I don't think it takes a rocket scientist to figure out that it isn't a Satedan weapon.
If it was Satedan, then why isn't everybody on Atlantis using them as sidearms along with P90's now, instead of being forced to use handguns with 15 shots or whatever before needing to reload.
In 'Runner' we see flashbacks, all projectile weapons. In 'Sateda' he goes into one of their armouries & comes out with projectile weapons again.
In JM's blog back in Oct. Someone asks him will we see the origins of Ronon's gun. He says yes, stay tuned. Less than a couple weeks later, we see something regarding this exact story....
In 'Travelers' we see them guns being used by every member of the new race, even a comment from Shep about them to Larrin!
Ergo, he managed at some point to get a hold of one of the Traveler guns!
1 of 2 things:
1) He was on a planet, a Traveler came down to do business. He traded or done a job for them. So they gave him a gun as payment.
2) He managed to get hold of it indirectly. A Traveler came down, done business, they traded food for weapons or whatever. Ronon came along much later on. Traded, done a job for the villagers, his payment was the gun. Heck maybe he even stole it from them. Maybe he was Running, came to a planet in which a Traveler ship had been to in the past. Maybe a trading party was on the ground, they came under attack from the Wraith. The ground party fled & dropped everything to get back to their ship. Maybe one or all were killed. Ronon came, then found the gun lying on them etc.
We've seen Satedan weapons being used in a couple of different ocassions now. They've always been projectile. Even on the second ep, he's alone, at an armoury & is forced to use projectile weapons. Which doesn't make sense, since he kept on needing to throw them away & move on to another every few shots. Surely if energy weapons with a much great shot capacity are around. That's the first place he would head to get hold of them.
Not to mention Atlantis personnel wouldn't be running around using Beretta's or whatever as back-up weapons. Such as in 'Aurora', even 'Submersion' or in the very latest ep, 'Spoils of War'.
Obviously the gun is a Traveler weapon & Ronon managed to get hold of it at some point using one of the methods I mentioned above.