GP zero for a .308 scout rifle.

From anschutz to tikka, post up about your favorite bolt action rifles.
Dashammer
Posts: 732
Joined: Fri Jun 08, 2012 4:57 pm
Has liked: 0
Been liked: 0

GP zero for a .308 scout rifle.

Post by Dashammer » Wed Nov 12, 2014 10:33 am

A friend asked me that question the other day and I have no clue. He was eludeing to a gp zero like for an AR-15 50/250, 25/300 that would have the least deveations threw like 300 yards. So what is a basic zero for let say a 16inch barrel .308 cal and a middle of the road bullet weight.

guncrank1
KAC Member
KAC Member
Posts: 6380
Joined: Sat Mar 03, 2012 8:48 pm
Location: Metro Louisville
Has liked: 3 times
Been liked: 15 times
Contact:

Re: GP zero for a .308 scout rifle.

Post by guncrank1 » Wed Nov 12, 2014 11:18 am

1.5 inch high at zero at 100 yards

Gaffshot
KAC Member
KAC Member
Posts: 213
Joined: Wed Feb 13, 2013 1:10 pm
Has liked: 0
Been liked: 0

Re: GP zero for a .308 scout rifle.

Post by Gaffshot » Wed Nov 12, 2014 11:41 am

I would zero at 200. That would put you about 1.5" high at 100 yards.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:14 am

If you are looking for the maximum point blank range"

Here is an example of MPBR: Let's say you are deer hunting. The vital zone of deer is roughly 8 inches. You want to know at what range should you zero so that you can put the crosshairs on the center of your target kill zone and get a hit out to 300 yards with no sight adjustment or hold over. That means that if you aim at the center of the vital zone of a deer at any range between 0 and 300 yards, you will hit the vital zone.

According to several online calculators the NEAR ZERO should be 21 yards for a 150gr projectile moving at 2760 fps (typical 16" barrel - only way to know for sure with your gun is to shoot the ammo you intend to hunt with and measure it yourself) with a 1.5" Height over bore sight. That would put your FAR ZERO at 256 yards with a max point blank range at 301 yards. So, in perfect conditions, and if you can shoot well, you SHOULD be 4" high at about 150 yards and 4" low at 300 yards. So if you aim center mass of an 8" kill zone between point blank and 300 yards you SHOULD get a kill shot.

Since no human is perfect I prefer to calculate a 4" kill zone and see what it gets me. Also my 308 has a higher HoB, so that changes things up a bit as well.

2.6" HoB. 4" target height. 308 150gr, 16" barrel. 2760fps.

Near zero 46 yards. far zero 213 yards. MPBR 246 yards.

This online calculator is probably the better one to use. http://www.shooterscalculator.com/point-blank-range.php
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:22 am

When measuring HoB you don't have to be gnat's ass precise. Obviously the more precise the better, but if you can get it measured with a ruler within .25 inches you should be good to go. You won't see much deviation from calculator to hits on target if you are off by .25 inches. Changing my calculations above to 1.75 vs 1.5 HoB made no significant difference to the online calculator. It changed the near and far zero by 1 yard and the MPBR by about 3.

You should be able to use a ruler and eyeball it within .25 inches, so no need for calipers and such.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:29 am

Gaffshot wrote:I would zero at 200. That would put you about 1.5" high at 100 yards.

The is a good zero if you are shooting out to about 250 yards max. You are only about 2" high out to 200 yards at the most. 200 yards is POA = POI but the you are about 9" low at 300 yards, which is going to require some hold over or sight adjustment if you plan to take that shot. This is perfectly fine if you know how much hold over you need to make and remember to do it when you are taking a quick shot on that trophy buck at 300 yards you did not expect to see.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
WLJ
KAC Member
KAC Member
Posts: 30498
Joined: Sat Mar 03, 2012 8:55 pm
Location: Epsilon Eridani System
Has liked: 1 time
Been liked: 109 times

Re: GP zero for a .308 scout rifle.

