Unfortunately I did not find this thread until it was 12 pages in, so at the risk or repeating what others have said and this post being somewhat pointless, I will give my input and some thoughts on some of the very intelligent people here, including Alex Wheelers accurate assessment on .338 rifle weight.
I built my .338 Norma mag to be light, scoped with March 2.5-25x52, loaded with 3 rounds, with 10" area 419 arca rail attached ready to hunt is 9.6 lbs. Now to touch on some points for the o.p.....
Anyone saying that a largeish .338 in this weight range will have ridiculous, unmanageable recoil, or will be unable to spot shots, is likely in one of these categories-
1. Thinking of an unbraked rifle (would have heavy, likely painful recoil)
2. Thinking of a supressed rifle (would be all but impossible to spot shots, but would almost certainly be more than 9.5 lbs with can)
3. Is using a muzzle brake that is not doing the best possible job (would make it hard to see impacts, and if inefficient enough, like a radial brake, may still be painful to shoot)
4. Has a stock that is not very conducive to staying on target (I find standard sporter stocks harder to see impacts with vs high cheek weld vertices grip stocks)
4. Has no actual hands on experience and is just taking (hopefully educated) guesses.
A rifle with these build parameters needs to have significant thought put into it if you want an effective long range rig that you can spot your own impacts with. First off, the most effective brake possible needs to be installed, there are only a couple I would consider. I put a 5 port MBM Beast brake on my rifle, and from field positions this hunting season I was able to watch the bullet impact on every animal taken, my deer at 560 yards and my elk at 887 yards, and my 5'4" wife was able to see her bullet hit on a pronghorn at 330 yards. I was on my pronghorn I shot at 200 yards right at or barely after impact, I did not have to search for it, and I saw the reaction to the shot as well as dirt kick up behind it. These were all on 20x or higher as well.
Second, the stock needs to be well fitted to the shooter. This is going to be different for every shooter, but a good consistent cheek weld is important, and I prefer a vertical grip. On my rifle, I use a Manners EH-1.
Next, we have to address the issue that Mr. Alex Wheeler stated, about inconsistencies with big bullets, lots of powder and light guns. If you just want a consistent 1-1.5MOA rifle at range, this is doable as is, but if we build a long range .338, we are likely looking for better than that. And I'm not talking about from a bench or consistent shooting platform, you will likely do better than that, I'm talking about one shot laying prone in a grass field, and the next laying pointing down 30° in an awkward position resting on rocks. I want my rifle to do what I tell it no matter where I'm at. You can't replace having good shooter form, however if a rifle is put together correctly, you can make it more forgiving.
You simply can't get away from the point Alex made, but you can work around it. Most of us that would build a rifle like this are hunting back country, and spend a good amount of time behind binos or a spotter on a tripod. So, what I did was put an arca rail on the bottom of my rifle and ditched the bipod or "rest on your pack" method. I have my tripod with me anyway, so I use it. I mount my 9.6 lb rifle in my 3.2 lb tripod with arca head, and suddenly my 9.6 lb rifle has an effective weight of nearly 13 lbs, making it much more forgiving. It also gives it 4 points of contact to the ground, making it very steady, and also has a heavy drag weight, meaning that a rifle with 13 lbs of effective weight in a bipod vs my 13 lb of effective weight in a tripod, my rifle takes much more effort to slide along the ground than one in a bipod, and also tends to bounce less and slide more. This could be the angle of the legs as well, but whatever it is, I really think this helps with consistency.
Another thing I unintentionally did was instead of using the 300 grain Bergers (which I started with) is I used the 270 grain badlands mono bullets. The bc is nearly a match to the 300's, .403 G7, however they are almost 200 fps faster in my gun, and have less recoil. And with their release of the super bulldozer 2, the new 250 grain has a higher bc than the old 270 and very close to the 300 berger, G7 of .410, I will be switching to that for even less recoil with no loss in ballistics. So, bullet choice can play a roll as well. However, with my current set up, even with 300 Bergers I think I would be good.
Those are my observations from field use of a light big bore. Hope it's helpful!
View attachment 244903View attachment 244904View attachment 244905