Zero help

[Hick]

Hello just got a 3x12x56 crossfire 2 vortex scope to put on my lr308 my question is what would be a good zero for hunting don't plan on going over 100 yds but could be possible  thought about a 36 yd zero would that not keep me in 5 inch radius point of aim out to 300yd all help is appreciated usually run iron  sights at 100 yd zero never really used scopes before  

Heard I could do a 25 yd zero at 1/2 inch high I believe was said would put me at 3 inch point of impact up to 220yds is this correct. All help is appreciated 

Also what ammo do yall use for hunting  just curious 

Edited September 30, 2020 by Hick

[Belt Fed]

I use Winchester deer season xp

 

[Belt Fed]

I have only done the 25 yard one time years ago and missed a nice buck. i don't know if it works for some ammo or not. it didn't with remington core locks back then. i always sight them in at least 100 yards. now i will leave them a inch or two at 100 cause i am shooting a long way in a clearcut now. if i only hunted 100 yards or less i would put it right on 100.

[98Z5V]

12 hours ago, Hick said:

Hello just got a 3x12x56 crossfire 2 vortex scope to put on my lr308 my question is what would be a good zero for hunting don't plan on going over 100 yds but could be possible  thought about a 36 yd zero would that not keep me in 5 inch radius point of aim out to 300yd all help is appreciated usually run iron  sights at 100 yd zero never really used scopes before  

Heard I could do a 25 yd zero at 1/2 inch high I believe was said would put me at 3 inch point of impact up to 220yds is this correct. All help is appreciated 

Also what ammo do yall use for hunting  just curious 

You can calculate your MPBR with this tool:

Pay attention to the block for "Vital Zone Radius" when you're filling this in.

https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

 

...You haven't said anything about the ammo or the gun you're using for hunting.  All the details on those two items will need to be input into the fields on that program. 

Edited October 1, 2020 by 98Z5V

[Magwa]

ok this is pretty simple zero your gun at 100 yards dead on..... shoot Barnes 168 TTSX ammo there you are  from zero to 200 you are good to go with a hold middle of body right behind the shoulder hold want three hundred aim high by 4 to 5 inches, so you are good zero to 300...this works in 308.... the 36 yard hold you refer to is for 5.56 and it is a good zero for zero to 300 with 55 grain ammo now go get em....

[DNP]

I just wanted to say...you guys have offered Zero help to the OP. Well done. 

[COBrien]

55 minutes ago, DNP said:

I just wanted to say...you guys have offered Zero help to the OP. Well done. 

[98Z5V]

Hey, we're here to help people with Zero shiit, and anything or nothing else.  That's just how we are... 

[Cliff R]

As mentioned in the other thread the distance your scope is above the barrel will effect bullet height above the line of sight in the mid-range.

A 56mm objective means it's going to be up off the barrel some in most cases.  That can work for or against you depending on the efforts taken to zero the weapon and get it ready for hunting.

Here is what I do here for all rifles when sighting them in. 

The upper is removed, remove the BCG and put up a target about 15 yards away with a small round black spot on it about 1/2" diameter.  Lay the upper down in a relatively stable rest and look thru the barrel and line up the black spot in the center.  Just like using a peep sight your eye will naturally center things up so it's not really fussy.  So line the spot up best you can then raise up and look a the scope and see where the cross hairs are at.  Spend some time here and move the crosshairs until they line up while the barrel is lined up with the black spot.

What you are doing here is bore sighting and saving time and ammunition when you get to the range.  I already know that on a typical AR platform establishing a "zero" at 15 yards will but the rounds pretty high at 100 yards so I typically set the point of impact an 1" or so low during this procedure.

When we get to the range and start sighting in we use the 25 yard target first.  For most set-ups I still set the point of impact a little low at 25 yards knowing that it will be pretty high at 100 yards.  Usually there is very little fiddling around with the initial sighters since we have already bore sighted the rifle.  I typically shoot 2 or 3 rounds, and if they are pretty much in the same hole move the scope if/as needed to get it where it needs to be.

I then move out to the 100 yard target.  I'll fire 3 rounds and glance over at the spotting scope and see where they are at.  With our 308-AR's and 175 grain Barnes hunting bullets around 2500fps I put them about 1" high.

