what kind of realistic accuracy can i expect
fron a short trac bar i was thinking of one for my son next spring probably in a 300 short mag

I had a BAR in 7mm Rem Mag. Best I ever got with it was 1.5" and most groups were a bit bigger than that. I liked the gun. It was very pretty and well made. But it had a couple of negatives. Besides the obvious accuracy issue (which is why Browning developed the BOSS system), it was a nightmare to clean and the gas operating system made the gun very hot. Load development took a long time because after a three shot string the gun needed about 1/2 hour to cool off.

LWD

1 1/2 to 2" at 100 yards is what I have seen out of several. One guy who developed a load for his 300 WSM got slightly better than 1 1/2"
but he finally traded his as he wanted better.

I had a short Trac in 308 and could never get better than 1 1/2 at 100 myself, so I traded it. I have an old BAR in 270 that will do just under an inch all day with Win Factory Supreme 130 gr. which is all I shoot in it!

Good luck with yours, if I was going to buy another semi-auto it would be the benelli or an AR platform of some type.

Being able to clean the Benelli's from the breech is a real plus too IMO

I've had 2 that would shoot 1" and under. I have had one that wouldn't do much better than 1.5". A buddy has a 7wsm bar and that gun will do .75 moa with handloads.