I currently am planning on buying a Weatherby Mark V Accumark in 300 Weatherby Magnum.  The place I am buying it from has a Weatherby Mark V Weathermark in 30-378 Weatherby Magnum, though, and it is a couple hundred bucks cheaper than the Accumark.  I like big cannons, so I am intrigued by the thought of the 30-378 and its claim as the "most powerful factory 30 cal."  One thing that is giving me some hesitancy, though, is I have road the throat erodes extremely fast on the 30-378.  It seems like overexaggerating to me, but I've seen people say there is a decent amount of throat erosion at just 100 yards down the tube.  Is that really the case?  That just seems way too fast.

It'd be an elk/moose gun, in case anyone is wondering the purpose of it.  I understand I may not need the amount of power it offers, but I'd like to know any other pros/cons of the round.  The 300 Weatherby is definitely more than enough and is still uber powerful, but not on the level of the 30-378.  If the throat erosion thing is true it'd definitely be a turn off from the round.  Also, what bullets would be recommended for it?  I've heard heavy, very well constructed bullets are recommended as it has a tendency to break apart smaller bullets due to the insane velocities.

I too have read that that cartridge is tough on the leade/freebore on barrels. When you compare the case measurements to other notorious barrel eaters, you see the 30-378 falls into what are referred "overbore cartridges". IE large powder capacity paired with a small bore dimension relative to that case size. This generates a LOT of heat fast. That being said, if you don't shoot them fast (too short of time to allow the barrel to cool  between shots) you can get reasonable barrel life out of them.

The same powder charge in a 378 Weatherby case with 378 diameter bullets will give you good barrel life. Add in modern and better barrel steels being used today and you can get noticeably longer barrel life. That being said, there are other better cartridges choices, driven by better powder options that can/will get you close enough to 30-378 velocities without the barrel wear.

And with prices ranging from $70/20 rounds to upwards of $100/20 rounds, ya better be rolling your own, or have money to burn. Then there is the issue of dealing with belted cases as a reloader. And rarely does a rifle exhibit its best accuracy at MAX velocities. I have been reloading since 1979 in rifle calibers from 22 up to 458. I have NEVER gotten maximum accuracy at maximum safe loads. Its usually from 1-2% below max to sometimes as much as 4-5%. THIS IS A VARIABLE THAT WILL BE DIFFERENT FOR EVERY FIREARM IN THE WORLD. It's axiomatic and MAY NOT APPLY to every firearm in the  world

TL:DR Better powders tend to negate the need for seriously overbore cartridges in search of max velocities.

ETA: Unless you're going to regularly be shooting at live game BEYOND 400 yards and can and will shoot the round count to be truly humane and accurate for such things, in my ever so humble opinion, its serious overkill.

Good luck finding brass and ammo.  
I would stay with 300 WM and the next step up is 375H&H.    Anything that has not been around for 50 years could become very expensive to find ammo for.  But if you can feed it have fun.

I can't find brass for anything right now and am just starting to see loaded ammo in basic calibers. There are NO large magnum rifle primers to be had.  As for loaded ammo: .308 seems to be available,  30-06 sometimes,  300WM sometimes,  300 WSM gone, other .30 calibers I'm not seeing them.   I would not buy anything I can't feed.

Consider the .375H&H in a Weatherby Rifle.

There's no way it's not a barrel burner. Are you going to reload? If not the 300 Weatherby is much more common.

Just do some poking around in load data to see how big of a case the 30-378 is. The case is bigger than a 338 Lapua by a good bit.
With 220 grain bullets
300 Weatherby 75-83 grains of powder
300 RUM 82-91 grains of the same powder
30-378 100-120 grains depending on powder. Not the same because the case is so much bigger and needs a slower powder. They even have load data for H50BMG powder

Thank you for the feedback so far, guys.  I don't reload right now.  I probably will in the future, but I don't mine paying for factory ammo for the time being.  But so far it sounds like it's better to just stick with the 300 Weatherby from what everyone is saying.  I may just do that.

My armchair-quarterback opinion:

Most people won't ever shoot enough rounds through such a cannon to cause enough throat erosion to hurt its use for hunting.  The few who DO shoot enough rounds through it... well, a new barrel would be a fraction of the cost of what you paid for ammo.  Either way, IDK if throat erosion is something to worry TOO much about.

As to bullets, Nosler has load data showing 125 grain bullets at ~3750FPS.  Use this for your neck prairie dog trip.  

I think in general you're correct. I comment frequently that most of the people talking about barrel life will never know. Rounds like this are crazy though. One thing they do that will affect most shooters is foul really quickly. Boss had one and it got hot quick. Sent me to sight it in and it was going great until I realized the mount/rings had worked loose. There goes a pile of money down the drain good thing it was his

Oh and did I mention how loud it was? LOUD

@ALASKANFIRE

How loud is it compared to a 338 Lapua?  My uncle has a 338 Lapua and it is excruciatingly loud.  My 50 BMG is way, way more concussive.  But I think under an awning his Lapua sounds quite a bit louder than my 50.  The Lapua, to me, is like an extremely loud crack, where-as the 50 is kind of a long drawn out boom.

