Minimum Overall Length

[ezypikns]

I just successfully loaded and shot my 1st 50 rds of .45 ACP (.6 gr. Unique, 230 gr FMJ). I noticed that the minimum overall length for this load was listed in Richard Lee's 'Modern Reloading' as 1.190. I set the overall length at about 1.260, which is what my factory ammo was set for. I know that bullet seating depth can alter pressures within the case. Am I O.K. to set this load at factory O.A.L.? Could the O.A.L. conceivably be set at 1.275 (max) without generating excessive pressures, or am I making this all too complicated?

 

[Black Snowman]

For pressure, the longer the OAL the lower the max pressure as a general rule. As the OAL shrinks you loose effective case volume and pressure increases. I try to seat my rounds as long as possible and have them still feed reliable (usually just shy of Max OAL).

 

[Jim Watson]

Lee does not test and develop loads, all that the Lee manual shows is a reprint of powder company data.

Published OAL figures do not mean a blamed thing unless you are shooting the EXACT same bullet. For some weird reason, Alliant uses the Hornady 230 grain truncated cone flat point bullet instead of ordinary roundnose. So THEIR number for OAL is going to be shorter than nearly anybody else's for a 230 grain .45 ACP.

1.26" is fine for FMJ RN. Longer, up to whatever your magazine will take, will increase powder space and tend to *reduce* chamber pressure.