Next we move out to the 150 yard target.   Since my bullets have crossed the line of sight before 100 yards, 1" high at 100 yards and still climbing this target is important.   I know that I want to keep the bullets close to the line of sight from zero to about 200 yards because this is were 99 percent of the game we will take will be in.  I don't typically like or take longer shots at game, like Elk and Deer as in a real hunting situation there isn't any time to set up on them and they are almost always moving.

If the rounds at 150 yards are not more than about 3" above the line of sight we leave things alone and move out to 200 yards.  If less than about 3" from the line of sight no changes are made.  I'll finish up the sighting in at 300 yards.  By that distance most of these calibers/bullet combo's have started to drop off enough that they are now moving back down toward the line of sight and some will have crossed and went below it.

The goal and key to success here is to find the most ideal scenario for your weapon and ammunition where you can use a zero hold for all shots to at least 200 yards, then use holdover if/as needed for longer shots.  One could also employ BDC features if your scope has them.  I just know the trajectory of the rounds I'm using and IF a really long shot presents itself and I know the distance using the correct holdover is equally as effective.

This procedure works pretty much for all rifles used for hunting.  For Varmint rifles you need to be a little more concerned with being high in the mid-range because the targets are often considerably smaller.  With my 22/250, for example I not worrying about any hold-over out to 300 yards or so.  It simply shoots flat enough doing that it's pretty easy since I'm using a Speer 52 grain bench rest bullet backed by a full charge of H-414.  At 3800 fps it will not turn into a mortar in that range and there is never a need to set it to shoot much above the line of sight out to that distance.

So bottom line and a shorter answer to your original post is to zero the weapon about 1" high at 100 yards no matter what it takes to get there, and check it clear out to 200 yards and make adjustments if/as needed so you haven't done like most knuckleheads do............shoot over a nice buck when he comes out at 150 yards because you read someplace on line that a 1/2" high 25 yard zero was good to go for one of these weapons.....hope this helps some.......Cliff

Edited October 2, 2020 by Cliff R

[Albroswift]

On 9/30/2020 at 7:03 AM, Hick said:

3x12x56 crossfire 2 vortex

Vortex crossfire is not a bad scope, careful not to over tighten the caps, their tubes are not as sturdy as some and you can knock the glass loose. My 308 zero is 200 yards and that hits about 1-1/2 inch high at 100 yards. 8 inches low at 300.

This table is based on 2.7" over bore, 150 gr bullet 2700 fps MV. Cantilever mounts on my ARs seem to be right around 2.7" center above bore, Aero, Burris, PA. 

 

 

[Cliff R]

Albroswift, did you happen to check the point of impact above the line of sight a couple of places between 100 and about 250 yards?......Just curious.....

[Albroswift]

No, my range only has 100 and 200 yard berms.

I did compare the table results with the labradar and played with the bc in the strelok app to get the 0 to 100 velocities correct.

After that its all math and Kentucky Windage.

Here is the table broken down to 25 yard steps.

Notice between 100 and 200 it tops out 1.7 inch high

 

.

 

[Cliff R]

It's always a good idea to do some testing at several distances between 100 yards and about 200-250 yards.  You'd be surprised as to how far above the line of sight the point of impact can be when you mount the scope a good bit above the barrel.  I've shot a few rifles on our range that folks had set-up to hit 3" high at 100 yards and the hit really high out around 150-175 yards, so much so you would have put pretty high hits on a deer with a good hold in the kill zone..........FWIW......

[Albroswift]

When the Sig BDX system was first introduced the sight over bore was set to 1.7", could not be changed without a Kestrel. Having one of their first pieces of the BDX technology I was on the phone with Sig quite a bit, and every time I bugged them about it. Later versions scope height is unlocked. 

FWIW, never had problems with their equipment, all the calls were related to pairing, un-pairing, bonding, etc with android devices. 

Anyway, subject at hand, for hunting in my area, a 200 yard zero works for the 308 and the 338 quite well for me. I have my 25-45 set up at a 100 yard zero for now and checked at 200, dope right on,  be out in the woods next weekend maybe  get a chance to blast an unsuspecting critter.