# Heavier bullets shoot higher in M&P 9



## berudd (Jan 22, 2016)

I just purchased an M&P 9 and have had it out twice and believe it shoots low. Now, as I am new to handguns I am perfectly willing to accept that this may be caused in part, or entirety, by my technique but I've been Googling it anyway and do see some similar experiences from others. While doing this I see several mentions of heavier bullets hitting higher than lighter ones. I'm curious about what causes this. My guess is that larger bullets travel down the barrel slower so the barrel it beginning to rotate up before the bullet leaves the muzzle. The heavier, and slower, the bullet the farther action has traveled through its reward travel and there is more barrel rotation resulting in a higher POI. Is that close to correct?


----------



## Steve M1911A1 (Feb 6, 2008)

Your conjecture is correct.
If you're shooting consistently low — and not low-left, which indicates a fault in technique — switching to a heavier bullet will raise your impact point.
Another benefit of using a heavier bullet is that it will be somewhat more likely to stop within its, um, target, thereby delivering more fight-stopping energy to it.

Note: I use "further," rather than f*a*r*t*h*e*r, because this forum's program turns the latter word into a fart.


----------



## berudd (Jan 22, 2016)

duplicate post


----------



## berudd (Jan 22, 2016)

Thanks for the confirmation. And how odd is it that it doesn't like f a rther. I thing its just the f a r t part. fart

I plan to get an M& Shield in the future. How would the short barrel affect this?


----------



## Steve M1911A1 (Feb 6, 2008)

berudd said:


> ...How would the short barrel affect this?


Probably not at all, practically speaking.

My pocket-size .45 semi-auto seems to hit close enough to where my aged memory says that a full-size 1911 does (in my hands).

Of course, I shoot against IPSC-style silhouettes, and not on bullseyes.
If I were strictly looking for precision, I'd probably find that the mini-pistol's short barrel, giving a bullet shorter dwell-time within it, makes the gun shoot a little bit lower than does the full-size pistol.


----------



## SouthernBoy (Jun 27, 2007)

Since I almost always shoot 115 FMJ out of my M&P 9 Pro Series 4.25" at the range, I have never noticed any problems with this. But as Steve mentioned, you are correct in your assumption. A bullet is long gone out of a barrel before pretty much anything takes place in the gun (recoil, rearward travel of the slide). But there is a very small reaction that does affect the travel of a bullet. And that's all it takes to cause a heavier bullet to striker higher on a target than a lighter one might (there are some other factors at play here as well).

As for the M&P Shield, they are fine little guns. Perhaps one of the best choices in their category. For shorter barreled guns like this, you are better off with a lighter bullet with a higher velocity because there is less barrel length to maximize a bullet's acceleration from the burning powder. Something no heavier than a 124 grain 9mm load would be the better choice. Both Federal (their HST series) and their sister company, Speer (Gold Dot) make fine examples of 124 grain loads with both available in +P ratings.


----------



## berudd (Jan 22, 2016)

Thanks for the info. I'm planning to head back out to the range this week so I'll pick up a few different types of ammo in larger weights and see how it goes.


----------



## AZdave (Oct 23, 2015)

berudd said:


> Thanks for the confirmation. And how odd is it that it doesn't like f a rther. I thing its just the f a r t part. fart
> 
> I plan to get an M& Shield in the future. How would the short barrel affect this?


Smelly test

f a r t h e r = farther
f a r t h e s t = farthest
f a r t h e r m o s t = farthermost
f a r t h i m = farthim
f a r t h i n g = farthing
f a r t h e m = farthem
p e n n y - f a r t h i n g = penny-farthing

FaRtHer FARTHER

SO when you want to say "f a r t h e r" just shout "FARTHER"


----------



## Steve M1911A1 (Feb 6, 2008)

FART her?
Why?
You don't like her perfume?

Shall I go farther with this?


----------



## AZdave (Oct 23, 2015)

No need to go any Farther.


