Saeed I wanted to know what is the difference between your 375/404 and a 375 RUM? What is the shoulder angle and neck length of your 375/404?

I have not seen a 375 RUM case, so cannot give you a direct comparison of the two.

Here are some details of our 375/404, taken from a fired, resized case.

Length = 2.820"
Neck = 0.375"
Body length = 2.320"
Diameter at base = 0.542"
Diameter below the shoulder = 0.530"

Saeed invented it first.

Thats why I was interested in knowing! I still would like to know the shoulder angle if anyone knows (Saeed I know you are a busy man and you dont have to look into it on my behalf).

Dont let him fool you, he isnt that busy.

Some analysis from my seat in the peanut gallery:

375/404 Saeed vs. 375 RUM
case length = 2.820" vs. 2.850"max (trim to 2.840"min)
neck length = 0.375" vs. 0.359"
rim plus base to shoulder = 2.320" vs. 2.387"
diameter at base = 0.542" vs. 0.548"(measured)/0.550"maxspec
diameter at shoulder = 0.530" vs.0.525"
semi-angle shoulder = ??? vs. 30 degrees

Measured 404 Jeffery Norma vs. Remington 375 RUM brass:

rim diameter = 0.540" vs. 0.534"
base diameter = 0.540" vs. 0.548"

And just for yuks the Clymer reamer throat specs for 375 RUM:
leade = 1 degree
freebore length = 0.1750"
freebore diameter = 0.3761"
neck diameter at shoulder juncture = 0.4070"
neck diameter at case mouth = 0.4060"

Water capacity of 375 RUM = 120 grains by my measure.
Water capacity of 375 Lapua = 119 grains by my measure.
Once upon a time Saeed said to me that his 375/404 had the same capacity as the 375 Lapua that I was proposing as play on these forums. It has been done in Germany as the 9.5x70mm Tornado.

Princes such as Saeed are to be forgiven their imprecision in not specifying shoulder angles or case capacities in grains of water, eh?

Anyway, the 375 RUM and the 375/404 Saeed might be within one grain of water of each other. Very close.

You might be able to close the bolt of a 375 RUM rifle on a 375/404 Saeed cartridge, if the rim would fit into the smaller RUM boltface. I doubt that you could close the bolt of a 375/404 Saeed rifle on a 375 RUM cartridge.

The better design is undoubtedly the .375/404 Saeed, IMHO. Mainly, I like the full diameter of the rim of the case instead of the micro-rebate of the RUM rim.

Maybe Saeed will measure the water capacity of his case in grains, and ferret out the shoulder angle? I'll bet they are very close to 120 grains and 30 degrees respectively.

Saeed ----- What is the speed of the 300 grain bullet. Good shooting.

Idealy a one diameter in length neck and a 30 deg shoulder would be nice for me. I am thinking on having one built, or get rid of my current 378 wby and build a new 378 wby.

smallfry,
I tried to get that shoulder angle out of Saeed years ago. Inquiring minds want to know. Alas, The Prince is a busy man. Perhaps someday he will let us know. Until then, we can only hope.

I was thinking on doing so on a McBros action, does anyone know off hand if thier 375length action also accomdates a 378wby? I am thinking about heading over to Mcbros tomarrow and picking at them a bit. I dont care much for my wby made 378, and I could care less if my next one is CRF or not, I would also shorten the brl to 24". I dont load my current 378 full steam anyways.

smallfry: I also shoot a .378 and I like it very much. Since I started reading AR in 2000 and learned about Saeed's .375/404, I have been fascinated with this cartridge, and the stunning success that Saeed has demonstrated using this cartridge. As far as shoulder angles goes, a person can take reasonably accurate measurements of angle from drawings and photographs, if you make a couple of assumptions regarding perspective of the object (principally you have to assume that you are viewing it at a right angle in more than one dimension). I took two shoulder angle measurements off of Saeed's photograph of his cartridge presented on this thread, one measurement off the right side and one off the left side of the photo. These are imprecise measures taken with a mechanical pensil and a Jeppesen Navigation Plotter PN-1 (a straight edge ruler with a compass attached) and imposing a grid on the photo, but they are very good approximations and both were slightly less than 30 degrees: left side= 28 degrees, right side 25 degrees, with an average of 26.5 degrees. I bet the shoulder angle is just less than 30 degrees. I am willing to be corrected though!

The measured velocity of many cartridges, including the .375/404, are listed in the AR reloading data webpage.

LV my 378 does ~2800 with 300 grain barnes Xs and thats not a hot load. For a long time I have shot other bullets, mostly at full steam but havent shot anything but the barnes for a long time at that velo. From 2600-2850 I dont find the recoil bad and can see why Saeed has his at 2700. If A guy was going to shoot 300 grain Xs he would be better off with a 378 or 375/404 than a 375H&H. When I loaded 300 Xs on my M70 375H&H, they rolled out at 2500 which at that point I swiched to the 270s and hit 2700(I wouldnt have thought). The way my 378 is set up, is not very practical in my eye for dangerous game, but makes a fine hunting/stalking rifle albet heavy, id like to have one with a 24"brl and a bit lighter. It is no secret why the cartridge is so effective, its the largest diameter for that range of speed, and its penetration is like no other.


rwj, how is your 378 set up? Taken much game with it? I have had mine for a long time, but have not taken much game with it.

