PEAX Equipment

Rifle sight in.

NDMuley said:
The bc of that bullet is .536 and it choreographed at 2915.
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At sea level and std atmospheric conditions, 145 grain ELD-X (bc of .270 G7 model), at 2,915fps, 1.5" scope height and a +/- 3" target zone, you have a maximum point blank range of 291 yds. (-3.1" at 300 yds, -8.8" at 350 yds and -15.5" at 400 yds). To zero this MPBR target 2.6" high at 100 yds.
 
Difficult to read most of this...some whacky advice and ballistics "knowledge" in this thread.

I'll give my advice.

IMO/E, about 90% of the shots I've personally missed, or seen missed have to do with the concept of sighting in for MPBR, and almost always result in shooting OVER.

Here's why...I've not seen anyone state where, in any of the various methods described in regard to sight in, where POI is in relation to POA at the highest point. Typically its around 150-160 yards, also, where a goodly portion of animals are taken. That's also where the POI is at the peak above POA.

I think it would be much better to have a zero range somewhere closer to 200 than 300, mainly because a vast majority of shots are taken inside 200. A 200 yard zero is also wayyyyy more forgiving on those typical shots at 150-170 yards than for a 300 yard zero.

If you have your chit together, and remember that you're going to be 2.6-4.5 inches high between 100-160 and aim at the lower 1/3 of the animal you're golden with a 300 yard zero. If you forget, and aim a little high on the critter, or there's an uphill/downhill angle involved...you're going to have problems and fall victim to shooting over a critter. Seen it, dozens of times.

I set my stuff up for where a majority of shots are taken, not for the occasional shot.

To recap...if it were me, I'd go 200 yard zero and have my drop information for 300-500 in 50 yard increments and also verify those drops via spent primers.

Getting as close as possible is almost never a bad move.
 
BuzzH said:
Difficult to read most of this...some whacky advice and ballistics "knowledge" in this thread.

I've not seen anyone state where, in any of the various methods described in regard to sight in, where POI is in relation to POA at the highest point.
Click to expand...

First, I acknowledge that much of this is academic because whether zeroed at MPBR or at 200 or at 3" high at 100 lots of deer have been harvesting without doing the math. But since the topic is on the table and we have over 20 posts on the point already we might as well get the details right.

POI vs POA is implicit in MPBR (and in fact is the whole point of MPBR). If you have a +/-3" MPBR you are never more than 3" high and never more than 3" low at any point between your muzzle and the MPBR. So, with NDMuley's cartridge he doesn't even need to think about whether he is at 120 yards or 190 yards or 260 yards, or whether he should aim at the upper third or lower third of an animal. He doesn't have to worry that a muley pops up at 50 yards. From 0 to 291 yards he just centers his cross-hairs and fires (taking wind out of the equation for the moment). Nothing is simpler. If a hunter over-shoots using a MPBR it means he either screwed up his end of the bargain or he got the distance wrong -- and no approach to zeroing a rifle fixes these problems.

Staying with this example, beyond 291yds NDMuley needs his drop table just like any site-in scenario (hence my giving him drops out to 400 yds in comment above), but in general, it is best that an average hunter stay within this MPBR.
 
I agree Buzz! I understand the MPBR and that in theory you will be +/- 3" from your POI but what gets me is exactly what Buzz stated.
Say the game animal is at 175 yards. Your bullet will roughly be 4" high at this distance given 2.6" high at 100. Many hunters are excited, buck fever, shaking from hiking or running up a small rise to get a shot, any number of factors. This coupled with the already 4" high can lead to shooting over a lot of the time. Also we must remember at these intermittent distances to aim at the heart which in most cases is the lower 1/3 of the body. Many hunters aim behind the shoulder leading to just over the animal shots also.
I run a 250 zero but dial all my yardages past 300 anyway and shot a lot of rounds a year practicing lots of different yardages.
For anyone hunting and using basic crosshairs and holding over a 200 yard zero is IMO way easier than MPBR.
 
VikingsGuy,

I've seen what MPBR advice can cause. Really, I could give a chit less, sight in and hunt anyway you want. Any lesson worth learning, is worth learning the hard way.

Keeping POA/POI as close to the same place as possible eliminates a mountain of problems...in my limited experience.
 
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cahunter805 said:
Your bullet will roughly be 4" high at this distance given 2.6" high at 100.

For anyone hunting and using basic crosshairs and holding over a 200 yard zero is IMO way easier than MPBR.
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This is just meant to be a friendly discussion, I really don't care how anyone sites their weapon, but for those newer shooters out there they should at least get accurate base data to inform all the other considerations that end up being as much or more important such as shot selection, wind, etc. To that end, sight in however you wish, but you can't be 4" high on a properly fired, properly sighted +/-3" MPBR setup unless you defy the laws of physics. I also don't see how "holding over" a shot is ever easier than "do nothing but aim don't worry about the distance what so ever."
 
