I am just getting into the longer range game, and everywhere I look mentions reloading. What makes the load better then say something like a GMM 308 getting a half MOA at 100? And could you point be in the right direction for reloading.

Thanks!

1.  The ability to tune the load for that particular rifle and chamber.

2. Certian bullets (especially those used for long range) require a faster barrel rifling twist.  These are typically heavier bullets than are offered in commercially manufactured rounds (80gr-90gr for .223 as one example, 240gr-250gr in .308 as another).

3. Cost.  You won't spend less, but you will shoot more.

That Gold Medal Match giving you 1/2 min at 100 yards may be opening up at 600 yards.   It may be even worse at 1000.  By reloading, you may be able to push "the edge of the envelope."  Part of the GMM losing performance at distance may be the velocity its shedding.  By reloading you can utilize a round that has a heavier (better flying) bullet, that is being  propelled faster (for that particular bullet), may be more accurate due to you being able to seat the bullet closer to-or touching-the rifling.
You may need to experiment with several different component parts (but if you have quality cases, I wouldnt change them).  Your equipment will also dictate the level of improvement you wil have.  Better quality barrels wil be more responsive.

Also with tbe heavier bullets,  you may find that the heavier bullets throught a fast twist will not "settle down" until approximately 200 yards.  I would not test them at 100.  

That explains alot! Thanks for your response. So your essentially just taking the best from other rounds and putting them into one. Is there a place where I can see how people load different rounds?

Youtube

Eh, yes and no.  In some ways it's kinda like making a new cartridge.  

As far as learning more about reloading, ARFCOM has a reloading section.  It's under the Armory tab.

For books, there's several reloading manuals you can get.  You'll need at least one.

Glenn Zediker makes a good book, "Handloading for Competition."  Its mostly geared toward the NRA Across theCourse and Long Range competitor.  It IS NOT a reloading manual.  But it does offer some good advice and directions you can take.

These other forums have reloading sections (and exterior ballistics) that may be of very good use to you.  

http://www.usrifleteams.com/lrforum/  the Long Range forum

http://www.usrifleteams.com/forums/ the Across the Course(XTC) forum.  Plenty of applicable Long Range reloading tips (XTC is 200-600 yards after all) and the XTC forum is more active than the LR forum.   You'd need to sign up for either forum, don't think "guests" are allowed.

Do you recommend any particular channel? Would like to avoid bad info so recommendations from people in the know would be nice.

Cool, thanks for the info! I really appreciate your help.

I will second Rob's recomedation to hit up SnipersHide's reloading section and also the one here. Both can be excellent sources and help.  Keep in mind here we have many calibers represented all across the disclipnes. SH tends to be a bit more precision rifle centered.  Again, both can be excellent sources.

The biggest reason is education.  You will learn more about the craft.  Better understand what's involved and feel a sense of pride when you load rounds that better factory performance.

It's pretty easy to get started in reloading, the only challenge right now continues to be limited powder availability, and limited brass.  The brass is no big deal if you have been saving your rounds.  Powder is a little tougher, but it's more available now then it was last year.  Probably will get better.  
If you want to start you need to figure out your budget.  Then buy a press, dies, case prep tools, powder measure of some sort, bullets, powder, primers.  I've had great luck producing more accurate than factory rounds for my 300 win mag, .270 winchester.  I've struggled a bit with .338 lapua (might be lack of Retumbo powder availability); 30.06 because I haven't experimented a lot.  I was reloading for .308 a little bit before I traded off my Savage 10FP mcmillan, I hadn't yet worked up a load that was better than Federal GMM, or even Hornady Steel Match.  both of those shot better then my reloads, but I didn't try very hard.  
I've had good luck with a Lee 4 hole turret press, lee dies, lee case trimmers.  Less pleased with the lee reloading scale I got with my press - quickly decided I needed to spend a couple hundred on an RCBS electronic dispenser.  I bought a Lyman case trimmer for $100, realized it produces more runout than I'd like, switched to the lee case trimmer that includes caliber specific length guides, and a simple tool that you can chuck up in a cordless drill.  Results in consistent trim length, with only about 0.001 runout vs. the Lyman tool that would produce 0.003 runout on trimmed cases.  You'll also need a priming tool, I like the Hornady tool, but it isn't compatible with the lee shell holders, as large primer setup won't work, so you need to by Hornady or RCBS shellholders.  The Lee EZ prime is junk compared to a Hornady tool.  
Buy the Hornady or Lee reloading manuals to get good step by step instructions.  The Lee manual tends to include more powder types per caliber than most other manuals, but a lot of the data is freely available online through powder or bullet manufacturers.  It's a fun, time consuming hobby.  I've been doing it 3 years now, and I've paid for my equipment based on cost per round, but I shoot a lot more now, so it's really kind of a wash.  But I can load better bullets than what is readily available off the shelf.