TESTED: Remington 700 Long Range 300 Remington Ultra Magnum

Anyone that knows me knows that I’m drawn to extremes. So when I heard about 300 Remington Ultra Magnum (300 RUM) I was curious- what would it be like to shoot such an extreme cartridge? Fast forward a number of years and here I am with my own 300 RUM rifle! This exploration of 300 RUM will include an overview of my Remington 700 Long Range chambered in 300 RUM (this article), reloading for the 300 RUM, and converting this rifle over to 300 PRC. Now this will be FUN!

About the Remington 700 Long Range

The Remington 700 Long Range rifle is all about quality and fundamentals.

From the Remington Product Page:

Engineered to make three shots look like one. From extended-range big-game hunting to printing one-ragged-hole groups from the bench, no rifle delivers like the Model 700™ Long Range. And we’re continually finding new ways to maximize our legendary action’s inherent precision.

The Model 700™ Long Range combines the added stability of a 26″ heavy-contour barrel with hard-hitting, long-action chamberings to stretch your lethal range.

    • Bell and Carlson M40 tactical stock – solid urethane combined with aramid, graphite and fiberglass
    • Aluminum bedding block for added accuracy and an extra swivel for bi-pod
    • 26” heavy contour barrel with matte finish, perfectly matched to its high-velocity caliber offerings
    • Concave target-style barrel crown
    • X-Mark Pro® externally adjustable trigger
    • Drilled and tapped for scope mounts
    • Magazine capacity – four in standard calibers, three in magnum

The Remington 700 long-range package is a solid foundation that you can build out the way you want. At minimum, this means selecting an optic and optics mount that fits your needs. The Bell and Carlson stock is very high in quality, and this rifle has all the basic features and construction details for a great long-range rifle.

X-Mark Pro Trigger

The X-Mark Pro trigger is standard equipment on all Remington 700 Long Range rifles.

Technical Information from Remington

  • User adjustable trigger features a 2 lb. range of adjustment
  • Comes pre-set at 3.5 lbs.
  • Trigger has vitually no creep and breaks like glass
  • Custom shop performance in a factory part

I ran a TriggerScan with the X-Mark Pro as it came set from the factory, and produced the following results: (click/tap to enlarge)

While this trigger was set to a higher pull weight than I prefer (about 5.3lb) It shot great for being that heavy!

Gavin’s Remington 700 Long Range Upgrades

Are you like me? Do you enjoy the process of taking a rifle “from the box” and getting it ready “for the range”? There’s a lot of satisfaction for me when I’m installing gear and accessories while anticipating first shots through a rifle. And here’s what I did to get this Remington 700 Long Range setup to my liking.

Threading the Muzzle

THIS is why I own my own Metal Lathe: who can run a shop and household without one? 🙂 Before putting a single round through this rifle I chucked it up in my Precision Matthews PM-1440GT lathe. Here’s the barreled action getting prepped for the lathe:

Did you know that you can thread a muzzle without removing the barrel from the action? You can also leave the trigger assembly installed if you are very careful. I was not worried about imbalance as I’d be using moderate RPM when threading. Everything worked out great.

Above: The finished product- factory crown, 5/8″ x 24 threading, all ready for a brake!

I just got my hands on the Hawkeye 7″ and 17″ Gunsmith’s Borescope Kit from Brownells, and let me say, this is an AMAZING tool set for evaluating bores, and more!

I used the Hawkeye 17″ borescope and the 90 degree angled eyepiece adapter to inspect the factory bore after cleaning and before shooting. The bore looked really good, with only moderate tooling marks. A good sign both for accuracy and cleanability/fouling. At this point I felt ready to go shooting, but I had a couple more things to do before taking this rifle to the range!

Scope Rings and Base

In order to mount the 30mm scope I’d be using with this rifle, I decided to go with the following components from Evolution Gun Works:

EGW Remington 700 Long Action 20 MOA Scope Rail

EGW Scope Rings, 30mm, Low

*Note, these rings were too low, I would go up to the next size for this configuration (Vortex 6-24x50mm, Viper HST). I substituted another set of rings.

