This isn't a great idea, for a few reasons.

1. The "jobs@firm.com" address often forwards to several people, not just one.  Different firms have different ways of reviewing applicants, so it's pretty much impossible to guess who those people might be. In some firms the people involved in hiring for one position are different than for another.

2. Firms use the "jobs@firm.com" structure specifically because they don't want applicants directly contacting individual staff - they want to choose when to review applications and who will do it.  If you send your materials to that address as directed, but then to specific people in the firm as well, then it's clear that you did know their preferred way of contacting them but you decided to ignore that.  That's rude, and marks you as someone who doesn't want to follow directions (so yes, you're overstepping.)

3. It's not always possible to guess the person's address based on the structure of other emails in the company - so you may be sending your materials to somebody who has nothing to do with hiring.  For instance, if they use the first-name-last-initial structure, but multiple people in the firm have the same first name and last initial, then the person who has that address will just be the one who worked there first, not necessarily the one you're trying to contact. (Example:  James Happenstance, their spec writer, has worked there since the dawn of email, so his email is JamesH@firm.com, while James Q. Hiringmanager's email is JQH@firm.com.  James Happenstance gets a lot of spam meant for Mr. Hiringmanager, and deletes it all without reading.)

4. The "office manager" in a lot of firms is some combination of bookkeeper, supply manager, facilities manager, or receptionist - but often has nothing at all to do with hiring.  It just makes you look silly if you guess at how that firm is structured.

Thank you for you response. Very good points. I had planned on this (the applications are scheduled but not yet sent) as a way to show I'm specifically interested in these firms in particular and not just mass-sending applications. I had read in some blogs that it is sometimes a good idea to research who might be in charge of recruitment and try to send them the stuff so that your application doesn't drown in a sea of candidates.

I was, indeed worried that I would be seen as an overstepping creep, basically. Most of these firms are small-ish, so I figured the person I had guessed to be the recruiter could really be the only one doing it. For when I haven't been able to find a suitable option I've simply addressed the principal. I'm guessing I can't go wrong with that.

If they have directions to send your application to a certain email address, then that is how they want to receive applications.  Sending emails to my personal in-box usually comes across as pushy to me, and even obsessive when someone does it more than once.  It also suggests that if we hired them they'd turn out to be one of those fabled "entitled millennials" who don't think directions apply to them.  If we're hiring then we're going to be checking our designated email account, and the way to show that you're very interested in a specific firm is to write an excellent cover letter that makes it clear that you know what that firm does and that you'd be an excellent fit because of x, y, and z.  There's no reason to annoy individuals - that doesn't show interest in a good way.

While I agree with other people regarding the following the application process, I had great success emailing directly to principals and director level people.  I landed two previous jobs just doing that and some interviews.  In fact, my mentor who is a principal of a large firm recommended that is the best way to reach people.  This may not be the optimal solution for every firm and some firms may prefer that you come through the proper channel, but i still think it is a great way to stand out among other candidates.  Good luck!  

When I receive an unsolicited application sent to my individual email address I add that applicant to our company-wide sender/domain block list. Why would we hire someone who thinks it's ok to waste our time by trying to go around the people whose job it is to initially assess candidates?

I've started getting unsolicited employment requests directly to my work email. Which is silly because I'm rarely involved in hiring, and have a fairly specific non-management position. I don't know why someone would think I'm going to make a recommendation to our HR department or any of the management team for a person i've never even met.

I just trash them, and if I ever recognized the name of someone from the email (which is unlikely since I basically don't read them) I'd make a note they probably don't have a good understanding how to connect to other people in a professional way.

Has anyone ever tried walking into an office with a 12 pack of a smooth drinking beers, randomly handing these beers out and talking to people, working your way around to the principal, crack that beer, discuss business, become a partner? 

I believe I saw this approach on one of those mini-documentary style beer instructionals on the tv.

The reason I set up a special email address for applicants is because I don't want big portfolio files jamming up the rest of my email while they try to download on my phone.  If I wanted those emails sent to my regular address then I would have put that address in the hiring info on our website, instead of making a special email for applicants.  There are lots of bloggers and articles out there with bad ideas for job applicants.  For awhile years ago people were getting my home phone number and calling on the weekends during dinner, because some career advice columnist wrote that it's a way to make a memorable personal connection (it is, but not a good one).  Then 10 years ago or so there was the trend of sending things to make their applications "stand out" - like putting their resume in the hole of a bundt cake, or in a picture frame (it does make your application stand out, but...)  Please just avail yourselves of the systems that firms set up for applicants, and follow firms' directions.

Unless you actually know the person it doesnt matter if you have their name.

We get a lot of unsolicited email applications. A lot. Since we are small it ends up being me or one of our staff who reads them all.

We have two rules, developed for the simple purpose of reducing our workload.

1. Anything bcc'ed is thrown out unread. You should mention our office name in the mail. Obvious form letters are binned as well.

2. Overflowing flattery is thrown out half way through reading. It indicates bad office fit. We are a fun office I think, and try not to be overly pretentious unless it is humorous. We value people who can keep things chill.

3. Get to the point, keep it real. No embroidery. What position do you want, when do you want it and if you want to get into the why then go for it, but it shouldn't be because you think we are awesome, or because you are awesome (even if you ARE awesome). Oh and we prefer pdfs over links to issuu, because it is not easy to review a portfolio on a website. In fact it is the opposite of easy.

Yes I know that was three points. The last one is not a rule, just advice.

For what it is worth, the e-mails with my actual personal name in it are creepy. Unless you know me or can say who introduced you and gave you my personal email. So, don't do that. It's a personal boundary thing. Just be professional and go through regular channels.