Post by WLJ » Thu Nov 13, 2014 9:31 am

What's the avg range for deer shots in Ky?
There are criminals among us who are both homicidal and incorrigible. Their parents took a shot at civilizing them and failed. Their school teachers took a shot at them and failed. The odds are overwhelming that government welfare programs and penal institutions took a shot at them and failed. If it ever becomes your turn to take a shot at them, don’t fail.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:37 am

WLJ wrote:What's the avg range for deer shots in Ky?

probably INSIDE 150 yards. But never plan for average.


I will expand.... never plan for average on your zero and never plan for average on your skills.

I would guess that the shorter ranges in most kills are the shots that connected not just the shots fired. even with a good shooting, properly zeroed rifle someone who has no knowledge of the basic shooting fundamentals is likely going to miss that 200 yard, or longer shot.

I know several guys who do not shoot all year, break out the deer rifle the weekend before gun season. Go to the range and zero at 100 yards, using a box of ammo or more then deciding it is "close enough" in disgust as they can't group worth a damn, and still manage to kill a deer inside 100 yards. I am betting that they take longer shots they do not tell me about an hit the dirt in front of that buck they were aiming at.
Last edited by ChopperDoc on Thu Nov 13, 2014 9:44 am, edited 2 times in total.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
WLJ
KAC Member
KAC Member
Posts: 30498
Joined: Sat Mar 03, 2012 8:55 pm
Location: Epsilon Eridani System
Has liked: 1 time
Been liked: 109 times

Re: GP zero for a .308 scout rifle.

Post by WLJ » Thu Nov 13, 2014 9:43 am

ChopperDoc wrote:
WLJ wrote:What's the avg range for deer shots in Ky?

probably 150 yards. But never plan for average.
Depends, zero too far out and you're trading hold over for hold under for quite a bit of range. Zero it at whatever range and train for that zero at various ranges for that zero IMHO
There are criminals among us who are both homicidal and incorrigible. Their parents took a shot at civilizing them and failed. Their school teachers took a shot at them and failed. The odds are overwhelming that government welfare programs and penal institutions took a shot at them and failed. If it ever becomes your turn to take a shot at them, don’t fail.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:45 am

WLJ wrote:
ChopperDoc wrote:
WLJ wrote:What's the avg range for deer shots in Ky?

probably 150 yards. But never plan for average.
Depends, zero too far out and you're trading hold over for hold under for quite a bit of range. Zero it at whatever range and train for that zero at various ranges for that zero IMHO
Why would you do that when you can use the point blank range ballistic profile of the projectile you are using?
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
WLJ
KAC Member
KAC Member
Posts: 30498
Joined: Sat Mar 03, 2012 8:55 pm
Location: Epsilon Eridani System
Has liked: 1 time
Been liked: 109 times

Re: GP zero for a .308 scout rifle.

Post by WLJ » Thu Nov 13, 2014 9:52 am

ChopperDoc wrote:
WLJ wrote:
ChopperDoc wrote:
WLJ wrote:What's the avg range for deer shots in Ky?

probably 150 yards. But never plan for average.
Depends, zero too far out and you're trading hold over for hold under for quite a bit of range. Zero it at whatever range and train for that zero at various ranges for that zero IMHO
Why would you do that when you can use the point blank range ballistic profile of the projectile you are using?
Part of the training I mention IMO but maybe I'm not being clear in what I meant. See too many guys who know the paper profile down pat but never practice actually shooting at those ranges. Throw in some changing variables like wind, ranging errors and there's no substitute for actual experience.
There are criminals among us who are both homicidal and incorrigible. Their parents took a shot at civilizing them and failed. Their school teachers took a shot at them and failed. The odds are overwhelming that government welfare programs and penal institutions took a shot at them and failed. If it ever becomes your turn to take a shot at them, don’t fail.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 9:59 am

WLJ wrote:
ChopperDoc wrote:
WLJ wrote:
ChopperDoc wrote:
WLJ wrote:What's the avg range for deer shots in Ky?

probably 150 yards. But never plan for average.
Depends, zero too far out and you're trading hold over for hold under for quite a bit of range. Zero it at whatever range and train for that zero at various ranges for that zero IMHO
Why would you do that when you can use the point blank range ballistic profile of the projectile you are using?
Part of the training I mention IMO but maybe I'm not being clear in what I meant. See too many guys who know the paper profile down pat but never practice actually shooting at those ranges. Throw in some changing variables like wind, ranging errors and there's no substitute for actual experience.

