OK help me out with this one.

WBY 338-378 WBY Mag Accumark. This is the best she will do! This is 104 gr IMR 7828. 225 Accubond at 3250 fps. Every load shot like this (all 225 AB's)



Now I have not tested flat based bullets yet but do you think boat tails can make this much of a huge difference?

It is bedded from the factory and it has a very sturdy optic set up. Talleys and SWFA SS 3x15.

What say you?

I'm loading for a buddy's 338-378 WBY and his didn't like the 225 A-bond either.

We were loading H1000 (his components) but the groups were similar and disappointing.

We settled on 225gr Barnes TTSX and H1000.

I was thinking a 200gr E-Tip or the 185gr GMX at speed would be perfect for his Elk load but he a believer in a big chunk of a bullet.

Holler if you want to try some leftover components!

Probably the bedding isn't right. Not if it is factory original. They (some Wby's at least) are not bedded FLAT, but bent into shooting position by the action screws. Bad way of doing things.

If you don't want to modify the factory stock, you need to buy a torque wrench and torque the action screws

!. to factory specs, then
2. play around with them to find the sweet spots if you need to.

Or: rip out the factory bedding and bed it properly.

I did this to a friend's rifle here in Kotzebue. It went from 5 inch groups (screws tightened snug without torque wrench) to MOA or less, no torque wrench needed.

His had an aluminum bedding plate in it, which needed milling out to flat-bed the receiver and barrel properly into the stock, which we did not have access to, so his barrel climbs upward toward the front of the stock, but the SOB shoots!. Which is what he wanted.

Just another good reason to avoid Weatherbys.

I torqued the screws at 65 inch lbs as directed by weatherby

65 in/lbs? Wow, that's pretty tight. Remington's "sweet spot" is right around 50 lbs. Might want to play with that. I remember reading a review on a Weatherby rifle at one time, and they couldn't get it to shoot. They loosened up the actions screws and it started shooting 1/2" groups.

Maybe the gun just doesn't do well with that bullet. Try another bullet just to see. If you get consistant results with 2 bullets, it is pointing to something other than a load issue.

I would try flat base bullets. My Varmint Master 22-250 didn't like boat tails and I was told Weatherbys have long throats even with standard cartridge. Some like boat tails buy many don't. YMMV

I'd seat em as long as the mag allows and bump the pressures another 100 fps with Retumbo.

I'd try another bullet and powder combo. Maybe a 225 grain NP and H-1000.

I have some 210 partitions and some 225 Sierra pro hunters. I will try them. I did try 3 different powders with the. 225 AccuBonds but they all were a no go.

You FLINCH !!



Jerry

Most factory 'bedding' is anything but well-done. So many things could be the problem. Is the barrel free-floated? How's the crown? Have you tried less-than-max velocity? If those groups are at 100 yrds, what are they like at 200 ( many BT bullets don't stabilize until further downrange)?

3 inches plus at 100 is not likely a bullet problem. The 1:10 twist is perfect for just about any 338 bullet, but I assume you know that. I think bedding, scope/mount issue or a very bad barrel. I had a Kimber rifle that shot like that and a new barrel shrunk groups to 1/2" with 225 TTSX.

IMO,try the 225 gr Sierras next,if those don't shoot well,then it is the rifle or possibly the scope/mounts.

I say you have had an astounding string of luck with your Weatherbys. It appears to now be over....

I won a Weatherby in a raffle one time, it was chambered in 270 Winchester, it was supposed to be the Grand Prize!

That is what I am thinking. The scope is a proven 3x15 Super Sniper SWFA in Talley rings. I might try the 225 AB's again at maybe 40-inch lbs of torque just to see if there is a difference.

Hey, worst case scenario she goes back to WBY. They are guaranteed to shoot well right?

The scope is proven,then my guess is the bedding. I would try the Sierras first just to see what happens and use the 40 inch lbs of torque. If there is an improvement in accuracy,then try the Accubonds.

If that does not work,send back to Weatherby.

They are guaranteed to shoot well using Weatherby factory ammo. Just for the hell of it, buy a box of Weatherby factory ammo and see what's what. If it still sucks you can always say that you tried the factory stuff in addition to handloads. Beware, look at the price for factory ammo sitting down........You can always reuse the brass.

http://www.weatherby.com/338-378-wby-mag.html

If anything, duplicate COAL. I would try seating deeper and work your way out. Don't get too hung up on barely fitting the magazine.

They were not mag length. More like 3.65"

Good God! Not even in my wildest dreams would I have thought a box of ammo would go for that much.

Oh, there's worse: https://www.midwayusa.com/product/9...-416-rigby-400-grain-partition-box-of-20

Here's a clue:

.308 WINCHESTER!!

Sell it and buy a Kimber

$50 for one cartridge.
http://www.shop.ammo-one1.com/product.sc?productId=350

Got one a rare gorgeous 308 Win. A Sako Finnwolf which I bought 4 years ago New!. It shoots great 165 accubond at less than 1/2" !


How does that help?

Don't have my load book handy Fotis, IIRC mine were 3.800" and put three into a third of an inch in calm conditions.

Gunner thank you I may try that but I do not think going from 3.65 to 3.8 will shrink a 3.5" group into sub MOA---though I could be wrong. Plus your barrel is custom if I remember well.

