OAL variation

[montana09]

I'm new to reloading and have just loaded and fired my first batch of test ammo, went great! I'm loading .38 special with 5.5 grains of Unique over 125 grain Berry's plated bullets. My question is about OAL variation. I don't trim my cartridge cases and used PPU, MAGTECH and Winchester cases for my loads. Berry's recommended an OAL of 1.445" and I'm getting a variation of 1.442" to 1.448" which I assume is due to the different manufacturers. Being new to reloading I wanted to ask is this something to worry about? The variation is so minuscule I assume it's nothing to worry about but thought I'd just ask? I'm firing them in a Ruger Blackhawk and a S&W 686 for anyone wondering.

[dallasb]

Originally Posted by montana09

I'm new to reloading and have just loaded and fired my first batch of test ammo, went great! I'm loading .38 special with 5.5 grains of Unique over 125 grain Berry's plated bullets. My question is about OAL variation. I don't trim my cartridge cases and used PPU, MAGTECH and Winchester cases for my loads. Berry's recommended an OAL of 1.445" and I'm getting a variation of 1.442" to 1.448" which I assume is due to the different manufacturers. Being new to reloading I wanted to ask is this something to worry about? The variation is so minuscule I assume it's nothing to worry about but thought I'd just ask? I'm firing them in a Ruger Blackhawk and a S&W 686 for anyone wondering.

I didnt look up ur powder load, but .005" of OAL variation wouldn't concern me at all.

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[robhic]

Berry's recommended an OAL of 1.445" and I'm getting a variation of 1.442" to 1.448"

When I started about a year and a half ago, I asked a guy in another forum who is a longtime, professional hand loader and teacher. He told me that if he gets the first 3 numbers, he's happy. Doesn't worry about thousandths.

If you're getting 1.445" + .001, 2, 3 you shouldn't have to worry. Nothing wrong with getting all the same but it's not that critical. Good luck!

[Nick_C_S]

There's actually several different answers here.

First, the round's OAL is a function of your die seater setting, and not the case length. All that will change with different case lengths is how far up the case mouth reaches the bullet; but the OAL will be the same. Well, will be the same, with some likely minor variance. . .

Which brings me to number two: You're at only 0.003" variance. That's pretty darn good.

And third: I've been loading 38 Special since 1984, have at least 5000 cases, and have never trimmed a one.

Glad your test ammo "went great." That is a good barometer right there. And 5.5 grains of Unique is a good place to be. Sounds like a good all-around range shooter.

[snakeye]

To put it in perspective a human hair is .003 to .005...that isn't anything to worry about...

[Unclenick]

Montana09,

As a general rule, cases fired at peak pressures of under 30,000 psi don't grow to need trimming. Indeed, some can shrink a little, as happens with .45 Auto fired in a typical 1911 chamber. Even at 30,000 psi or a little over, many handgun cases, like .357 Mag, seem only to stay about the same length. The main reason for trimming would be just to ensure exactly even crimp strength, and even that becomes important only in a few instances.

COL is not critical in most instances unless you are having problems jamming a magazine or some such thing. If your bullets have crimp cannelures or crimp grooves, as long as the crimp lands in that area, you are normally close enough.

[montana09]

Thanks for all the help guys, I'm learning a lot! This is all good information

[Nick_C_S]

The main reason for trimming would be just to ensure exactly even crimp strength

This may come into play with 357 Magnum, heavy loads, using slow propellants.

I have trimmed 357 Mag cases. My personal spec is that all cases >1.283" get trimmed to 1.278". Otherwise, I leave them be - that puts 99+% of my 357 cases within 0.010" of each-other; and that's plenty close enough for me.

Some of my 357 brass have stretched over the years (many loadings) and a few were long to begin with. For instance, Speer is often close to 1.290" (SAAMI max) after discharging the original factory load.

That is the only handgun brass I've ever trimmed. And yes, it did help with a more consistent roll crimp.

[RC20]

What should be stated is that bullets are not uniform.

They vary on their length.

As you are seating to a fixed distance with a device that goes over the curved part of the bullet (OGIVE) - (not the point) it does not know that COAL.

OGIVE varies (not as much as the tip), so the cartridge COAL varies.

While Pistol is not an issue in rifle if you are into the lands that variation can stick some bullets and not others.

You just adjust by loading the average a bit shorter.

[mikld]

I normally don't recommend plated bullets to new reloaders as there isn't a lot of easily found info. (I see many, many questions in forums from new reloaders asking about charges, crimping, and OAL) and I usually suggest starting with jacketed bullets with a cannalure. I only reloaded about 1,000 plated bullets in 2 semi-autos and one revolver and found not much if any advantage over my home cast bullets. I measured a few 45 cal bullets and found differences in diameter (.002") and length (.004") but not enough for concern with my type of shooting.

For the extremely forgiving, easy to reload 38 Special, .004" OAL variation is well within safe, accurate hand loading tolerances...