Well the donor's boltface is one facet of consideration. Another for me,is volume...in that a 223/223AI is always gonna win the logistics and bang for the buck race,as well as High Volume Funtitude.
"Chassis" to me,means short barrels and modest contours at best. The A5 is THE Supreme Giggles Stock and has no equal for increased contours.
I'd not want a 223AI greater than 21",nor a 6BR greater than 20". Every chassis comes replete with an AICS footprint DBM,which can add ALOTTA happiness to the equation,both in round count and COAL. It nips F/F too,which will help lotsa folks.
So I'd say for the gent who wants a Handy/Dandy Killin'/Thrillin' Platform in either 223AI or 6BR(amongst a host of others),that a Modest Chassis will reliably align stars. For a dedicated Play Toy and when talking greater case capacity(recoil),the added mass of an A5 wearing more contour,will certainly assist in seeing trace/impact and in recoil reduction. I don't brake,so fuck them.
Putting C-Note(18" Rem mag contour Mike Rock) in a MDT LSS wearing a 2-ounce Shilen trigger,really sweetened the pot. Nice to be able to scrunch the RSS buttstock and make it even handier/dandier for transport and it's the fucking Rock Of Gibraltar on a Baby Man Harris swivel 'pod. It's a Pass Shooting pleasure and shit is simply right proper fucked.
A 1-8" or better 270 configured same,is a fucking hoot and rates a thunk,as it melds 223 logistics,with the 6BR's pile driving ass.
Food for thought.................