Case sizing and O.A.L

Hi all,

Very new to reloading etc and trying to take it all in is fun to say the least.....especially when you have experienced people to talk to who have differing opinions! :D Anyway.....to my question:

I loaded up a heap of .270 ammo the other night and the OAL on them are not all consistent. To me I didn't think it was going to be that big of a deal but apparently it is. They are maybe a maximum of 1mm difference (non digital calipers so roughly guessing) Now are they differing in OAL because maybe the case sizing's are inconsistent by - say a maximum of 1mm or should case sizing not alter the OAL? The bullets are SST so I can understand the polymer tip on them are probably not all at the same height. Cases are all the same brand and once fired and also the loading was all done in one hit (fuck i'm slow at it!!! still fun though :) )

I hope I'm making sense?

Cheers,
Grunta

OAL will be set by the seating/crimp die. Variation in the press handle bottoming out would cause OAL variation. The projectile is seated by the die maybe 5mm down from the tip so measuring OAL off the ogive of the bullet will tell you if there is a real difference.

as above measure off the ogive not the tip

Mint. Cheers guys for the quick replys.....and on a friday evening at that!!

Too drunk to be anywhere near firearms or reloading gear is the reason

Try running them all through the seater again paying attention to what you do withthe press handle. Might have short stroked a couple. Usually if measuring the tip you should still be within a spread of4-5 thou. Digital callers help here. The other thing to check is to make sure the primer are fully seated and not sitting slightly proud. Sit the loaded round on something flat and hard and see if it pivots

Its best to measure off the ogive but there is no way a sst is going to be out by a mm from the ogive to the tip.
FL sized or neck? compressed load? all the same brass? same no of firings?

If your seating depth varies excessively then it is most likely due to inconstant neck tension. This could be from different brands of brass or some new and some well work hardened.

Very compressed loads tend to push the pill back out a bit and this should be constant but will exacerbate any neck tension issues

Wow,!!!!!! Cam knows something :) was that fancy word? Exasbrate WTF duz it mean? HTF do u proniunce it? My boat doest have freeboard :):):(:(

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Originally Posted by baldbob

Wow,!!!!!! Cam knows something :) was that fancy word? Exasbrate WTF duz it mean? HTF do u proniunce it? My boat doest have freeboard :):):(:(

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You heading in with a hold full of slimy orange gold bob?

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Originally Posted by veitnamcam

You heading in with a hold full of slimy orange gold bob?

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sittin here drivin crane right now:) had a deckload bro...... Chur....

Oh God its in coverage!!!
Who the hell lets you near a crane??


Sent from my iPhone using Tapatalk. So please forgive my sausage fingers!!!

Cheers Guys, good info :) I did think about running them through the seating die again. I think i'll get the reloads out and check the OAL more precisely and go from there. I check the primers seating depth when i do them so they're all seated good. The brass is all the same - once fired federal. Loads not compressed (59gr 2213) OAL should be a around 85.3mm. I'm off to the range tomorrow so i'll batch them into overall weight groups as well and see how it all goes.

Thanks again guys

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Originally Posted by R93

Oh God its in coverage!!!
Who the hell lets you near a crane??


Sent from my iPhone using Tapatalk. So please forgive my sausage fingers!!!

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The boss!!!! And im the bos so I let me drive it!!!! How ekse would I be set free upon one..... Duh!!!!

Yep, I can see you now in the sand pit with your flash new Tonka crane. Not giving any of the other kids a turn.
Mean old Bob.


Sent from my iPhone using Tapatalk. So please forgive my sausage fingers!!!

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Originally Posted by 7mmwsm

And DON'T try to reseat the primer in a loaded round.

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I never mentioned that but maybe should have.
Good to see your checking the primers when you seat them rather than later GRUNTA saves potential drama. If primers aren't fully seated they can ruin your oal measurements and flatten/act in other ways generally related to pressure etc when fired