does this sound reasonable? I'm just looking for opinions

I don't think your request is unreasonable, but generally speaking I wouldn't expect a gun store to give you all of your money back on your purchase towards a trade. In my experience you can expect to get roughly 60%. of course this will depend upon your relationship with the store.

Now regarding you approach, if you are a loyal customer of this store, having purchased several guns from them and are having a problem with a purchase you should take it to them directly rather than asking for a refund through an email message. Being a loyal customer, you should know the name of your salesperson or even better, the manager and talk to them directly.

Just curious, why a letter and not going in person to speak with them? It is usually harder to turn someone down in person in my experience. I'm not suggesting a confrontation, by the way.

Tell us about your Taurus's failures to feed:
• Was the fired cartridge always fully ejected, but no new cartridge fed from the magazine? (That's a magazine problem, maybe only dirt. Easy to fix.)
• Did the fired cartridge stay in the pistol's chamber, and not eject at all? (This is usually a failure of the shooter's technique, not of the gun.)
• Did the fired cartridge stovepipe, or otherwise stay trapped in the gun's ejection port, thus preventing a new cartridge from feeding? (This may indicate a dirty gun, or even a failure of shooting technique, but it also may be the fault of a too-well-used recoil spring or a broken extractor.)

More information, please.

I agree on going in to see them in person. My experience has always been that it is better to discuss things in person as letters and/or Emails can often times be misinterepted. We've all heard it said "it was taken out of context"!
If this were me, my guy would see me there to discuss it in a non-confrontational manner!
Just my $.02!!

I also believe that discussing it in person is the best way to go. I don't think your letter precludes that. Give it a try in a non-confrontational manner and see what can be worked out.

I agree with the panel. You purchased the gun in person, and this is how you should approach it. Personally, I think any dealer who sells used guns (or used equipment in any industry) should check it before selling it. Perhaps they did, and the problem arose after their tests, or the sale to you.

If it were me, I would you give you the full amount in trade for another gun, and then set about trying to figure out what happened. I would want not only a happy customer, but also to ensure that my sales and tech people and systems are working.

Make a list of everything you have done with the gun: type of ammo, did you clean it, lube it, drop it, etc. Be as helpful as you can so they can be helpful to you.