OAL question

[korben88]

I'm new to reloading, and was given the opportunity to go to a buddy's house and reload some .40 s&w. I got some bumblebee round nose cast bullets. The only data on OAL we could find was for cast bullets was for flat nose (1.125" Lyman's manual). We set a round to that OAL, but it was obviously wrong.

Is there a formula or Data for round nose bullets?

Thank You,
Troy

 

[The Sarge]

OAL is 1.250 in all the material I have.

 

[JimKirk]

There are usually three things that control cast bullet OAL ...

1. Magazine length/function

2. Bullet design/crimp groove placement

3. Chamber dimensions/throat/rifle lead

The bullet has to function out of the magazine or you have a single shot pistol.

Most bullets have a crimp groove, some have more than one, you almost have to use one of those grooves or look for a different bullet.

The bullet has to enter the chamber and not be jammed into the rifling/throat so that the action does not close.

The trick is to get all three of the above to work at once... If you do ... don't worry about a specific OAL.


Jimmy K

 

[Tilos]

No formula, try this:
With the barrel removed, drop a bullet in the barrel, followed by a fired case.
The case will slide over the bullet and stop when it gets to the step in the chamber.

Carefully remove the bullet and case as an assembly, and measure the OAL, while finger pinching the bullet/case junction to limit any movement.

That OAL measurement represents the MAXimum as the bullet was touching the rifling, and something shorter (-.020") will chamber but needs to be checked for mag function.
Try it, and good luck.

 

[korben88]

Thanks for the replys, we ultimately just played with the depth until we had good magazine action and feeding. Cycled a magazine full through and went with that. I forget the oal we ended up with, I'll measure when I get ho$e and record it.

I'll try the method tilos suggested on the next batch and see what they come out to.

 

[ArchAngelCD]

korben88,
Just be sure the OAL isn't longer than the SAAMI limits, then work back from there until you get perfect feeding from the mag.

 

[rfwobbly]

Troy -
Welcome !

JimKirk gave you the best all-around answer. ArchAngel has embellished Jim's #1 point on magazine function in that the magazine size is developed around he maximum cartridge length, which is set by SAAMI. So, first rule then is that the maximum cartridge length cannot be longer than the SAAMI max or the round simply won't go into the magazine.

After you spend the time discovering an OAL for a particular bullet, you need to get a full-size notebook and write down what you discovered. I set aside one whole page for each bullet, then fill in the rest of the page as I shoot that bullet at different loads. By the time you finish testing a bullet with 4 or 5 different powders and 5 or 6 loads each, you'll definitely have an entire page filled.

Hope this helps!

 

[korben88]

Where would I find the SAAMI maxes? I looked on the wiki for .40 but only saw the SAAMI pressure max.


Check that, I found this on their website. It lists the min oal @ 1.085 and the max oal @ 1.135. I'm guessing that max oal is for every bullet regardless of nose shape

 

[W.E.G.]

Where would I find the SAAMI maxes?

http://www.frfrogspad.com/miscellk.htm

 

[Tilos]

korben88 said:
"I'm guessing that max oal is for every bullet regardless of nose shape."

That's exactly why SAAMI max oal is only relevant to roundnose, ball ammo and has nothing to do with your gun, barrel, mag, load, or bullet profile.
You cannot use any stated minimum oal for a round nose bullet and apply it to a flat nose or hollow point bullet profile.
It is the location of the bullet base that determines the volume for the powder.
The OAL is used as a reference, for different bullet profiles, not an absolute.

Don't get lost in the numbers, do as I described in my other post for every different bullet profile for YOUR gun/mag and you won't have any problems with feeding or pressure.

Here's somone having trouble with factory ammo being too long: http://thehighroad.org/showthread.php?t=552344

So as you can see, it is ultimately the BARREL/MAG that determines the OAL.

 

[korben88]

yeah, I saw that thread, thought it interesting.
When I do the bullet in the barrel method I'm guessing I would use a sized and expanded?

 

[Walkalong]

Where would I find the SAAMI maxes?

Most, if not all, reloading books.