----------



## oldfart64 (Feb 14, 2015)

SouthernBoy said:


> Since I almost always shoot 115 FMJ out of my M&P 9 Pro Series 4.25" at the range, I have never noticed any problems with this. But as Steve mentioned, you are correct in your assumption. A bullet is long gone out of a barrel before pretty much anything takes place in the gun (recoil, rearward travel of the slide). But there is a very small reaction that does affect the travel of a bullet. And that's all it takes to cause a heavier bullet to striker higher on a target than a lighter one might (there are some other factors at play here as well).
> 
> As for the M&P Shield, they are fine little guns. Perhaps one of the best choices in their category. For shorter barreled guns like this, you are better off with a lighter bullet with a higher velocity because there is less barrel length to maximize a bullet's acceleration from the burning powder. Something no heavier than a 124 grain 9mm load would be the better choice. Both Federal (their HST series) and their sister company, Speer (Gold Dot) make fine examples of 124 grain loads with both available in +P ratings.


and both were highly rated in the nicely done evaluation of 9mm with short barrels done by shootingthebull410 on youtube. 
I am just really puzzled (sorry guys I am a physicist ) on how a heavier bullet (and therefore a slower velocity) all things being equal can have a higher point of impact than a lighter buller with a higher velocity. Please help me out here because I am sure Newton is rolling in his grave.


----------



## Steve M1911A1 (Feb 6, 2008)

The heavier bullet necessarily moves more slowly. That's because there is a limit on chamber pressure, which, in turn, puts a limit on the velocity which can be imparted to a given mass. A less massive bullet, given the same pressure limitation, can be propelled at a greater speed.
The heavier, slower bullet spends more time in the barrel, compared to a lighter (and therefore faster) projectile going through the same barrel.
But recoil, which begins at the instant of firing, operates on the elevation of the barrel's muzzle during a period of fixed length which is independent of bullet weight.
So the lighter, faster bullet comes out of the barrel sooner, before the barrel's muzzle reaches full recoil-induced elevation. The heavier, slower bullet exits later, after the muzzle has elevated somewhat further than it would have at the moment of the exit of the lighter bullet.

Does that make it clear?
If not, ask more questions.


----------



## SouthernBoy (Jun 27, 2007)

Steve M1911A1 said:


> The heavier bullet necessarily moves more slowly. That's because there is a limit on chamber pressure, which, in turn, puts a limit on the velocity which can be imparted to a given mass. A less massive bullet, given the same pressure limitation, can be propelled at a greater speed.
> The heavier, slower bullet spends more time in the barrel, compared to a lighter (and therefore faster) projectile going through the same barrel.
> But recoil, which begins at the instant of firing, operates on the elevation of the barrel's muzzle during a period of fixed length which is independent of bullet weight.
> So the lighter, faster bullet comes out of the barrel sooner, before the barrel's muzzle reaches full recoil-induced elevation. The heavier, slower bullet exits later, after the muzzle has elevated somewhat further than it would have at the moment of the exit of the lighter bullet.
> ...


Excellent and simple.


----------



## berudd (Jan 22, 2016)

oldfart64 said:


> and both were highly rated in the nicely done evaluation of 9mm with short barrels done by shootingthebull410 on youtube.
> I am just really puzzled (sorry guys I am a physicist ) on how a heavier bullet (and therefore a slower velocity) all things being equal can have a higher point of impact than a lighter buller with a higher velocity. Please help me out here because I am sure Newton is rolling in his grave.


Steve's response covers it. You were probably confused on this for the same reason I was; you're thinking about it like you would a rifle. With a rifle shooting distance measured in hundreds of hards the bullet travels along a parabola. The force of gravity causes all bullets to be pulled down at the same rate but since the lighter bullet is faster, gravity has less time to pull it down over a given distance so lighter bullets have a higher POI for a given POA. Not so in the short distances of handguns as Steve explains above.


----------

