I recently bought two Win. 94 in 45 Colt and 44 Mag and a Marlin in 357 Mag. My first time out today shooting them and I had a little trouble getting the cartridges inserted far enough. Are there any special tricks? I know I'll improve with practice but if you experienced troopers have any suggestions, I'm all ears.

Btw, I had a blast with them. Should have got one years ago.

... somebody's  been shooting a lot of .38 specials, clean the throat

Loading gate or chamber?

A little of both. These are about 10-15 years old but shot very little if any. I cleaned them before going out and only one had a little residue in the barrel.

On a loading gate, you insert the round about 3/4 of the way in and then use the next round to complete the load and so on till the last one which you need to push all the way in or use a spare round to finish. A lot easer. Also, for your chambering, don't treat the lever gently, through it with authority. You won't hurt it. Also, practice rechambering while it's still on your shoulder. Makes for much quicker follow ups.

With regards to chambering issues, many leverguns can be sensitive to the overall length of the cartridge. Quite simply, there may be rounds that your gun just doesn't like.

Sounds like all three are giving him some/same problems as it isn't specified. That's a lot of common issues across three different levers and two manufactures, hence my above.

I"m sure my loading issues are because of inexperience. Using the following cartridge to finish the prior one will help a lot. Dummy me!

Try a Henry

Henry"s easier to load?

This; saves fingertips & frustrations.

Most Henries use a loading tube as opposed to a loading gate. You turn the end of the tube slightly and pull out the rod. Once it out far enough, a slot will show and you insert your rounds into it. Once loaded, you push the rod back in (which has a spring in it to push the rounds back) and turn in the opposite direction to lock it.

My 39A uses a loading tube. It's not the quickest way to load but the 39A holds a lot of .22's so it's not really a drag on plinking time. Two things I don't care for about tubes is you do have the possibility of losing the tube if it's not secured properly and the other is topping off. I don't really like sticking my hands in front of a loaded firearm and it's a bit slower though admittedly, some guys are pretty quick, with practice of course.

As a side note, I stick a dummy or snap cap in as the last round on any .22 without a hold open, sans revolvers of course, to prevent dinging up my chambers or wrecking the pin. Just mentioning it for what it's worth.

JETA: One thing you may consider is a nice pair of thin, soft leather, fingerless gloves. I use a really nice set when I know I'm going to be using levers all day. The constant throwing starts to wear on the back of my bony old hands. Makes for a much more enjoyable session.

...and there's my #1 reason (in red) for not liking end loaded tube magazines on guns, preceded by my number two reason (in green).  It's a violation of my personal gun safety protocol to top off a tube fed gun with a round in the chamber.  Effing with a tube rod at the bench with an empty mag isn't a big deal.  Messing with a tub rod while out in the filed is a PITA.

I see your point but why not just open the action and leave it open while you are loading more rounds?

The gun cannot go off with the action open, with that being said, you still want to have the barrel pointed in a safe direction and keep your hands away from the muzzle the best you can.

I really don't see it as an issue. Plus, how often are you "topping" off your gun in the field?

That's what I do on my .454 levergun that has both the levergun-style loading gate and rimfire-style loading tube. Empty the chamber then empty the tube. I actually prefer it, compared to jacking every round thru the action every time I want to unload the gun the way most leverguns are done.

Of course, if you cycle the lever after firing, opening the action to top off involves ejecting a cartridge.  
It's not an issue for some people, just like some people don't mind effing with the tube rod to reload; others have different preferences.

How often does one top off in the field?  Well, it's not really a matter of how often as much as it is, does it happen enough that it is a valid consideration?  How often do you use/need a seat belt, smoke detector, fire extinguisher, home/auto/life insurance, your carry and conceal firearm, etc?

Ask someone hunting deer using a .30-30 w/ a 4 round magazine if they've ever topped off a magazine in the field.

There are often sharp edges in the loading port.   This makes loading difficult.   On my Rossi M92 rifles I deburred then and reduced the loading gate spring tension.   Worked great.   Also the magazine spring length can be reduced a little.