Question on seating .38spl lead bullets

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ScotchMan

New member
I have a bulk pack of 140gr .38spl bullets I bought some time ago. They have two rimmed indentations, the bottom of which is painted red, and the top is not.

How far am I supposed to seat these bullets? I thought they should be just enough to cover the red paint, but now I am beginning to think I am supposed to cover the second one as well? They chamber and fire fine with just the red covered, but the OAL is longer than factory rounds I've compared them to.
 
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Tuzo

New member
Cast bullets have one or more lube grooves. In your case red paint in the lower groove is not paint (at least it should not be paint) but a waxy lubricant required for proper firing. The higher groove is for a roll crimp.
 
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jepp2

New member
Painted red? Are you talking about the lube ring? Do they look like the picture below? Are you using a roll crimp?

If they look something like the picture of the 158 gr. bullet, I would seat them to the ring closest to the nose of the bullet.

 
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Unclenick

Staff
That crimp groove at the top should be level with the case mouth, then the crimp set to roll the lip of the case mouth into the groove. Whether you need a heavy crimp or a light one depends one how much recoil your load has. A heavy recoiling load can require a heavy crimp to prevent the bullets backing out during firing and jamming rotation of the cylinder. That's why the crimp groove is there. But if you are using a light target load (say, 3 grains of Bullseye) and the gun isn't a flyweight, then a light crimp will usually do, and that extends brass life because it takes more reloading cycles for a light crimp to work the brass to the splitting point.
 
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spaniel

New member
Following the OAL dictated in the recipe should get you close. You're talking about a significant different in seating depth....while it sounds like you are seating them too far out, not following guidelines for seating depth can be dangerous. If you seat too deeply it can significantly increase pressure.

The top groove is the crimp groove.
 
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Sport45

New member
For all my revolver loads I let the crimp groove or cannelure dictate the OAL. I don't even bother to measure them.
 
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ScotchMan

New member
Thanks. I need to push the bullets further in and re-crimp. They are currently seated just enough to cover the red.

So far these rounds have only been fired in an SP101, and an 11oz J-frame. I noticed they recoil more in the J-frame than 158gr +P ammo does, which got me looking closer at them, because they shouldn't. I know that increasing seating depth increases pressure, so I will probably only shoot the remaining ammo in the SP101.

I'll back off the load significantly for anything I want to shoot in the J-frame, but its primarily a backup carry weapon. The load I'm using is 140gr bullets over 5.3gr of Power Pistol. They recommend 6.1gr for 125gr bullets and 5.4gr for 158gr bullets, so I thought this would be more than safe.

Any idea why a light charge, with too much OAL would cause a round that recoils worse than 158gr +P factory ammo?
 
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armoredman

New member
Ditto on COAL really not being the critical measurement for revolver loads - the crimp groove is what you're looking for. The crimp groove is usually the top one, with the bottom band of that groove being beveled, and the top band being squared. :)
 
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zxcvbob

New member
The top groove (near the bullet nose) is where you crimp them. That will establish the overall length for you automatically. You don't have to get crazy with the crimp on .38 Specials (you do on some .357 Magnum loads) and crimping lightly will extend the brass life.
 
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aarhunt

Moderator
Scotchman asked a good question.I was wondering the same thing myself about the seating depth.i just loaded some 158 lead semi-wadcutters in some 38specials and the oal i used from my book is 1.550 which is just under the crimp groove but not off my much.now i know to go by the crimp groove and not the actual oal. :) But on some bullets i load there is no crimp grove or cantelure.Should i go by the oal then?????????:confused:
 
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Unclenick

Staff
In a revolver, as long as the bullet is still in the case and is not sticking out of the cylinder, it will usually function. If you seat it too short, though, pressure goes up. If you are developing your own load data, for Hornady swaged bullets or others that have no crimp groove, I usually just seat them so the front end of the bearing surface (the cylindrical full diameter portion of the bullet) protrudes about .020" to 0.50 from the case mouth. You can also simply call the bullet manufacturer and ask what they intended the COL to be for their load data.

If you want to use data from other bullets in a revolver, then you want to match seating depth of the base of the bullet into the case mouth rather than COL for that data. This is to keep the amount of space for powder the same, as that matters most to getting the pressure to match. It also assumes your bullet is the same weight and construction (lead, jacketed, etc.) as the original bullet used in the data. You need to know the length of the bullet and the COL in the data you are trying to adapt to your bullet. Subtract the length of your bullet from the original load's bullet length, then subtract the result from the original COL to get your COL. Keep in mind that if the first subtraction results in a negative number, that you add rather than subtract in the last step. Same rule as for subtracting negative numbers that you used in algebra class.

The above will work as long as the resulting COL doesn't stick out of the chambers in the cylinder.
 
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Hal

New member
Any idea why a light charge, with too much OAL would cause a round that recoils worse than 158gr +P factory ammo?
Click to expand...

According to Alliant's site, 5.3 gr of Power Pistol under a 146 gr JHP is a recipe for a +P load.
Alliant lists 5.5 gr. as the max for that +P load.

What you assumed to be a light load is in effect in the over pressure catagory.
 
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bossman

New member
aarhunt thanks for the info. Like I said I was just curious, thinking of buying a new manual this year, and knew that was a different listing from the ones I have now.
 
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