Spike Camp

Favorite handloads and/or Factory Loads for the 30-378 and 338-378 Weatherby Mag

What are your favourite handloads or factory loads for these ultra-calibers?  What kind of performance have you come to expect from them (i.e., How they work for you on game, the target groups you get, the speeds you get on your chronograph)?

My favorite load, so far, for the 30-378 Wby. Mag. is the 180 grain Nosler Partition, backed by 112.0 grains of Hodgdon's Retumbo powder.  I use Federal 215 Match primers.  According to my chronograph, I'm getting an average of 3400 ft/s, nine feet from the muzzle.  It has averaged a little over an inch at 100 yards for 4, 3 shot groups off the bench.  In my opinion, this appears to be a sensible maximum in my rifle.

This coming November will be the 30-378's maiden voyage for whitetail deer.

I haven't begun to reload for the 338-378 yet but plan to in the near future.  Hopefully, I'll get a chance to hunt with it, too.  The 250 grain Nosler Partition Weatherby factory load appears to be splendidly accurate for me.  It has averaged an inch at 100 yards for 4, 3 shot groups off the bench.


  • ***
  • 124
    • View Profile
retumbo and 180 nolser is a great combo.I have also shot 200 nolser accubond with good results.The 338/378 loves the 250 nolser partition.

I just started shooting the 338-378. I also just moved and all my reloading gear is still in boxes along with my loading data. However I remember shooting a Nosler 200 grain Accubond with pretty fair results. The rifle will shoot 2 1/2" groups at 200 yards and I think it will do better than this once I figure out what my particular rifle likes.

One thing I found kind of annoying is that after a few shots the barrel gets hot enough to play with the sight picture a little. So I would just pull the bolt open and prop the gun up on a shooting bag and let it cool down. I think I'll try the sun shade extension the next time I take it to the range. I'm using a Bushnell Elite 4200 8 X 32 scope. The sunshade extends the front of the scope out at least 6".

I'm looking forward to shooting acrossed my chronograph soon. This gun makes a ton of noise especially with the muzzle brake on. Our gun club makes all the rifles with muzzle brakes on shoot at the extreme right side of the range. But the muzzle brake does a great job of making such a brute of a caliber shootable. To me this gun with the muzzle brake on doesn't recoil as hard as a .300 Winchester mag I used to shoot. I think the key to this gun is the powder. I haven't had a chance to shoot any Retumbo yet, in fact I've only shot one powder in it so far.

Shooting this gun is way too much fun for me. I love it!
Old Long Range Guy

I load for the .338-.378 and use 112 grains of RL 25 with a Federal 215 Match primer and the 200 grain Nosler Balistic Tips.  Unfortunately Nosler decided to drop the Balistic Tips for the .338 and reintroduced them in the Accubonds.  This is a wonderful load, can consistantly put 5 shots touching at 100 yards with out even trying.  Nosler claims that the Accubonds and Balistic Tips "should shoot exactly the same and not need any sight adjustment" but we will see.  For what I do with mine, shooting white tail deer, black bear, and targets, I really don't need to use the Accubonds or spend the extra money but Nosler took care of that by eliminating the Balistic Tips, which ran about $15- $20 a box of 50, and are only selling the Accubonds, which run from $28-$35 a box of 50 depending on where you get them.  I will be the first to tell anyone at less than 150 yards go for the neck, unless you want a big hole in your deer, after 150 the bullet "calms down" enough to go for a behind the shoulder shot.  One other bit of advice I have is put a disposable ear plug in your ear that is closest to the muzzle, namely left if your a right handed shooter or the right if left handed, because of the great muzzle blast. 
Nothing is better than a Weatherby, big bore magnum, or a Colt.


i totally blew apart a nosler partition, 250 gr, on a close  shot   on a whitetail buck at close range with my .338-.378. i switched to a barnes 250 gr tsx at 3100 fps. accuracy is  just ok. i recently shot a spike bull elk at a ranged 350 yds and still lost part of the x of the bullet. any suggestions?

