I shot mine 4 times with some medium 235g and my mounts looked like the ones on that simmons setup
That's what I get for being cheap(mounts did same thing on 300wm
I'm going to try Leupold QRW, maybe with a smaller scope
Anyone have pointers on the QRW?

here's a free tip on scopes

get the lightest you can, with a quality name... less enertia to crash your scope mounts..

secondly, gorila glue aint for plastic.. that crack COULD (will) become a problem

3: the simmons aetec scope is cheap and heavy.. and the rings look like they were not put on tightly (the base if moved)..

I shoot 416, 458, 470, 500 and sometimes 577nitro (550 is coming) and the level of recoil is amazing on some of these... but NOT warp/bend .250 of steel, if mounted correctly.

kinda like telling me a 458 lott can "throw" an elk backwards

jeffe

That base or ring didn't bend, it only broke loose and slid forward. It is a spherical aberration of a closeup photo. The windage screws on the rear base didn't hold and the scope slid forward in the front ring, which may have been loose/poorly fit, not lapped and friction compound fit or glued, or loosened over time.



I quit using those Redfield type mounts a long time ago. Anything over a 30 bore and they are no good for recoil, if the rifle is light or the scope is heavy, etc., as Jeffe says.



The Lepold QRW's with the square recoil shoulder on the bottom of the ring are fine, not the old style with the round cross bolt.



Warne Maxima. Talley. Ruger rings on Talley bases. Integral bases and QD rings. German claw mounts. These are a few of my favorite things.



And don't forget to turn any 6x48 screws into 8x40 at least, and whatthaheck, put everything together with epoxy if it is practical to use low torch heat to get it apart later if necessary.

Here's a tip from Obi-Wan Seyfried (He in turn swiped it from Martha Stewart): Put Scotchkote Electrical Coating by 3M (part # 054007-14853) on your scope body and the inside of your rings. If the scope or rings shake loose, they will do so as a unit. I bought a 15 ounce can for about ten bucks about 6 years ago at Big Sparky's Electrical Emporium. It sticks tighter than my ex wife to my debit card.
JCN

Mr. Hyena,
Get that f****ng war club off of your rifle. That sucker is going to rear back and cut a divot out of the inside of the back of your skull!
JCN

I have a new 375 RUM and love it, but would never consider this round if I did not handload. This case is a joy to reload and very forgiving with reduced loads to duplicate the 35 Whelen, 9.3X62, 375 H&H at greatly reduced recoil. The power of a 378 Weatherby is there if you need it, but there are so many other applications that this round is good for, it is a shame to just use it for DG.

My pet deer load is 59 grs of XMP 5744 behind the Hornady 225 gr spire point for 2600 fps.

I've got a rem 700lss in 375 ultra-a great shooter.
I dumped a moose with it last year,a 270gr x ahead of 100grs of RL19 for just over 3000fps,it sure got his attention!

I just sold my .308 Warbird and found myself in quite the predicament...Had a wad of cash, and I wanted the 375RUM, but I still wanted something fast and flat, around the .30 caliber range...and then it hit me...there was a 300RUM LSS sitting right next to the LSS 375RUM I was going to buy...problem solved! Walked out of the store with both of them. Now I have two matching LSS Remingtons, in 300 RUM and 375 RUM! Can't wait to get scopes for the both of them and start loading.

Surprised to see this thread dredged up!

I see some more good news and hot tips added, too.



We moved and I'm still getting the 'stuff' arranged, so pix and the first firing of the rifle are but a couple of weeks away.

The latest glitches in this project involved fitting the scope/base and the length of the action screws/fitting the action to the synthetic stock.

The stock fit the 700/7mm that came in it perfectly. It does not fit the 700/.375 Ultra in the same manner...

It took some judicious scraping of the triggerguard area to get the action to seat properly.

Now, the action screws are about 1/8" too short...and I can't find the little bag from Brownells with the extra-length screws! I KNOW I bought 'em, I just can't find 'em!

