Bigrich954rr,
I would build it exactly the same way I built my personal 338 Kahn.
First off, I personally feel that for building a rifle in a round of this size, only Chrome-Moly Receivers should be used. This is simply because the CM steel is more resistant to lug and recess set back compared to the softer Stainless Steel.
The Rem 700 is a great action, pleny stout enough for the 338-378 class of round but this is about its limit in cartridge size.
Make sure this guy knows how to properly accurize and action and how to cut the Rem 700 bolt face to min specs to allow as thick a nose section as possible. There is plenty of steel here for the 338-378 but if one gets sloppy then things get thin real quick.
Also, when teh bolt lugs and receiver recesses are tured, it is critical to only take off enough steel to square them up, generally only 0.001" to 0.003" is needed to be removed.
Since we are dealing with the outer limits of this actions, we need all the steel we can get, again there is plenty to start with but if we get sloppy we are just taking strength away from the receiver.
Next the lugs need to be lapped for 100% contact, nothing less. We need a solid large foot print on both sides of the bolt to control the bolt trust produced by either of these rounds.
A properly accurized action is a much stronger action then one that is tuned up poorly. Your smith should know what he is doing if he has been around long.
When fitting a Sako extractor, again, we want things tight with only 0.002" clearance between the extractor and the slot machined into the bolt. This will ensure that an effect gas seal will still be present. If a primer fails or a case head seperates, this tight fit will greatly help in containing the gas leak or at least slow it down to prevent major damage to the action and shooter.
The extractor will also need to be fitted to allow JUST enough clearance to slip over the rim while in the bolt nose recess in the barrel. We want as much steel in the extractor as possible because these are big cases which sometimes can be a little hard to pop loose of the chamber.
Other then that, I would recommend steel bedding an insert into the mag box opening to stiffen up the action. The '378 class rounds are to much for a repeater as far as length goes when loaded with the long range bullets so a single shot is the only way to go.
Weldsmith makes a great inset that perfectly matches the contour of the bottom of the action and alignes the round perfectly with the chamebr for smooth feeding.
Also, have the bolt stop modified to give as much bolt throw as possible. Depending on your throat length, you may still need to pull the bolt to eject a live round when needed but often the bolt stop can be modified to allow a round with an oal of around 3.900" to clear the port freely.
Trigger wise, I went with a Rifles Basix 2 to 6 oz trigger basically to see how it compares to the Jewel. They are fine triggers in my mind but I will admit that I turned mine up to 6 oz because I like to be able to actually feel the trigger on my finger before the rifle fires, 2 oz is to light for this kid!!
I would also recommend replacing the factory striker assmebly with a Gre-Tan assembly. This will greatly reduce firing pin spring rubbing in the bolt body and the stronger spring and lighter firing pin increases lock time considerably. They are also a better fit to the firing pin hole generally which will help limit primer flow into the firing pin hole with top loads.
Now for ahead of the receiver. I would recommend a Holland Comp Recoil Lug which is vastly stronger and basically perfectly even in thickness for that perfect non stressed barrel fit.
As far as the barrel fitting goes, it is important that the barrel be fitted very snug to teh bolt nose with 0.005" clearance in depth and 0.005" total clearance in diameter. This to will increase the controll of a gas leak in such an eveny. A barrel recess fitted this tight can make it tricky to fit the Sako extractor to perform properly, make sure it does before you take the rifle home. If it does not this just tells you the smith did not perform a live fire test on the rifle before sending it home.
Chambering and crowning are pretty general stuff. YOur smith better be using live piloted reamers and cutters so that he can match the pilots perfectly to the diameter of your barrel. This is critical to producing the most accurate product you can.
As far as brands of barrels, I use only Lilja barrels on my personal rifles and on all my customers if they leave it up to me. I have shot enough 1/5 moa groups at 500 yards and sub 1/2 moa groups at 1000 yards to know they will perform eveytime. There are certainly other top quality barrels but I use Lilja.
Barrel length is a personal thing. Anything over 28" is plenty for these calibers, especially the 338. I have a 34.5" Lilja on my 338 Kahn and am very happy with its performance.
Perhaps more important then length is diameter. The Rem 700 will accept a 1.350" diameter barrel and still look good. This is basically the same diameter as the receiver and it actually looks pretty neat to have the barrel, recoil lug and receiver basically the same diameter.
To be honest, I would not recommend building a rifle on the Rem 700 without using a barrel bedding V-Block system. A +28", barrel of at least 1.250" straight cylinder is a heavy barrel. My 34.5" 1.350" barrel weights around 14 lbs. This is far to much weight to hang off a Rem 700 action which only has about .700" of thread engagement with the barrel.
I used my own V-Block system which is 10" long and is embedded inthe forend of the stock starting in front of the recoil lug. This barrel is drilled and tapped for 3, 1/4x28tpi bolts that secure the barrel into the V-Block. The recoil lug area is reinforced with steel bedding compound but the entire action is free floated which turns it into a totally stress free componant of the rifle. You could hang a 30 lb 45" long barrel of 1.750" diameter off it and the receiver would perform totally stress free.
As far as stocks go, my favorite is the McMilland MBR Tooley 1000 yard BR stock. I weighted mine for a finished weight of 8 lbs. This makes for a 26 lb rifle with the addition of a muzzle brake of my own design which is a 4 port brake that weights in at 3/4 lb.
I would recommend a brake on any extreme range rifle especially with a round like the 338-378 firing 300 gr pills at 3000 fps. Recoil is not painful but slowing a 25 lb rifle down after recoil has started it moving will wear on your neck and back something fierce. A quality brake will eliminate this problem. My 338 Kahn with the 300 gr Wildcat ULD loaded to 3100 fps recoils about like a 308 Win in a 10 lb rifle.
Back to barrels, I would go with a 3 groove in the 30-378 for its longer throat life compared to teh conventional 6 groove. IT will also foul less.
In the 338, Lilja does not offer a three groove but this round is not overly hard on the throat compared to the 308 caliber version.
Other then that, have fun with your new cannon. Let us know how it shoots!!!
Good Shooting!!
Kirby Allen(50)
