30-378

[Mike375]

Over the years I have owned about 20 Mark V Wbys and have also been directly involved with a lot of then that were not mine. At the moment I have a pair of 378s from the Wby custom shop sitting at an Australian gushop waiting for our stupid gun law paper work. I have also had a lot of direct involvement with Rem 700s chambered in Wby calibres with standard freebore with JGS reamers and also chambered without freebore.

There is no doubt that if bench rest accuracy (or at least the full potential of the barrel) is the goal then the freebore is a negative.

However, if the freebore diameter is very close to bullet diamter then the accuracy can be extremely good. If the feebore diamter is too big accuracy is often poor and very load critical.

If there is one thing I have learnt about Wbys rifles is that it does not pay to bet against one on accuracy as some of them are incredibly accurate.

One thing I have noticed with Wbys and I think the freebore is the reason is that they seem to give their accuracy (unless freebore diameter is too big) over a wide range of powders and bore fouling conditions.

If I wanted a nice rifle I would rather have an Accumark in 300 or 30/378 than a Rem Sendero in 300 Win or 300 RUM. But if the ultimate accuracy was the goal then I would take the Rem Sendero and would be expecting to dump the barrel.

Wby triggers with the trigger return spring replaced will virtually always adjust down to a reliable 1 pound.

Mike

 

[1894]

Mike375

Hi, haven't seen you around a while. I can only get on AR at home which limits me somewhat.

I seem to remember you were going into bullet making a while back - how is it going?

Cheers

 

[Mike375]

1894

I ended up putting it on hold due to my mothers health which involved a 24 hour care situation for a couple of years. But now that these 378s have arrived and things are returning to normal I will probably revive it and in 375 bore size. Price will also be a lot more attractive now due to US/Aus dollar exchange.

Mike

 

[Fiftydriver]

Cam,

As a smith specializing in extreme range varmint and hunting rifles, I prefer not to use the Wby Mk V action for the reasons mentioned already.

In the amount of time it takes to lap in the lugs of a Mk V, I can have ten Rem M700 actions blue-printed and ready to go.

I can cut the locking lug recesses, rear surface of the locking lugs on the bolt and lap the lugs in to +95% contact in very little time.

This is not possible with the Wby action.

I am in the process of building my personal 1500-2000 yard rifle right now and I will be using a Rem M700 action with a standard 06 bolt face that I have opened up and installed a Sako extractor to.

The barrel I will be using is a 34" 1.350" diameter straight cylinder, Fluted SS Lilja in .338" bore with a 1-10" twist.

The chamber will be cut to the 338 Kahn(338-378 Wby with a 35* conventional shoulder) I feel the double radius shoulder is another accuracy weak point for the WBY rounds.

The barreled action will be riding in a McMillan Tooley 1000 yard BR stock and I will be using a barrel bedding block system of my own design.

For extreme range shooting, I would recommend the 338 over the 300 but both work well with the real heavy bullets.

The thing to remember about the 30-378 is that these huge cases work better with heavy bullets. 220 gr is where I would start. If I were rebarreling I would use either the Sierra Mk 240 gr or the Graves 230 gr ULD.

If your using a 26-28" barrel you might as well use the 300 RUM as it will run within 100 fps of the bigger Wby case in those barrel lengths.

With barrels in the +30 range, the big Wby case will start to pull away from the RUM case.

For the money, I will go with the 300 gr Sierra Mk or 350 gr Graves ULD 338 bullets over any 308 bullet.

Course as a 50 BMG shooter, I like heavy bullets that land hard!

Good Shooting!!

50

 

[pc]

There is another thought for the 30/379 as it needs a big action and that is to use the cz 550 safari magnum in say .300 win mag and open up the bolt face and rails and re-chamber....or start with the .416 Rigby and rebarrel

 

[Brent]

Mike, Fifty...

Thanks for your thoughts there, good stuff.

What kind of MV do you figure you'll get from the 338 Kahn with the 300gr SMK in a 34" tube?

What OAL will it be throated for?

My Bro's M700 in 338/378 WBY is throated for a 4.1" OAL, in a 32" bbl and gets 3000 fps near max load (118gr H870), probably 3050 is on the top edge if he pushed it more, maybe a tad better if he switched to H50BMG, which he'll probably try sometime.

I'm tossing around the idea of a 338/500 Jeffery (Horneber brass of course), as I can still use the 700 action on that case too, but gain on case capacity.

 

[Fiftydriver]

Brent Moffitt,

In talking with Dan Lilja when researching my extreme range rifle project, he told me about his two long range hammers, both 34", one in 338-378 Wby and the other in the 338-416 Improved.

He listed data that reached nearly 3200 fps but he was also using custom actions and not the Rem M700.

There is not doubt the M700 can handle these rounds as it has roughly the same bolt lug surface aare and shear area as the Wby Mk V action, especially when you figure that with a factory Mk V, your lucky if 6 out of the 9 bolt lugs actually contact the reciever.

I do not wish to drive this rifle to full tilt max pressures, I am looking for 3050 to 3100 fps but accuracy will be my number one priority.

I would think that your brothers 338-378 would run a little faster with a quicker powder. From what I have seen, burn rates in the H-1000, Rl-25 and Retumbo are about right for the big 338.

H-870 and H-50BMG would be better suited for the 30-378 from what I have seen.

I ordered my reamer for a throat of .300" long at .0002" over bullet diameter. This system has worked very well for me in the past. This will also allow the 300 gr Sierra to be loaded so that the junction of the boattail and bullet shank will be seated to the junction of the case neck/shoulder.

