338/375 Ruger or 375 Ruger with high BC bullets?

[AZShooter]

I realize that many here might suggest I use a RUM case. I would consider it if the magazine constraints were not 3.6". The action is an Interarms Mark X set up for 375 H and H. I cannot imagine that lengthening this integral box magazine/floorplate design would be an easy inexpensive job.

This is why the 375 Ruger as the basis for a fun to shoot hunting/semi long range rifle.

The bullets that are being considered are:

350 SMK for the 375 Ruger and the upcoming 250 and 300 Berger VLDs for the 338/375.

Any and all thoughts on extending the magazine length or using either Ruger configuration would be appreciated.


Ross

 

[Overkill338]

The .338-375 Ruger is called the .338 Campfire. Do a Google search, should net you plenty of info.

 

[grit]

The 338 ultra and the 375 HnH both have a max col of 3.6. Gotta be close.

330 Dakota would fit too. About a twin of the 338-375 ruger.

 

[AZShooter]

Thanks for the suggestions. I nixed the RUM case with that magazine, the long VLDs or that Sierra would be deep into the case.

This thread is quite old. I have decided to go in another direction with this free donor action in a McMillan stock. The 375 H and H barrel profile is quite stout. I ordered a #7 30" Lilja SS in 7 mm. Will make it a 7 Rem Mag with lots of room for seating leeway. I ordered a reamer from Pacific Tool and Gauge. Had the reamer made so the 180 Berger VLD is seated out past SAMMI specs with lots of room to chase the lands. While this magazine does allow the 7 STW or the 7 RUM to fit there is not much room for seating depth changes unless it becomes a single shot.

Who knows if the 338 RUM or similar is on the horizon. With Berger coming out with those VLDs it may spur me to build something.

See you around this site.

 

[rigmaster10]

I Recently Pushed My 20" Barreled 375 Ruger Alaskan To 2500 Fps With A 350Gr Smk. No Pressure Signs. Now I Have A 28" Tube Coming And A Special Reamer Coming For Longer Throat. I'm Hoping To Get 2700 Fps. But We Will Just Have To See. One The Best Cases I Have Ever Seen.

 

[rbTanzan]

One The Best Cases I Have Ever Seen.

Absolutely ideal for anything in the 30-39 calibre range.

More isn't needed until the .416", where the Rigby allows for 350 grainers at 2800-2850 fps with only normal modern rifle pressures.

 

[rigmaster10]

The Rigby Is Also A Bit SaFer When Going Down To Sea Level.

 

[rifletuner]

Hi Ross

Apologies in advance for the hijack, but how did the build with the doner action turn out? I have the exact same action, and am really conflicted on how to use it. Am thinking about a 375 RUM using an aftermarket mag/bottom metal, but conflicted as to whether this is the best use of any of the components.

So very interested to hear if you are happy with how your project turned out for you. Did the 7mm build you decided on live up to expectations?

 

[AZShooter]

IMO no hijack.

The 30" 7mm Rem mag would still be that chambering but I was mislead into getting a 1 in 7 twist 3 groove. It shot the 180 Berger hunting VLDs excellently with the accuracy velocity of 2975 or so. Got up to 3050 fps but not as consistent. Unfortunately this barrel configuration go to round count 225 or so and began to occasionally throw the VLDs away from POI.

I first discovered the diverging bullets when I went to shoot my coues wt at 400 yds! It wounded the animal instead of the easy hit it should have been. I shot another four with some off by FIVE feet! I grabbed my other rifle my friend was using and finished it off with next shot.

I tried 180 Target VLDs and 75 rounds later THEY also had issues with the worn barrel. Finally used 140 accubonds till I was disenchanted by ho hum wind drift numbers and pulled the barrel.

I sent that #7 SS lilja to Dan Pederson in Prescott and he rebored/rifled the barrel to 338 dia. I gave him my 338 RCM reamer and had him long throat it for the 300 gr Berger hybrid. I shot it for several years.

Just this past spring I FINALLY got around to making a 7mm/375 Ruger on that platform. It is not the LRM version but simply necked down to 7mm. My friend sold me a 7 STW with 400 rounds through it for $200. It was 30" #5 fluted 6 groove lilja 1 in 9 twist. I chopped off the threaded shank and rethreaded for the Mark X action myself. Then chambered it to 7mm/375. It shoots the 180 Berger match target hybrid @ 3200 fps with RL-33.

