Home Forums Hunting & Shooting Hunting Rifles 45/70 zero question

If a 45/70 rifle were sighted in for 100 yards with a modern 300 gr factory load such as Federal.... where would the bullet hit at 25 yards?

About inch low? 2 inches low?

only one way to know. Go to the range and find out!

You could get close with a little information:
How high is the scope mounted above the bore? How long is the barrel?

Depends on the height of your sights, although the difference between a scope and open sights wouldn't amount to a squirrel's head. Using some generic numbers for velocity, BC and sight height the bullet would be dead on at 25 with a scope or 1/2" above line of sight with open sights.

if you know the actual numbers you can plug them in here.

Hornady Ballistics Calculator

TC encore pro hunter with a 24 inch barrel. Scoped with a Leupold 4x33.

Assuming 1880 fps which is Federal's listed MV and a BC of .197, sight height of 1.5" above the bore which is fairly standard for scopes, you're still dead on at 25 yards with a 100 yard sight in. You can fiddle with those numbers some but you won't change the point of impact by more than about 1/10 of an inch.

So, if you're gonna shoot the flea off of a deer's back at 25 yards, you might go to a higher power scope with adjustable objective...

Anything being shot with a 45/70 will be just as dead at 25 yards with a dead on hold from a 100 yard zero

I understand that. But if punching paper I was curious. A 5.56 is zeroed at 100 and is an inch and a half low at 25. The 308 pretty similar. So I was just wondering

If the 5.56 is on the AR platform, then the difference is in the height of the scope above the bore. A typical AR15 mount places the scope centerline about 2.7in above bore. In a bolt or lever gun, the scope is probably 1.5 to 1.7inches above the bore. As suggested above, plug the numbers into a ballistics calculator. For a big-bore lever gun sighted at 100yds, the bullet will cross the scope line of sight around 25yds (plus or minus 3 or 4 yards).