Of course not. But if you have no idea of the 'paper profile' and attempt to zero at 100 yards because someone said that is "what to do with a 308", AND also have no command of the shooting fundamentals things like shooting from elevation, wind, etc are going to have a much more profound effect. At least have 2 of the 3 to give yourself a chance. If you can have practical experience at the ranges, know your ballistic profile and verify it with your gun and projectile, AND have a proper zero using the MPBR info you give yourself a much better chance even if you are shooting in windy conditions.

Many people do not practice enough. If they would just zero properly and understand the ballistic profile of their round as computed they would give themselves at least a little bit more of a chance of success.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

guncrank1
KAC Member
KAC Member
Posts: 6380
Joined: Sat Mar 03, 2012 8:48 pm
Location: Metro Louisville
Has liked: 3 times
Been liked: 15 times
Contact:

Re: GP zero for a .308 scout rifle.

Post by guncrank1 » Thu Nov 13, 2014 10:06 am

I zero for 100 yards (POA/POI) and get MOA at the range with factory ammo in .270

I have no problem killing deer out to 300 yards
Most of what I have killed has been under 100, a few at 50 or less.

I practice as much as possible and don't get into ballistic charts/ programs, I am pretty well versed in external and internal ballistic. :llama:

User avatar
WLJ
KAC Member
KAC Member
Posts: 30498
Joined: Sat Mar 03, 2012 8:55 pm
Location: Epsilon Eridani System
Has liked: 1 time
Been liked: 109 times

Re: GP zero for a .308 scout rifle.

Post by WLJ » Thu Nov 13, 2014 10:32 am

With a 100yd zero your hold under within that is very small and can almost be ignored. After 100 you only need to worry about hold over for range which is easy for many to deal with and many scopes are marked to deal with it. Leave wind and whatnot out of this for now.

With a 200 or 300yd zero you now have a hold under problem for much of the range which includes probably the most likely deer shot range for Ky. This problem can only for the most part be mitigated by proper training and practice that many people can't or are unwilling in many cases for whatever reason.

So I feel that for many a 100yd zero since you pretty much only have to dead with holdover is preferred is is much easier for most people to deal with.

Does this make what I'm thinking clearer?

All IMO
There are criminals among us who are both homicidal and incorrigible. Their parents took a shot at civilizing them and failed. Their school teachers took a shot at them and failed. The odds are overwhelming that government welfare programs and penal institutions took a shot at them and failed. If it ever becomes your turn to take a shot at them, don’t fail.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 11:11 am

WLJ wrote:With a 100yd zero your hold under within that is very small and can almost be ignored. After 100 you only need to worry about hold over for range which is easy for many to deal with and many scopes are marked to deal with it. Leave wind and whatnot out of this for now.

With a 200 or 300yd zero you now have a hold under problem for much of the range which includes probably the most likely deer shot range for Ky. This problem can only for the most part be mitigated by proper training and practice that many people can't or are unwilling in many cases for whatever reason.

So I feel that for many a 100yd zero since you pretty much only have to dead with holdover is preferred is is much easier for most people to deal with.

Does this make what I'm thinking clearer?

All IMO

I guess I am not sure why there is confusion, so just to be clear I am talking about any caliber from any rifle. You can't just choose 100 yards as a zero on any rifle and be 'good'. ZERO is going to be based on your MISSION for that rifle. You cannot successfully set your rifle up for that mission if you do not have a grasp on the ballistic profile of the projectile from your barrel. Certainly the calculator could be different than what you see on paper. Factory ammo likely does not give you the muzzle velocity printed on the outside of the box for one thing.

So, for me, using the max point blank range data gives me the starting point for my rifle. If 100 yards comes up as the best zero then I will use that. With .223, .308, 30.06, using a 4" kill zone the 100 yard zero will not come up as the best option because it will require some sight adjustment or holdover. If you choose a 100 yards zero then you absolutely should know your hold over at various ranges.

