How critical is overall length?

carguychris · May 20, 2008, 08:44 AM

Howdy all,

I have a n00b handloading question here...

I've been handloading for a couple of months now and haven't had any major problems until now, but I'm trying to load some .38Spl+P Hornady 125gr XTPs, and they're giving me fits.

The problem: the minimum OAL in the Hodgdon load data is 1.455", but this puts the case mouth just barely at the bottom edge of the crimping groove in the bullet. When I crimp the cases, the crimp pulls the crimping groove downwards and seats the bullets slightly deeper, and I wind up with an OAL of ~1.447".

It seems to me that 0.008" shouldn't be the end of the world, esp. since they're not maximum loads. However, I'd like to hear some opinions from folks with more experience first. Is this enough to critically increase pressures?

Thanks!

Sevens · May 20, 2008, 08:56 AM

In my far-from-expert opinion, you hit it exactly-- 0.008" will likely NEVER be the end of the world! If you are using bullets from a reputable bullet maker (for sure, Hornady is exactly that!) and these bullets are intended for your caliber, and they have a cannelure on them, I say you are good to go with no worries. Especially if they aren't max loads. If they are max loads, I'd still think the difference isn't a problem.

There's a lot of safeguards built-in with .38 special. The fact that we typically use them in a .357 mag revolver is yet another one.

Best move from this point is to load up 5 rounds and shoot them and then inspect the brass VERY carefully, and note the sound, blast and recoil and try to compare them to what you typically see and feel.

Grandpa Shooter · May 20, 2008, 09:48 AM

You should not have any problem with the rounds being slightly shorter. The real issue is whether or not the fill feed and chamber in your pistol. That slight of a difference, especially in a revolver is insignificant.

If it bothers you, switch to separate seating and crimping dies to eliminate the bullet moving into the case when done in one operation.

Tuzo · May 20, 2008, 04:01 PM

The Sierra reloading manual specifies a 1.450" C.O.A.L. with a 1.150" trim to length case for 125gr JHP. This places the cannelure in the proper spot for a firm roll crimp. My research has revealed two important factors for reloading revolver ammunition: do not exceed C.O.A.L. and a firm roll crimp in the middle of the cannelure to prevent bullet extraction from recoil. Hope this helps.

wncchester · May 20, 2008, 04:35 PM

Manual makers shouldn't even post OAL measurements. They didn't do it until fairly recently. It's of little help and is causing a LOT of confusion.

Two simple OAL rules; 1) If the OAL is too long the cylinders in a revolver can't turn and the ammo for an autoloader can't feed from the magazine. 2) If the OAL is too short the cartridges will look funny.

Seat your ammo so case mouths crimp into the proper groove and don't worry about it UNLESS you are stuffing powder into it to absolutely foolish levels. But that's dumb anyway, no matter what the OAL is.

carguychris · May 20, 2008, 04:41 PM

Thanks for the replies everyone! I think I'm going to blow off the 0.008" discrepancy and finish off the box of bullets.

Since the loads are 0.3gr short of the maximum load per the book (4.7gr Titegroup vs. max of 5.0gr), I seriously doubted it could possibly cause excess pressure- I'm just a bit new at this!

SL1 · May 20, 2008, 09:29 PM

I would expect that Hornady load data for Hornady bullets would place the case mouth at the proper place in the cannelure for a good crimp. The fact that this is not happening for you suggests one of two things for me:

Either:
1. your cases are shorter than the cases Hornady used for their test loads, so the case does not reach as far forward when loaded to the same overall length,
Or
2. the Hornady manual has a misprint. (Mine has two that I have found in the past, and BOTH were cartridge overall lengths.)

You should load those cartridges to the length that gives you a good crimp. As others have said, changing the seating depth by 0.008" or even a little more should have no significant effect FOR A .38 SPECIAL because the case is so large compared to the change from the difference in bullt seating depth. However, that is NOT A UNIVERSAL RULE. For example, seating a bullet 0.008" deeper in a 9 mm case would make a substantial difference. (There was a reference that I just reread yesterday that cited an increase in pressure from 25,000 psi to 63,000 psi from seating a 9mm bullet just 0.03" deeper in the case, but I can't get to it now to give a proper reference.)