As for the base/scope fit, my buddy used a hand grinder and some crocus cloth to get the front of the base sloped down for clearance. He's a machinist by trade and did a great job; all it needs is some flat black paint now.

The 8-40 screws/holes will have to wait a bit.

I will try something in the rings to hold the scope tighter.

The front sight set will be knocked off for the smooth look.

Everything will come together and I'll get a firsthand idea of what the .375 Ultra Mag feels like when it goes off in my new rifle.

Fortunately, I've got a PAST Super Mag Plus strap-on recoil shield to benchtest with~~~!



Nice to hear from you guys with the new rifles and great tips.

Well, you'll have to keep us informed! I'm real keen on how you like it and how it shoots for you. This is still a future project for me, so I'm on pins and needles for any new reports on this cartridge. maxman

I found the 300 grain Swift bullet in the Remington factory load to be extremely accurate, and to give just over 2800 fps in the 26" barrel of the M700 SS.

I have a CZ 550 Magnum AHR action that got a 23" barrel and a custom walnut stock. I paid $125 for the simple checkering, after the first artisan died before he could get around to doing it ... that rifle was in the works for nine months mainly because of the shipping to and fro for checkering ...

Anyway, the CZ box holds 4 of the broad-shouldered 375 RUM cartridges, though it will easily hold 5 of the slope-shouldered 404 Jeffery ... plus one up the spout.

To feed the 375 RUM well, the converted CZ 550 Magnum (with a standard generous sized CZ box for .375 H&H) did require some minor reshaping of the rails and some polishing of all contact surfaces of the box, follower, ramp and rails.

Now, I considered but decided I would be very hesitant to rebarrel this rifle to 404 Jeffery. The 375 RUM is a more versatile cartidge than 404 Jeffery. Though the Jeffery's .404 may be better for dangerous game up close, the 375 RUM is adequate for anything. Plus, the 375 RUM makes a great sheep rifle, and it does it all with a 300 grain bullet.

BTW, the 23" barrel on my CZ 375 RUM averages 2780 fps with the Remington factory 300 grain Swift bullets. It has a tight throat, shoots well, and seems to kick pretty hard for the ballistics it gives in this rifle that weighs about 10 pounds, field ready.

It wears a 1.75X-6E Leupold scope in Talley QD lever rings (medium height), and there is silicone adhesive (unseen) in the rings where they contact the scope tube, no grit or resin/rosin for me, please. This scope will never break loose from the rings, and the Talley rings will never break loose from the CZ integral bases.

I haven't done any hand loading for the 375 RUM as yet, because I have a good supply of the 300 grain Swift factory ammo. I have taken one white tail buck with the 375 RUM, shot from a tree stand at 25 yards.

I would pair the 375 RUM with a 470 NE SXS double for a 2-gun safari, or take the 375 RUM alone plus a shotgun if bird shooting was on the menu.

Finally, please, another call for any pet loads for the 375 RUM that are accurate and tamed down to only 2700 fps with the 300 grainers? Just to see what has been going "Boom" successfully in other hands.

Of course I can always refer to Saeed's 375/404 loads, as that cartridge is nearly identical, ballistically, to the 375 RUM.

Only the 375 Wby could be more versatile than the 375 RUM AND the 375 H&H, because the 375 Wby can dine on 375 H&H fodder to good effect. And, the 375 Wby can also get 2800 fps with 300 grainers, in a 26" barrel, no sweat.

RIP,

I echo your call for some good RUM loads.

I have tried 95.0gr AR2217 (H1000) with the Woodleigh 300gr PP. Speed only 2397 fps Av but heck the recoil seems a lot more than it should & accuracy sucks. Then I ran out of time at the range as I had another 2 sets of loads in 2gr increments up from there still to shoot. I think I will give up on those. Mike 375 told me about slow burning powder & light loads. Loud boom & big recoil. He's right.