While I hesitate to get involved in these accuracy mysteries, I'll present an example of how bedding and action screw torque can effect accuracy. The example below is a Savage Precision Target Action stock, a single shot with three pillars for the action screws. Only the action major diameter is bedded, with all three pillars precision fit to the action, and the epoxy bedding placed it such a way that it is exactly flush with the top of the pillars. Nothing else touches the action, barrel nut or barrel. except the rear of the recoil lug, Bottom and sides of the recoil lug are free floated. The entire rear tang of the action from the rear pillar on, including the trigger, is free floated and does not bear on the stock. Likely on a magazine rifle this will not be possible as two screw actions require a rear tang screw.



The following picture shows the effect on grouping by action screw torque. Note that the targets are read from bottom left to right then top left. The scope was adjusted to provide closer point of impact during the test, and we are only interested in the group size. Numbers are relative to action screw torque set by a precision torque gauge starting with the front screw rearward, in inch-pounds. xx front-xx middle-xx rear. Best performance was with the front and middle screw set at 35 in lbs, and the rear screw at 30 in lbs. Tightening more opened groups, and is not shown.



Now we come to one other factor, primers. The example shown below points out the difference made by two finalists in a test of various primers.



The same rifle, polygonal rifled barrel and load were fired for both groups. I assumed that the Federal 205M primer would be the better performer, but was astounded by the Winchester Small Rifle primer. While none of this may correlate to a .338-378 Weatherby, the assumption is that these factors do effect accuracy. My largest caliber is a .375 Epstein Magnum, which develops somewhere around 4,500 ft lbs of muzzle energy using a Hornady 270 grain bullet at 2,754 fps. This rifle was built by RCBS using a Shilen barrel and a Mark X action. How the rifle is held, on the rest, and the degree of compaction of the sandbags, multiplied by the flinch factor all effect accuracy. Some of my rifles will not group Accu-Bond bullets as tightly as others, but if your groups continue to cause misery, I recommend having it checked by the factory.

Yes, but with standard WBY free-bore, so was a buds, identical to your rifle, seat em long and drive em hard with Retumbo is what both our rifles liked, good luck to ya Fotis.

Fotis, as I said earlier, I would most definitely try a factory round before I went any further. It will yield lots of info and give you a reason to return the rifle to Weatherby and let them worry about it. No need to buy more powder and bullets. Spend the money on a half a box of factory stuff.

............Before you become involved with any bedding/torque issues and go in that direction to solve this issue, I would first experiment with different powder and bullet brand load combos using 225 grain bullets. Your rifle seems not to care for IMR 7828 behind the 225 ABs..........If you are getting bad groupings with all 225 gr AB loads using a wide variety of powders then dump the 225 gr ABs.

Squeeze---111 gr of H1000 with the 225 NAB did the same more or less

will try 250 AB's 225 Sierra pro hunter and 210 PT

You just have not stumbled upon the right load combination yet.

My 300 Wby took 430 rounds to settle in. Frustration was putting it lightly. It now stacks 180's in tight holes.

With a hunting rifle I expect and want to hit the game with my first shot at it from the cold barrel,

If a more shots are needed then of course a 'group' is also wanted,

Thus I keep records of all shots and am prepared.''

Here is a target shot with a favorite rifle:

Aluminum bedding blocks really are a joke... more so than the brand.

What are the other "good" reasons you have to avoid Weatherbys?

Bed a set of dual dovetails on it. Lap them. Try at least one other "proven" scope. By that I mean pull it off a known shooter in the safe.

mwarren.\::

Besides coming from the factory with inferior bedding? (not confined to WBY, admittedly)

Well, let's see, overly hyped, overly expensive for what you get, overly heavy (some), overly flashy (some), Brand ammo outrageously expensive for no good reason, Mags burn too much powder for too little gain in velocity (which is less important than accuracy, anyway), hard recoil (Mags), Customer service sucks (at least the 2 times I've tried it on customer behalf), doesn't kill any better than far less expensive brands

If I wanted to waste another 30 seconds thinking about it, I could probably come up with one or two more.

Roy and PT Barnum were soul brothers.

If someone were to offer me 3 brands of guns in comparative spots in brand product line - Say Savage (which I don't much care for), Winchester 70, (which I have never owned) and Weatherby, I would take the Weatherby, sell it to some sucker, and buy the other two with the proceeds.

YMMV, and welcome.

If someone were to offer me 3 brands of guns in comparative spots in brand product line - Say Savage (which I don't much care for), Winchester 70, (which I have never owned) and Weatherby, I would take the Weatherby, sell it to some sucker, and buy the other two with the proceeds.

YMMV, and welcome. smile

Fired the 225 Sierra pro hunters yesterday. With Imr 7828 the best group was 1.5 inches.
With H1000 it put 2 in 1 hole another .7" inches away and a fourth .8 inches way but on the opposite side.

Evidently, there is hope I guess.

This is exactly what the group looked like.






OH BTW I screwed up the torque. WBY suggests 50-55 lbs on the stock screws, not 65 as I thought. So I tighten them to 50-inch lbs.

Fotis, you want me to send ya a big handful of the 300 gr Accubonds for testing, those sombucks sing long and hard.

seat the bullet deeper when your group forms a triangle group like that. when they are two in one out seat bullet further out.