I have a new to me Savage target action, rechambered in .223AI. It has a 1-9 twist, so I would like to shoot 69gr SMK's.

I tried the Max Varget load, from the Sierra Manual, for the standard .223rem.

This turned out to be a little hot and was cratering primers and even pierced one.

I will back off about 10% and try again, but I thought I would check to see if anyone else is loading this bullet/cartridge combo.

Something else is a play.

What primer? SR primers are of two types- low pressure ( cci 400s, late win SR, kvb223) and hi pressure/mag-(cci 450s, 7.5s, cci mil spec, kvb223M/556 etc).

The former set of primers is for 22 hornet type loads ( maybe not by design, as in the WSR), in practice hi intensity 223 loads pierce them with regularity.

May want to start there, then confirm the chamber and throat- not sure what throat( free boe/leade angle) the average 223AI has.

But 223 rem saami chambers are short and steep and often play havoc with heavy/long bullet 223 loads.

I am using CCI 400's

Also, I seated the bullets touching the lands. The OAL is long enough that a standard .223 plastic box will not close on them.

If you are actually touching the lands that alone might be responsible for driving pressure up. Back off a tad ( technical term ) and see if that helps.
I shoot a number of 223AIs a bunch, but I don't shoot the heavy bullets, so can't be much help there.
I have however learned if you are looking for data, Use the .222 Remington Magnum data that is available ( gonna be tough to find it for heavy bullets though...) it is usually a good guideline for middle of the road AI loads...

i would pay attention to what hpmaster said.