I do not think I would use the 338-500 Jeffery on a Rem M700 action, that case will create a hell of alot of bolt thrust, much more then the big Wby case.

If it were me I would go with a custom action such as a BAT or McMillan or Windrunner for that round.

Good Shooting!!!

50

 

[Brent]

Fifty,

The Jeffery has a rebated rim, it's smaller in diameter than the big WBY, Lapua or Rigby rim so it actually produces "less" bolt thrust when operating at the same pressure, .575" I think it measures. The Gibbs/CheyTac case rim is just way too big though. Another plus for the Jeffery case.

Have you ever had any problems with the 300gr SMK bullets being oversize and chambering in a tight freebore? You said .0002 over bullet diameter; I assume you measure the bullets and don't just figure they'll be .338 when specing the reamers?

All the 300's my brother has bought have been at least .3385, most all are usually about .3388 though. They throated his after reaming the chamber, so they had problems using the .3385 freebore/throater with the oversize bullets and getting the OAL right, as the bullet would give a false reading it was so tight.

Maybe I'll try some Retumbo and RL25 in his rifle for him while he's gone working in Nome this summer. Hmmmm, maybe I'll get very attached to it by hunting season this fall and just use it instead of my 300 Ultra. Heck, maybe I'll just use his 500 Jeffery and some AMAX's! Oh the choices I'm gonna have this fall.

I think you'll get 3000-3100 fps pretty easy based on what he gets from his, and be pretty easy on brass too.

 

[Ron Johnson]

Hello All,
I had a 30-378 built in '79 with a 30" douglas s/s bull barrel, on a Ruger #3 action with Canjar trigger and Fagen wood. I used a 24X leupold at first and then a 5.5-22 Nightforce. This rifle was bedded with glass and I tried several different tuning methods to tighten groups more. I built it to hunt with more than target shoot. I have used several powders as listed.
T-5010
T-5020
T-5050
T-5070
H-1000
R-22
IMR-7828
H-4831
WC-860 AND WC872. I mostly shot 200 and up to the 240's. Little time spent with lighter weight bullets. Shot a cotote in AZ with a 150 Win silver tip pulled from 30-30 ammo at about 3600 fps. Brown furr and red mist. Using the 200 gr. Sierra Matchkings shot several deer and a couple of elk out to about 700 yds. This chamber had little freebore and the 200 grs can touch the lands when the breech was closed. Max loads were as follows: 180 gr = 3550,
200 = 3350, and 220 = 3150, with the 240 limited work was done but about 3050. The Lieca 1200 works well and I have used it to a little over 1000 yds, but the beam is large at that distance. We found by ranging cattle and sheep with several laser rangefinders and a Wild rangefinder that if we aimed the Lieca at thier feet we got closer to real numbers. Can anyone comment on that thought that beam divergance is too great and you actually get a reading back from the ground beyond the animal??
Thanks for your time,

 

[CAM]

Fiftydriver

This post was started in Jan. of 2002
I have the 30-378 in a Nesika action and a Kreiger barrel smithed by Howard Wolfe.

Your points are well taken and I would maybe go in a different direction also but it is too late for this project, I have been using this gun to kill elk for the past two years.

I have learned a lot about long range, my shooting skills, and trying to find the right powder for this large case. It has been fun. I will never look back to what I could have done only ahead to what to do next!

Big bommers are addicting to say the least.
It is fun to shoot and just plain insane to hit steel ground hogs out past 1K fairly consistently.

When I get ready to rebarrel I will be looking into the 30 Wolf. I have a good Nesika action and I know more about reloading and the importance of top quality brass than I did when I started this project.

I wish you luck with your new gun but you don't need luck you have picked a great setup and only time will tell.

Keep us informed of your project and post some pixs when you can.

CAM

 

[Ron Johnson]

I hane had a 30-378 and I have tasted quite a bit. It was built in 1980 and had a no freebore. It wasuilt on a Ruger #3 action with a 30" Douglas barrel. Canjar trigger, Fagen wood and several different tuning fore3arm setups.It can do 3400 with heavy loads in 200 grs,m and 3550 in 180 gr. 220 at 3250 and 240 at 3150 fps. I fyou want I can send you info on loads. E-mail me @ [email protected]

 

[CAM]

338 Nemesis

I will send you an e-mail.
Thats about the same as what I have gotten for velocitys also.
I have NOT tried the 240 grns just mostly the 200, 210 and some 216

Thanks CAM

 

[gvonblohn]

Cam, for what it's worth, I've worked up loads from Barnes using the new TSX 180 (only) and Retumbo. I've worked up to and over the max load listed in the Barnes new book. The farthest I've been abel to shoot is 300yds but the groups were awesome for me and teh rifle. It best group was 2 1/8" at that range. It chronos real fast at over 3600+ fps. I did get it to over 3700 but the bolt was starting to stick at 114gr. Yes I was freaked, but there are no abnormal pressure signs. I backed off to pub max of 113 and load the TSX to the last driving band. My rifle is starting alot of freebore. I have not tried 200gr, but I have used AA8700 with good success too. Velocity at 2g over max was 3375fps with still no extraction problems. I chose to consult teh Weatherbyman.com for load data and info. All this was with a 4.5x14 Leupold VXIII. Chrono was accurate too because I verified it with my other long-range handgun '06 and 338'06 loads.

 

[CAM]

Danville
Thanks for the info it's all worth while!

I also use 113 grn Retumbo, for the 180 grn bullets. I have had good luck with 180 grn Failsafes. These are shot in my factory Weatherby with freebore.

The customs best group was 5 shots using WC872 and 200 accubonds at 100 yds.

Thanks for the info
CAM