"voodoo" question regarding the 454 casull with different loads

20 May 2002, 14:57

Fiftydriver

Dr. John,

While I in no way will tell you I know why your getting your results, I do have a theory from my own testing.

As you state, the full tilt 260 gr loads produce much more "felt recoil." This is true with magnum handgun rounds that drive a substantial bullet, in your case a 260 gr pill to very high handgun velocities, in the 454, it can be near 2000 fps. This creates a very fast recoil velocity and makes the recoil feel much more severe then it really is.

In the case of the larger bullet. Recoil velocity may be much less but recoil energy is usually greater, if not equal. Given the lower velocity of the heavier bullet which produces a longer barrel time, the barrel will be raised higher vertically and thus the higher impact on target.

In essence, even if the lighter bullet load recoils more severely, it leaves the barrel much quicker and thus less infuenced by the movement of the handgun under recoil. In the opposite corner the heavier, slower bullet load will leave the barrel at a higher point of recoil.

Just my experience!!

20 May 2002, 22:52

<Matt77>

Maybe one reason is the LARGE difference in bullet weights.... I wouldn't doubt it one bit at all. You'll have to sight the scope in for one loading or the other.

20 May 2002, 23:53

<Crawfish>

I seem to remember reading in one of the gun rags of a series of tests done by a staff guy that involved just this observation. He set up a number of handguns in Ransom Rests and just changed bullet weights to see the effect on POI. Came to same conclusion as that posted by Fiftydriver. Go figure as if there wasn't enough to think about when you shoot handguns now you need to consider barrel hang time. Don't ya just love it.

------------------
Handgun Hunter
LOVE THOSE .41s'

21 May 2002, 02:55

<stinkeypete>

quote:
shot some corbon 360gr penetrator rounds. recoil less severe and shot 12" high at 100 yards. I am at a loss.

Here is my theory. I'm really happy to have found this site, because I've found others that share the theory, and have found many practical suggestions on how to reload that take advantage of the principles. It's a theory, and it really plays out on rifles and Contenders- I've found the longer the barrel, in general the bigger the effect.

1) When you touch off a round, it makes a huge bang. Of course. Imagine hitting an unattached barrel a mighty blow with a hammer, smack dab on the chamber.

It would make a loud ringing sound. The barrel is vibrating.

2) The muzzle of the barrel is tracing out a lissajous figure- it swings back and forth, and around in a circle, too.

3) The bullet takes time to get from the chamber to the muzzle. When it leaves the muzzle, that is the direction it is going.

If the muzzle is at the far end of vibration, it has just finished moving one direction, has stopped, and is about to begin moving in the other. Small variations in speed would lead to the least change in point of impact. If the barrel is at the middle of the swing, it's moving the fastest, and small changes result in big angular changes.

4) I first noticed this when loading up handloads in .5 grain of powder increments. I found the point of impact generally made a spiral shape as I incremented loads. This is accounted for by the vibration theory.

5) Heres a cool webpage on how to use this in developing handloads, while minimizing boring loading and punishing range sessions-
http://home.snafu.de/l.moeller/Laddertest.htm

6) Here is what I've found-
a. It is quite a trick to get different loads to print the same point of impact. It took me almost 2 years to find a light load and heavy load that both shot same POI for my .357 Maximum. My idea was to have a deer load in one cartridge and a squirrel load in another, and I could just swap cartridges in my single shot, depending on game seen. It was a serious handloading challenge- in retrospect, I advise everyone to simply toss a small .22 in your game bag. In sixguns, I guess a fella just needs another holster!

b. handloading is fun, and gets 100% of the capability of your gun. It's not that hard, and people can help you on-line. .454 is one of the easiest to reload, because it's so large and cases are so tough, and factory ammo costs so much!

c. I expect 3" groups (scoped, from bags) at 50 yards, or better. This is the minimum group size I need to be sure that if I miss- I have full confidence it was ME! To get this, I need to handload. and once the sights are set, any change in load I expect will move the POI. Even changing primers can do it!

d. Welcome to the mysteries of shooting. Hardly a science, even yet.

Pete

21 May 2002, 03:31

<Dr. John>

I really never expected the point of impact to be the same. However I did expect the much heavier bullet to strike the target at a lower point than the lighter bullet.

sometimes when you think you have a handle on all the basics something like this happens. fun isn't it.

I have to let the idea of barrel vibration stew in my head for a while. the ruger barrel is very thick, and not long. I guess if barrel vibration were such a huge issue I would also expect my group to be very erratic. but it wasn't. just point of impact. however, slower-bullet-in-barrel-during-recoil makes more sense to me.

this just goes to prove.....ALWAYS test fire new ammo to verify point of impact. do no assume anything.