To the OP, I have to ask why you are griping when YOU apparently never contacted the manufacturer to get it fixed right.

While I acknowledge they have been putting out a less than perfect product, how do they know if you don't tell them it isn't satisfactory.

My new 39A has been nothing but trouble and I don't want to send it back to Marlin because I gather the company is in turmoil. After many hours of work I have got the thing performing somewhat better, with only the occasional misfire or fail to extract.

When I started, the gun would fail to fire every fifth round or so, and consistently fail to extract. Here's what I've done to bring some improvement:
1. I lengthened the firing pin 0.015" by cold forging near the cartridge end of the pin. Filed away all tool marks and polished both sides of the pin on a very fine, flat stone.
2. Filed 0.015" of material off the lower hammer rebound stop and restored the original contour.
3. Removed the lever and lengthened it by welding material to the end. The purpose here was to make the bolt close completely, which it was not doing. I ground and filed the weld material to original profile, heated the reworked end to dull red and quenched in oil. Total length added - about 0.030". Your gun may be different but the bolt must close completely. This is a fitting process - You'll know it's right when the lever handle will not quite touch the underside of the receiver when fully closed.
4. Discovered the lengthened firing pin was striking the end of the chamber leaving a burr. Cartridge will not extract if the chamber is burred. Gently filed a small 45 degree ramp on the end of the pin to eliminate this problem.
5. Removed the burr at 12 o'clock position of the chamber, caused by the lengthened firing pin. A cartridge should nearly fall into the chamber of it's own weight with very little added effort and any burr will interfere.

The results are good. The firing pin now hits the cartridge more decisively - you can hear the difference. And misfires have been for what I suspect is insufficient primer in the cartridge instead of a wimpy action. I would guess the gun is 95% reliable now and the failings to fire all seem ammo related. I've been cycling the cheap Remington stuff.

UPDATE: I continued to have FTF, especially with Remington Thunderbolt, of which I have several bricks. I did some research and found that lots of folks cycle Thunderbolt with no problems so I decided to try it in my Marlin model 60. Thunderbolt worked without a hitch in the model 60. So I gathered cases from the 39A and the model 60 and compared them under a 20X stereoscope. The firing pin impression was definitely longer and deeper on the model 60 casings so I went back to work on the 39A firing pin and action. I reshaped the end of the firing pin, making it slightly longer in footprint while keeping the same overall firing pin length. My intent was to match the firing pin impression of the model 60. Then I removed the rebound stop and took another 0.015" off the lower end of it. When I reassembled I put a 1/16" thick washer between the hammer spring and the retainer bracket, to add just a touch more hammer power. I can now cycle through a box of Thunderbolt without any FTF. I hope this helps someone out there who's having 39A problems.

Also, on the aesthetic side, the lever comes from Marlin with uncomfortably sharp edges. If you do a lot of shooting these will cut your hands up. I took a file and some emery paper and put a nice radius all the way around. This really improves the fun factor. Chemical bluing is next.

Still had the occasional fail to extract and I did write to Marlin for a new extract spring in hopes that will take care of it. In the mean time I took an old file and shaped it to fit in the extractor recess right next to the barrel. I gently worked about .010" of material out of the recess so the extractor spring has a better grab at the spent brass. This has completely solved the extraction problem. Marlin, you can keep your new spring

Maybe these steps will be helpful to someone with similar trouble. Do yourself a favor: measure and photograph everything before you make changes. You must know your starting point so you can tell where you've gone. Take notes. Make your changes one at a time and test each result. It's unfortunate that Marlin's quality has sunk to this. You are essentially buying raw material if you buy one of the newer 39As. I've invested about 20 hours in troubleshooting and reworking this gun.

2nd UPDATE: After 1 week of shooting (at least 500 rounds) I'm upgrading reliability to 100%. I have had NO failures to extract, No failures to eject, NO failures to fire, and NO failures to feed.

3rd UPDATE: Marlin did send me a new extractor spring this week and threw in a chamber guide spring to boot. I have no plans at this time to install the new springs as the rifle is now functioning flawlessly.

I bought a Marlin 39a in 09. I haven’t had any problems with it at all. I have fired shorts, longs, and LR’s through it. I have also fired sub-sonic ammo thru it with no problems. I have probably fired 2000 rounds through it. The walnut stock for a factory gun has beautiful piece of wood with nice grain to it, a beautiful finish and the checking is beautifully done. The stock fits the receiver very well with very little or no gaps between metal and wood.
One of the safe hunter education instructors I teach with has an old 39a handed down to him from his grandfather. We use both of the guns on the gun handing table so the students get a feel for the different types of actions. It is in fairly good shape. It has been used as seen by evidence of the nicks and scratches on the stock and the worn bluing. It probably needs some cleaning and oiling. But in my opinion it doesn’t function any better then my new one and and not quite as smooth.
The only problem I have had is with ejecting if I don’t push the level completely forward the new round doesn’t chamber. The new round isn’t lifted completely up and the round hangs in the receiver. As long as I move the lever completely forward and forcefully it works like a champ. Basically, that is what has to done with the old one as demonstrated by the students operating them. I am well please with my Marlin 39a and would recommend them.
MaxJr

I have a 39AS made in 1990. I bought it used in 2011 at the LGS. I talked to the last owner about how many rounds had been shot thru the rifle. He said that he was the 2nd owner and that he and his family had shot 'many thousands' of rounds thru it. It still looks like new and has only misfired once since I have had it. I took the misfired round and tried in a Marlin 81 and a Heritage 'Rough Rider' revolver. It wouldn't fire in either of those guns either. I don't have problems with the rebounding hammer. As long as a gun functions perfectly as this one does, I'm a happy camper. After all the bad rep that Remington/Marlin/etc. is getting, I would not buy a gun from them. I have guns from most manufactuers besides CZ and Ruger and have had very little problems with any of them.

When I wrote to Marlin I told them it was the worst $500 I had ever spent on a gun. The 39A had such a great reputation but after the abysmally poor fit, finish and function of my copy I felt I had been sucker punched. I would hope by now the production problems have been fixed but I still recommend buyer beware when it comes to the new 39As..

Am I correct in believing that the lever action rifles' production at Remington was halted a few months ago? Or was it just the 39As? And if it was halted, has it been started again?