Elftmann Remington 700 Trigger

I decided to upgrade the trigger (something I evaluate any time I’m evaluating a firearm and/or ammunition). This time I thought it would be interesting to try the Elftmann Tactical ELF 700 SE. With this trigger, I was able to reduce the trigger pull from about 5.3lb (X-Mark Pro) down to about 1.0 lb as I had adjusted it. A huge improvement!

I screwed on an AR-Stoner AR-10 muzzle brake, installed my Harris Bipod, and was set to go! And the rifle looks awesome! (click/tap to enlarge)

300 Remington Ultra Magnum: Powerhouse 30 Cal

Above: A 300 Remington Ultra Magnum cartridge (left) next to a 223 cartridge (right). Wow.

The 300 Remington Ultra Magnum is an impressive cartridge- right in the top few cartridges for powder capacity in the 30 caliber category. Unlike some of the 30 caliber magnums (like 300 Win Mag), the 300 Remington Ultra Magnum is a beltless cartridge, which can make it easier to deal with then reloading.

Here’s the cartridge specifications:

Some quick facts:

  1. Bullet diameter: 0.308″
  2. COL: 3.600″ (300 Win Mag is 3.340″)
  3. Case rim and bolt face: Same as 300 Win Mag
  4. Powder charges topping out at over 100 grains!

I’ll note that it was because of item #2 above that I chose this rifle as a “Starting point” for my budget 300 PRC build. 300 PRC has a Cartridge Overall Length range between 3.575″ and 3.700″. The internal box magazine for the Remington 700 Long Range 300 RUM measures 3.728″ in length- so I’m hoping most 300 PRC loads will work with this magazine/stock/action configuration without modifications- we’ll see!

Results with Factory Ammunition


For my initial testing, I had two varieties of ammunition on hand, and I started things off with Remington’s HTP 180 grain 300 RUM ammunition featuring Barnes solid copper bullets.

I broke in the rifle with this ammunition, following the following sequence:

  1. Clean bore
  2. Shoot 3 shots
  3. Clean bore
  4. Shoot 5 shots
  5. [repeat steps 3,4 until done]

During break-in, I shot some groups with the Remington HTP ammunition. The first 5-shot group I shot was reasonably good coming in at just over 1.5 MOA:

Focusing on Accuracy with Magnum Power

After the break-in process was complete (about 60 rounds total) I started to refine my shooting technique, and got used to the new trigger. At this point I also decided to try out Remington’s Core-Lokt 180 grain 300 RUM Ammunition.

I’ll say, I was surprised at how manageable the Remington 700 Long Range is with 300 Remington Ultra Magnum. No bruises on my shoulder, no black eye from my scope, and a rifle setup that I can shoot confidently with out too much recoil anticipation (it’s a mind game and requires a lot of focus). With some tweaks to my shooting setup, I was able to stabilize the rifle much better, especially along the windage axis (see first 5-shot group above with large horizontal dispersion).

For these groups, I shot with the following gear:

These tweaks in combination with the Elftmann tactical trigger helped me get to my “5-shot Sub MOA with factory ammunition” goal. Here’s one of the groups shot with the Core-Lokt ammo and the setup outlined above:

OK, now we’re talking! I’m sure that with more practice, more pointers from my “magnum minded friends”, and with some reloads, this Remington 700 300 RUM will shoot even better!

Please stay tuned, because I’ve got a lot of related content coming up, including:

  • Reloading 300 RUM for the Remington 700 Long Range
  • Upgrading the 300 RUM Remington 700 Long Range to 300 PRC
  • Comparison of 300 RUM and 300 PRC
  • Upgrades, tweaks, and perhaps some hunting!

If you have something specific you’d like to see, please let me know!

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2 thoughts on “TESTED: Remington 700 Long Range 300 Remington Ultra Magnum”

  1. .300 RUM and 30-378 Weatherby Magnum are beastly .30 caliber cartridges. Have fun. My 325wsm has 35 ft.lbs of recoil energy and that is about as much as I prefer to shoot from a bench all day lol. Your probably close to 40 ft lbs of recoil energy with the RUM. I guess your hoping to drop an elk at 1000 yards-lol.

  2. My experience with the Remington X-Mark Pro triggers on two guns was replace it as soon as you can. Adjusting it to a lighter pull made it very inconsistent. One of mine varied more than 1.5 lbs. I don’t own them anymore.

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