Sniper Country Duty Roster collective wisdom

Scopes: On Ballistic Cams:

Mk. IV M3 Update: An Australian regular of this page informed me yesterday that
Leupold is looking into the manufacture of a BDC for the new 175 gr. M118LR and its
commercially available cousins. We'll keep you posted as we hear more. For those of you
with the scope, you can purchase either the 168 gr. Match BDC or the 173 gr. "M118"
BDC for the scope (I assume that Leupold has similar cams for the new Long Range M3
variable power scope). Remember, these cams are calibrated for 59 degrees Fahrenheit at
sea-level. (Gooch, Rich, this correct?) Your performance may vary.

Mr. Bain
Anytime, Anywhere USA - Tuesday, September 22, 1998 at 20:44:44 (EDT)

Mr. Bain, I did get the mark IV M3 on your advice, but there wasn't any calibration info in
the box just the instructions on how to zero. The scope came with four cams, ony one of
which is for .308, the 168 match king. I would like to get the calibration info if it's
available, what velocity for each bullet and the enviro conditions. Does anyone remember
who was selling the blank M3 knobs? (I would really like to have one for the 155 palmas)

Rich <>
WA USA - Wednesday, September 23, 1998 at 01:33:21 (EDT)

Rich: Yikes. You got an M3 because of me? Seriously, I recommend you call Leupold and
order the blank cam from them (same thing for those wanting the military "M118" cam.)
As for calibration, I suggest sighting in the rifle at the distance you want and then setting
the elevation knob to that distance. Any distance marked on the cam, other than your set
distance, will not align perfectly with your actual elevation. You need to know what the
discrepancy is and then factor that in (along with humidity, altitude, light, etc.) the next
time you shoot. Remember, the scope was designed for rapid enagement of body targets,
not the precision shooting available with 1/4 MOA scopes. I suggest zeroing at 100 yds.,
the distance for true precision work, and then learning the idiosyncracies of the rifle at 200
- 1000 yds.

Mr. Bain
Anytime, Anywhere USA - Wednesday, September 23, 1998 at 11:49:11 (EDT)

Last comment. For those who find that they are having trouble with their bdc's and ammo which does not match their dials. There is no reason to "come up short" You just need access to a chronograph and a good reloading manual or a ballistic software program. Once you find the velocity of your load, look at the back of a reload manual and find out how much the bullet drops from a 100 or a 200 yard zero. If the book says the bullet will drop 400 inches at 1000 yards from a 100 yard zero at a given veloctiy, then that bullet better be hitting 40 inches high at 100 yards if you want to be on at 1000. You then find out how many clicks it takes to get the bullet to hit 40 inches high and there you are! Nothing beats actualy shooting at 1000 yards but this will get you close. Once you have all of your zero's , (the number of clicks it takes to get on at different ranges) the best thing to do is commit them to memory! This is not an impossible task. Every 4th grade child is required to memorize 20 times that much info with their multiplication and division tables. If you do this then you will be able to dial in the range even when it is too dark to read the dials.
Steve <>
S.C.D.H., Ohio, USA - Saturday, February 06, 1999 at 00:30:12 (ZULU)  

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