Zero Ranges Benefits/Drawbacks Specific for 6.5 Grendel

[LR1955]

I know this is an old thread, but here goes. Have finished my project, A-2 left handed clone 6.5 grendel. We have no ranges in the area worth messing with, better to find an open area and set up a target. My question: Need POI vs POA for a 36 yard zero as in Marine Corp zero. There are sites that discuss this for the 5.56, but not for the Grendel. Appreciate the replies...and plz don't be too hard on this noob... Had fun building it...and looking forward to building the next one for hunting. This one is for defense.

[ATTACH=CONFIG]19717[/ATTACH]

UMP:

Out to 300 yards or meters depending on your likes, the trajectories of almost every rifle round are extremely close. They vary a few inches and this is meaningless in terms of upper torso shots on humans to 300.

Zero it at 25 or zero it at 36 yards and you will hold the upper torso at 300. The 25 meter zero will probably give you more danger space when past 300 but both will work.

Just understand that any reduced range zero was originally intended to get the shooter on paper at the true zero distance. Then the guy gets his true zero.

I would not trust any short range zero to be good enough to risk my life unless it was with machineguns.

Why 36 yards I wonder? May be technically correct for issued ball and issued carbines and issued sights but in reality my bet is most military shooters wouldn't be able to tell the difference between a 25 meter and 36 yard close range zero.

You say this is for defense. Do a short range zero at what ever distance you want, 25 meters or 36 yards. Then confirm on a E Sil at the true distance. It should be 300. If you think you only need a shorter zero, put your target up at the range you think is right and zero it there. A 25 meter zero will shoot high to about 250. A 36 yard zero may be closer to center at 250 but will probably be a bit low at 300.

Bottom line -- confirm at the distance you want the zero.

LR55

[65Carcano]

I know this is an old thread, but here goes. Have finished my project, A-2 left handed clone 6.5 grendel. We have no ranges in the area worth messing with, better to find an open area and set up a target. My question: Need POI vs POA for a 36 yard zero as in Marine Corp zero. There are sites that discuss this for the 5.56, but not for the Grendel. Appreciate the replies...and plz don't be too hard on this noob... Had fun building it...and looking forward to building the next one for hunting. This one is for defense.

[ATTACH=CONFIG]19717[/ATTACH]

That is a cool project, I've thought a classic M16 6.5 Grendel would be a fun rig. Maybe sometime down the line I'll follow in your footsteps. Can't help on the zeroing front, but as an aside my Grendel is zeroed based on MPBR for Hornady SST factory loads out of a 20" barrel. Most of my scoped rifles are sighted in with the MPBR method.

[Stinky Coyote]

I would appreciate information on zeroing for the 6.5 Grendel and the benefits/drawbacks associated with each. (100yds? 200yds?) I'm trying to get an idea what everyone uses: Is one better than the other for hunting? Is one better for target shooting?

what do you shoot with it?

if it's for hunting coyotes to big game, zero 200, even with a 16" barrel around 2386 fps 123's that gives you about 5.3" mpbr window to about 235 yards, no more that 2.6" high or 2.7" low all the way to 235, which is small enough for coyote work, and if you set up to shoot beyond mpbr then you can figure out your elevation correction solutions from there, 200 is the easy number to remember and start from for most of the slower cartridges fyi...anything under 2700 fps....for the fast stuff like 2900 fps then start looking at 250 yard zero...I've never used anything else from .204's to .270 wsm on faster end I go 250 yard zero, even a .270 win, but 308's and grendel's etc. I go 200 yard zero

100 yard zero is for the target guys and good for range work only, there are prs long range guys arguing the benefits of the 100 yard but they are just trying to sell it, do not set foot out there hunting without moving the zero to 200, you will meet Murphy when you least want to if you do, so many examples in the field from hunting and using mpbr zero that I can't start, even my first kids first deer would not have happened if not set like that, but hunting means KISS principle and remove as many variables as possible, it's an automatic to use mpbr zero for hunting, anyone trying to tell you otherwise is talking from the bronze star

oh and first shot without time to range....always hold fur, most guys who hold over thinking it was further will miss, the animal is usually closer than you think, so follow those 2 rules, mpbr zero, and if no time to range, always hold fur on first shot, never hold over

[MachV]

Good advice on the hold fur on the first round but with the little Grendel I have done well with a 100 yard zero and useing moa hash reticle or dialing if time allows . The first five antelope dropped in their tracks between 375 and 453 yards, the sixth my elbow slipped on my knee at the shot at 153 yards and took out both knees.
Of coarse time in the dog towns is great practice????

