stoney1666
Member
at 25 yds a 155gr drop 5" and the 208gr drop 3" both using 10.3gr of 2400, why do the 155 drop more then the 208? This is 762 round.
rifle bullet drop with subs
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farmerboy78
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Momentum, once started, the heavy is harder to slow down at sub speeds.
mcb
Member
Exactly same powder charge for two drastically different bullet weights? I would bet the heavier bullet is achieving higher pressure, due to less usable case volume and its mass. Thus the 208 gr bullet is likely going faster than the 155 gr bullet, and that is at least part of the reason it's shooting flatter. Did you chronograph the loads?
JeffG
Member
My 180gr round nose, sighted for 25 yards, are an inch low at 50 yards, and 3 inches low at 100. 950 fps, moly coated. 308 Winchester
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More info needed, I assume 300 BO. What type of rifle? At what range is it zeroed. Where are the bullets impacting at other ranges? On an AR the sights are 2" above the bore. At very close range the bullets will always impact lower because the sights are above the bore. The bore is never parallel with the ground because of this.
The muzzle will always be slightly elevated in order for the sights to work. The bullet will leave the muzzle at a slight upward angle and at some point will intersect with the line of sight. It will continue up for a distance before coming down at some point down range. It will again cross the line of sight.
The 1st time a bullet crosses the line of sight is normally considered the zero for a handgun. Rifles are normally considered zeroed when it crosses the 2nd time on the way down. On most guns having the sights 1/2" to 1" above the bore the distance the bullet rises above the line of sight are normally minimal. But AR's with the sights 2" above the bore are more exaggerated.
It would be pretty hard for a bullet to be 3"- 5" low at 25 yards.
The muzzle will always be slightly elevated in order for the sights to work. The bullet will leave the muzzle at a slight upward angle and at some point will intersect with the line of sight. It will continue up for a distance before coming down at some point down range. It will again cross the line of sight.
The 1st time a bullet crosses the line of sight is normally considered the zero for a handgun. Rifles are normally considered zeroed when it crosses the 2nd time on the way down. On most guns having the sights 1/2" to 1" above the bore the distance the bullet rises above the line of sight are normally minimal. But AR's with the sights 2" above the bore are more exaggerated.
It would be pretty hard for a bullet to be 3"- 5" low at 25 yards.
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