OAL VARIANCE=full shell plate/single

[ffgats]

HI,

Interested to know of how much is your OAL VARIANCE with a full shell plate versus single brass on the press. Its for my 550 and 223 rem.

With a single brass, from my 2.242 OAL will get increase to 2.250 with all 4 stations loaded, its almost .008 OAL difference.

thanks

[Sarge]

sounds about right. I don't load 223 but with 9mm there is a distinct difference in oal when loaded one at a time vs filling the plate.

[Youngeyes]

I always recheck the OAL of the first couple and the last couple of rounds. Those are the ones that will be different due to a less than full plate.

[benos]

An OAL measurement is only valid with a full Shellplate.

[RDA]

The variance will also be different depending on the tightness (or lack thereof) of your shellplate. Have a thrust bearing with properly adjusted tension can minimize that variance.

Edited February 13, 2014 by RDA

[SevoTT]

The roller bearing definitely minimizes this along with using single headstamp vs mixed brass and minimizing the operations being done, i.e. with 223, one pass decaps/sizes, swages and trims, the next pass primes, drops powder, seats bullet and crimps.

[ffgats]

An OAL measurement is only valid with a full Shellplate.

Thats what Im doing right now, but dont you think .008 is a little bit high. anyways, will filling or single brass shellplates will also affect the resizing dimemsions?

Using 2 toolheads die setup of my 550.

thanks

[dillon]

.008" is fine. One time I measured the individual ogives on 100 9mm 115 gr RN FMJ bullets from a major manufacturer. I had a total of .026" variation in the box of 100.

[808win]

ffgats, do you know where your seating stem contacts the bullet you're using? It's probably not at the bullet tip. Then you would need to consider the bullet to bullet variance from the contact point to the tip.