The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores Re chambring 375 hh to 375 ultra magGo | New | Find | Notify | Tools | Reply | |
| One of Us |
I am thinking of having my 375 HH mod 70 rechamberd to 375 rum. Has any one done this and how did it work out? Any good load data on 300gr for the rum. Thanks You can't kill them setting on the couch. | ||
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Why were you wanting to go to the RUM? To be honest with ya, if you chamber for 375(NOT 378) Weatherby, you can use 375H&H in a pinch if your ammo gets lost. I believe the Weatherby shoots about as fast as the RUM. I am in the process of getting some 300gr Partitions for load development. For right now all I have is load data for 250 and 260gr bullets. | |||
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.375 RUM has a longer neck than the .375 H&H (barely) and has same overall brass length. .375 RUM will not clean up the .375 H&H shoulder area. .375 Weatherby will clean up the .375 H&H shoulder. Think about it. If you want a .375 RUM from your .375 H&H, then you will need to set the barrel back a thread at least, or the entire threaded shank should be taken off and re-threaded. I and others can vouch for this. Been there and done that. | |||
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Wholly cow, does somebody smith educated agree with me?? too cool. | |||
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There is also a difference in the bolt face. You should maybe look at simply buying a Rem. 700 .375 Rum and save that Win. till we know about the .375AR which Jeffe is developing. Of course you could also get yourself a Rum Barrel and a new bolt and swith back and forth. Frank | |||
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I believe this is correct but setting the barrel back a thread or two isn't much of a trick at all. I'd want to know that my smith will be able to correct any feeding issues that might come about with the slightly larger case. I also disagree that the weatherby is equivalent to the RUM. It's not. Loaded to the same pressures the Weatherby cartridge is barely better than the .375 H&H. /////////////////////////////////////////////////////////////////////////// "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." Winston Churchill | |||
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gixxer, My "gunsmith education" has come from employing and learning from more than Seven Gunsmiths in the last 20 years. The Magnificent Seven I recall, from Anchorage to Tallahassee: Willis Fowler Walt Sherman Bill Alexander Kelly Olson Harry McGowen Kevin Jenkins Rusty McGee There were a half dozen others who got no repeat business and whom I would rather forget. But anyway, I agree with you. The .375 Weatherby with its 2001 Throat will get within 50 fps of the .375 RUM at equal pressures and using less powder in the .375 WBY. They are both maxed out in the 2800 to 2850 fps range with 300 grainers in a 26" barrel. The .375 Weatherby is not rebated. It shoots factory .375 H&H ammo to good effect. It cleans up a .375 H&H chamber. The .375 Weatherby is 2.860" in brass length and has a 0.354" neck length. The .375 H&H is 2.850" and has a 0.352" neck length. Hey, short necks aren't bad.  | |||
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Feeding issues are minimal. You must be thinking of the old sloppy freebored .375 Weatherby from about 1949. Things have changed. I have shot a lot of .375 caliber rifles. The .375 Weatherby as new since 2001 is within 50 fps of the .375 RUM when loaded properly. I consider the .375 H&H maxed out at 2600 fps with 300 grain bullet and 26" barrel, while using the same bullet, barrel, and normal handloading techniques, the .375 Weatherby can do 2800 fps. IT IS ALL IN THE THROATS AND THE EFFICIENCY OF THE .375 WEATHERBY. | |||
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I used my .375 RUM in Zimbabwe and South Africa last July for Buffalo and plains game. The rifle is a Remington 700 stainless with a 26" barrel that I had fitted with a KDF muzzle brake. I re-stocked it with a laminated stock from Richards Microfit with a Limbsaver recoil pad. I pillar and glass bedded the action and barrel channel, and the barrel is free floating. It is topped with a Leupold 2-7x scope. My load was the 300 grain Barnes Triple shock bullet in front of 97.2 grains of H4831SC and a CCI 250 primer. Cases are R-P. When I worked up this load, Barnes did not have any data for their Triple Shock bullet, but for their X bullet they listed 92.0 grains of IMR 4831 for 2614 fps to a maximum load of 97.0 grains for 2756 fps. My load groups moa to 200 yds. 2" high at 100 yds is dead on at 200 yds. My buffalo was shot at about 50 yds behind the right shoulder. The 300 gr Barnes took out the lungs and broke the left shoulder. A perfect Barnes mushroom. He only ran about 50 yds and was dead when we got to him. I also shot 3 antelope and a zebra with my .375 RUM on that trip. From a bushbuck at 30 yds to an nyala at 210 yds, the 300 grain TSX did massive internal damage and a 1" exit hole. I had a great trip and I was 100% satisfied with the .375 RUM and the Barnes TSX bullets. NRA Endowment Life Member | |||
