Okay reloading experts need a little help here.. I've been researching like crazy and I'm trying to figure out what depth to seat my bullets. I'm shooting a 300 win mag sendero and measured my chamber for the 208gr amax and it's 3.65 C.O.L. I've read that it's okay to seat .04 inches below that c.o.l but the books have a 3.340 inch max length.. I really don't want to have to worry about pressure so should I stick with the book or back .04 inches off the lands?

I wouldn't start with it run into the lands. Start your charges at minimum, for whichever length, and you'll be fine. If you see any pressure spikes because you're too close, then you'll know before it gets out of hand. If you intend to use the magazine, check that they fit, also. That could determine your starting seating depth. Then experiment to find the right load. From what I understand, the A-max is typically pretty easy to tune.

Also, the books go by SAAMI specs, which, in this case, is largely determined by what will fit in a magazine. The closer you get to the lands, the more concern there is with pressure spikes, so at the book's COL, there's no concern regarding that.

Thanks Sneaky I'll check that out.. There is so much more that goes into reloading than what I thought!!! lol

That's no joke.

Trim lengths, O.A.L. and the like are beneath hand loaders. Make your ammo fit your rifle. You are only bound by magazine length. Other than that seat your bullet in relation to the lands where it shoots best. Size your brass .002" less than your chamber, damn what the books say.

Bingola.

First, SAAMI is for industry guidelines and not for reloaders--that's why it is the Sporting Arms and Ammunition Manufacturers Institute.
COL for a rifle is determined by the bullet's ogive and meplat, the length that can be held in the magazine, and the length of the chamber throat. In some cases, like my AR, it is also determined by the feed ramp as my AR is quite fussy.
In general, best accuracy is with the bullet just in contact with the lede/rifling/lands or very close.
There is no minimum load, there are starting loads. I always start my rifle load work-up at one of two points:
the longest COL that fits the magazine or, if firing single shot, with the bullet just a hair off the lede/rifling/lands and ALWAYS at the lowest starting load I can find.
Next, pressure vs. COL is so much less with a rifle round compared to handgun rounds, if only based on total case volume vs. volume change due to COL variation. COL can be important for a little case like 9x19, but a LOT less significant for a Magnum rifle. Next, media reports are that shorter COL in rifles often produce lower pressures, assuming it is due to longer flight of bullet before hitting lede (but who knows, as all they supposedly have is pressure data).

YEP!!!!

Thanks guys!!! I'm shooting now and I'm letting my barrel cool 15 min between shots so I'm not going through the rounds like I wanted to.

That's the worst part of testing loads this time of year, so hot, barrel never cools. Take a .22 with you next time and plink while big boy cools. you have to change up your front and rear rests but it beats twiddling your thumbs.

cool rags on barrel help too.