I've had an Epiphany!

Monkey Spanker

Well-Known Member
Reading the thread about ranges to zero a .308 at got me thinking.

Most of us zero about an inch high at 100m and actually do this at 100m range.
This then gives us two points of true zero which for most calibres will be about 75-80m and again at around 150m.
So here's a thought...............

Why not just zero at the closest point of zero. I can see a good few advantages of doing this...
  • Less walking to check the target!
  • Less influence on trajectory from environmental factors such as wind.
  • A definite point of aim i.e at the centre of bull.
  • Target closer and therefore easier to see with a limited power scope.
You will obviously need to check exactly what your chosen setup does at longer range, but once this is established, a quick first point of zero check should be all that is required. What do ya reckon?:cool:
MS
 
I was wondering why we don't all zero at 100 smack on and just aim up an inch at 200m, after all most stalking shots are around the 100 meter mark :D
 
I was wondering why we don't all zero at 100 smack on and just aim up an inch at 200m, after all most stalking shots are around the 100 meter mark :D

If you are bang on at 100m with a 308, you will be 2-3" low at 200m, depending on the bullet fired.
 
does that mean i can claim for all the time and money you will save as i started the 308 thread:lol:
 
i may well be getting my coat and leaving in a minute but you say definate point of aim without having to hold an inch over to zero at 100. dont you just aim spot on at 100 and get bullet stricking 1 inch high. or shall i get my coat
 
when i first started re-loading i did most of my range work in my parents back yard at 50m , then once i had a load i i used to zero 1"high at 50m then i test at 100m and it was spot on so happy days , i dont walk if i dont have too !
 
Ahhh the closest point where the bullet strike crosses the reticle or line of sight is about 25-30 yards depending on the height of the scope above bore line. It's not new information as it's been about and believe Marlin Rifles used to have the concept and instructions on their web site.
 
I have always used what you call the first true zero as a quick/easy way of confirming that my rifles are still zero'd and expect to see a single small ragged hole in the X-ring.
 
Ahhh the closest point where the bullet strike crosses the reticle or line of sight is about 25-30 yards depending on the height of the scope above bore line. It's not new information as it's been about and believe Marlin Rifles used to have the concept and instructions on their web site.

I have heard that theory, but it does not seem to work for me on any number of rifles. It may be that this rule works useing smaller US style scopes much closer/lower to the bore.

Useing a 50mm scope, clearing the barrel by 5mm roughly, I find that if I zero a 243, 260 or 270 bang on at 35m or thereabouts I generally find I am quite high at 100m, maybe 4-5" high. I usually get a rough zero by keeping the POA about an inch low at 35m, this leaves most rounds 1" to 2" high at 100m.

You really need to zero at 100 to verify the theories. You also need to shoot at 200m and 300m to verify your drops.
 
You may have a significant paralax error potential at 30 or 50 yards.

Also a small error, maybe in the order of fractions of an inch and perhaps rather less than the group size, will have a significant effect on the point of impact at 200 or even 300 yards.
 
You may have a significant paralax error potential at 30 or 50 yards.

Also a small error, maybe in the order of fractions of an inch and perhaps rather less than the group size, will have a significant effect on the point of impact at 200 or even 300 yards.

Using good quality optics have can you honestly say you have encountered parallax errors? The only time I encountered any was with the rotten cheaply made Chinese Nikko Sterling scope which was awful for it. I cannot say I have noticed it with the other scopes.
 
I have heard that theory, but it does not seem to work for me on any number of rifles. It may be that this rule works useing smaller US style scopes much closer/lower to the bore.

Useing a 50mm scope, clearing the barrel by 5mm roughly, I find that if I zero a 243, 260 or 270 bang on at 35m or thereabouts I generally find I am quite high at 100m, maybe 4-5" high. I usually get a rough zero by keeping the POA about an inch low at 35m, this leaves most rounds 1" to 2" high at 100m.

You really need to zero at 100 to verify the theories. You also need to shoot at 200m and 300m to verify your drops.


As I said :-

"Ahhh the closest point where the bullet strike crosses the reticle or line of sight is about 25-30 yards depending on the height of the scope above bore line. "

Theory it's not as it works in practice. Raising the height of sight line above bore line alters the distance. In fact it's the way that the sighting on the Lee Enfield rifles was checked. With sight set for 200 yards the centre of the group should fall about 3/4" above POA using std velocity .303 MkV11 cartridges at 25 yards..
 
