I also have a Montana 1999 action on order. I told them a Magnum sized action and want a 375 RUM. I have posted and also closely followed similar posts relating to the same. I am set against a standard 375 H+H. I'd like something more unique. I have several questions or opinions and want the rifle set up to what I thik is the proper way for MY RIFLE. Never been to Africa, but will go in the next 5 years. The intentions are to have a heavy plains game rifle. Unless I hit a Lotto, Buff will not be on the agenda for some time, I am only 31. This so far means a 26" tube, McMillan synthetic, no sights, and a 2.5-8 Leupold.

My caliber is still debateable. Several argument occur in these debates for which is best. I will state that Saeed, whose videos we've all watched, is said to have run his 375/404 at 2700 fps with 300's. I will try to follow advice of people with as much "experience", as I have none.

To the gravy:

Will a 375 AI hold as many rounds in the mag? 3+1, 4+1, or 5+1? Does it really improve velocity over a standard 375 or is it just due to running at higher pressures?? Die availability??

I want a 375 RUM. It should be able to be loaded down to the levels above, as well as hot rodding if needed. No fire forming needed. Correct headstamp. Magazine capacity, I don't know, maybe 3+1?? 4 seems like enough rounds in a rifle to me. What are some thoughts?

Jesse,

Sounds like a fun project. One of the Gunsmiths I work with built just such an animal. A .375 Improved, comercial mauser action, can't recall brand, 21" barrel, Synthetic stock. I went shooting with him last saturday and he shot a 1.04" ten shot group! He is pushing 300s over 2700 and isn't near max yet. The rifle is suprisingly not bad to shoot. You don't loose any mag capacity over 375 h&h. You will loose capacity if you go with the ultra mag, probably.

In my oppinion a 26" tube is a little much for such a caliber. You don't gain enough velocity to justify making the rifle substantially less handy.

Have fun with it!

If you want more info e-mail steve (the guy with the 375 imp) suntiet@hotmail.com

Later,

Aaron

Ammo availablity could be a concern in Africa if yours gets lost. I am not sure if there is much .375 RUM ammo anywhere.

I have a .375 H&H and another in the Improved version. Both are good for their purpose. I am not impressed by someone who is "bored" by the .375 H&H which to me is a legendary cartridge and one that dreams are made with. Here is her site, the queen of them all the .375 H&H http://webpages.charter.net/375magnum/

Having owned a .378 and seen a .375 Rum I would go with the standard .375 and then jump to the .416's.

Jesse

I think if examined strictly on the merits of ballistics, loading flexibility etc. then the 375 Ultra is the best big bore of all of them. Isuspect that is why Saeed has settled on a pair of 375/404s for his two main guns.

However Saeed's 375/404s probably highlight a problem with the 375 Ultra which does not relate to ballistics.

I think the 375 Ultra (remember his rifles are not 375 Remington Ultras) has a low "desire to own" factor. One reason possibly being "Remington" which is not normally associated with big bores and that is compounded by the Rem 700 rifle.

If I was buying a new rifle tomorrow and the following rifles were available (I know that they are not available) in both 375 H&H and 375 Ultra then I would pick the following.

Sako 375 Ultra
Reminton 375 Ultra
Weatherby 375 Ultra
Savage 375 Ultra
Winchester 375 H&H
Ruger 375 H&H
CZ 550 375 H&H
Montanna99 375 H&H

Mike

There is always the question of lost ammo on such inquiries. How often does this really happen in the real world??? If it's that much of a concern, the AI would be perfect as the standard could easilly be used. I would agree, athough never having been hunting outside the US, that the Ultra is not going to be as common world wide, but again how many times is ammo lost??

Anyone else no the expected capacity of the M1999 in an Ultra configuration?? I could probably call, but I hate to bust balls as their phones are probably busy constantly. This is going to be a lefty so no other actions are really feasible anyhow.

I hunt with several other wildcats and have used my 6.5 WSM as of late. This rifle, along with my 350 Remington custom only hold two down, and one up. I guess more would be better, but I don't find it a big hinderance.

