243 case lengths

[hairlesshunter]

Hi all to cut a long story short I recently bought 100 243 Sako once fired case and forty or so measure 2.030 long can theses cases be used and do I have to alter the O.A.L. length if I do use them and any other information I may need or should I just Bin them cheers

 

[Lateral]

The AOL should remain the same, based on what suits your chamber.

SAAMI spec Page 71

 

[Cottis]

From memory max trim length is 2.045". These 40 cases that are 2.030" do they represent the shortest in the batch. If yes, trim them all to that length and be done with it. Unless you have some cases that are a good way under 2.030, then I would just trim all your cases to the shortest length you have in the batch and then load them.

I am not close to my reloading notes at present, so cannot check what mine are but I know they are pretty close to 2.030"

OAL is generally a term used to define measurement of the overall length of a loaded cartridge (brass, primer, powder, bullet etc) Trim length is just the length of case head to end of neck.

Anyway, in terms of trim length they will be fine. Crack on.

 

[hairlesshunter]

The AOL should remain the same, based on what suits your chamber.

SAAMI spec Page 71

Cheers lads reading this will keep me busy for a couple days weeks

 

[Miki]

2.045" is the 'case length' (51.94mm in CIP) .. from the Head to the top of the Neck which is also called the "Trim length" as @Cottis said above,
They should be fine at that length.

Typically the seating depth (how far the bullet is in the neck) is around the 9mm mark with a BT and 6.5mm with a flat base,... (based on a quick look in GRT). The neck should be at least 6.1mm long (difference between L2 and L3).

Load a few and then fire them in your rifle and measure again.
What is the case length after you have full resized them in you die ?

The OAL should be as per SAAMi or CIP (68.33mm 2.690") and is independent of the case length. If you have the ability/equipment you could measure the distance from the boltface/head to the lands and set the OAL (seat the bullet) to be 20 to 30thou less than that and compare this to the specs ...

 

[hairlesshunter]

when these cases are loaded will it alter my POI If loaded to the same spec as my other home loads were the cases are all 2.035

 

[Miki]

If you load to exactly the same OAL then the bullet will be seated deeper in your old case by 5 thou (0.127mm).
Will this additional amount of 'grab' effect your MV ?, I doubt it, if it does it will make really no difference to POI from 0 to 500M, you might be a few mm higher after that (as the bullet is faster by that few fps).

The cumulative differences in powder charge, neck tension and air temperature/humidity on the day will probably have a larger effect.

 

[hairlesshunter]

Cheers Miki thank you for all the information