I am not sure where you are getting the hold under info, but certainly on SOME zeros out to long distances there could be significant deviations at shorter distances. A 308 from the data I posted above using the 4" kill zone will never be more than 2" above my line of sight out to the far zero point. At the near zero (where I set my initial zero target to make adjustments) of 46 yards the POA should equal the POI. Once I set the scope, sights, etc then if I can I should verify to the far zero distance of 213 yards. If this is impossible then I will shoot as far as I can to see where POI is compared to POA. At 100 yards that zero should be 1.68" high (yeah, I won't be that precise when measuring bullet holes) and if it is 4" high, with good shot groups, then I know something is off and I need to figure out what it is.

The whole point of using the MPBR is because I want the mission of deer rifle to be a point of impact as close to my point of aim out to a certain distance with no holdover because deer are unlikely to always give me a nice stationary target. I will know the hold over beyond that MPBR distance just in case, probably out to 500 yards. I won't take a shot beyond 500 yards right now because of multiple factors, one being my skill level. I probably would not take a 400 yards shot, but I would never say never on a 400 yards shot and know the data anyway. There is no place I frequent where I could practice a 400 yard shot so knowing the calculated data and verifying it as closer ranges is all I have got.

I use a 50 yard battle sight zero for my AR for this reason as well. From 10 yards to about 230 yards using 55gr or 62gr rounds I have a potential 2" deviation over or below my line of site. At about 200 yards the POI = POA. At 300 yards I am about 7" POI low from point of aim and at 500 yards I am about 4 feet below POA. I have tested this on my AR to 100 yards and the ballistic profile, with quality ammo, is pretty close to the calculated data. I get bigger groups and deviation with Wolf ammo, obviously.

So, to sum it up, it depends on the mission. If you like a particular zero range for whatever reason just know WHY
you are using that zero, know the ballistic profile and test it as far as you can and know your hold over.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

guncrank1
KAC Member
KAC Member
Posts: 6380
Joined: Sat Mar 03, 2012 8:48 pm
Location: Metro Louisville
Has liked: 3 times
Been liked: 15 times
Contact:

Re: GP zero for a .308 scout rifle.

Post by guncrank1 » Thu Nov 13, 2014 11:36 am

Ok now I am on a mission.

"Cranky reporting for deer hunting , Sir!"


:llama:

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 12:09 pm

knowing the calculated data can also save you some headaches at the range.

An example is the 30-30. Using the CorBon DPX 150g if you look up your MPBR you see that is calls for a near zero of 24 yards. The far zero is right at 100 yards if you are using 1" HoB. If you are using a scope and bumped up to 1.5" HoB then your near zero range is 36 yards.

How much easier is it going to be to zero your rifle at 24 or 36 yards initially then verify at 100 yards than to just choose a 100 yard zero and go shoot it, adjust and re-shoot multiple times at the 100 yard target? knowing the calculated data is important on multiple levels.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

guncrank1
KAC Member
KAC Member
Posts: 6380
Joined: Sat Mar 03, 2012 8:48 pm
Location: Metro Louisville
Has liked: 3 times
Been liked: 15 times
Contact:

Re: GP zero for a .308 scout rifle.

Post by guncrank1 » Thu Nov 13, 2014 12:52 pm

Gunsmith response to clients-

"for 30-30 zero at 75 and long range 150/225"

"for .30-06 family zero at 100 and long range 300"

"for .223 zero at 100 and long range is up too shooter."


Just about what has worked for deer/elk/hog hunter ie FODS for 30 years.

Tell all of them sight in at 25 and readjust at 100.

Charts?
B/C ?
POA/POI Ugh??
I get glassed over eyes.
Heck for a good fee I sight in their gun for them.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 2:10 pm

Certainly. because we should never use any new technology to makes things easier or more precise or more efficient.

a 75 yard zero on a 30-30 150g projectile gets you 1' drop at 100 yards and a 4' drop at 150 yards. yes, it could work, yes it could have worked for 100 years. When you know that you can zero that same gun using that same bullet at 24 yards and not get that 4" drop until about 200 yards why would you not take advantage of that more efficient ballistic arc?

same goes for the other weapons? Why would you not want to find the most efficient arc for the intended use of the firearm?

