Well-Known Member
Jan 2, 2002
I have the weatherby accumark 30-378. Im looking for a gun smith with knowledge of the 30-378. Im interested in accurizing the action, supply and installing a new 30" +/- barrel. Any and all suggestion will be greatly appreciated.

[ 01-05-2002: Message edited by: Cam Clegg ]
One more try. Any suggestions on a gunsmith. Also, With a new barrel any advantage or disadvantage of the 338-378 vs 30-378. Is there a better trigger for the Weatherby?
Most gunsmiths I have talked to don't like Weatherby actions and suggest remington action and a standard 300. I'm left handed and can't find a remington mag action. Nesika bay has left handed actions. I do need a safety do the triggers have the safetys and I don't understand carrier or pinned. Any suggestions? I just want an accurate cannon out to 1000 yds.
Where are you located. Here in Pa., we have quite a few very good gunsmiths who specialize in long range rifles. Many 'smiths are against using the Remington action for the 378 case as it is a bit too large and leaves only marginal metal around the case head. You could go with the 300 Tomahawk and that should work well in a Remington action. It is the 300 Ultra Mag improved. Look on the board, DC posted some info about a project rifle in this caliber.
I don't know anything about Weatherby actions so can't help you there. Try calling Ray Romain, he builds a lot of long range rigs and has the reamer for the Tomahawk.
Email me if you'd like further info.
Cam, Couple of questions.. Why the rebarrel? I am assuming that you either attempted but could not find the accuracy and or speed your looking for with loading or have shot the barrel out? I ask this because I am looking for accuracy in the same caliber/gun although I have just gotten through breaking the barrel in with factory ammo and am awaiting the rest of the tools needed for reloading/ accurizing the ammo. I have quite a bit of starting data for 150 and 180 grain loads but have yet to find much for 220 grain. Everything I have read on this board says chop up the gun, get rid of the freebore, get a longer barrel etc. I will get a longer barrel after I wear this one out, but for now I think I am going to try and work with concentricity, neck tension, and possibly bullet crimping for more reliable powder ignition and maintain the freebores potential velocity. This versus having the freebore taken out to "set it in the rifling" and increase pressures and make it a 300 RUM with just too much case capacity. All of this to say....What is the most accurate powder you have found for 200-220 grain balls?

Just had a phone call from a fellow in Colorado who finally got his accumark (30/378) to shot with 180 grain bullets.
As a matter of fact, Weathertby heard about it and wanted to have the rifle back so they could check it out because of all the problems with accuracy complaints they have had.
As he told me, the 180 gr does him NO good as he wants to reach out much further and wants to use the 220 gr in it.

Not only is the Freebore the problem with accuracy but, normally out of the 9 small locking lugs on a Weatherby action, most of the time, there only three (3) that are touching when engauging the bolt . You must lap these in and that takes quite a long time to do in most cases.

All you would have to do is have the barrel set back 1/2" to 3/4" to eleminate the freebore and lap the lugs. Would help that rifle alot. You would then have less then 26" of barrel to use though. A new 30" custom barrel would give you 100 to 140Fps more velocity and it would be much more accurate then the standard Weatherby barrel.

They (Weatherby) advertise a 28" barrel which is not true. The barrel is 26" and with the brake on, it measures 28". The brake does NOT add to barrel length because the bullet can NOT touch it in a any way. The bullet must have at least .016" clearance around it when it exits through the brake for the brake to work. Therefore, that extra two inches is not acting as a rifled barrel.

I would get rid of the freebore and lap the lugs first. If that didn't work, a NEW barrel would be installed.

Call Ray Romain (Romains Custom Guns) at 814-265-1948. He can help you out.

Darryl Cassel
Only have experience with one Weatherby but the results were very good. The load was with H870, CCI mag primers, and 180gr Nosler BT. With a near max load, the vel was over 3400fps with 1/2 MOA accuracy. Brass was sized using FL RCBS dies and seated using a die from the same set. Bullet length was kept so that rounds would feed from the magazine. Brass life has been good.

Another load with Speer Grand slams was horrible. 2 to 4 MOA groups. Bullet probably not designed for this velocity. H1000 was also tried but results were not good.

This rifle also shot the Factory loads with Barnes X 180 very well. Maybe just a lucky gun. No work has been done on the rifle except to mount a scope. Muzzle break left on.

I shoot a 300Weatherby in a custom rifle. There is also freebore but accuracy is excellent. Freebore may not be that big of an evil if loads are prepped properly. I neck size and there is a very close fit in my case and seating die. Ammo is concentric.

Good luck...


I am agreement with the removal of freebore to increase accuracy. It just happened in my 300 Weatherby because that was the style of the reamer used. It does, however, illustrate that if ammo is prepped and loaded properly, many mechanical sins can be overcome. At least this should be tried before a potentially accurate rifle is gutted.

With the 30-378 Weatherby, maybe it is just a "lucky" gun. 180 gr bullets is all that is desired by the owner. Accurate to minute of mule deer out past 700yds. Not bad for an off the shelf rifle. The owner used to think 300yds was a LOOOONG ways off.