Meh, you are not going to get close to the same performance from another 30 cal smaller then the 300rum..PERIOD, I don't give a shit what magic pixy dust you use...All of these bigger 30 cals from 300 win mag on up will all use the same basic powders for the same heavy for class bullets that a long range shooter would load too...
Weather its retumbo/H1000/RL33/RL26/H50BMG/H869/7828/ or any of a dozer or more others...for each bullet/case size there will be a preferred powder/bullet/primer that works best, and as long as every load is loaded to its best, there will be a ramp of performance from the smaller cases with lower velocities to the biggest cases and higher velocities...
Steps just like you see between .308 nato/30-06 Springfield/300 Wm./300 Weatherby/300 Norma/300 RUM/#0-378 Weatherby....All the new fangled 30 cals like the prc and such, they at best especially when shooting the heaviest bullets can match performance from similar sized cases, but they don't come close to the biggest cases performance wise...



Meh, anything can be a barrel burner...a lot of things determine barrel life...OP, I've been shooting the big magnums for a long fucking time..And I mean shooting them, I used to shoot year round at distance..Average life expectancy on any of the big 30's is going to run about 1500 rounds sub moa, with everything being good enough to shoot sub moa (shooter/barrel/load)..Some will do better than that, some will do worse..What most have noticed is short fat cases erode the throat faster than narrow long cases do..But short fat cases will generally give better performance with less than heaviest bullets for bore..Which is what we (my buddy) found with his 300prc versus his 300wm....The PRC ran into pressure faster than the win mag did, to the point he had to back down the charge while the win mag hadn't hit pressure yet, loading the 230 Berger HT's and the 250 hornadays... but the PRC is better with the lighter 200.20 berger...A few others have had similar results...
 Now if you really want/need what the big magnums bring to the table, and if you understand that barrel life on all of these cases are going to be proportionately the opposite of velocity..the bigger/faster the case, the bigger faster it is going to wear barrels..It's a balancing act, and you have to decide what is acceptable barrel wear..For me the pain about barrel wear was having to ship off the action so the barrel could be properly fitted to it..I could do it locally, but I know if I want that expensive barrel to really perform, I want a top smith doing it..With that said, you can now setup rifles with self change barrels, weather its a rem/sav nut setup or its an aftermarket action with known dimensions that can have prefabbed shouldered barrels spun on at home...That for me makes the big magnums viable...I love shooting my rum..it is still a blast to shoot, still enjoy every time I get to take it out...

Oh and just because..Go look over a 300rum, it will do everything you want and it has far more good choices for brass at better prices as well than the 30-378 does...

I’m sure they’re pretty similar noise wise. Only Lapua I’ve been around was suppressed. Mainly I was being funny with the noise comment as anything magnum with a brake can be brutal.

You are right, both are pretty equal noise wise, have buddys with both 338lm and 30-378...I will say the air movement with the 50 bmg is impressive..thats the first big cartridge I can't stand right next to, I have to get back 10-15 feet of it, or the air hurts my brain...

I am very familiar. I wish Suppressors were a better solution for them but some guns like the Barrett 82's can't use them and most people with them on bolt actions talk about the recoil being punishing.

Haha I knew you'd be in here to recommend the RUM!

Only reason I am looking at the Weatherby rounds is I really want a Mark V.  If they had a Mark V in 300 RUM that is honestly what I'd probably go with.  I've shot a lot of 300 Win Mags and they're cool, but I want to step up a bit.  300 RUM would be my first choice if I could it find it in a rifle I wanted which would be a Weatherby Mark V, Sako 85, Winchester Model 70, or a Ruger M77 Hawkeye.

“A man should be so lucky as to burn out the barrel of a rifle.”

Paraphrased from Jim Carmichael.

I hear you, and good for you wanting what you want..I find far to many people on here are full of it with magnums..the only difference cost wise between the biggest and smallest 30 cal magnums is some grains of powder..thats it unless the brass is stupid expensive..which, Weatherby can be...My brother has a 338 lazaroni, he had built some years back..can't go shoot it because of how fucking expensive the brass is..cool round but utterly worthless if you can't get brass...For sure if you want a Weatherby, get one..you will never regret buying something you want, only for settling for something you didn't want..

I would just get a 30-06...

I don't have any experience with a 30-378, but my .300 RUM barrel shooting a 190 gr SMK at 3,400 fps went from 1/2 MOA groups to about 3 MOA groups right around 1,100 rounds. It was a sudden degradation as well, so much so that I thought my scope was broken.

Overall, it was an expensive and fairly abusive pursuit, but fun. I don't recommend it.

I like the caliber because its empty cases give me a perfect 1.75oz load of #5 lead bird shot for the BP shotgun when I use it as a measure :)  Really need to trim one of the cases I have down to be 1.5 and another to be 1.0oz ...

Got my cases from a buddy who built up a 30-378... 200 rounds before barrel is toast.  But he says there is something to be said about driving a 180gr partition at 3500+fps

Surprised you only get 200 rounds from a barrel, that makes life expensive, not to mention has to be a pain to do load work ups with...

My uncles has a Weatherby Mark V in that caliber.

Flat shooting and loud as hell is what I remember. I saw him shoot a doe with it at 120 yards once. Exit wound was pretty gnarly.

Last I checked ammo was around $100 a box. Definitely not something you would be shooting often.