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**Mal H** · January 21, 2000, 10:33 AM

Both Hornady and Sierra are right. The OAL is not a fixed length for any particular caliber. It varies with the type and shape of the bullet. For example, a JHP will most likely have a shorter OAL than a FMJ. The important dimension is the length from the base of the bullet to the inside bottom of the case. You should find that dimension mre of a constant than the outside OAL.

So the answer is to use the OAL specified for the particular bullet you are reloading, not the OAL of a factory round unless the bullets are similar in shape.

The variations you noticed in factory rounds is not unusual. That is one reason why handloading can yield more accurate rounds.

If you are crimping correctly (a short taper crimp for the 9mm), then the crimp measurement will take care of itself. No need to worry about it. The differences are most likely due to slight differences in case thickness.

January 21, 2000, 10:33 AM	#2
Mal H Staff Join Date: March 20, 1999 Location: Somewhere in the woods of Northern Virginia Posts: 16,955	Both Hornady and Sierra are right. The OAL is not a fixed length for any particular caliber. It varies with the type and shape of the bullet. For example, a JHP will most likely have a shorter OAL than a FMJ. The important dimension is the length from the base of the bullet to the inside bottom of the case. You should find that dimension mre of a constant than the outside OAL. So the answer is to use the OAL specified for the particular bullet you are reloading, not the OAL of a factory round unless the bullets are similar in shape. The variations you noticed in factory rounds is not unusual. That is one reason why handloading can yield more accurate rounds. If you are crimping correctly (a short taper crimp for the 9mm), then the crimp measurement will take care of itself. No need to worry about it. The differences are most likely due to slight differences in case thickness.