SAMMI spec tolerance

[AussieShooter]

Hey Guys,

I was wondering if it would be safe to shoot some brass that have a headspace length 0.3mm smaller than the min SAMMI spec?

How much room does the SAMMI spec have to play with regarding this dimension?

I know you can disregard the COAL provided that you know your Ogive and further you can go past the max powder load on the proviso that you work your load up checking for signs of over pressure.

I'm not after a smart asses opinion that says you CANT play around with SAMMI specs otherwise you'll blow the chamber up, however if someone can explain to me the maximum deviation outside the SAMMI headspace min from experience it will be highly weighted.

 

[HodgdonExtreme]

That's .012" under the SAAMI spec.

If it's fresh brass, it'll be fine - though it'll stretch and thin the case just ahead of the web. Provided you size the brass properly in the future, it'll be fine for many reloadings.

If you load the bullets so that you're jamming them into the lands, it will keep the casehead in contact with the boltface, causing the case to stretch *forward*, keeping the casewalls from thinning ahead of the web.

If the brass is many times fired already - you should be careful, because the cases could already be significantly stretched, and you could have a CHS.

 

[AussieShooter]

Thanks HodgenExtreme,

It's once fired Lapua that I pushed back to far.

I'll anneal the brass pre-reloading and do as you suggest so the projectile is deep in the lands.

Thanks for that.