Like Mainecat said...do it yourself! If you ever shot my gun you would be asking me to do your trigger! All the how to info can be found in the most informative place on the WWW! Marlinowners.com! We know more about leverguns than the average gunsmith! Not the ones that specialize in them, but the average! ;D
I agree with the suggestions that you do it yourself. For the price of what an action smith will charge for the job you can buy the tools and parts for an excellent tune yourself. Plus you can do it in a couple of hours when a smith might have your firearms for weeks or months.
I ordered a Palo Verde spring kit and Aluminum oxide lapping compound kit from Brownells. I disassembled the action like I was giving it a good clean. Where I saw the wear on various parts I applied a few dabs of the water soluable lapping compound and reassembled. I worked the action 100 times disassembled again a did a thorough cleaning of all parts with soap and water. Reassembled only this time I installed the Palo Verde springs (mainspring and fingerlever spring) NO OIL at this time. The difference is amazing. It is even way smoother than my 60+ year old 336SC. Folks jaws drop when they cycle my GS. I didn't oil at this time because I want to let the surfaces to "burnish" a little further on their own.
Now I've got the tools, and lapping compound that I can work with all my other Marlins with.
Be careful. A light hammer spring has been known to cause irregular or un reliable primer ignition causing accuracy issues. All you really need is a stone to polish the parts. Well everyone does it different. ;D
Lever addict makes a fine point. Be careful. The reason I decided with the springs I used was of the nylon bushings provide a friction reducing guide for the hammer strut. You can also adjust spring tension to suit your needs. And you still have the original unaltered hammer spring you can either put back or repair one of your other Marlins.
Easy-to-install components let you fine-tune your Marlin lever gun for a smoother-operating action and more consistent trigger pull without making permanent alterations to the rifle. Simply replace the factory hammer spring and lever-plunger spring with the springs from the kit, then use the color-coded nylon bushings and adjustment washers to select one of seven hammer spring tension settings. The difference between each setting is about 8%, so you can get the hammer spring tension that suits you best simply by choosing the right combination of bushings and washers. Tough, friction-reducing nylon bushings keep hammer spring aligned and prevent it from crawling over the front of the strut or Mfg: Palo Verde Gunworks SPECS: Zinc-coated steel springs, nylon bushings/washers. Kit contains hammer spring, lever-plunger spring, (2) white hammer spring bushings, (2) blue hammer spring bushings, (4) red adjuster washers, and instructions. Fits Marlin 1894, 1895, 336, 444, 39A.