Gentlemen,

I do not have the drawings for this cartridge, they are with my friend Dwight in the US.

I will ask him and let you know the exact measurements.

With a 240 Gr Bear Claw, we got 3162 fps with 99 grains of H4350

With 300 Barnes X maximu was 2942 with 97.5 VVN 160.

With our own Walterhog 300 grain bullets we got 2948 with 93.0 grains of H4350.

Last year in Tanzania, we used 2 loads with our Walterhog bullets.

One was 88 grains of H4350 at 2790 fps, and the second was 93.0 grains of H4350 at 2948 fps.

Both worked very well, but I have settled on the slower load for this year's hunt.

Less wear and tear on the rifle and cases, and no noticeable difference in the field performance, and both shoot about 1/2" groups at 100 yards - 0.489 for the slower one, 0.507 fps the faster one.

Most of our hunting is done at relatively close range, and the few rare shots I had taken at the longer ranges, say 300 - 400+, I had no problem hitting them with the slower load.

My rifle is sighted to hit about 1.8 inches high at 100 yards. A setting I have found works fine for me.

I think for all practical purposes, our 375/404 and the 375 RUM are as close as two cartridges can get.

Any differences between them could only be due to the rifles involved.

The day we chronoed them with Roy in 01 before your hunt wernt they going 2700fps. I remember that you were fire forming the brass too.

Saeed�s .375/400 is basically the .375 Dakota. Brass and reamers are available for this cartridge from Dakota.

The 375 Dakota is on a shortened 404 case.

Ours is more like the 416 Dakota necked down to 375.

In fact, I use the 416 Dakota brass for some of my loads, as they are easier to form than the 404.

All I do is run them through the 375/404 die, which forms a shoulder on the original shoulder.

That way I do not need to fire form them, as my friend Eric mentioned.

Got it.

.375 Dakota Overall Case Length - 2.570"

.416 Dakota Overall Case Length - 2.850"

Assuming the diameter at the neck-shoulder juncture (neck-1) is equal to 0.4070" as in the 375 RUM, and using the other data that Saeed supplied, one may then use the tangent function of trigonometry to calculate the shoulder semi-angle of the .375/404 Saeed:



26 degrees and 12 minutes



But what is the true neck-1 diameter of the case? Also might be affected by brass make and sobriety of caliper operator.



The nominal angle read off the reamer specs is what the peanut gallery is rooting for, going on two years now, lest we forget. Just curious.

Off topic: Saeed what contour and barrel length do you have on this rifle? Which make and how many flutes? Is it a Mcmillan stock?

One rifle has a Shilen barrel, 0.780" at the muzzle. It is 23 inches long.

The seond one has a Dan Lilja barrel, same contour, finished at 26 inches, 0.760" at the muzzle.

Both have 6 flutes.

One has a McMillan stock, and one has a MPI stock, with pillars added.

Thanks a lot..

I am having a 375Rum build on MRC 1999 action, fluted 26" barrel and Echols Legend stock. It will turn out somewhat similar to your guns.

Quote:

---

One rifle has a Shilen barrel, 0.780" at the muzzle. It is 23 inches long.

The seond one has a Dan Lilja barrel, same contour, finished at 26 inches, 0.760" at the muzzle.

Both have 6 flutes.

One has a McMillan stock, and one has a MPI stock, with pillars added.

---

Saeed:

I've been following this thread for some time. What kind of pressures are you getting from this round? Somewhere around 65,000 PSI, give or take?

I agree, as wildcats go (and I have some), this one seems to fall into the "sensible" category.

Thank you, Saeed, and take care.

Russ

RIP,

My freind Bill Steigers, the inventor of the first and still best bonded hunting bullet, the Bitterroot, has been necking the 404 case up and down since the late 1970's.

I believe his line of wildcats used a 25 degree shoulder which gives a one caliber neck length for any bullet diameter.

I think he has blown out the case and necked it up or down to the 30, 338, 358, 375, 416, and 458.

I tried the 458 x 404 improved as you know but not the others. My 375 improved on the H and H case gives me 2800 fps with a 300 gr Bitterroot from a 22 1/2 inch barrel with a case full of low pressure 4831 so I never saw the need to go to the 404 case.

Bill also invented this case and necked it up to 416 several years before the late G. Hoffman. In fact his reamer was probably used by Georges gunsmith to chamber Georges first 416 Hoffman!

George did make the 375 Weatherby x 416 prior to this however.

Interesting trivia.

Andy

Saeed My Friend,
Just curious for a little info, that is all that I and others are asking for. Please, what is the shoulder angle of your pet wildcat, the .375/404? Have all records of reamer and dies vanished? Is this figure classified, top secret?