┬  When I am hunting deer I don't go nuts over the fact of if the bullet remains intact or not as long as it does what it's intented to do namely obtain penetration and cause effective one shot kills.├é┬  In situations where deep penetration is needed, such as for grizzley bears, I opt for the heaviest bullet weight and toughest construction.┬  I use Nosler bullets almost exclusively and can't complain a bit about them.┬  I've used the Partitions and Ballistic Tips for years and they preform very well.┬  My Dad uses 180 grain Ballistic Tips in his .300 Weatherby and 210 Partitions in his .338.┬  These bullets are very well constructed and to the job even better.┬  When it comes to big calibers with fast moving bullets, such as the .338-.378, I don't think there is much chance of recovering an "intact" bullet at close ranges┬  because they are going so fast and have so much energy when impact occurs and the engergy is transfered it is such a violent act something is bound to break and from my experiences it's the bone hit and bullet.┬ 

┬  To put it in simple terms it is like hitting a walut with a sledge hammer, the walnut shatters and since the bullet has great force and velocity which is transfered over such a small area shattering of what is hit and the bullet are bound to break.┬  Even if you put enough pressure on a diamond, which is supposed to be the strongest material known to man, it will break and I truely believe the same is the same when it comes to bullets.┬ 

 Someone is bound to say why don't the bullets shot out or a .458 Winchester Magnum or the mighty .460 break appart because they have even more energy.┬  My theory is that even though they have the same or even more energy they don't have the same velocity.┬  To go one step further I have shot deer with a .270 Winchester with 130 grain bullets and the bullet was in lots of pieces.├é┬  Personally I am going to stick with the Noslers.┬ 

┬  If you want to recover intact bullets you might want to experiment with other bullets such as the Trophy Bonded Bear Claws, Speer Grand Slams, or Swift A-Frames.┬  I only have experience with the Speer Grand Slams in a 7x57 Mauser so I really don't know how intact they would be when fired out of the .338-.378.┬ 

┬  Besides if we truely understand what happens when a bullet impacts an animal there are two wounds created, a temporary (the expanding and contracting of the surrounding muscle) and permant wound (the hole left).├é┬  Both play important factors in the "killing force" of a bullet and both occur due to energy transfered from the bullet to the object, in an animal's case the bone and tissue which is impacted.
« Last Edit: December 10, 2007, 06:39:12 PM by Chris »
Nothing is better than a Weatherby, big bore magnum, or a Colt.

For the .338-.378 weatherby I load 111 g of H1000 and a 225g Nosler Accubond with a Federal GM 215 Match primer. I have a fully custom made heavy barrel rifle built on a .340 Weatherby action and I consistently get 1 7/8" groups, or better, at 500 yards with an 8.5 - 25 X 50 scope. This is a sweet load for a sweet rifle.

For the .30-.378 Weatherby I load 100g of H1000 with a 180g Nosler Accubond bullets and a Federal GM 215 Match primer. This is a Weatherby factory made Accumark, but I can still get about 3" groups at 500 yards, if I try real hard. I have had this rifle accurized by a competent engineering company and I use a 6 - 25 X 56 scope.

I have a factory Accumark 338-378. I have run only Weatherby factory load 250gr nosler partitions through it. I love the rifle, I've killed a lot of moose with it and a few caribou and grizzly. I have to be very careful chambering a round though. I have been having a problem with the action pushing over the lead point of the Partitions. This makes them shoot VERY eraddic. Has anyone else seen this.

I have found partitions in the far shoulder blade of a moose that I shot with a 338, and they weren't mushroomed. I have yet to find one that I've shot with the 338-378. I think I'm going to try the Accubonds soon.

It's a late reply, but why not... my Mark V is on it's 2nd Shilen barrel and 3rd barrel overall and I've run more loads and bullets through it than I can count.  My powder of choice has always been Reloder 25, and I'll occasionally use H-1000 or Retumbo.  However, Retumbo has been tempermental and has given me unexpected pressure probs.  I used to use H-870 by the truckload, but when Hodgdon quit making it I had to go elsewhere.  Recently I got my hands on a supply of AA-8700 which is basically the same thing, but I haven't had great luck with it yet.  The two loads I've been playing with lately were RL-25 and Retumbo, with Barnes Tipped TSX's and Sierra Gamekings respectively.  For the record, the Sierra's, the 215's anyway, aren't stout enough but they shoot very well and will kill light game just fine.