Sometimes technology can really muck things up. Sometimes it actually does make our lives easier.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

User avatar
PDM
KAC Member
KAC Member
Posts: 5786
Joined: Thu Oct 30, 2014 5:17 pm
Location: Bardstown
Has liked: 87 times
Been liked: 44 times

Re: GP zero for a .308 scout rifle.

Post by PDM » Thu Nov 13, 2014 3:00 pm

Doc has this one right. I shoot a 243 which has a much flatter trajectory than the 308, but the principle is the same. My zero is at 50 and 200yd. For medium sized game, I aim dead on from zero to 300 yd.
"The unlimited power of the sword is not in the hands of either the federal or the state governments, but, where I trust in God it will ever remain, in the hands of the people."
Tench Coxe

guncrank1
KAC Member
KAC Member
Posts: 6380
Joined: Sat Mar 03, 2012 8:48 pm
Location: Metro Louisville
Has liked: 3 times
Been liked: 15 times
Contact:

Re: GP zero for a .308 scout rifle.

Post by guncrank1 » Thu Nov 13, 2014 4:01 pm

And CD I use whatever technology is available, my customer are not all "mission capable" type of guys.


That said what zero is based on whatever you zero it.

My rifle kills deer and ground hogs with a 100 zero and it has worked for others as well.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Thu Nov 13, 2014 6:39 pm

guncrank1 wrote:And CD I use whatever technology is available, my customer are not all "mission capable" type of guys.


That said what zero is based on whatever you zero it.

My rifle kills deer and ground hogs with a 100 zero and it has worked for others as well.

"Mission" was not intended to mean anything other than the intended use of the rifle. Not inferring that the person operating it needed to be an Operator Operating Operationally on a specific and covert Operation.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

GPtuners
KAC Member
KAC Member
Posts: 249
Joined: Wed Feb 06, 2013 7:33 pm
Has liked: 0
Been liked: 0

Re: GP zero for a .308 scout rifle.

Post by GPtuners » Thu Feb 12, 2015 9:45 pm

ChopperDoc wrote: I use a 50 yard battle sight zero for my AR for this reason as well. From 10 yards to about 230 yards using 55gr or 62gr rounds I have a potential 2" deviation over or below my line of site. At about 200 yards the POI = POA. At 300 yards I am about 7" POI low from point of aim and at 500 yards I am about 4 feet below POA. I have tested this on my AR to 100 yards and the ballistic profile, with quality ammo, is pretty close to the calculated data. I get bigger groups and deviation with Wolf ammo, obviously.
I second this. Doc was at my RWI Rifle course and his printouts worked wonders. I will be using the same technique this year, when I'm going to try and hunt for the first time. (I can't judge distance worth crap, so this "set it and forget it" approach is right up my alley. I can concentrate on technique and not have to worry about adjusting my scope or attempting a holdover.

Thanks,
Carlos

User avatar
AErrorist
Posts: 148
Joined: Mon Mar 05, 2012 9:10 pm
Has liked: 0
Been liked: 0

Re: GP zero for a .308 scout rifle.

Post by AErrorist » Fri Feb 13, 2015 8:44 am

The Burris scout scope I have on my Ruger GSR is marked for drop with a 100 yard zero, so that's what I use.

User avatar
ChopperDoc
KAC Member
KAC Member
Posts: 5778
Joined: Tue Mar 06, 2012 4:14 pm
Has liked: 0
Been liked: 1 time

Re: GP zero for a .308 scout rifle.

Post by ChopperDoc » Fri Feb 13, 2015 7:59 pm

AErrorist wrote:The Burris scout scope I have on my Ruger GSR is marked for drop with a 100 yard zero, so that's what I use.

as well you should.
"You rarely rise to the occasion, you usually just sink to your lowest level of training."

Return to “Bolt Action”

×