Lighter 38 bullets shoot lower or higher?

Lighter bullets (with less recoil) and those at higher velocities tend to shoot lower with the same sight setting, because the barrel time is shorter - the barrel does not rise as far in recoil before the bullet exits the muzzle. The 125 grain loads should shoot lower, closer to point of aim.

PRD1 - mhb - MIke

You can't do anything with the front sight.

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Traditionally gunsmiths would file down the front sight to adjust point of aim. Most left the factory with a little more metal in the front sight than needed to allow some to be removed.

For punching holes in paper bullet choice isn't as important. But for SD I'd want 158gr or heavier from a 38.

With practice you can learn how to hold the gun to get POI where you want it at SD ranges.

Lighter bullet, less time in the barrel, less muzzle rise before bullet clears, lower POI.

Howdy

I have heard the 'less time in the barrel' explanation for muzzle rise for years. It simply is not true. The time in the barrel is measured in microseconds. Not enough time to affect the amount of muzzle rise. The simple fact is, a heavier bullet simply makes for more recoil, which causes the muzzle to rise more before the bullet leaves the muzzle.

Driftwood Johnson said:

The time in the barrel is measured in microseconds.

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A "microsecond" is one millionth of a second. The bullet's time in the barrel is measured in microseconds??? Really?

An 800 fps bullet is inside a 4” barrel for 12.5 milliseconds, by my calculation. Or 0.0125 seconds.

I am no math wizard, so it won’t hurt my feelings if someone has a more accurate calculation. Time in the barrel would be the same for a 158 grain bullet or a 130 grain bullet if traveling at identical rates of speed.
So, that would make the statement by @Driftwood Johnson regarding recoil a correct one. In my opinion.
Also, 12.5 milliseconds is 12500 microseconds.

Pat Riot said:

An 800 fps bullet is inside a 4” barrel for 12.5 milliseconds, by my calculation. Or 0.0125 seconds.

I am no math wizard, so it won’t hurt my feelings if someone has a more accurate calculation. Time in the barrel would be the same for a 158 grain bullet or a 130 grain bullet if traveling at identical rates of speed.
So, that would make the statement by @Driftwood Johnson regarding recoil a correct one. In my opinion.
Also, 12.5 milliseconds is 12500 microseconds.

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I agree - except the "800 fps bullet" is not going 800 fps the whole time it's inside the barrel. It's going 0 fps to start with.
Nevertheless, Driftwood Johnson could very well be right regarding recoil. But only if both the 158 grain bullet and the 130 grain bullet are "traveling at identical rates of speed" - as you said.

The easier thing to do is change your sight picture. Do you use a 6 o'clock hold (top of front post at bottom of bullseye) or a sunrise hold (top of front post at middle of bullseye)? Fixed sight aiming has to be modified to the sights of the gun, rather than adjusting the sight to suit the aim. If you are dead on at 7 yards, you'll be shooting low at 15 yards, and even lower at 25 yards. Change your point of aim until your hits are where you want, then remember what your hold over amount is, and do that for each distance you regularly shoot at. when at distances between what you usually shoot at, you'll have to modify your hold to suit the new distance.

If you go changing your loads, they'll only be good for one distance using your sights, and you'd have to compensate for different distances anyway.

I call it Kentucky elevation. When adjusting POA. My Ruger black hawk in 40sw/10mm is a bit of a challenge when swapping rounds. I would get zeroed with 10mm. Then go to 40sw and have to start over again. It drove me nuts. So i settled for a middle of the road zero between the 2. Accurate enough for S/D if needed. When i want to pop cans. I Adjust my hold over/under as needed.

These two 357s shoot HIGH with heavy bullets. I was searching for a load that would hit close to POA at 25 yds. As you can see the 125gr accomplish this. I started with the 105gr (Can't remember if it was a barnes or cutting edge (not that it matters), as you can see it hit quite a bit lower than the 125s. Point of aim was center of the cardboard (where the bule 125 is penciled in). The laser was zeroed after this target.

Blue = S&W 360 PD
Yellow = Ruger LCR



Paul

A practical demonstration is possible for the handloader: choose a bullet weight and load a few rounds with a starting-level load, and then a few with a top-end load (both within the pressure range appropriate for your specific revolver), and shoot them at the same range with the same sight picture. The lower-velocity load will print higher than the higher-velocity load.

PRD1 - mhb - MIke

deleted, no facts to add.