Well let's see. I have been shooting a 375 JRS mag. for about a decade now and just aquired a new Model 70 Winchester last week in 375 H&H. An improved 375 sounds like a good idea but I believe I will stick with the stock H&H from here on out. If you need more power I think you need more frontal diameter and bullet weight. I am becoming weary of fireforming and wasting good components for what I get in return. My opinion for what its worth, stay with the stock 375 which has worked since 1912 or if you feel you need more in a 375, go with a factory offering. The 375 Ultra does sound good and I would pick it over any wildcat.
Doug

Jesse

I would think about a .375 Weatherby chamber instead of the Ackely . Either one is going to do about the same thing , but you have the advantage of factory ammo and headstamped brass if you ever require them .

I also like the concept of the .375 RUM . There is something about that case in the medium -large bores that just "looks right" .

sdgunslinger

One problem with the 375 Wby is the long freebore. If the that chamber has a freebore diameter a bit too big, then it is hair pulling stuff for accuracy.

Mike

Could be Mike . But you could cut the chamber without freebore . That would negate the advantage of factory ammo , but you would still have the advantage of headstamped brass .

I recentely picked up an older push-feed M-70 .375 ; I think it is going to get reamed to a larger chamber . The factory throating is so long , I don't think a Weatherby reamer will even touch in that area.........

sdgunslinger,

Cutting the chamber without freebore is easie said that done and especially with Weatherby calibres. Firstly if the reamer is made for 375 Wby the freebore is there.

The Weatherby shoulder prevents chambering a 375 barrel with a 340 Wby reamer and then having neck and throat done. If it is done the full length dies in 375 Wby won't get all the case.

Every Model 70 I have seen in 375 is from 1970 or so vintage up until today and they have maybe .25" or .3" bullet jump when a 270 grain Hornady Spire Point is seated to the cannelure. Sakos and Remingtons I have have owned were the same. Also a JGS reamer our barrel maker uses is about the same.

What is yours like?

Mike

Mike

The lands on this rifle are 0.4 inch from the front end of a once fired Winchester case . Or , you can load a 300 gr. Hornaday rn to 3.7 inch overall and still not bump into the lands .

Not sure what the Weatherby freebore is supposed to be , but figure I got a fair start on it . And the gun is virtually unfired .I can use several grains more RL15 than JJ Hack's hot 270 gr loads , and barely best 2700 fps.

I guess I am presuming Weatherby reamers can be had without freebore......I know a number of .340 fans have their chambers cut without the freebore........

[ 03-24-2003, 20:48: Message edited by: sdgunslinger ]

sdgunslinger

I will check a JGS chambered barrel tomorrow.

A 270 grain Hornady drops down in diameter right in front of the cannelure.

In a Model 70 try 86 grains of IMR 4350 with 270 grain Spire point. You will only get that into a neck sized case and the bullet with maximum compression will seat to about halfway between base and cannelure. Should 2820 to 2850.

82 grain IMR 4350 with 300 Hornady round nose. Should do 2620 to 2650.

71 grains of 4064 should do around 2610 to 2630. That is the same load as in the old 270 grain power point ammo.

76 grains of Re 15 from 26 inch JGS chambered barrels does around 2820 to 2840. I have never chronographed it in a Model 70 but would expect about 2740. Looser chamber and 2 inches less barrel.

73 grains of Re 15 and 300 Nosler and 300 Hornady. Just over 2600 from 26 inch JGS chambers.

In my opinion the 375 has the most overstated velocities of any calibre on the forums.

Mike

Also, try 39 to abot 41 grains of H4227 and 220 Hornady seated to cannelure and Fed 210 primer. Very accurate and does around 2100 f/s

For testing the rifle try 78 grains of Win 760 and 300 Hornady round nose seated to the cannelure in either new brass or full sized brass. I can't rememeber seeing an accurate 375 that would not shoot well with that load. 300 Sierra does well with that load as well. It does freom 2400 to 2450.