Been following your Tomahawk project and was wondering how close the improved 300 Weatherby's would get in vel. launching the 240MK out of a 30 to 34" barrel? I am guessing that the improved 300W look very similar to a 7STW necked up and maybe more shoulder angle/less taper.

Thanks for the feedback,

Hello Jerry

I have the 308 Baer, the 30 Goodling and my 300 DC Super IMp. which are all based on the Improved 300 Weatherby. As a matter of fact, they are all VERY close in measurments also.

I like the design of the 300 RUM case better then the Imp 300 Weatherby style cases.
So far, I am quite sure the 300 Tomahawk will outperform any of the 300 Weatheby Imp cases that I have.
I have taken the 240 gr 30 cal to 3168 FPS without any signs of pressure yet.
I end up with pressure signs after two loadings with any of the 30 Imp using much less powder and 220 gr bullets.
I am confident that 3200 to 3250 fps is within reach. I have quite a bit of powder volumn area to use yet. The 30 Weatherby IMP would not have held near as much as I have used so far in the Tomahawk. The cases have been loaded 3X in the Tomahawk.

As soon as the weather breaks here a bit, I will resume the testing as there are several people interesed in this.

Darryl Cassel

For benchrest or excellent LR accuracy, the 1000 yard shooters eleminate the excessive freebore and try to get the bullet within .010" of the lands and sometimes into the lands softly. I know the Accumark is NOT a benchrest rifle but better accuracy can be gained from most of them.

Your Weatherby not only has the freebore but a magazine box that restricts the overall length of the loaded round. If you eleminate the "jump" of the bullet into the lands caused by the freebore, most Weatherbys shoot MUCH better. Try seating some heavier longer bullets out in the case neck further and see if it chambers. You may not be able to get to the rifling though and will have to make a measurement to see how far away you are. If 180gr is all you want to shoot, and at the range you want to shoot, stick with it.

Maybe you have an exceptional one that likes JUST the 180 gr bullets. For LR shooting the higher BC and heavier bullets are much more desirable to most.

My wife and I shoot at Williamsport with (4)---300 Weatherbys. Two in the 16 1/2 Lb class and two in the heavy benchrest class.
NO freebore EVER in ours. Our gunsmiths wouldn't chamber the freebore into them anyway.

Darryl Cassel

[ 01-21-2002: Message edited by: Darryl Cassel ]
THANK YOU for all your help. Sorry I have been busy at work and the Olympic stuff here. Mostly wanted to say THANK YOU! and report back. I talked to Ray Romain NICE GUY and I would not hesitate to have him work on any rifle. Also talked with Howard Wolfe his pet is the 30-378. To get to the point! I ordered a neiska action, Timney trigger, Howard has ordered a 32" kreiger barrel, and is going to piller and glass bed into my elkridge laminated stock. Keeping the weatherby as is for now.

Prime time I live in Utah, I just like the 30-378 and know the remington action is to small.

HoytemanPA good to know you have a 30-378 all I have loaded for is the 150's and the 180's I plan to load for the 200 MK's with the new gun and maybe the 220 MK's so not much help yet.

I feel like a beginner when it comes to reloading. Could just go by the book and load a accurate load for 100 yd's then go hunt. Things change! Need to get a chrony, rangefinder, etc. Also keep better data when working up a load. What do you guys keep track of when reloading?

The best powder for the 150's was RL-25 for the 180's was H-870. But not knowing the actual velosity drives me crazy need to save up again.

Any Info on the new powder Hodgdon RETUMBO is for large over bore's? also Leica 1200 rangefinder is out anybody tried one?

Thank you all again, very good Info on this board and lots of talent!

I'm just waiting now for all the parts and pieces to turn into my first custom.

Hi Cag,
Congrats on getting the custom built. The RL25 with 150's and 870 with 180's is consistent with others' favorites on other boards as well. I have been working up mainly the 220's with RL25 and H50BMG. With the H50 I am still a couple of grains shy of max listed on the hogden site and starting to show pressure signs (ejector marks). But it sure seems to like the load. Seems to be cleaner than the RL25 as well. The jury is still out on the RL25 I've got one more set of test loads before I give up on that powder.
Talk to ya later,

Hodgdon powder has a new powder for large overbores but they have some DOT issues their permits or something was in the World trade centers. The powder is called Retumbo might try this out when available?

They have loads on their web page http://www.hodgdon.com

Same is true with Alliant powder, they have one I've been playing with, that would be like a Reloader 30 or such. Same DOT problems
I have the very first 30-378 Weatherby stock. It came from a rifle that was a contract item from the factory to the US Army ballistics lab in Huntsville, Alabama. The contract was for a single shot test fixture, 30 cal. that would project a solid aluminum 100 gr slug over 6000fps to do impact analysis on armor plate. The rifle was never fired by the army with the stock attached as the stock was removed and thrown in the trash. I got that stock before it went to trash disposal and now want to sell it. It has been sitting in my closet since the early '50s. Where would be a good place to advertise it for sale? Any help is appreciated. [email protected] 256-955-2746
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