I would tend to agree with Dakor here on this one. While it is nice to go hog wild on a full custom rifle
, it may not be the best investment for alot of people.
First off, what do you want to do with this rifle?
YOu asked about 800 yard shooting and beyond, to be honest, if your only going to be shooting at 800 to 1000 yards, you will be just as well served with a big 7mm or 30 cal compared to the monster 338s.
That said, I am never one to discourage the use of very high powered rifles. Once youget used to it, 800 yards will be a chip shot with a quality rifle.
As an example, I took my little fast twist 6mm-284 out this morning before the winds came up and did some range practice at ranges from 500 to 1100 yards. Of the 30 rounds I sent down range, only 6 missed their mark and of those only 1 missed by more then a foot because of a wind shift I was not paying attention to.
This rifle is a factory stock, Win M70 Heavy Varminter which has been fitted with a 30" #7 contour fluted Lilja barrel with a 3 groove 1-8" twist. IT shoots the 107 gr Sierra Mks at 3450 fps into some pretty scary groups.
I got the rifle used at a gun show in its original 243 chambering for $480. I payed Lilja $400 for the 30" fluted barrel and the labor would have amounted to around $550 total which included action accurizing, fitting-chambering barrel, bedding and trigger job.
SO for all that your under $1500 for a total rifle ready to ship. To save even more you could go without the flutes which would cut another $115 off the total cost. For another $1100 you could damn near afford a 5.5-22 NXS nightforce to really top the rifle off well.
Like Dakor said, do not think your bound to a complete new rifle for the sake of extreme accuracy. THis is simply not the case by any shape or form.
Personally, if this is going to be an extreme range rifle chambered in one of these rounds, I would recommend a Rem 700 converted to single shot along with modifying the bolt stop to allow a longer bolt throat to spit out the long live rounds of these monsters loaded with true long range bullets.
At ranges past 800 yards, a repeater is really not needed. Havign a supply of ammo right off your trigger hand will allow second shots just as quickly as a repeating rifle but with the advatages of the stiffer action and better bedding area if you choose a conventionally bedded design.
If you want to go to the extreme, a Barrel Bedding V-Block rifle is the tops in extreme range performance but they do cost more depending on options. My Extreme Range Rifles will run in the $3200 to $3500 range while a smaller V-Block rifle like the 22-6mm AI I just sent out would run in the $2200 to $2400 range again depending on options.
I am not saying you should use me because there are alot of quality smiths around the country, make some phone calls to different smiths and find out what they are charging and what level of accuracy performance they demand in their rifles. Often rifles out of smaller shops are even better quality and at a much lower price.
Just something to think about before you jump in!