits are where you think they are supposed to be.

 

[thomis]

These are all good points. I do have a chronograph and I've been using it to do the calculations in the ballistic tables.
The reason I liked my .243 sighted in at 25 yards, it hits zero again at about 240 and only deviates 3" above the line of sight. It has a 6" holdover at 300 yards.


What I like about the 200 yard zero, that you mentioned, is that it only deviates 2" above the line of sight, but it has a 8.5" holdover at 300 yards. Tit for tat I guess

 

[sage5907]

thomis, your calculations show what I was talking about. I don't like my bullet to be 3 inches above the line of sight because if you're shooting a steep downhill angle or steep uphill angle it can cause you to shoot over the target. Even if your rifle is shooting 8 inches low at 300 yards on a deer you can shoot a high shoulder shot near the top of the back and make a good hit. I noticed that your tables indicate a 32 degree day. A change in temperature from 32 to 70 can decrease the bullet drop by a minute of angle based on the burn rate of the gunpowder.

 

[osprey176]

One easy way to get an idea of where your bullets will impact at longer ranges is to blow up several balloons and tape them near your paper targets.You can shoot and adjust your holdover until you break them.This will give you a starting point for holdover.If you have a spotter,you can set a clay bird halfway up your backstop and have your spotter help you adjust your aiming point. I hang steel plates and shoot them from field positions after sighting in from a bench.I figure if I can hit a nine inch steel plate at 400 yards with an improvised rest,the deer in my neck of the woods are in trouble.Ballistic charts are good,but there really is no substitute for trigger time.

 

[adelbridge]

1 click at 100 yards = 1/4" so one click at 300 yards = 3/4", determine the drop

FYI the clicks measure the movement of the reticle and not the POI