As long as the trigger can move to fire, the lever is doing what it is supposed to do with that "little nipple". Thats simply a trigger out of battery safety feature. What you "might have" is a poorly fit lever curvature. This is a common Marlin issue that can be easily corrected by opening up the bow curve of the lever around the trigger. To make sure this is your problem, you would need to put a dummy cartridge in the chamber as you normally would with the lever locked up and hammer back, push in on the firing pin. It should show you that it's sticking out by about 3/32". Now, lower the hammer onto the firing pin nice and easy. Carefully watch the hammer position on the FP while you at the same time slowly lower the lever. If the hammer pushes the FP in all the way with only the slightest lever movement away from the lower tang, You have a too early lock drop away from the hammer FP. This condition is caused by the lever's inability to push the bolt lock up far enough to fully align the 2 firing pins. Light hits are what this does. The good thing is, the levers are not very hard and can be bent easily in a set up bench vise without marring the blueing much at all. Opening the bow sightly will push the lock up farther to fix the issue. Another way to go in that direction is as you suggested, grind the stop back until there is just a tiny bit of space between the lever and tang. This will put the lock up higher as well but it may not be enough to get full alignment. Before you do all this, I assume you checked FP tension movement with them aligned -bolt out of the gun-. Be sure the FP push down spring isnt binding their movement forward. Also, if the lock is not all the way up, it gives a tad more headspace, exacerbating a light hit issue.

 

Never seen a Marlin lever with a recess in the lever like that. Before I'd file it down, I'd look for another lever (OEM or after market) that doesn't have that gap.

 

I've always used relatively heavy hammer springs, or the stock ones. Doing that I've never had a light strike..

 

+1. Use a stock hammer spring. It was designed by Marlin Engineers to fire every time, even under difficult conditions.

 

It still has all the stock springs... Everything seemed to be fine when the bolt was out: firing pin seemed to move freely. I did the test xtriggerman suggested and with the hammer closed on the FP with the lever closed, the FP was sticking out. Then I had to drop the lever a good bit off the 'nipple' before the FP moved all the way in. I saw a few people sell a one piece FP, so I ordered one of them last night. Mine has the crossbolt safety, and I'm pretty anal about using it as well as general firearm safety. It's mostly used on my property anyway. Thank you for all the input.

 

Have you disassembled and cleaned your bolt? I had a similar issue with a 375 Win Marlin, cleaning the bolt was the solution to the problem.

 

I agree.

At about 1000 rounds, I started having light primer strikes with my Remington made Marlin1894 44Mag.
Like the OP, I ordered a 1 piece firing pin. While waiting impatiently for the back ordered 1 piece to show up, I took the bolt apart, and found a combination of chunky lube & dirt. I cleaned out all the crap, lightly lubed & reassembled. Since cleaning, no more light primer strikes. I never did installed the 1 piece firing pin, it's sitting in the parts bin.
edit- both of my Remington made 1894's have Brownell's light hammer spring kits in them.

 

+ 1 on making sure the bolt is nice and clean. Sometimes the channel the firing pin sits in can get dirty, especially if there is old oil in there. This can increase the friction and lead to light strikes.

Another cause can be a weak or worn out hammer spring, but that is easy to check. You can easily replace this spring or use a homemade solution with small washers to increase the tension.

Since you’re shooting reloads, I would also consider how you are priming your brass. I’ve seen issues with people using a Lee loader and “hammering” the primer in causes light strikes.

 

I had the spring in the firing pin work it way loose from the front part of the firing pin which meant it was not thrusting forward well. Installed the new one piece firing pin and all is well...