I am not someone who sets adjustable sights and then shoots just one particular load forever, nor do i adjust sights once i get it centered and good for the majority of my loads. Fixed sights, naturally, are pretty much come-as-you-are, but I will paint the sights to make them more visible.

Like the guys above, I will adjust my POA up or down as needed to hit my spot and let fly.

My targets are rarely of bullseye competition quality, but this has been working for me for so long Im used to it now.

Stay safe.

jmr40 said:

Traditionally gunsmiths would file down the front sight to adjust point of aim. Most left the factory with a little more metal in the front sight than needed to allow some to be removed.

For punching holes in paper bullet choice isn't as important. But for SD I'd want 158gr or heavier from a 38.

With practice you can learn how to hold the gun to get POI where you want it at SD ranges.

Click to expand...

158 or heavier?

Driftwood Johnson said:

Howdy

I have heard the 'less time in the barrel' explanation for muzzle rise for years. It simply is not true. The time in the barrel is measured in microseconds. Not enough time to affect the amount of muzzle rise. The simple fact is, a heavier bullet simply makes for more recoil, which causes the muzzle to rise more before the bullet leaves the muzzle.

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So if time in the barrel is so short as to not matter one way or another, how is there enough time for recoil to create muzzle rise?

Of course it’s not an exact science simply because no too guns tolerances are identical but most fixed sight guns are regulated around a particular round. A older .38 Model 10 for instance was designed around the use of a 158 Grain Lead bullet at 850 fps. A 148 SWC is close enough to that that they generally shoot to the same point of aim. Loaded low enough people would load their target Wadcutters for accuracy (750 fps) but also so that a 6 O’clock hold aka “Pumpkin on a Post” was perfect. Also take into consideration a persons shooting form or lack there of. A flinch can set you off in a wild goose chase accuracy wise.

You can certainly load loads that shoot to a different height. If it is shooting high you need to load faster loads or lighter bullets.

An example of heavier bullets shooting higher is the .38 S&W. The standard British load (for use in their top-break revolvers) was the .38/200, with a 200 (or, later, 180) gr. bullet. The sights of the revolvers were regulated for this round. Currently available .38 S&W ammo uses a 145 gr. bullet. This will shoot low in unaltered pistols. That's why you see the front sights filed down, to raise the point of aim.

This is counter-intuitive. Ballistically, a heavier bullet should have a lower trajectory. The explanation of greater barrel whip with a heavier round makes some sense. Would that still hold true if the pistol was held in a machine rest?

JohnKSa said:

It's both, but they are inter-related.

In a given caliber, heavier bullets tend to have both slower muzzle velocities and higher muzzle momentums. That means that there's more recoil (more muzzle momentum, more recoil) and longer time in the barrel. The muzzle tends to raise more and the bullet tends to exit later and the combination of both means higher impact on the target.

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^^^ Best answer! While "barrel dwell" may be measured in milliseconds, the difference it makes on POI can be great. Shooting my X-Frame at 75 yards, the difference in POI from POA comparing a 200 gr to a 300 gr, is almost 12 inches. If there was no "barrel dwell", amount of recoil would make no difference.

I've had experiences where It goes both ways....different factors coming into play.

So recoil is not an effect of the bullet exiting the muzzle but leaving the casing and entering the bore??

whughett said:

So recoil is not an effect of the bullet exiting the muzzle but leaving the casing and entering the bore??

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First one, then the other.

As chamber pressure builds, the bullet is pushed out of the case and down the barrel. The bullet is being forced in one direction, whilst the entire gun is forced in the opposite direction. The bullet is much lower mass, so moves far more from this force than the gun does, but the gun still moves. And because we rarely see guns that are stabilized directly behind the bore line by the shooter (so that the gun would recoil straight backwards), they tend to climb upwards. It's not much of a climb, but we all know what 1/60th of a degree equates to at 100 yards.

As the bullet leaves the barrel, so do all the gases that created the pressure to force the bullet from the barrel. This also causes recoil. To get a better idea of how gases can cause such an effect, use a high pressure air nozzle and feel what 90 PSI does when you hit the trigger quickly. Then consider how many thousands of PSI come out of the muzzle of a gun.

When using the equivalent powder charge, lighter bullet = higher velocity and lower POI, and a heavier bullet = lower velocity and higher POI. However, that all goes out the door when assessing loads of vastly different energy levels.