SL1

May 20, 2008, 08:44 AM	#1
carguychris Senior Member Join Date: October 20, 2007 Location: Richardson, TX Posts: 7,523	How critical is overall length? Howdy all, I have a n00b handloading question here... I've been handloading for a couple of months now and haven't had any major problems until now, but I'm trying to load some .38Spl+P Hornady 125gr XTPs, and they're giving me fits. The problem: the minimum OAL in the Hodgdon load data is 1.455", but this puts the case mouth just barely at the bottom edge of the crimping groove in the bullet. When I crimp the cases, the crimp pulls the crimping groove downwards and seats the bullets slightly deeper, and I wind up with an OAL of ~1.447". It seems to me that 0.008" shouldn't be the end of the world, esp. since they're not maximum loads. However, I'd like to hear some opinions from folks with more experience first. Is this enough to critically increase pressures? Thanks! __________________ "Smokey, this is not 'Nam. This is bowling. There are rules... MARK IT ZERO!!" - Walter Sobchak

May 20, 2008, 08:56 AM	#2
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	In my far-from-expert opinion, you hit it exactly-- 0.008" will likely NEVER be the end of the world! If you are using bullets from a reputable bullet maker (for sure, Hornady is exactly that!) and these bullets are intended for your caliber, and they have a cannelure on them, I say you are good to go with no worries. Especially if they aren't max loads. If they are max loads, I'd still think the difference isn't a problem. There's a lot of safeguards built-in with .38 special. The fact that we typically use them in a .357 mag revolver is yet another one. Best move from this point is to load up 5 rounds and shoot them and then inspect the brass VERY carefully, and note the sound, blast and recoil and try to compare them to what you typically see and feel. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

May 20, 2008, 09:48 AM	#3
Grandpa Shooter Senior Member Join Date: November 13, 2007 Posts: 140	You should not have any problem with the rounds being slightly shorter. The real issue is whether or not the fill feed and chamber in your pistol. That slight of a difference, especially in a revolver is insignificant. If it bothers you, switch to separate seating and crimping dies to eliminate the bullet moving into the case when done in one operation. __________________ Old enough to know better and way too old to care!

May 20, 2008, 04:41 PM	#6
carguychris Senior Member Join Date: October 20, 2007 Location: Richardson, TX Posts: 7,523	Thanks for the replies everyone! I think I'm going to blow off the 0.008" discrepancy and finish off the box of bullets. Since the loads are 0.3gr short of the maximum load per the book (4.7gr Titegroup vs. max of 5.0gr), I seriously doubted it could possibly cause excess pressure- I'm just a bit new at this! __________________ "Smokey, this is not 'Nam. This is bowling. There are rules... MARK IT ZERO!!" - Walter Sobchak

May 20, 2008, 04:01 PM	#4
Tuzo Senior Member Join Date: June 14, 2007 Location: Louisiana Posts: 797	The Sierra reloading manual specifies a 1.450" C.O.A.L. with a 1.150" trim to length case for 125gr JHP. This places the cannelure in the proper spot for a firm roll crimp. My research has revealed two important factors for reloading revolver ammunition: do not exceed C.O.A.L. and a firm roll crimp in the middle of the cannelure to prevent bullet extraction from recoil. Hope this helps.

May 20, 2008, 04:35 PM	#5
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	Manual makers shouldn't even post OAL measurements. They didn't do it until fairly recently. It's of little help and is causing a LOT of confusion. Two simple OAL rules; 1) If the OAL is too long the cylinders in a revolver can't turn and the ammo for an autoloader can't feed from the magazine. 2) If the OAL is too short the cartridges will look funny. Seat your ammo so case mouths crimp into the proper groove and don't worry about it UNLESS you are stuffing powder into it to absolutely foolish levels. But that's dumb anyway, no matter what the OAL is.

May 20, 2008, 09:29 PM	#7
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	I would expect that Hornady load data for Hornady bullets would place the case mouth at the proper place in the cannelure for a good crimp. The fact that this is not happening for you suggests one of two things for me: Either: 1. your cases are shorter than the cases Hornady used for their test loads, so the case does not reach as far forward when loaded to the same overall length, Or 2. the Hornady manual has a misprint. (Mine has two that I have found in the past, and BOTH were cartridge overall lengths.) You should load those cartridges to the length that gives you a good crimp. As others have said, changing the seating depth by 0.008" or even a little more should have no significant effect FOR A .38 SPECIAL because the case is so large compared to the change from the difference in bullt seating depth. However, that is NOT A UNIVERSAL RULE. For example, seating a bullet 0.008" deeper in a 9 mm case would make a substantial difference. (There was a reference that I just reread yesterday that cited an increase in pressure from 25,000 psi to 63,000 psi from seating a 9mm bullet just 0.03" deeper in the case, but I can't get to it now to give a proper reference.) SL1