Why is the Johnson Rear sight in METERS?

[Ridge Runner 0]

I have a match coming up for 100/200 and 300 yards. I just noticed that my rear sight elevations are in meters?

Why is this? How do I adjust for YARDS?

Up to this point I have only been shooting it at 100 yards.

Any help would be appreciated.

[webmaster 0]

The rear sights are always in meters, this is explained in the parts section on the main site (been there since the beginning).

As we know all JSARs and LMG's were originally ordered by the KNIL or the Chileans (all U.S. used weapons were drawn from the KNIL orders). Both of these countries use the metric system of measurement i.e. meters, kilometers etc., not the imperial system of measure (inches, yards etc.). There are no non-metric scale sighted military JSAR's.

An easy measure is that 200meters is approx. 220yards (218 to be precise!) and 300 is 330 (328 in fact).

[Alasdair MacDonald 0]

A couple of thoughts for your match. 1. Is your Johnson and early one or later production? Early sights had a very tall front sight necessitating the rear elevator to be put on 600 meters to hit dead on at 100 yds. I have one of these. 2. I assume that you have zeroed the rifle, and if you have this problem will be evident. I recommend that you sight the rifle in at 200 yards as this is half way between your three distances you will be shooting. If possible shoot all three distances and see where the bullets print at those ranges. Log the "dope." Be sure to use boatail bullets for accuracy, they have an advantage over 200 yards. 3. The terms "barrel time and lock time" is the amount of time the bullet is in your barrel after squeezing the trigger and the shot fires. This will depend on bullet speed and length of barrel. What this extrapolates to is the shooter being able to "hold the rifle" until the bullet leaves the barrel. This is also referred to as the area of "wobble" for both elevation and lateral movement. The reason I brings this up, is you probably can NOT hold the difference it would make on the POI from meters to yards depending on the positions, wind, temperature etc. Let us know how you do. Cordially, Alasdair

[Jim Peden 0]

Depending on your zero point, here are the approximate changes in point of impact in inches and centimeter. One inch = 2.54 cm is about one MOA at 100 yards.

Without a precision (dial) match grade elevation sight, you may need a little kentucky elevation, but certainly not much.

Short Range Trajectory (100 yard zero)

100 Yds 0 in, 0 cm

200 Yds -3.3 in, -8.4 cm

300 Yds - 12.3, -31.2 cm

Long Range Trajectory (200 yard zero)

100 Yds +1.7 in, + 4.3 cm

200 Yds 0 in, 0 cm

300 Yds -7.3in, - 18.5cm

100 yards is 91.44 meters

200 yards is 182.88 meters

300 yards is 274.32 meters

Your biggest drop will be between 200 and 300 yards, where the meter/yard scale differential could be off by a couple of inches in point of impact.

This is still in the 10 ring, don't worry, be happy. The worse that could happen is you might miss a few X's.

This is, of course, assuming you shoot as well as Art.