Ahhh the closest point where the bullet strike crosses the reticle or line of sight is about 25-30 yards depending on the height of the scope above bore line. It's not new information as it's been about and believe Marlin Rifles used to have the concept and instructions on their web site.

It's never going to be that close with a modern stalking rifle with a large (50mm+?) objective. Most scopes will sit about 1.5-2 inches above the bore line. If my 25.06 crossed at 25 yards it would be very high at 100m!

You may have a significant paralax error potential at 30 or 50 yards.

Also a small error, maybe in the order of fractions of an inch and perhaps rather less than the group size, will have a significant effect on the point of impact at 200 or even 300 yards.

The parallax at 75-80m should be negligible on most scopes and some will even be able to adjust it to the exact range. The small group size at closer range is exactly what is desirable. Yes, any errors will be exacerbated at longer ranges, but so will those caused by external factors. The group may be smaller, but the MPI should remain constant, and i doubt many of us or our rifles can shoot a one hole group consistantly even at 50yards!;) The more external factors we can remove from the equation the better! Congrats on your 1000th post!:thumb:
MS:)
 
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It's never going to be that close with a modern stalking rifle with a large (50mm+?) objective. Most scopes will sit about 1.5-2 inches above the bore line. If my 25.06 crossed at 25 yards it would be very high at 100m!

For a normal zero (say 175-200m) the first point that the bullet crosses the line of sight will be very close (25-35m); bullet then rises to highest point in its arc (say 100-125m) then drops back through the line if sight at the second zero. If you set your gun to have a point of impact at say 70m chances are that this will be the first and only point the bullet coincides with the LOS...it will therefore hit very low at distances beyond 150m. I would always advise that a gun is zeroed on a long range.

regards
 
nah...I always zero from 100, that's where the bench is:D.
Then I dial my hold over to whatever distance I would expect soemthing to show.
Zero up in cover, 1" up in open terrain, from there on I dial in.
edi
 
It's never going to be that close with a modern stalking rifle with a large (50mm+?) objective. Most scopes will sit about 1.5-2 inches above the bore line. If my 25.06 crossed at 25 yards it would be very high at 100m!
MS:)

MS has this correct, there is no way a modern HV round with a 50mm scope crosses line of sight at 25 or 30m unless the 100m POI is very high.

The actual initial crossing point is around 60 - 70m for 1" high 100m zero. The bullet will continue to climb to around 1.75" high at about 130 - 140m, and drop back to an inch or so low at 200m.

Obviously these are approximations and there will be differences dependant on calibre, velocity, Bullet BC etc. A 25/06 with a 100gr bullet will behave slightly differently to a 308 shooting 165's.

Typically, Brithunter is trying to use bullsh1t data from obsolete rifles and cartridges which I doubt are used by 0.5% of deer stalkers to justify his spurious arguments.......:zzz:
 
It's never going to be that close with a modern stalking rifle with a large (50mm+?) objective. Most scopes will sit about 1.5-2 inches above the bore line. If my 25.06 crossed at 25 yards it would be very high at 100m!

For a normal zero (say 175-200m) the first point that the bullet crosses the line of sight will be very close (25-35m); bullet then rises to highest point in its arc (say 100-125m) then drops back through the line if sight at the second zero. If you set your gun to have a point of impact at say 70m chances are that this will be the first and only point the bullet coincides with the LOS...it will therefore hit very low at distances beyond 150m. I would always advise that a gun is zeroed on a long range.

regards
If you are normally shooting large animals at longer ranges, then yes. However, if your points of zero are 25-30m and 175-200m, then unless you are firing a laser your shot will be far more than an inch high at 100m! Most deer in uk are shot at around 100m or less which is why it is generally accepted to have the best average based around this range. I'd personally rather have to aim slightly high at the odd long range animal than slightly low for almost every shot I take. I generally use a 25.06 or a 30.06 which are both relatively fast and flat trajectories so it isn't so much of an issue anyway. My points of zero with the 25.06 are about 75-80m and 150m. This puts me about 3/4 inch high at 100m and about 3.5 inches low at 200m. That's probably the optimum solution for the ranges I normally shoot at, ie below 200m!
I would therefore only advise you to zero your rifle at long range if you intend to do most of your shooting at long range. Your choice really, and one which should be based around your calibre, use, and ability!;)
MS:)
 
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