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BuzzH said:
VikingsGuy,

I've seen what MPBR advice can cause. Really, I could give a chit less, sight in and hunt anyway you want. Any lesson worth learning, is worth learning the hard way.
Click to expand...

I respect that each hunter gets their own opinion and hunts their own way. I also understand that much of these threads perseverate over minor details that often aren't that important. But, I also feel it is a disservice to newer shooters to suggest there is some lurking flaw in MPBR. When done properly it is the most dummy-proof way to sight in a gun for typical hunting usage. A 200yd zero is fine too, but if somebody is shooting over the top of a deer it is not because they used MPBR to sight - it is caused by any number of other problems that sighting in any manner can't/won't fix.
 
Viking

I agree that you should be +/- 3" of your line of sight but I guess there are many factors that determine the actual POI and that may be more complex and the basic hunter needs to worry about.
MPBR is an option which many hunters can use and be accurate if they understand it and setup their rifle correctly.
Just for friendly discussion As to the OP rifle. To accurately setup his MPBR would you just shoot a group at 100 and set it 2.6" high measured of the center of a 3,5,10 shot group? Or would you set a target at 291 yards and zero it?

In the end more important than MBPR or what zero yardage is that many hunters don't take the time to test their actual rifle and ammo. I've seen so many guys at the range the week before season saying oh the box says it's 3000 fps and about 1.5" high at 100.
 
VikingsGuy,

Here's where the MBPR theory falls on its arse...in reality.

When you shoot a 3-5 shot group at say 100, how often are all your shots exactly 2.6 inches high? Is there usually 1 or 2 that may be 3.0 or maybe even 3.1? Some are going to be above 2.6, some below...right? Correlate that to the highest point in the trajectory...now we're up to 5+ inches high.

Take an average ND mule deer, for example if they're comparable to the Eastern Montana mule deer chest is 20-24 inches deep...total vital area may be closer to 18-20

You have a buck at 170 yards...you aim lets say 2 inches above the center-line of the body because you aint perfect, you forgot your sliderule, or maybe you're excited. The cold bore shot you're about to shoot is just a pinch higher than the theoretical 2.6 perfection that also aint reality, that now makes your POI 7+ inches above POA. You're handicapped 7" before you blink an eye and that's doing everything to that point what you think is perfect. If you're lucky, you may spine the buck. If you aren't, you'll shoot right over it.

There's the reality of what I've seen happen dozens and dozens of times in the field, by guys sighting their rifles in 2.5-3 inches high at 100 and following the advice of just "aim for the center and shoot" at ranges near the top of the trajectory. A place where we tend to get a good number of shot opportunities.

If you're going to use MPBR, you need to have your chit together...and many don't.

You're also wrong about no other sighting in method reducing the problems associated with MPBR...the closer POA/POI is to the same place, no matter the distance, the more room you have for error, inherent to the platform, or the nut behind the trigger, and that's just a fact.

There's a damn good reason why I have my 13 year old nephews (new hunter) rifle sighted in the way it is...and isn't anywhere near MPBR. He doesn't need to relearn the same lessons that I already have. And he wont.

But, like I said...use whatever gives you a warm fuzzy.
 
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cahunter805 said:
Viking

As to the OP rifle. To accurately setup his MPBR would you just shoot a group at 100 and set it 2.6" high measured of the center of a 3,5,10 shot group? Or would you set a target at 291 yards and zero it?

In the end more important than MBPR or what zero yardage is that many hunters don't take the time to test their actual rifle and ammo. I've seen so many guys at the range the week before season saying oh the box says it's 3000 fps and about 1.5" high at 100.
Click to expand...

Generally, one would go for 2.6" high at 100, but really depends on what distances your range provides. Mine gives me a 109yd and a 207 yd option - guess the tape measures where broken the day they did this install :) so I calculate to those distances. As for how many, I typically use 3 shots for big game and 5 for varmints. But this is true for both MPBR and 200yd zeros. Either way you have inherrent error in every shot so we estimate using multiple samples to decide where it is actually aimed/hitting. But again, same question exists for any zeroing strategy..

I agree zeroing choices are not the biggest problem. Not practicing shots away from the bench in the postures you will shooting from in the field, taking shots at distances you aren't prepared for, relying on factory velocity for drop tables, not verifying ammo in your gun, etc. -- I assume we can both agree these are definite shortcomings.
 
BuzzH said:
VikingsGuy,

Here's where the MBPR theory falls on its arse...in reality.

When you shoot a 3-5 shot group at say 100, how often are all your shots exactly 2.6 inches high? Is there usually 1 or 2 that may be 3.0 or maybe even 3.1? Some are going to be above 2.6, some below...right? Correlate that to the highest point in the trajectory...now we're up to 5+ inches high.

. . .

You're also wrong about no other sighting in method reducing the problems associated with MPBR...the closer POA/POI is to the same place, no matter the distance, the more room you have for error, and that's just a fact.
Click to expand...