Andy,

Thanks for noticing my plaintive wails. I am guessing the .375/404 has a 25 degree shoulder angle. Thanks for the historical info/interesting trivia. Looks like Saeed just doesn't know and is so busy he forgets to look it up as he said he would. Designed by someone besides Saeed, someone named Dwight ????? , or something like that.

I spoke to Dwight yesterday, but I am sorry I forgot to ask about the shoulder angle of this one.

I will look at my reamer later on when I go down to the workshop - just for you RIP, as I normally leave the workshop alone at night

Russell,

I am afraid I have no idea of what pressure we are getting.

I have loaded some ammo until the primers became loose, but I do not use those loads.

My hunting loads are relatively mild - I have some cases which have been loaded 17 times - some are going on safari to Tanzania next month.

One bit of data we are missing is the case weight for the two rounds. Primed 375 RUMs average 278 grs.

Thanks, Saeed.



RIP, would you think that .375 RUM data could safely be used? That would give me an idea of the pressures Saeed is running.



Thanks again.



Russ

Russ,

Others say that they have used Saeed's .375/.404 data in their .375 RUM's with good results.



I am still working through a supply of excellent factory loads with the .375 RUM and have been loading for other cartridges lately. When I get around to loading for the .375 RUM, I will go directly to Saeed's data for trials, along with 93 grains of IMR-7828 and the 300 grain Swift!



I think the .375 RUM may be about 1 grain of water bigger than the .375/404 Saeed. Just my guess, but I think Saeed would find 119 grains of water fills his case and 120 grains of water fills a .375 RUM.



Wanting to know the shoulder angle is my pesky way of hero worshipping Saeed. Inquiring minds want to know!



If you can do any pressure computations based on my 119 grain water case capacity estimate versus 120 grains, that would be interesting. I measured the RUM at 120 grains. Just my number.



Sabot might offer some numbers too.

can a 458 bullet fit into a standard 404 Jefery case and still have enough shoulder to head space on?

Well,

I looked at the reamer, and the only thing written on it is the neck diameter, 0.408"

I will try to pry this very important, ultra secret detail from Dwight next time I talk to him

The 404 has been necked up to 458, as you can see here.



As done by my friend Roy Vincent.

He developed two wildcats. One to be a direct replacement for the 458 Winchester, and one is full length.

Loading data for both of these is available on our Reloading pages.

Saeed My Friend,

Thank you for attention to this important matter. I am still guessing 25 degrees.



I calculated 25 degrees 16 minutes based on a neck diameter (neck-1) estimate of the brass of 0.407". If the chamber reamer has a 0.408" neck-1, then it ought to be pretty close to 25 degrees.



We are getting close to having your cartridge fully described.

BTT, just to pester My Hero, Bwana Saeed!

Saeed -

That Vincent short is a very nice round...looks like an easy convrsion for a 458 winnie with more pop than the Lott.

Is there also one based on the RUM case? Just a bit easier as the bolt face works right out of the box and I am overrun with 375 and 338 RUM brass.

Andy



I know Ross Seyfriend, Tom Siatos and David Tooley has played around with the 404 for a long time. I think Remington should have kept the standard 404 case.





Saeed- Could you give us the missing data? It can't be to hard to find a Dwight Scott, who is a gunsmith and have buffed horns with a buffalo Who made the reamer and reloading dies?



Cheers

/JOHAN

RIP,

I think you will find there is more difference in makes of brass and bullets than between the Remington and 404 case.

Ive used the Huntington Die specilties (HDS) basic brass in my 458 x 404 improved (25 degree shouder rather than the GA which was 15 I think), two kinds of Norma, RWS, and MAST.

RWS weighed 295 gr av with primer, new Norma, 298.6 av. (very consistant), old Norma 450 GA brass, 299.9 gr, HDS, 289.7 gr., and MAST 310.4 gr. Most of the MAST weight was from a longer neck.

So you will need to decide which 404 brass you are talking about!

PS I have some HDS and Norma if anyone needs it.

Andy

Lb404,
Yes there is enough shoulder to simply neck up a 404 to 458 if one is satisfied with the 35 or 400 Whelen and some are not, they both suited me as it really takes very little shoulder indeed to hang onto a round..

I'm not sure but I believe the 460 G&A first version, was simply a necked up 404 with no other changes...I had a client that shoot a 458 on a std. 404 case and it was a super rifle I thought, it fed and extracted like poop through a goose...I have considered building one for several years and have not gotten around to it....I did have for a few years a 416 on a 404 case as bullets were very hard to come by back then..BTW I also had a 416 on a 450-400-3" case and I still have those dies, they may be the only set in the world and a collectors items for all I know...

Ray:
Have you ever used the 450 Nitro express? Seems that with the low pressure, and good ballistics, it should be the caliber by which all others are judged?

I know I would much rather pull the trigger on a 480 grain bullet at 2200 fps at 38000cup, then a 500 grain, at 2350, at 60000 cup....
s