Overall length on 40 S&W

horseman2

horseman2

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Reloading 40 S&W today using Hornady Custom Grade dies with a taper crimp.
The instructions are confusing but YouTube helped.
Seating Berry Bullets into Remington Brass and there was as much as 7/1000 variation in the Overall length.
The moment it appeared to be set at 1.120", the OAL would go between 1.112 to 1.119.
The OAL on Custom and Factory loads was 1.120.
Sierra gave an OAL of 1.125 and Hornady was 1.126".
They all gauged but it was frustrating to see the OAL vary so much.
 
OAL depends on the bullet, chamber, and magazine. If it works use it. Its a pistol, not a br rifle.
When setting up my seating die for plated bullets I always seat a couple on empty cases and them pull them. Make sure the case does not crimp hard enough to damage the thin plating on the bullet.
 
Count_x said:
OAL depends on the bullet, chamber, and magazine. If it works use it. Its a pistol, not a br rifle.
When setting up my seating die for plated bullets I always seat a couple on empty cases and them pull them. Make sure the case does not crimp hard enough to damage the thin plating on the bullet.
Click to expand...

Not really a good thing to say, When in .45acp the same charge at 1.260" would be OP in a 1.200" OAL.
 
As mentioned before there are many variables that will determine the overall length , I also will consider the specific powder you use , some of them could spike in pressure with very short overall length.My preferred load for 40 cal is with : 180 gn Barry minor load for IPSC around 130pf 1.135" with 3gn Clays powder about 735f/sec.
 
Measure some bullets themselves without being seated - is the variation there? If you've got a bullet comparator you could try that and see if you get more consistent measurements. Have you got the right seating plug? Getting consistent contact with the bullet?

Let us know.
 
One other factor to look at it the actual profile of the bullet. Majority of .40 cal bullets are TC/FP profiles. Aka Truncated Cone/Flat Point with little or no curature except the slight raduis edge at the edges of the flat point and at the base. Depending on the bullet seater, you may be using a die (or insert) which does not push evenly on the bullet. If you are using RN bullets (Berry's makes 155gr RN for .40's) they may not sit the same due to the conical variation on the taper of the seating die (or visa versa in the case of TC bullets and a RN seating die). Individual bullets may all be uniform length to a vernier, but the curve may sit differently in the seating dies.

Other factors which may add a thou or more variance:
How much you are actually expanding the case mouth prior to seating?
What type of press are you using? Some presses will flex more than others (due to resistance in the stroke, be it seating, general friction, etc...).
Are you bottoming out the strokes? (aka 100% full travel of the ram?)
 
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