OAL driving me flippin crazy

sweaver

First off I have a question. I loaded some .40 cal today with 200gr. jacketed bullets. Both books say min OAL for 200gr. is 1.135, well in the Lee book it states the max OAL at 1.135. Not much room for error there, right?

Now on to my problem thats driving me crazy. I got the die set for the 200gr. bullet. From the first to the 150th bullet they all came out to the exact same length without any adjustment to the die. Well now, get out the 165gr. bullet. So, I load up the first bullet, its a little short. I pull it out a bit, adjust the die, and bang-the correct length (1.125). So now I think I've got it set (that's how I worked the 200gr). On to the second bullet, it's a little long (1.139). Measure it three more times to make sure it was right. Yep, it's long. A little adjustment so now it's right on. The third bullet, run it into the die, it's a little short (1.118). Without adjustment I put the fourth in: 1.119. The fifth: 1.120. The sixth: 1.118. Ok,so I adjust the die back out a bit. On to the seventh bullet, its 1.129. I adjust it down a tad till it measures 1.125. Take the ninth, unloaded round, run it through the die, guess what...1.120. I went back and using the sharper edge, measured the cases, they're all exactly the same.

What the fudge is going on???????????????????????

I give up for the night.

Shane

sf340flyer

Can't say for sure, but you may need a different seater plug. The different grain bullets may have a substantially different oglive (SP?). O.K. I tried to use the right work but my spelling may leave a bit to be desired. Let's just say the shape/profile may be different so slight differences in shape may be touching the sides of the seater plug rather than bottoming out at the top of the plug. I think I have 3 different seater plugs for various weights and types of bullets in 40 S&W so that might be something to look into. I had this problem when I started using Rainier Ballistics and noticed that when seating, I was getting a ring cut into the plating and seeing the same change in OAL that you saw. Once I switched to the proper plug, it worked great.

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Tailgunner1954

Wait until you start using a ogival seater with spitzer bullets (rifle rounds).[:D] Bullets vary in length, mostly in the curved portion.
I've never seen a manual that specified a MIN length, only max and "tested at" lengths
What your seeing is fairly normal (+/- .005) Set-up for 1.130 AVERAGE, 1.135 MAX Excessivly short can cause problems, but being as short as 1.125 won't be a problem. If you have feed issues at that length, shortem them up .005 at a time until you get reliable function/feeding.
BTW, case length has nothing to do with OAL (unless your measuring over a extractor burr on the rim), but it does affect the amount of crimp (more so with a roll crimp than a taper crimp).
I just checked a LEE seater, and they use a 20TPI, so 1/4 turn of the adjuster will move your bullet .0125, 1/8 turn .0062 etc.

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Some guys like a mag full of lead, I still prefer one round to the head.

Iconoclast

As sf noted, you may well need different seater plugs for different bullets, although that is more usually a matter of not marring the nose. I'd check to be sure there is (a) no crud in the die or plug (b) everything is properly tightened. IME, those are the two most common causes of such dramatic variation.

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sandwarrior

sweaver,

One more thing to add to iconoclasts last post. Due to what everybody has said here you have what seems to be bullets that are hitting the die somewhere before you intend them too. It may be your feeding technique. I have to tell myself sometimes to feed them exactly the same way every time. I keep my fingers on the bullet most of the way up then push the head against the shellholder. More than once I've noted the shell hitting the side of the die before the bullet starts to seat. That will make for the non-aligned, therefore different length seating. It seems to me it would be more pronounced when using wider tipped pistol bullets.
-Good luck

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n/a

This is probably the result of minute differences in the shape of your bullets. The seater plug is contacting the bullet at about the same diameter of your rifling. If your bullets are not EXACTLY the same shape (and none of them are), the OAL will be slightly different on each round. If one bullet has a longer or shorter taper to the point, from the diameter where the seater plug contacts the bullet, it may be a little longer or shorter.

Eric

All American Arms Company

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sweaver

Ok, so help me out here. I am really new and very inexperienced concerning tolerances etc. So it says the OAL should be 1.126. What is the low and high that it can actually be? I thought the OAL had more to do with the pressure inside the bullet than feeding.

Thanks to all!

shane

n/a

quote:Originally posted by sweaver
Ok, so help me out here. I am really new and very inexperienced concerning tolerances etc. So it says the OAL should be 1.126. What is the low and high that it can actually be? I thought the OAL had more to do with the pressure inside the bullet than feeding.

Thanks to all!

shane




Seating depth can affect pressures, but with semi-auto handgun ammo, I think it has more to do with feeding than anything else. You just do not want to exceed the OAL b/c of possible jambs, etc...

Eric

All American Arms Company

www.galleryofguns.com
VIP Code: AAAC

Veteran Owned and Operated

Tailgunner1954

OAL can effect both pressure and feeding. To long and you can jam the bullet into the rifling, to long and it will jam in the mag/not feed. To short and it might not feed, to short and the pressure can go up due to the reduced internal volume.
SAMMI says the max OAL for the 40 S&W is 1.135. Speer #13 shows they tested at a OAL of 1.120 If your manual calls for a OAL of 1.126 (with that bullet) it's for 1 of 2 reasons A) to get enough shank in the case for proper grip and reliable feeding due to the ogive location.
You might measure up a few of those 165gr bullets for length consistancy (bet you will find most of your variation right there). I personaly wouldn't worry about variations of +/-.005 (1.020-1.030) as long as I'm not exceeding the MAX OAL and have good feeding (in my bolt rifle rounds I almost always exceed the OAL spec, my Garand won't allow longer than spec. rounds to enter the Mag well)

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Some guys like a mag full of lead, I still prefer one round to the head.

Bittersweat

The last time that happend to me, I found wax bullet lubricant up in my bullet seating die.
Enjoy.

Smoky14

What loader are you using? I had a similiar problem with a dillon and had some worn parts. Does it make a difference if you have a shell in all stations, if progressive?

Smoky the loader


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JustC

turn die over,..spray generously with carb cleaner or break cleaner,..then try again.



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