I think I might try either AR2209 (H4350) & AR2213SC (H4831SC) for around 2700fps with the 300gr bullet & good accuracy. At the moment my Rem 270gr factory ammo is my most accurate load & that to a Handloader like me is disappointing to say the least.

Regards
JohnT

Friend John,
I am trying to keep a low profile since I like synthetic stocks and stainless steel. Oh the shame!

Anyway, I was counting on using H4831SC.

The Swift reloading manual shows what looks to be some excellent loads for their 300 grain A-Frame/.375 RUM:

Remington 9-1/2M primer
Remington brass
24" (1:12" twist) barrel

H4831 92.1gr >>> 2642 fps
H4831 99.0gr >>> 2780 fps (with a load density of 96%)

That trouble free 2700 fps load ought to be in there somewhere. I think H4831SC will be the powder for me to try, whenever I get finished burning up the factory ammo. I like to keep it simple. If H4831SC does the trick, I will look no further.

Light charges of slow powders are dangerous. Don't do that! Might blow up your rifle with a detonation.

Hey Bro,
Try original recipe long cut H-4831. Then you go from minimal to no sloshing around. This may sound a bit odd in this context, but if the 4831 concept doesn't pan out, perhaps some RL-15 and Dacron?
JCN

Has anyone opened up a Remington factory load to see what they're packing in it? Just curious.

I've had it drummed into my head, especially here, that I'll be needing to start gathering reloading equipment for my .375 Ultra...and now that I've got a place to make room for it, I'll be checking into and looking forward to it!

BusMaster007,
Good thought. I need to pull a 300 grain Swift from the factory ammo and weigh the charge. Good help for guessing the identity of the powder. Since Remington and IMR/Dupont are/were related corporately, I am going to guess IMR7828 as the powder, before I go weigh the charge. Be back later with a weight.

BusMaster007,
The .375 RUM factory load with the 300 grain Swift was pulled and the charge weighed:

93.0 grains of what sure looks like IMR 7828.

The Swift manual shows:
IMR-7828 88.4 grains >>> 2540 fps
IMR-7828 95.0 grains >>> 2761 fps (92% load density)

Again, for a 24" barrel with 1:12" twist, remington brass, and Remington 9-1/2M primer.

I'll bet the factory powder is IMR-7828.

The Swift manual shows a max load for the 270 grain Swift A-Frame as 103.0 grains of IMR-7828 giving 2958 fps and 98% load density.

For H-4831 it shows a max load for the 270 grain Swift A-Frame as 106.0 grains of H-4831 giving 2957 fps and 101% load density.

For Charlie, I hear you. I believe the Swift manual is using H-4831 "long cut."

7828 is the powder that works best for me. Factory loads using it that deliver 300 gr velocities at or near 2800 fps are MILD in the pressure department. You don't need more power, so just load with 7828 to that velocity and smile...Don't forget the 350 gr Woodleighs for DG.

For plains game way out yonder, the Nosler 260 grainer breaks 3000 fps at modest pressure with 7828 as well.

Think of the 375 RUM as a 270 Win in the velocity and trajectory department...the bullets just happen to be twice as heavy.

I have a bunch of IMR-7828 that I have been meaning to find a good use for.

So, now I know what load my rifle likes so much, 93.0 grains of IMR-7828, heh, heh, heh. It would be hard to improve on that factory load, though it might deserve comparison to H4831.

I have found that the load data provided by Nosler for the 375 RUM is dead on for my Rem 700. Quite honestly, it does well with 4350, 4831 and R25 as well. Its just that the 7828 seems to have a lot of room for more pressure once you get to the factory velocities...I have gone to the Nosler Max of 100 grs with 300 gr Sierras and when i stand the rifle up and nudge the bolt up it falls open and ejects using gravity only.

The loads that Saeed has on the loading pages for his .375/.404 w/VV160 work extremely well in my RUM.

Joe