It has a Near Mfg picatinny rail and a Joel Russo stock. Factory trigger set at 1 lb. It IS unusual to use a Mark X for a F class style rifle but it works, feels great and gets some interesting comments. I'd say put your action to use!

So that platform has two barrels 338 RCM and 7mm/375 and looks like this:

 

[rifletuner]

Hi Ross

Thats awesome! Thanks for all the info. That does prompt me with a bunch more questions, so I hope you dont mind (incidentally, nice how you brought the thread back on topic due to the barrel rebore to 338! ).

It looks like the barrel profiles you have used are all on the long side, in heavy contours - I take it you do not experience any negative issues hanging this much barrel off the action? Mausers are not renowned either for tack-driving accuracy or stiffness (or have much tenon for that matter), so I was worried the action just may not stand a heavy profile. It doesn't look to have been the case for you, so gives me a bit more confidence for my planned project.

Did you do any other work to the action to true it up prior to the barrel work? All my Zastava (Mark X / Daly) actions are rough out of the factory. I intend to polish up the raceways, but wondered if they would benefit from a full-on blueprint.

What performance/ballistics are you getting from the 338 RCM? I am interested in the mid range 388s, and the 338/375 Ruger seems to have some good potential here as an easy to form, beltless case. I know thats not the same as the DCM, but your findings with the DCM version s still worthwhile data to bear in mind.

Lastly, what die set are you using fr the 7mm/375 Ruger? That cartridge also seems to have a lot of potential, and is something I am seriously considering for another project.

 

[AZShooter]

The larger 338 cal barrel is a #7 unfluted lilja profile. It is totally floated. The receiver is bedded in the action. I torque the action screws: rear 35 in/lb, front 40 in/lb.

No work has been done to the action. It is an older Mark X and is quite smooth compared to the newer Mark X/Daly. The trigger was reworked by Joe at Lawson's here in Tucson.

The long throated 338 RCM ( see pic) with 300 gr Berger 57 gr of RL-17 vel 2550 fps. It isn't as bad as it seems. Retains 3000 ft/lb at 550 yds. Wind drift at 500 yds in 10 mph crosswind is 8.8" (4000 ft elevation) The recoil is very tolerable with this 13 lb rifle. Can shoot 8-10 shots before it gets warm. Cleanup is easier with such a slow bullet speed.

Die set for 7mm/375? I have an assortment of dies on hand including a whidden 338 RCM combo FL/bushing die.

Here is how I made the cases with dies I already had: (from my documents file)

Procedure for necking down 375 Ruger

1) Hornady 338 RCM FL die
2) 300 RUM FL die to taper mouth of case
3) 7 RUM seater followed by FL to reduce neck dia
4) Whidden 338 RCM bushing die with .329 bushing
5) Whidden 338 RCM bushing die with .312 bushing
6) Open up with K and N mandrel, neck turn to .013" neck wall thickness
7) Run brass into Whidden 338 RCM bushing die using .310 bushing


I used the 7mm/375 reamer on the body tube of a 7 rem mag Redding comp die for seating.

338 RCM:

 

[rifletuner]

Thanks for that. It helps me confirm some of my thinking on this. I am going to go ahead with my 375 Ultra build on this action. I think I have sourced a barrel, and have the action on hand. So I think I am on track for this project.

I am going to have to do some research on the 375 Ruger case. I am swinging back this way for a 7mm, and can see some real benefits for a 338 on this case too.

 

[AZShooter]

A 338/375 Ruger would be easy to form. The 338 RCM and 375 Ruger share the same shoulder diameter and angle. You can use a 338 RCM FL die to neck the 375 down and size necks of fired cases. Could also use the 338 RCM seater die. A 375 Ruger FL die can do the shoulder/body sizing.


I forgot to mention I use a 375 Ruger die for my body/shoulder bump die. Even though it doesn't size all of the shoulder of the 7mm/375 I am getting excellent accuracy without bolt closing issues.

 

[rifletuner]

Thanks. Right now I am thinking I will use a 338 RCM and 300 RCM for the forming stages.

For day to day loading, I think I will bite the bullet and get John Widden to make me up a set of his dies with a full length bushing die and micrometer seater. Not cheap, but very nice.