.308 149-grain bullets usually have approx. how much drop from 100 to 200 yards? Maybe just 3"?

[Ignition Override]

The ammo is new-production Swiss "7,62x51" (not outsourced). The rifle is an Aussie FAL with 21" barrel (very nice rifling and shine) on an Imbel upper, which has been tweaked in a few ways by the US' best FAL gun smith - Mark Graham of ARS.
Exactly like the photo except for a wooden carry handle.

One this rifle hits ok at 100 yards, I will try it on a gong at 200 yards, then even 300 yards.

The problem is that either grass/weeds and moist soil generally surround these metal plates. So you can seldom know where the Missed bullets go (missing the entire plate). All of these plates are in a 500-yard gulley.
--If you Don't hear a Thunk, unless a buddy can be there to try to "spot" for corrections, you don't know whether your bullets go above, below, or to which side of these gongs..

 

[someguy2800]

 

[JFrank]

A tad over 3” drop at 200 yards or 1.6 ish moa should do it.

 

[Robert]

If your L1A1 is like my FAL, the lowest sight setting on the rear is 200m. Something to keep in mind. I'd try it on paper, if possible, at 50, 100, and 200 to see where she is hitting.

 

[Charlie98]

I'd try it on paper, if possible, at 50, 100, and 200 to see where she is hitting.

+1

Shooting steel can be fun, but very frustrating if you are missing... the only way to know what's going on is to put it on paper at those distances.

 

[doubleh]

Goolgle is your friend to get a close Idea. The only way to be exact is to do as Charlie98 has already posted.

 

[lightman]

Going by memory I'm going to say 1-1/2 inches at 200 yards and 9 inches or so at 300 yards.

 

[TonyAngel]

With a known velocity for your rifle, you can calculate your drop pretty closely with a Ballistic calculator, like Strelok. The more data you accurately enter, the closer you will be. Still, I agree with the above. The only way to know for sure is to put it on paper.

My .308 only has an 18" barrel and with a 100 yard zero, I dial 1.75 minutes.

 

[illinoisburt]

You didn't mention the size of the steel targets. There is a fairly significant difference between shooting at standard IPSC target (30x18), 66% (20 x 12) or the various gongs or plates from 5 feet down to a few inches. It's very possible the sights are significantly off zero while still getting consistent hits at 100 on the larger targets.

The FAL standard sight is supposed to be zeroed at 200 meters. Going with generic ballistics for a 308 and 200 meter zero you shouldn't really have any elevation adjustments needed for hits in the first 300 yards on the IPSC plates (about +2 100, 0 200, -8 300). Best advice is get to a steady bench and zero the rifle on paper at distance.

 

[Ignition Override]

Thanks—I solved it yesterday, with 4 or 5 post (360 degree) rotations upwards.

Illinoisburt- sorry i didn’t mention the Gong size…
The main issue was only the roughly 6" high offset, with the largest bullseye on a Shoot N See black “paper”, 100 yards.

Whether at 100 with paper or 200 on the approx. 16” x maybe 12” white steel gong….
My eyes are the other challenge—

Hitting any gong at 200, or even at 300 (a spotter is a Must) is rewarding.

 

[illinoisburt]

Thanks—I solved it yesterday, with 4 or 5 post (360 degree) rotations upwards.

Illinoisburt- sorry i didn’t mention the Gong size…
The first issue was with the largest bullseye on a Shoot N See black “paper”, 100 yards.

Whether at 100 with paper or 200 on the approx. 16” x maybe 12” white steel gong….
My eyes are the other challenge

No need to apologize. A 16" tall target is a lot of real estate at 100 yards. I think the front post is supposed to move a centimeter per click at 100 meters so you could have been a foot high at the start. Glad you got it sorted out

 

[Land Cruiser]

So asking this question from the opposite direction would zeroing a .308WIN rifle with M80 ball at 100 yards to group 3 inches above the POA result in the bullet impacting at POA at 200 yards? Thanks!

 

[illinoisburt]

So asking this question from the opposite direction would zeroing a .308WIN rifle with M80 ball at 100 yards to group 3 inches above the POA result in the bullet impacting at POA at 200 yards? Thanks!

Not exactly. When you look at a ballistics charts it's a curved line that drops off at increasing rates with longer distances. The peak of the curve is usually somewhere past 100 yards depending on how tall the sights are above the centerline of the barrel. You can play around with a ballistics calculator and look at the resulting graphs and numbers table to get a rough idea of what different zeros will produce. For a 200 zero it's usually going to be 1-3/4 to 2 inches high at 100.

 

[Legionnaire]

For future reference, JBM Ballistics. Use the trajectory calculator.