Mike

[ 03-24-2003, 20:57: Message edited by: Mike375 ]

I have tried a number of powders from 4895 and 4064 to H414 to RL19 and found it dam tough to best 2700 with 270 gr spire points out of this rifle . I presumed it was due to a longer than average throat .

At one point I was thinking the H&H hype was a steaming pile , this thing will barely best a warm .35 Whelen load.

It will probably show up much better with 300 gr. slugs.

Jesse Jaymes,

I have 3 .375's at the moment, 2 .375 H&H's and 1 .375 Weatherby, and if you want more than the H&H gives I would like to recommend the .375 Weatherby. Availability of ammo being first and the ability to use H&H ammo if needed. You have something happen to your RUM ammo(airline looses it for one) and you're up the creek. Everyone like to talk about the freebore of Weatherby's affecting accuracy but I haven't found that to be a problem. My .375 will shoot around that inch mark all day, usually just under. Lawdog

I've never shot one, but have considered rechambering to the 375 Weatherby. I've noticed with the sloping H&H case, when you aproach a maximum load, it will have increased effort opening the bolt, on some rifles before any measureable head expansion. If Ackley is right the improved case should cure this. I also wouldn't be concerned about freebore screwing up accuracy, since I've never owned a .375 that would let the bullet be loaded out to the lands unless you shoot it as a single shot. Normally you set the longest overall length by making them just short enough that they'll load in the magazine without getting stuck. I have two Whitworths, have owned two Model 70's and a Sako, none would seat close to the rifling anyway, a couple of those shot .7 groups, none shot bad.

Also, my rifle with 270 Hornady bullets and RL15 will go 2780 with a near maximum load. I have two chronographs(a new one and an ancient Oehler) they show velocities within 10 fps of each other. The old Oehler is one that is so old you have to look up the velocity in a table and has 5 foot screens. When I bought the new one, I thought I'd compare them to satisfy my curiosity.

375 RUM. Why? Well....
The 375 H&H head spaces poorly so triming is frequent and brass life is not great. At full maximum loads the H&H gets into heavy powder compresion and is still a little slow with heavy bullets.
The 375 Weatherby is a bit faster than the H&H, is very accurate (in all of the rifles I have owned and shot), and is easy to please on the reloading bench. 375 Weatherby brass is hard to find and is very expensive. I have also found the Weatherby to be a little sluggish in the velocity department. You can make it go but you have to lean on it harder (high pressure)than I would like.
The 378 Wby is very fast but will give you a headache and will rip your trigger finger to the bone if you are not careful!(O.K. I like this one too)!
The 375 Ultra holds 3 rounds in the mag (I have a new BDL), produced 2800 fps with 300 grainers on its first outing, is accurate (the most accurate says Nosler), and while it will part your hair it will not remove any flesh in recoil. The brass is so cheap it is almost free, and it is sewar pipe tough.
I like it a lot!!

Let me know where you're finding that cheap brass. I see $0.50 or so a round, for the .300 RUM. Love to find a cheaper source.

Pertinax

There are two reasons that justify the 375H&H AI, over the others you list! #1 is because you want it!, and #2 because if your ammo gets lost in transit, you can shoot factory 375 H&H ammo in the rifle to complete your hunt!
In reality, there isn't anything the others will do that the old 1912 origenal will not do just as well, and in most cases feed far better. I've owned all the 375 Rounds except the RUM, and the 376 Steyer, and in my battery, today, there are three Mauser actioned 375 H&H rifles, and the others have gone with the wind!

[ 04-03-2003, 22:43: Message edited by: MacD37 ]

Because the Improved 375's do everything the original does, plus a little bit more. - Dan

Jesse, consider another optic for your rifle. I had a Leupold 2.5-8 scope and found that my little Leica 10x25 binoculors gave me thirty more minutes of hunting time than I could see through that scope. I traded it and got a 1.5-6 Burris signature on my dangerous game rifle and put a 3-12x44 Burris signature on my plains game gun. You may want to consider a LPS or other quality optic.