[Stinky Coyote]

lots to be said for picking your gear and method then becoming a master at it, the more variables the more likely you'll meet Murphy, it's up to the individual to boil it down to as simple a KISS principle as possible for what they want to do, a lot of things we shoot at will give us plenty of time to use all sorts of gear and methods, practiced or not, beyond mpbr is most often when you do have time to solve for elevation, wind etc. it's inside that window when you have the least amount of time and by a large margin, you're in their wheelhouse of senses and sight, so you are going to meet Murphy when you least want to, that's just how it is, there's no arguing it, so set up to take advantage of where 98% of all game is taken with fewest possibilities of meeting Murphy...do whatever for the 2% stuff, most target strategies work

Alberta here, coyotes, whitetails, muley's, bears, wolves, antelope, sheep, moose, elk...there's only one way to set up best for all them. To ignore the trajectory of a 2400-3000 fps projectile and the general size of kill zones just defies logic, these things only cost you when it's a truly amazing animal, most won't notice otherwise. Amazing to me how it gets argued however. I have no issue with 100 yard zero to make sure you're on for a new location but dial it to the 200/250 before you start hunting or know where it hits at 100 if that's all you can come up with to confirm things, ie; 2.5" high at 100 or whatever it is. Starting from 100 is just a 100 yard handicap, some like the challenge though. That phrase 'the more you fack around the more you find out' is perfect for this imo.

some guys hunt only a few of those species and not the flighty ones, so just about any method will work, but chase whitetails and elk in non-baiting areas, coyotes, wolves, bears as well...you'll find out, the sight/distance defence based animals like muley's, sheep, and antelope give you all kinds of time if you're far enough away they don't perceive you as a threat...fill yer boots with the target gear and set up, most of the time you'll be alright, you still run a risk of meeting Murphy however, that risk goes way up with the flight/defence based animals that flee first and ask questions later lol, you don't have time to play sniper, just get on fur and shoot, use that 2400-3000 fps advantage properly

[gldprimr]

I am one of those East of the Mississippi hunters and zero 1.5” high at 100 yards as that will give me a point of impact +/- 1.5” from point of aim from muzzle - 200 yards with my load and rifle though I am using a bolt action and a fast load for a 6.5 Grendel (2624 fps at muzzle). Given that all my hunting shots are off hand without a rest I know that I can’t hold that close so for me it takes all thinking about adjusting sights completely out of the equation. Distances are usually close, time short and when opportunity for a shot presents I simply aim and take the shot. It depends on where you’re hunting and distances you’ll be taking game at. If I was hunting where shots > 200 yards were likely I might sight in differently.

[Klem]

Ulmapache,

For a Point Blank Zero you need to know what bullet you will be shooting, its muzzle velocity, and vertical diameter of the kill zone on the target. Then use a ballistics calculator to work out the zero range for the most amount of distance to target a bullet aimed at the target, will land within the kill zone.

JBM Ballistics is a free online resource that can do this. Enter your bullet and its velocity. Set the range increments to 1 (yards or metres) and click Point Blank Range. Watch how the bullet is already in the kill zone, climbs and passes the POA, climbs above it to apogee which is the top of the kill zone, then drops past the POA again, back down to the bottom edge of the kill zone.

For example, a 120NBT at 2340fps with a kill zone/'vital-diameter' of 15-inches crosses the line of sight at 16yds, climbs to 7.5" at 226yds, falls past the POA again at 382yds, then drops to the bottom edge of the kill zone at 448yds. This is with a sight system 2.5" above the barrel axis like on an AR. I believe 15" is the vital zone the USMC uses, but don't quote me on that.

Obviously if only part of the target is showing you will then have to aim slightly below or above, depending on how far away it is. So you still need to be able to judge distances. For fully exposed targets out to 448 yds just point and shoot.

For hunting game with a PBR your kill zone needs to shrink to match the size of the intended target, and to be humane. Not the size of the animal, the diameter of its vital organs.

If you choose the closest bullet/POA intersection to zero the gun (16yds using the above example) your distance to target and zero needs to be absolutely precise. This is because any error will be magnified downrange. You could use the farthest intersection to zero but then that's a bit of an effort to check targets at 226yds (above example). Target structures normally sit at 100yd intervals on rifle ranges so you may as well use that to zero. Check JBM's prediction of where the bullet will be at 100yds. Using the above example it will be 10" high at 100yds. Zero the gun to be 10" high at 100 and you're good to go.

