What are you using for a trim to length on these cartridges?
I'm getting different lenghts from different manuals. What if your brass is shorter than trim to lenght, does it matter?

For the 470 NE Norma brass I use 3.233" for trim length. The brass comes short from the factory, but not really consistant in length. The important part is to get consistancy in length, as long as you are at trim length or slightly under. I don't have experience with the 458 Lott, so I can't help you there.

I really don't pay attention to the trim data in the reloading manuals.

I trim all my cases to the same length as the shortest case.

If I remebre correctly my Hornady .458 Lott brass is 2.79" I have a 2.87" chamber so no trimming for me for a while !!

Thanks for the replies guys. It seems that most of my brass is short of the Trim To Length listed in the manuals. I'll just trim to my shortest case and not worry about it.

Erik,

Correct length for the Lott is 2.800", however some Lott's are chamberer .2850" long, to use full length belted basic brass. I did find with my previous Lott if I didn't trim cases after sizing, the grew enough to be crumpled when seating/crimping.

Not sure what the dimensions are on the 470 NE. I can make copies of the relevant pages of the A-Square manual if you're interested.

Trim length on a double rifle is of little concern unless you crimp, and why crimp a double...I have an undersize resizeing button in my dies and use a case full of powder or a filler whichever the case may be...

When I do crimp with my present double gun accuracy goes heywire, unless I just barely crimp at the cannalure..At any rate in any big bore rifle to be used on Dangerous game and you do require or prefer to crimp then the best route is a trim file die as they are just more accruate...OAL is not critical with doubles as they have excessively long throats as a rule and you only fire two shots so the bullets don't move if properly loaded..

Always crimp for a bolt action that is to be used on dangerous game as recoil can become a culprit under certain circumstances, therefore exact trimming is needed thus a file trim die...

I checked an old batch of original (Cordite) Kynoch .470 that I have on hand. Case length is 3.235".
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"Serious rifles have two barrels, everything else just burns gunpowder."