Attempted to contact Diamondback and talked to FFLs with mixed messages from both.

If someone had a DB15 pistol 10.5 and wanted to convert over to rifle, what would they need besides the complete upper assembly?
The DB15 has a SB Tactical brace on it.

Is it just the upper assembly?
Or is it upper assembly and rifle buffer spring + tube?

DB15 is 5.56 - 10.5"

Thanks

Usually the upper is all that is needed. You might need to change buffers and I have no idea if your brace setup uses a standard one. If you want a different stock you will need the corresponding buffer and buffer tube.

You probably have a standard carbine buffer tube, spring and buffer. The SBA3 fits on that. If you pull down on the SBA3 lever you can take it off. Look on youtube for videos. Then you can look at it and measure it.

You could switch the upper, and then put on any sliding butt stock on what you have there like Mil-spec or Magpul.

Or you could shoot it with an SBA3 on it until they may be made naughty plastic by the AFT.

Are you planning ahead and dont want to shoot a bare buffer tube?

If he has a rifle upper on it, the SBA would be considered the same as a stock.  If a rifle though, I would put proper stock on it.  

It should be simple plug and play.  IDK what buffer they use, so there might be a tuning opportunity there depending on how the new upper is gassed.

Most likely, you can just get a 16" upper can move on (I would swap the SBA3 for a stock if I was going rifle)...but...keep in mind that when the proposal hits, one thing you can do is simply pop off the SBA3 while you wait for all the lawsuit to take place.  It will stay a "pistol" that way.  

Before you go buying new parts, read a lot of the FAQ's on the site because there are a lot of terms that can be confusing at first.

For instance, the legal definition of a rifle is a lot different than getting a rifle length buffer tube (or rifle length gas system).  You don't want a rifle length buffer tube unless you are going with an 18 or 20" barrel.    When we say "rifle" upper.....for an AR15, it is in the legal sense.   So must of us are talking 16" barrels (or 14.7/5" pin and welds) with carbine buffer tubes, carbine buffer weight, and either carbine or mid-gas length gas systems.  It can all get confusing if new, so just chill for now and read up, before you start spending any money.

Yea, trying to plan ahead. Pretty fn annoyed about all this

Thanks for the responses. I'll do some more reading on here and figure out what I'm going to do.

UPDATE for future references

Diamondback sales or customer service went and asked the Diamondback Gunsmith. He stated that the buffer and spring are the same in the pistol as the carbine. So, all that is needed is the upper assembly and you're mechanically good to go ??