When I do the bullet in the barrel method I'm guessing I would use a sized and expanded?

Pics may help.

http://www.thehighroad.org/showthread.php?t=506678
.

 

[korben88]

Walkalong,
Given the pic in the first post it looks like flush or slightly below is what I'm looking for. I pulled my barrel and dropped a loaded round from the first batch. I don't have my calipers, but my calibrated eye says I'm sitting .002-.003 below flush.

Also I had a question about my crimp... How does it look to you?

 

[Jim Watson]

Your chamber check looks OK to me.

I see no crimp on your loaded rounds, in fact there appears to be some residual flare in the picture with the cartridge vertical.

 

[korben88]

Your chamber check looks OK to me.

I see no crimp on your loaded rounds, in fact there appears to be some residual flare in the picture with the cartridge vertical.

Is it okay to re crimp them? Can I back the seating die back and the crimp screw down?

 

[Walkalong]

Yep, a tiny bit of flare left.

Screw the die body down and the stem up for most dies. The FCD is different of course, just screw down the stem a hair more. Just remove the flair and/or a hair more.

Some crimps:

http://www.thehighroad.org/showpost.php?p=6284211&postcount=63

 

[Tilos]

korben88:
Your in good hands now, with Walkalong.
He's not a scenter and only reponds when there's something to add.

Welcome to the science of reloading, and I'll be asking you whether you are a reloader who shoots or a shooter who reloads some time in the future.

 

[rcmodel]

Where would I find the SAAMI maxes?

Speer, Hornady, Lyman, and most all other published hardcopy Reloading Manuals contain cartridge drawings with SAAMI Max case & cartridge dimensions in full glowing splender.

Better get'sum reloading manuals.
And don't rely entirely on what some stranger tells you on the liernet.

rc

 

[ArchAngelCD]

If you're having trouble setting the crimp on the combination seating/crimping die you can buy a seperate crimp die or use the same die in a seperate operation as you described. I now there are a lot of reloaders who feel this is an unnecessary step but I don't mind doing it.

 

[korben88]

rcmodel Speer, Hornady, Lyman, and most all other published hardcopy Reloading Manuals contain cartridge drawings with SAAMI Max case & cartridge dimensions in full glowing splender.

Better get'sum reloading manuals.
And don't rely entirely on what some stranger tells you on the liernet.

I have the Lyman Manual, I just didn't realize that the drawing was actually the SAAMI specs, and it only shows the Max Oal.

ArchAngelCD If you're having trouble setting the crimp on the combination seating/crimping die you can buy a seperate crimp die or use the same die in a seperate operation as you described. I now there are a lot of reloaders who feel this is an unnecessary step but I don't mind doing it.

I plan on getting the LEE classic turret press, and it has the 4th die pocket for the separate crimp die. These were done on a single stage rock chucker that a fellow was kind enough to let me try out, just to get an idea of what reloading was all about.

Jim Watson Your chamber check looks OK to me.

If you were to try and improve the seating depth, which way would you go? I'm thinking next time about .005 deeper, my OAL now is 1.16. 1.155 would take it closer to the factory ammo that I tested.



*** on an sort of unrelated note ***
If I was to pull these bullets, are all the components reusable (powder and bullets)? and would I need to resize/flare the cases again, or would the lack of crimp negate those steps?

 

[Walkalong]

I would size (sans the decapper), flare, seat, and crimp.

 

[ranger335v]

"we ultimately just played with the depth until we had good magazine action and feeding. "

With that, you have all an OAL is supposed to accomplish.

SAAMI only specs the minimum chamber throat, they don't even suggest varying loaded OALs for different bullets - too many bullets out there and they really don't care what OAL we use anyway. Thus, the max OAL is all you really gonna get from a book and that's mostly to help you not exceed common magazine or cylinder lengths; you wont blow yourself apart if you vary the book lengths. Bottom line, if your ammo feeds, chambers and functions properly, it's good. If it doesn't, fix it til it does. And then develop your charge.

For all but heavy, large bore handgun ammo the only "crimping" you need do is enough to remove the mouth flare. If you don't do that, it may not chamber fully.