Was able to marry up my TBAC 9" Ultra 30 cal can to my Rifle Dynamics RD 704 pistol.  My adjustable port screw is screwed all the way in, righty tighty, and i'm still getting brass thrown 30 to 35 feet.  I'm pretty sure i'm over gassed by quite a bit.  RD says to adjust to 10-12 feet. Thinking the 9" can is holding back a lot more gas than say a 7" or even a 5" can?  Ideas?

Did you measure ejection WITHOUT the can? If not, I'd try that for starters.

I did not but I will by the weekend.

About 1/2.....18 ft.....the distance of the suppressed.

I'm assuming you have adjustable port screw still all the way. If so, you are slightly over-gassed even without the can.The shorter barrel of a pistol compounds the problem so it isn't clear to me what other easy remedies can be tried. Maybe a stouter recoil spring? AK's are designed to be a bit over-gassed but there's no quantifiable definition of what that means. I'd start worrying if your trunnion is getting smacked so hard that the effects are visible (i.e. peening). Maybe some other experts can chime in here.

I found this is a good way of getting control of the gas system.

Yes, per the Rifle Dynamics video on adjusting their proprietary gas block, the screw is turned "in" or "righty tighty", all the way in.  I sent an email to RD and hope they will have some good ideas to resolve the issue.  Would hate damage a firearm meant to save my life.  Any idea what peening of the grunion would look like?

Peening--I would describe it as divots from metal to metal impact. The deeper, the worse.

Just curious, have you tried different ammo? I wouldn't expect drastically different results but it would be a relatively cheap and easy experiment and you get to pull the trigger and release endorphins.

Have tried lots of different ammo but was only looking at accuracy and velocity w/o the can.  Thinking about it more, the benches we have to shoot off of are covered.  I do recall "all" brass was slung quite aways down to the right; as many as 5-6 benches away.  I also noticed yesterday and in the previous months, the brass is ejected out at quite a high angle; like 10 o'clock high.

Problem solved.

After several emails, w/ and w/o pictures and a call with Jeromy @ Rifle Dynamics, I took a nylon bore brush, dipped in a good carbon solvent (I like 50/50 mix of Kroil/Shooters Choice) and ran the brush down into the gas port with the adjustable set screw removed.  THEN, I was able to run the set screw beyond flush, all the way until it totally cut off all gas.  I was able to adjust the gas so both suppressed and unsuppressed ejected and the brass is not totally destroyed.  Now, to figure out much to open up the screw so it will run that Brown Bear 196 Subsonic ammo I have......Boy is it quiet!