Monday, November 17, 2008

Ballistically Speaking...

Mayberry got his Mosin Nagent today! HOORAY!
And my response to him got me to wondering just what he should do for his battle-sight zero, which got me to do some googling- a new experience for me. (I google something about as often as I eat Okra.)
Okay, enough about my eating habits.
Lots of times we hear people talking about, "I hit it at point blank range." Then ask them what the range was and they say something like "twenty yards". Okay, sounds good to me. Or they'll say something like "300 yards". Okay, I get out the salt shaker and ask next, "What're you zeroed at?" IF they know, they might say, "One hundred yards."
Let me back up a bit to last month.
Being a member of the local shooting club, we have a yearly deer hunting sight-in days for hunters who are not members, so we gather some volunteer members and help these people zero. Mind you, deer hunting up here (MN) is big business and the woods are loaded with nearly half a million hunters each November. Perhaps three-fourths will get a deer, plus or minus a few percentage points. But I digress again.
This 'hunting zero days' is the biggest event we have each year. Hundreds of people show up to zero or get their rifles zeroed. Always, always, always, there are people- young and old- who will ask a club member to zero their weapon. Usually the weapon is a .308, 30-06, .270 or larger caliber- the monsters like .300 Weatherby mag. So the club member will donate a shoulder and experience and zero the rifle, all the while talking to the owner about his shooting habits, how long they've had the weapon, etc. We'll explain where each shot goes (using out spotting scopes) and what we're going to do to change the point of impact.
The owner who has the club member do the shooting usually responds with, "Oh, got it last week cuz the 'old gun' was a little small/old/rusty/wrong caliber/I like this one better/etc." Asked if they've ever shot the gun, their response is about 99% "Nope."
So then we'll ask them to shoot it a few times.
Notice, please, everyone wears earmuffs or plugs, even the spectators, so the noise level is kept down a little- but with ten or more folks on line shooting at once, it can get LOUD!
Quite often the gun owner will say it's not necessary, they 'trust you' with the zero. Many times the person will take position at the bench and snuggle up to the stock, look through the sights/scope and blast a shot downrange. A good number of them miss the bull, some even the target. While they shoot, the club member will watch them, not the target, cuz we know where that bullet's going to go if all things are equal.
Many times, the shooter is over-gunned, afraid of the recoil, bothered by the noise when the trigger is pulled, jerks the trigger rather than caress it, or moves their head before the shot, or will hold the gun away from their body. Some just really don't like shooting but hunt 'cuz it's 'expected' of them, so they buy a rifle and go with the gang for a week to chase deer through the woods.
It's the first group we're gonna talk about, though.
You gotta hold that rifle close as a lover, tight to your shoulder and don't flinch as you ease back the trigger- you shouldn't even know when the shot goes off, just feel it. And you should see the strike on the target (more or less) as you do the 'follow through': keep the sight on target after the shot. (Same with a pistol: do the sights recoil to the target picture?) That is how you learn to 'call your shots'.
Now back to Mayberry's M-N. Cool. Learned some interesting stuff.
Oh, Point Blank Range, first. Federal Cartridge defines Point Blank Range as that distance from muzzle to point of zero to impact from zero where an eight inch drop is terminated. In other words, PBR (not the beer) is that distance your bullet drops to a depth of eight inches below the muzzle. But it ain't always that simple. The 'zero' is the deciding factor.
Using my 30-06 as an example: using 150 grain Federal bullets, I zero it to be 3 inches high at 100 yards. Using that zero, my PBR is from muzzle to 300 yards. That's the distance that, if I put up an eight inch plate, the bullet leaving the muzzle would hit the plate dead center, and at 175 yards will hit the top of the plate, while at 300 yards it will hit the bottom of the plate.
Clear as mud, huh? That's pretty much a simplified description of PBR and a battlesight zero. It gets a lot more complicated if you really want to get into it: wind direction/speed, air temp, clear/cloudy, cold bore or hot...a lifetime can be spent just learning this stuff.
All right, I promised Mayberry's M-N zero.
From what I found here>>> 7.62x54r Ammunition Evaluations , my estimate is he should zero about 175 yards for a ten inch plate out to 300 yards. Beyond that, gravity begins doing it's best thing: pulling hard. My example is with Czech ammo, 148 grain ball ammo. If he really wants to find out a more exact point of aim, he will have to go through the tables with one of his bullets to verify the headstamp markings, load, manufacturer and year of manufacture.
Still, it was fun to do some sneaking around and I want to thank Mayberry for giving me a fun hour of play. Thanks, Mayberry. :-D
Oh, hopefully some others out there with new M-Ns or other weapons, will find this a bit useful as well.
Bless God, God bless,
PS: I wonder if I should put that composite of Old Glory and my Marlin on the banner? Any thoughts?


  1. Go for the banner, and thanks for the info!

  2. Very useful! Helps me too Shy. Thanks.

  3. Excellent points made above sir. And very true, most deer hunters sight in their load, and then just from time to time fire to see if still zeroed . Practice just for the sake of practice is rare - a box of ammunition will often last several years. Five or six to sight in, followed by one shot before season to verify still sighted in (close enough he grunts).


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