Varying OACL

Araxis33 · August 9, 2008, 02:25 AM

I just got into reloading and am having trouble with the OACL. I'm using an RCBS pro 2000 to load .45 ACP. Rainier 230gr RN over 5.2gr 231 and Federal LP primers. I figured I'd start with an OACL of 1.262 and work from there. However, the first OACL will be 1.262 then the next will be 1.264, then 1.258, 1.265, 1.263 and so on. I'm suspecting the Rainier bullets. The soft copper plating cuts easily and gnurls up in front of the case mouth as the bulet is seated and crimped. I went from a .471 crimp to .472 which seems to only be removing the bell from the case mouth but I'm still having said problem. Any ideas?

Shoney · August 9, 2008, 09:52 AM

Araxis33: W E L C O M E TO THE FORUM!!!

The OACL, more commonly written OAL (Over All Length) or COL (Cartridge Overall Length), will vary quite a bit with lead bullets and slightly with jacketed bullets.

Presuming you have enough bell on the case, to prevent the case from cutting into the bullet, you should be seating the bullet to depth on one operation, then crimping it very lightly in a second operation. The accuracy will improve greatly.

Araxis33 · August 9, 2008, 01:10 PM

Thanks Shoney. I'm using the RCBS carbide 3 die set wich as I'm sure you know seats and crimps at the same time which is why I suspect the soft copper coating on the bullets. It can't handle the seating AND crimping together like a copper jacketed could. I did consider seperating the process as you suggest but that would mean losing the use of my lock-out die

If I understand you correctly, I should expect some varying OAL

with these plated bullets even if I seperate the seating and crimping into two steps? Does the amount of variance I listed sound excessive? I have pulled a few of the bullets apart and don't believe the belling is a problem since the bullet only shows the marring at the point of crimping.

joneb · August 9, 2008, 01:43 PM

Are you using mixed brass ?
My RCBS dies came two seating plugs one for round nose and one for SWC, are there any marks left by the seating plug ?
What is the difference of your crimp measurement and a measurement taken 3/16" down from the case mouth ?
Have you dropped a loaded round in the chamber to see if it is head spacing properly ? When I am loading a bullet new to me I will remove the barrel from the gun and use it as a gauge.

steveno · August 9, 2008, 01:49 PM

the differences in oal length you are talking about are nothing to worry about. all you have to do is get out your calipers or micrometer and set them at a .002 gap. you will see that the .002 difference you are seeing doesn't mean much.

Shoney · August 9, 2008, 09:46 PM

First, yes, those variances are normal.

It sounds like you are overcrimping the bullets. They require very little crimp, and neck tension usually is sufficient. Try backing off on the crimp a bit.

Araxis33 · August 9, 2008, 10:26 PM

I'm using Winchester once fired brass. The case measures .472 roughly 3/16 below the mouth and .471-2 at the crimp. How much of a crimp is everyone else using, if any? I've noticed there seems to be two schools of thought on this subject. Some advocate NO crimp other than enough to remove the belling of the mouth, and those who insist you HAVE to crimp. My speer reloading manual calls for a slight taper crimp

To crimp or not to crimp........that seems to be the question

joneb · August 10, 2008, 12:20 AM

I would bell the case a bit more ? if you think that is appropriate. As Steveno stated the variation is minor, but why is it there ? When seating JHPs with a delicate nose I do as Shoney suggests, seat and crimp in different steps or I reduce the crimp. If the bullet is being deformed from the seat/crimp step it should not effect the COAL much, but it could effect load density.

Quote:

are there any marks left by the seating plug ?

?
Is there a impression of the bullet base in the case body, and is it consistent around the circumference of the case ?
Is it possible the case is trying to squirt the bullet out a bit

August 9, 2008, 02:25 AM	#1
Araxis33 Junior Member Join Date: August 9, 2008 Location: so.cal. Posts: 5	Varying OACL I just got into reloading and am having trouble with the OACL. I'm using an RCBS pro 2000 to load .45 ACP. Rainier 230gr RN over 5.2gr 231 and Federal LP primers. I figured I'd start with an OACL of 1.262 and work from there. However, the first OACL will be 1.262 then the next will be 1.264, then 1.258, 1.265, 1.263 and so on. I'm suspecting the Rainier bullets. The soft copper plating cuts easily and gnurls up in front of the case mouth as the bulet is seated and crimped. I went from a .471 crimp to .472 which seems to only be removing the bell from the case mouth but I'm still having said problem. Any ideas?

August 9, 2008, 09:52 AM	#2
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	Araxis33: W E L C O M E TO THE FORUM!!! The OACL, more commonly written OAL (Over All Length) or COL (Cartridge Overall Length), will vary quite a bit with lead bullets and slightly with jacketed bullets. Presuming you have enough bell on the case, to prevent the case from cutting into the bullet, you should be seating the bullet to depth on one operation, then crimping it very lightly in a second operation. The accuracy will improve greatly. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

August 9, 2008, 09:46 PM	#6
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	First, yes, those variances are normal. It sounds like you are overcrimping the bullets. They require very little crimp, and neck tension usually is sufficient. Try backing off on the crimp a bit. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

August 9, 2008, 01:43 PM	#4
joneb Senior Member Join Date: December 10, 2005 Location: Central , OR Posts: 1,888	Are you using mixed brass ? My RCBS dies came two seating plugs one for round nose and one for SWC, are there any marks left by the seating plug ? What is the difference of your crimp measurement and a measurement taken 3/16" down from the case mouth ? Have you dropped a loaded round in the chamber to see if it is head spacing properly ? When I am loading a bullet new to me I will remove the barrel from the gun and use it as a gauge.

August 9, 2008, 01:49 PM	#5
steveno Senior Member Join Date: June 18, 2004 Location: Minden , Nebraska Posts: 1,407	the differences in oal length you are talking about are nothing to worry about. all you have to do is get out your calipers or micrometer and set them at a .002 gap. you will see that the .002 difference you are seeing doesn't mean much.

August 9, 2008, 10:26 PM	#7
Araxis33 Junior Member Join Date: August 9, 2008 Location: so.cal. Posts: 5	I'm using Winchester once fired brass. The case measures .472 roughly 3/16 below the mouth and .471-2 at the crimp. How much of a crimp is everyone else using, if any? I've noticed there seems to be two schools of thought on this subject. Some advocate NO crimp other than enough to remove the belling of the mouth, and those who insist you HAVE to crimp. My speer reloading manual calls for a slight taper crimp To crimp or not to crimp........that seems to be the question