Attempting to farm SF

With my ranger, I have been taking henchies into Sorrows Furnace hoping for some decent (bow) drops from the bosses. The problem is I can't seem to solo them. I use the hencies and clear out the surrounding mobs, then lead the henchies way out of sight and flag them. I go back and attack the boss, but we seem to be at a bit of a stalemate, I just can't seem to overcome them. Im heavy into marksmanship (12) and beast(11), and Poison arrow is my elite skill. The rest are the best dps I have for bow. The bosses are lvl 28 I believe.

Am I running a bad build or am I just expecting to much from a ranger class ?

you may want to try another build, burning arrow?
and you need alot more expertise

Degen and run. Burning arrow+poison tip sig+barbed arrows+toxicity=profit. Use dash and natural stride. This means speccing into wilderness survival and marks/expertise.

If you already brought henchmen into Sorrow's Furnace you might as well use them to help you kill the bosses. Even if you flag the henchmen/heros as far away from you like at the other side of the map and you go and kill a boss alone that doesn't up your chances of having a good drop happen and doesn't count as a solo kill. Your party will still split the exp, gold, and drops.

Bringing henchmen with you in any explorable area will have your chances of a drop happening cut down. Say you bring 3 henchmen including you so a party size of 4, you drop chance is at 25% and the gold you pick up will be shared 4 ways. Sending them far away from you won't get rid of that effect, they are still with you. You have to be truly alone with no one in your party to insure a 100% drop rate.

Like just said you already brought the henchmen with you, might as well use them.

Completely wrong. Henchmen Flag out of Area of influence meaning that they are grayed out on the map allows all drops assigned to you.

Unless you are using a bunch of pet skills, there's no point in putting a lot of points in Beast Mastery. BM only affect the amount of base damage a pet does, which is not very much - the pets health and armor is determined by it's level, not BM.
If you are using pet skills, it might be best to concentrate on either Marksmanship or BM but not both.

I have to admit to doing it the easy way - ignoring my Ranger's primary skillset altogether and going /Rt for spirit-spammery.

Thanks for the replies... it's nice to know it's doable and just my inexperience that's causing me problems. I'll experiment with some different builds.

Ranger is a very good spirit spammer, bring painfull bond and pain inverter and he is dead meat.