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.280 ai load info

07 Jul 2013
@ 04:32 pm (GMT)

charlie porter

hi Nathan 7/7/13

I looked again at your email to me and it now occurs that the .280 ai appears to be referencing the .280 Ackley improved. if im right- here is some data you requested. if im wrong-again I just need the full case capacity of whatever cartridge you mean.

data given me:
.280aI cartridge
27" bl
coal 3.602
bullet 162 amax 1.43 lgth

initial work up charge of h4831 at 86% load density=55.5 gr
emv =2652fps
ecp=42165 cup/46020 psi

approx. max charge =61.3 gr
emv= 2929 fps
ecp= 50978 cup/59380 psi

look forward to your thoughts on both cartridges and will happily make any adjustments/corrections if the original given data for both cartridges is not correct.

[email protected]


07 Jul 2013
@ 04:57 pm (GMT)

Nathan Foster

Re: .280 ai load info
Start load was correct. Never found max but stopped at 60.5 grains for 2929fps.

Barrel was ultra thin (not my build). Do you want to take a guess at the accuracy sweet spot?
07 Jul 2013
@ 09:56 pm (GMT)

charlie porter

Re: .280 ai load info
7/7/13 9:15 pm

well Nathan - a quick calculation of my 61.3 gr near max vs your 60.5 stopping point is within 98.7% accuracy level for my estimate- not bad. im willing to bet that with your actual internal case capacity supplied me vs my computer generated case capacity supplied for my calculation- we'd be within 99% of each other for near max load. regarding your rifle's sweet spot - unfortunately- correct barrel vibration patterns cant be "computer corralled." as you well know.
all the while of course these figures I supply are best backed up by solid range testing but the point being that these calculations are far better than merely looking up reloading book data and spending excess time and money experimenting with countless powders- most of which don't burn correctly for the bullet weight-case capacity ratio anyways. these calculations represent the thinking reloaders approach to load work-up and cant be beat. I appreciate you letting me help out john with his 7 x 57 mauser. its not my intent to use your forum regularly for reloader questions - as its your forum. my intent is to help reloaders privately on a one to one basis to quickly find the most efficient powder for their rifle's expansion ratio and spend less time experimenting and more time shooting.
actually my original intent was simply to enter your website to get a bit of feedback for my boattail partition bullet concept which you most generously approved of. as ive said- when im ready with the prototypes- ill happily forward some boxes of them for you to test and hunt with and then advertise them with your help as a top professional to represent me.
in the meantime ill be very happy to and would very much enjoy to continue developing load data calculations for you personally at any time should you need them or want them for verification or prediction purposes in your endless research on hunting loads and your website knowledge base. could be a great and productive way to stay in contact.

thanks Nathan

[email protected]
08 Jul 2013
@ 05:48 pm (GMT)

Nathan Foster

Re: .280 ai load info
No probs.


We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.