[Bonas]

I zero everything at 100. That way, with insignificant exceptions, all my DOPE is up. No matter what rifle I grab, if I'm significantly inside 100, hold up. If I'm signficantly outside 100, hold up. In terms of practical accuracy, I think this is as good as a MPBR zero, and it reduces the risk of blowing your hold if you have to shoot outside of your MPBR zero. If the shot is so long that I can't easily estimate the hold well enough to hit, for my shooting, I'll have enough time to check the hold before I have to shoot. I used to zero rifles differently based on their intended uses and finally just simplified it.

[Stinky Coyote]

Ulmapache,

For a Point Blank Zero you need to know what bullet you will be shooting, its muzzle velocity, and vertical diameter of the kill zone on the target. Then use a ballistics calculator to work out the zero range for the most amount of distance to target a bullet aimed at the target, will land within the kill zone.

JBM Ballistics is a free online resource that can do this. Enter your bullet and its velocity. Set the range increments to 1 (yards or metres) and click Point Blank Range. Watch how the bullet is already in the kill zone, climbs and passes the POA, climbs above it to apogee which is the top of the kill zone, then drops past the POA again, back down to the bottom edge of the kill zone.

For example, a 120NBT at 2340fps with a kill zone/'vital-diameter' of 15-inches crosses the line of sight at 16yds, climbs to 7.5" at 226yds, falls past the POA again at 382yds, then drops to the bottom edge of the kill zone at 448yds. This is with a sight system 2.5" above the barrel axis like on an AR. I believe 15" is the vital zone the USMC uses, but don't quote me on that.

Obviously if only part of the target is showing you will then have to aim slightly below or above, depending on how far away it is. So you still need to be able to judge distances. For fully exposed targets out to 448 yds just point and shoot.

For hunting game with a PBR your kill zone needs to shrink to match the size of the intended target, and to be humane. Not the size of the animal, the diameter of its vital organs.

If you choose the closest bullet/POA intersection to zero the gun (16yds using the above example) your distance to target and zero needs to be absolutely precise. This is because any error will be magnified downrange. You could use the farthest intersection to zero but then that's a bit of an effort to check targets at 226yds (above example). Target structures normally sit at 100yd intervals on rifle ranges so you may as well use that to zero. Check JBM's prediction of where the bullet will be at 100yds. Using the above example it will be 10" high at 100yds. Zero the gun to be 10" high at 100 and you're good to go.

That's huge vital zone, for coyotes you want to be closer to 4", the Mississippi guy above has a 3" for 0-200 yard fast offhand and that's a great choice, for combined coyotes and big game I aim for around 4-5", the grendel made me squeeze up to around 5.3" as 200 is the round number for that in my short barrel rigs with hornady black, I don't do as much coyote work as I used to so it's ok, a strictly big game hunter will often choose 6-8". The the points have been made by choosing the nearest round closest to that. Ie; 200 or 250. For most slower cartridges 200 works best, easy to remember for zero checks etc. Multiple rifles, you know the baseline zero is 200...like the guy above trying to simplify things for all his rigs, he's handicapping himself by at least 100 to 150 yards in order to do this so a negative trade off for one who prioritizes hunting over all others things though. There are only so many windows considering the bulk of the cartridge choices to game sizes we use. We're talking 2400-3200 fps and 4-10" verticals to land inside, when you play with those calculators you'll see where the rounds land for the game sizes you want to have a point shoot window and the round numbers that land to them. Did all that ages ago so it's institutionalized 200 for bulk of average speed cartridges and 250 for the faster cartridges. 100 will always remain a target or a mental only convenience and an easy 100-150 yard handicap zero for hunting. It's not really a discussion, you can't really argue with the velocity numbers vs the kill zone sizes, those are set in stone, and you can't really argue where 98% of all game is killed inside either, and you can't really argue that inside that window is when game most likely to sense you and reduce your time available is at it's peak, and so you can match them all up with the maximum odds or you can play a lottery with mr. Murphy and run some other logic that will still likely work much of the time but it's not the best for task at hand and it will catch you out...typically on animal of a lifetime, it will slow you down. The killers know how to set up for 'hunting'. Everything else is 'fack around and find out' territory.