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the rum will kick the SNOT out of you in a comforable weight 375HH Turn it back a thread (.083 or so) and clean it right up. no boltface issues you'll HAVE to buy the winchester RUM box and follower, or don't bother... OR... just shoot hornady heavy mag 375... but but but but there's little practical gain, though there's a measurable one jeffe opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Thanks guys I want the 375 rum just to be difernt! I have a 300 and 338 rum so the 375 just seams the way to go. Talked to my smith and he said hes been there done that so off it will go. Buffybr, what did your load crono? the 300gr TSX is THE bullet that I want to shoot. Planing on africa and buffalo in 08. You can't kill them setting on the couch. | |||
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Well, then at least I can offer some advice on load development. I would not go with anything slower than RL22 or H-4831. IMO loads with H-4350 do not hurt as bad as slower stuff like RL22 for example. Check this out. https://forums.accuratereloading.com/eve/forums/a/tp.../347107724#347107724 | |||
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Here is a question, If you are starting fresh (like I may be when I order my next rifle) what 375 would you choose? Choices are H&H, Wby, and ultra. My biggest fear is when I die my wife will sell my guns for what I told her they cost. | |||
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PRDATOR, no, I didn't crono that load. I was in a time crunch to work it up for the trip, but that's another story. I started with 95.0 grains and worked up to 98.0 grains in 1/2 grain increments. No signs of excessive pressure such as hard extractions or flattening of primers. 3 shot groups with each load. 97.0gr grouped in 5/8", 97.5 in 1". I then loaded 8 at 97.3 gr. All 8 grouped in 1", with no excessive pressure signs. Loaded 40 more at 97.2 gr, and they went to Africa. This load is 0.2 gr OVER the 97.0 gr maximum load listed in the Barnes book for their 300 gr X bullet. The groves in the TSX bullet will reduce its pressure some from the standard X bullet. This load worked great in my rifle, if you try it use standard reloading practices and work up to it. Using Remington's balistic charts, with a 300 gr bullet, the .375 RUM has the trajectory of a 180 gr 30-06, and the muzzle energy of a 400 gr .416. I think its a great cartridge. NRA Endowment Life Member | |||
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Just thought I would pass this on...I am sure people have seen it. Guidelines from Barnes on loading their TSX's:
I would imagine buffybr's load was in the 2800-2850 ballpark. Sounds like a pretty lethal combo to me. | |||
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| Moderator |
what would *I* do with a "new" gun for a .375 bore starting fresh? totally new? 376 steyr empire square bridged mauser (cut for ruger rings) blackburn fat drop box (5-6 down) barrel - i am torn 1/2 octagon, full rib, swapped quarter rib OR Soda straw diameter with an necg sight setup quarterswan turkish stock either 7# or 8.25# depending on barrel jeffe opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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I always reccomend that people do not try and salvage old barrels through rechambering. It's a whole lot cheaper and better to just get a new barrel contoured to match your old one, cut the threads,chamber and headspace,crown and add iron sights. When you try and rechamber from .375H&H to .375RUM remember, a std .375 Rum reamer is basically only supported by the floating reamer holder initially and WILL Wander a bit at first. There is no foreward support at all. The pilot engages nothing and just wobbles around until it eventually enters the bore. Thats quite a ways in a .375 H&H chamber. It eventually straightens out, but you always wind up with some form of a egg shaped chamber( if you don't believe me do a chamber cast and compare the dimensions to that of the reamer), Does it matter on a DGR, well not often, but it does to me. In addition, you have to shorten the threaded barrel shank and cut a new shoulder which will accurately allign the iron sights. Considering the barrel must be marked with the new caliber anyway, unless there is some really important personal reason to save the old barrel, I'd suggest the alternative described here. Finally, the .375 RUM is a excellent caliber well worth the effort although, I kinda also like the .376 Steyr after wacking a pig with one at about 200yrds at night at the last STC hunting trip.-Rob Never underestimate the power of stupid people in large numbers to do incredibly stupid things- AH (1941)- Harry Reid (aka Smeagle) 2012 Nothing Up my sleeves but never without a plan and never ever without a surprise! | |||
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Rob, speaking of 376s... that one is NEARLY done!! what a sweet rig jeffe opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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| One of Us |
There are some marked exceptions to this concern... Like for a specific example if you have a takeoff heavy barrel chambered for 308Win and you really want a heavy barrel for 30-06AI a 30-06 Reamer will not clean out the OD of the shoulder of a 308Win chamber, a 30-06AI will... Reaming first with a 30-06 reamer the 30-06 reamer with it's narrower shoulder dimension will completely engage the pilot to the bore before cutting begins. There are specific conversions where the results would be indistinguishable to anyone from starting with a "virgin (unchambered) barrel" granted the specific case of opening a barrel from 375H&H to 375RUM is NOT one of them, no, I wouldn't try that conversion either and infact I'd probably go with the recommendation of a short throated 375Weatherby, which is in essence a 375H&H Roy Weatherby Improved the question is that on a Safari Rifle would the results necissarily be horrible? AD If I provoke you into thinking then I've done my good deed for the day! Those who manage to provoke themselves into other activities have only themselves to blame. *We Band of 45-70er's* 35 year Life Member of the NRA NRA Life Member since 1984 | |||
