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Difference between 50 yd and 100 yd impact points

Posted: Wed Mar 04, 2020 10:51 pm
by stevemoorer
How many inches difference is there between the 50 yard impact point and the 100 yard impact point with 22 long rifle cartridges? I haven’t shot small bore in a while and the last time I ran out of clicks moving from 50 to 100 yards. I don’t have a 100 yard practice range to sight in on. Thanks in advance.

Re: Difference between 50 yd and 100 yd impact points

Posted: Thu Mar 05, 2020 12:38 am
by Bob Foth
Depends on your sight height above the barrel.
Some people use a two step front sight base with 2 levels to minimize clicks.

Re: Difference between 50 yd and 100 yd impact points

Posted: Thu Mar 05, 2020 5:45 am
by Tim S
For a typical 0.22 match rifle, with no raiser blocks under the sights and no extension/bloop tube, shooting subsonic target ammo the change between 50 and 100 is about 7 Minutes of Angle (Moa) . For the older 10-click (1/6 Minute) Anschutz sights, 35-40 clicks will get you roughly in the middle, wind allowing. As Bob notes adding raiser blocks will affect this. Bloop tubes do too, as the difference between tube and barrel diameter and the length change the height of the foresight; the longer sight base also makes the rearsight clicks finer.

If you run out of clicks going from 50 to 100, a slim (4mm) raiser under the rearsight should free up enough elevation. You will need to re-zero for 50.

Here in Britain many shooters use a flip-over tunnel that changes the elevation. The inside of the tube is bored eccentrically, so a half-turn changes the height above the bore, just like Bob's stepped base. These are quite useful for rifles which have the foresight mount cut directly into the barrel.

Re: Difference between 50 yd and 100 yd impact points

Posted: Thu Mar 05, 2020 9:01 am
by jhmartin
For most of our shooters, 4 full turns up gets them very close to the 10 from 50y/m to100y/m.
Each gun is a touch different as above have mentioned with risers and tube.

Our shooters are strongly encouraged to put these in an easily accessible table in their shooting journals.
(Oh also ... and sighting changes as they chane positions in 3P)
Nothing makes a coach cringe more than the 1st sighter shot in a new position heading out into the 0-3 ring areas

Re: Difference between 50 yd and 100 yd impact points

Posted: Thu Mar 05, 2020 9:52 am
by rgibson
Winchester 52D, Palma rear, Olympic front, CCI Standard Velocity, (1070 FPS advertised) 9 minutes from 50 to 100.
Sent from the 1970s via my time machine.
Bob

Re: Difference between 50 yd and 100 yd impact points

Posted: Fri Mar 06, 2020 5:02 am
by Wile E Coyote
You're asking a lot from the limited data given.

Example:
sighted at 50 yards
sight is 1.5" above bore
bore to target height differential 0"
no wind
sea level
60 degrees F
RH 80%
atmospheric pressure 29.5 in Hg

100-yard impact point will be
-7.607" - CCI SV
-7.195" - Lapua Midas+

Re: Difference between 50 yd and 100 yd impact points

Posted: Fri Mar 06, 2020 7:34 am
by batty
Simple answer is - the impact should be approximately 3.33" higher than the center of the bull at 50y.

using rough maths from my kiddywink years - on a 6click/minute sights its 40 clicks from 50s to 100s. which is 6.67minutes of angle. at 50's it is 0.5" per minute of angle.

6.67min x 0.5" = 3.33"

in target terms this is about a bullets width above the 1 ring at 50's