Being in 1SIR dosen't necessarily mean rifleman.
He could be a scapegoat CQ/Storeman, sleeping armskoteman, pencil
pushing clerk etc etc... the list goes on.
Though, seriously, chances of that happening aren't high if he's
combat fit.... 
Anyway, if all else
fails, there's still the support company to join.
On a side note, Asrama is nearly quite literally 1SIR's backyard
now. Training is going to be easier then ever. And they're the only
combat battalion in camp, with some other buildings filled up with
folks who stay out. Draw your own conclusions about the intensity
of guard and COS duties... I'd really hate to be in 1SIR right
now.
Edit: Sorry, by easier, i meant, more accesible....