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I'll have to talk to my smith he said he's done it three times whith no issues. He is a top notch guy so he may have a trick up his sleve. Thanks for all the info IF this dosent work out I may just build a 458 lott off a win 70 acction that is now a 7stw. You can't kill them setting on the couch. | |||
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| one of us |
The answer is always the same. If the chamber dimensions match that of the reamer it's a good chamber. If not, well you deceide, assuming it will extract and resize and accuracy is acceptable to you. To each his own. Chamber casts are cheap, but are like opinions, everyone has one, but doesn't want to look at the other guys. You might be very unhappy if you actually look and measure what you thought was a great job. I'm not saying all rechambering efforts are a waste of time, and there are some that will work just fine. Specifically the .375H&H to a .375 Rum isn't one of them. Finally, a .375 Rum may be called upon to make some 300-400yd shots in Africa, it isn't simply a 25yrd DGR. Thats where crappy chambers tend to show their accuracy and precision problems.Been there and done that.-Rob Never underestimate the power of stupid people in large numbers to do incredibly stupid things- AH (1941)- Harry Reid (aka Smeagle) 2012 Nothing Up my sleeves but never without a plan and never ever without a surprise! | |||
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In my opinion, neither one of them are better than the 375 H&H. However, if one wants something else the 375 Wby makes more sence than the RUM. With the 375 Wby you can simply re-chamber,and fire 375 H&H cartridges in the chamber to fire form your wby brass, and use 375 H&H ammo in a pinch if ammo is lost.  Neither one of them will gain you any killing power over the origenal. The extra speed will only benefit you with a slightly flatter trejectory at over 300 yds, but the amount of that benefit is less than you can hold at that range, under hunting conditions.  IMO, either way you go, you are fixing something that isn't broken!  ....Mac >>>===(x)===> MacD37, ...and DUGABOY1 DRSS Charter member "If I die today, I've had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"~ME 1982 Hands of Old Elmer Keith  | |||
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I know it's not broken I just dont want a 375H&H  I'll look in to the 375 weatherby. I may just sell/trade the 375 and build a 375 ulta and a 458 Lott. I guess what I realy need to kill bufalo, is a 470/500/600/700 double!! Thats what I realy want but the last loto tickit came back like all the other ones  Thanks for all the info though I was just goijng to do this but I may not now for this may be the only DG rifle that I ever have. ( less guns more hunts) You can't kill them setting on the couch. | |||
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PRDATOR, there is absolutely nothing wrong with building a rifle simply because that is what you want! I've done the same thing on many occasions, back in the 1950s "Ackley Improved" craze! Out of 110 firearms today, only two are wildcats, and none are the Short Mags, or the ultraulmsuperzapZ-hat Remchestvages that are the craze today. I guess at 69 yrs old, I simply got a lot of moss hanging on my tree!  ....Mac >>>===(x)===> MacD37, ...and DUGABOY1 DRSS Charter member "If I die today, I've had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"~ME 1982 Hands of Old Elmer Keith | |||
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Macd37 HOLY COW 110 rifles You are my new hero!!!!!!!!!!!!!!! DO you have any doubles? I would love to hunt with one of those some day!!!!! Well Im 37 now and have 1 kimber and 8 winchester mod 70s all of them a sub moa so I cant complian there. I looked at the 375 weatherby in the barnes #3 and it lookes like I couls get to 50 fps of the 375 ultra I may just go that way. DO you have one and waht kind of fps on 300 tsx ( and loads if you have any) thanks I m planning my first trip to africa in 08 hopefully for a couple of big old buffs. You can't kill them setting on the couch. | |||
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PRDATORI wrote that wrong! That should have been 110 firearms, not rifles! Yes I have several double rifles, both S/S, and O/U, also one that is a muzzle loader, a 58 cal Pedersoli. Most of the firearms I own are gunsafe queens, I only use about ten of them on a regular basis. I hunt mostly with double rifles, for every thing from jackrabbit, to Hippo! In the 375 department, I have three, two Whitworth Express rifles, one in the factory wood, and one in a synthetic for Alaska's rain. The other is an FN Mauser, and all three are chambered for 375 H&H. ....Mac >>>===(x)===> MacD37, ...and DUGABOY1 DRSS Charter member "If I die today, I've had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"~ME 1982 Hands of Old Elmer Keith | |||
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