Heavier bullet goes ...lower?

[wiiawiwb]

I have a Glock 40 MOS (10mm) with a red dot which I reload MBC Hi-Tek coated 180gr. It is the most accurate firearm I shoot, bar none.

I recently bought some factory-made Underwood 220gr ammo and my shots were all low and off the pie plate. To make sure it wasn't me, I've had two buddies shoot it and their shots were all low and off the pie plate.

What would cause this phenomenon? I've always read that a heavier bullet shoots higher.

https://underwoodammo.com/shop/10mm-auto-220-grain-hard-cast-flat-nose/

 

[JackSprat]

Gravity..If they are going slower they will drop more,because they are in flight longer..

 

[grampajack]

Gravity..If they are going slower they will drop more,because they are in flight longer..

Yep. All objects fall at the same rate. Every bullet begins falling as soon as it leaves the barrel, but a faster bullet will drop less in the same distance.

 

[243winxb]

Velocity. Faster hits lower at 25 yards. At least using iron sights.

The Underwood 220gr ammo is listed at 1200 fps. Thats faster than any Hodgdon date with 200 gr. jacketed bullets.

And some 180 grs need a maximum load.

But then, coated lead should be faster than jacketed??

 

[koz4guns]

Normally a heavier bullet will group higher at 25 yards or so, it's caused from the gun moving up in recoil while the bullet is still in the barrel.

I suspect though that the Underwood ammo may be going fairly fast or faster than your reloads and its getting out of the barrel quicker and causing it to group lower.

Koz

 

[jmr40]

. Every bullet begins falling as soon as it leaves the barrel,

Only if the barrel is parallel to the ground. Since the sights are mounted above the bore all rifles and handguns have the muzzle pointed slightly upward in relation to the breach. When the bullet leaves the muzzle it is at an upward angle. At close range you'll hit below where your sights are aligned until the bullet is at the same height as the sights. It will continue to climb and will hit above your sights for a while until gravity starts to pull it back down where it will at some point be back in alignment with the sights. Most hand gunners use the 1st zero. Most riflemen use the 2nd.


Generally speaking heavier bullets generate more recoil which leads to muzzle rise before the bullet exits the barrel and can result in them hitting higher at closer ranges. Gravity doesn't become a factor until further down range. But it depends on the load. Your 180 gr load may be the one with more recoil

 

[grampajack]

Only if the barrel is parallel to the ground.

I didn't explain that very well. I should have said they begin to be effected by the acceleration of gravity as soon as they leave the barrel.

 

[Slamfire]

Anyone consider the concept of flinching? That will certainly cause bullets to print below the point of aim. When I shoot my revolvers, the lighter bullets print lower. I don't clearly remember if my 230 RN print higher than my 200 LSWC's in the 45 ACP, but I would not doubt it.

 

[wiiawiwb]

I was fully expecting the heavier 220gr to shoot higher and was obviously wrong.

I haven't chrono'd my 10mm using the MBC 180gr but would expect ~1,150 fps. The Underwood are advertised at 1,200 fps.

 

[Rule3]

At what distance are you shooting???
Different type (lube) bullet
Different powder (Unknown)

Lots of things that are not apples to apples.

 

[Steve C]

I would guess you are fighting the added recoil from the heavier bullet at higher velocity and pulling the shots low. The only way to check actual point of aim vs impact is to shoot from a rest that precludes pulling the muzzle down when shooting.

 

[RPZ]

From my experience and writings of others, heavier bullets tend to shoot higher in handguns. Lighter bullets are faster, generally, and tend to exit the barrel quicker; hence less influence on point of impact due to muzzle rise.

All things are relative of course. A mild load with a heavier bullet may strike lower than a hot load with a lighter bullet.

 

[RPZ]

Only if the barrel is parallel to the ground. Since the sights are mounted above the bore all rifles and handguns have the muzzle pointed slightly upward in relation to the breach. When the bullet leaves the muzzle it is at an upward angle. At close range you'll hit below where your sights are aligned until the bullet is at the same height as the sights. It will continue to climb and will hit above your sights for a while until gravity starts to pull it back down where it will at some point be back in alignment with the sights. Most hand gunners use the 1st zero. Most riflemen use the 2nd.


Generally speaking heavier bullets generate more recoil which leads to muzzle rise before the bullet exits the barrel and can result in them hitting higher at closer ranges. Gravity doesn't become a factor until further down range. But it depends on the load. Your 180 gr load may be the one with more recoil

Think it has more to do with bullet time in the barrel. Remember the "every action has an equal and opposite reaction"? The longer the bullet is in the barrel - milliseconds - the morning muzzle rise. Every fraction of a milimeter, inch, whichever way you want to phrase it of muzzle rise before the bullet clears the muzzle crown will raise the point of impact.

 

[RPZ]

I would guess you are fighting the added recoil from the heavier bullet at higher velocity and pulling the shots low. The only way to check actual point of aim vs impact is to shoot from a rest that precludes pulling the muzzle down when shooting.

If you ever want to master a handgun, in the context of accuracy, you hold a 9mm pistol as firmly as you would a .500 magnum. If you are holding your pistol or revolver differently dependant on how hotly loaded it is you are not going to master it from an accuracy point of view.

Pulling the muzzle down, like dropping the muzzle in anticipation of recoil .... is .. a .. bad .... habit. That needs to be conquered if you are ever going to master a handgun, or a rifle.

If you want to know if you are pulling the muzzle down, or lacking follow through, are blinking, flinching etc, have someone else load your (rifle, shotgun or handgun) mag or cylinger that some where along the way is a snap cap. You'll find out that way and can work toward correcting it.

A good dry fire practice is to balance a one cent piece or other coin on the barrel. If you drop the muzzle, or exhibit any other bad habit it is going to fall off.