And how do you know you are zeroed at 200 or 170 or whatever distance you choose? There is inherent error in every shot regardless of your approach to zeroing. Some will be high and some will be low is definitely a fact, and true to all scenarios, but why do you choose to prefer a "shoot low" bias, missing low is just as much of a miss as missing high. My best guess is that most misses are high because hunters aren't very good at judging distances and tend to over estimate and then try to aim over to compensate. As for which part of the animal to shoot for, that has nothing to do with zeroing and that goes to shot selection.

As for your "POI/POA fact", I agree that a rifle that you knew you were going to shoot exactly 170 yds should be zeroed to exactly 170 yards. And generally that is my experience in Northern MN as deer shots are mostly well under 100 yds and most of us just buy some cheap rem corelokts, zero at 100 or 50yds, whichever is available at the local range and go out and fill you tag without much more thought about how to zero. But my understanding was that OP was going open western shooting and that can present shots from 50 - 600 (he picked the long range not me - that is a whole other issue). In this scenario MPBR is very useful. I will leave it at that - we will just have to disagree on the presence or absence of a downside.
 
I have put in all the bullet data in my ballistic calculator and it is telling me that at 100 yards I am 1.4 MOA high and 2.1 MOA low at 300. This is for a 200 yard zero. So if I zero it at 200 wouldn't a guy just be able to hold center and the bullet would still hit vitals? Understanding this does not take into account human errors.
 
VikingsGuy said:
And how do you know you are zeroed at 200 or 170 or whatever distance you choose?
Click to expand...

Well, by actually shooting and zeroing at 170, 200, or whatever your zero is...unlike what most do when using the MPBR theory. How often do guys shoot at the point where their trajectory is highest to verify? My guess...not many. Most sight xyz high at 100...then calculate where their POA/POI cross down range...again rarely verifying.



VikingsGuy said:
There is inherent error in every shot regardless of your approach to zeroing.
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Agreed, but when you add the inherent error, along with the 4 inch high POI/POA problem you have from a perfect shot...where does that leave you?

VikingsGuy said:
Some will be high and some will be low is definitely a fact, and true to all scenarios, but why do you choose to prefer a "shoot low" bias
Click to expand...

Again, pretty obvious because POI is 2.5-4+ inches above POA. I want the bullet to impact as close to the center of the body as possible...every time. The ONLY way to do that sighting in at MPBR is to hold on the lower 1/3 of the body anytime you're near the maximum trajectory height. There has to be a whole lot more shit go wrong to shoot lower than POA with a rifle where POI is purposely 4-5 inches high from the get-go. Intuitively obvious, even to a casual observer.

VikingsGuy said:
My best guess is that most misses are high because hunters aren't very good at judging distances and tend to over estimate and then try to aim over to compensate.
Click to expand...

Not been my experience in 36 years of hunting...most shots are missed at moderate ranges because people don't understand what sighting their rifles in 2.5-3 inches high means at the ranges they shoot a majority of their game...100-200 yards.

VikingsGuy said:
But my understanding was that OP was going open western shooting and that can present shots from 50 - 600 (he picked the long range not me - that is a whole other issue). In this scenario MPBR is very useful. I will leave it at that - we will just have to disagree on the presence or absence of a downside.
Click to expand...

Odds are very high that even in the open western shooting, his shots are going to be under 200.

The bottom line, is that MPBR is NOT setting yourself up for where 90% of your shots are taken, even in the wide open. IME, its lead to missed animals, almost always shooting over them, that should be an absolute chip shot.

I personally use a 250 yard zero, but I also ALWAYS apply POA at the lower 1/3 of the body on every shot I take at an animal between 100-200...without exception, and for the most obvious of reasons. POI is typically near the dead center of the critter, which be the goal.

Everything past 275 is POA/POI intersection...holdover is a suckers bet.
 
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NDMuley said:
I have put in all the bullet data in my ballistic calculator and it is telling me that at 100 yards I am 1.4 MOA high and 2.1 MOA low at 300. This is for a 200 yard zero. So if I zero it at 200 wouldn't a guy just be able to hold center and the bullet would still hit vitals? Understanding this does not take into account human errors.
Click to expand...

Range verify and rock on...and stay within 300 and you'll be golden.

Assuming you understand MOA does not equal inches...2.1 MOA low is 6.6 inches low at 300.
 
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NDMuley, 3 inches high at 100, hold hair to 300. After that, it gets more complicated. mtmuley
 
in my 270win i shoot a Barnes TTSX in 130 grain, @ 3090fps. playing around at the range, for my particular load i sighted it in 2.25 inches high at 100yds. from actual shooting at the range this gives me a 318 yd zero, this is using a 6 inch target area. it's definitely worth doing field research with a load to find actual trajectory, using a ballistic calculator of any sort i feel just gives you a baseline to work with, actual range time to is needed to confirm or deny the results and make the necessary adjustments.
 
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