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300 Remington Ultra Mag (RUM) Ammo 2026: Big Game Loads From the Makers

By , EditorUpdated How we verifyEditorial standards

We checked 5 current .300 Remington Ultra Mag loads on Remington's and Hornady's own product pages on November 5, 2026: 3 from Remington and 2 from Hornady. The bullet weights, velocities, energy figures, test barrels and statuses below are copied from the maker pages. We don't use retailer prices or third-party ballistics. This is a comparison of popular loads from 2 makers, not every .300 Remington Ultra Mag load sold.

Federal and Remington loads show the usage label each maker prints on its own page, copied as written. Hornady is listed in its own table, because Hornady prints no usage label. The Cartridge column shows the name the maker page uses.

Remington loads

Figures are copied from each maker page. The usage label is the maker’s own wording.

LoadCartridgeItem #BulletMuzzle velocityMuzzle energyTest barrelBoxMaker usage labelMaker status (Nov. 5)
Remington Core-Lokt300 Rem Ultra Mag27641180 gr Pointed Soft Point Core Lokt3,175 fps4,029 ft-lbNot listed on maker page20Big Game, Long RangeAvailable
Remington Premier Scirocco300 Rem Ultra Mag27950150 gr Swift Scirocco Bonded3,450 fps3,964 ft-lbNot listed on maker page20Big Game, Long RangeAvailable
Remington Premier Scirocco300 Rem Ultra Mag27936180 gr Swift Scirocco Bonded3,250 fps4,221 ft-lbNot listed on maker page20Big Game, Long RangeAvailable

Hornady loads

Hornady's pages show no usage label and no stock status on our capture, so these loads are listed by product line, such as Outfitter and Precision Hunter. Velocity and energy are the muzzle figures from each page's ballistics table, and the test barrel is the one the table names.

LoadCartridgeItem #BulletMuzzle velocityMuzzle energyTest barrelBoxMaker status (Nov. 5)
Hornady Outfitter300 Rem Ultra Mag82084180 gr CX® Outfitter®3,200 fps4,093 ft-lb24 in20Not listed on maker page
Hornady Precision Hunter300 Remington Ultra Mag8209220 gr ELD-X® Precision Hunter®2,910 fps4,136 ft-lb24 in20Not listed on maker page

Velocity and energy are the muzzle figures in each maker's ballistics table. Test barrel is the length the maker lists. "Box" is the round count per box. Status is the maker's own wording on its product page, and it changes daily. All pages checked November 5, 2026.

Which bullet weight? What the makers' numbers show

Loads in our tables run from 150 gr to 220 gr. The lightest is Remington Premier Scirocco 150 gr (27950), and the heaviest is Hornady Precision Hunter 220 gr (8209). The fastest listed muzzle velocity is 3,450 fps, Remington Premier Scirocco 150 gr (27950), with no test barrel listed. The highest listed muzzle energy is 4,221 ft-lb, Remington Premier Scirocco 180 gr (27936), with no test barrel listed. Because test barrels differ or are not listed, compare across makers with care.

The makers label loads for game or for target use. They don't tell you one weight is right for a species. The right choice depends on bullet construction, range and your state's rules. Check your state hunting rules and your state wildlife agency before you buy.

Barrel length matters: the test barrels

Muzzle velocity depends on barrel length, so compare loads tested on the same barrel. Of the 5 loads, 3 list no test barrel, 2 list 24 in. The loads with no test barrel are from Remington. A rifle with a shorter barrel than the maker's test barrel will likely give lower velocities than the box. SAAMI's test barrel for the .300 Remington Ultra Mag is 24 in.

No barrel-length-velocity page exists yet for the .300 Remington Ultra Mag, and we have not charted one. Our barrel length vs velocity data covers other cartridges, so do not read those numbers as .300 Remington Ultra Mag data.

.300 Remington Ultra Mag: what SAAMI lists

SAAMI lists the cartridge as "300 REMINGTON ULTRA MAGNUM [300 REM ULTRA MAG]" in ANSI/SAAMI Z299.4, its centerfire rifle standard (approved Feb. 10, 2025). The cartridge drawing was issued 01/07/1999 and revised 05/26/2022. SAAMI lists a maximum average pressure of 65,000 psi, measured by transducer (the table shows 650 in psi/100). Crusher pressures are not established. Cartridge overall length runs from 3.450 in minimum to 3.600 in maximum. Case length is 2.850 in (−.020), and bullet diameter is .309 in (−.003). Bore is .300 in and groove is .308 in, with 6 grooves and a twist of 1 in 10.00 in, right-hand (marked optional). SAAMI reference velocities are Not yet verified, because the PDF text does not clearly pair each bullet weight with its velocity. Read the standard at the SAAMI Z299.4 PDF. The .300 Remington Ultra Magnum MAP row is also on our SAAMI maximum average pressure table (Z299.4, 65,000 psi / 650 psi/100).

SAAMI says all standard rifle test barrels are 24 in long and that exterior ballistic data for centerfire rifle cartridges is based on that length. Its listed exceptions (7.62x39, 277 Sig Fury, 30 Carbine, 300 AAC Blackout, 300 HAM'R, 350 Legend, 350 Remington Magnum, 360 Buckhammer, 400 Legend and 44 Remington Magnum) do not include the .300 Remington Ultra Mag, so SAAMI measures it on a 24 in barrel.

Not yet verified

These makers and loads are not in the tables.

Rifles for .300 Remington Ultra Mag

The .300 Remington Ultra Mag is a rifle cartridge, and the loads in the tables run from 150 gr to 220 gr. See also new rifle releases and the new hunting rifles of 2026.

Where to buy

We link only to maker pages, listed in the sources below. Federal and Remington show availability on their own product pages. Hornady's pages show none on our capture. We don't track retailer stock or prices. Before you order, check your state's ammunition rules, because some states require a background check or restrict shipping.

For more ammo, see .300 Win Mag ammo, .300 WSM ammo, .300 PRC ammo, .338 Win Mag ammo, 7mm Rem Mag ammo, .375 H&H Magnum ammo, .338 Lapua Magnum ammo, .30-06 Springfield ammo, the SAAMI maximum average pressure table, the barrel length vs velocity data, new ammo for 2026 and all ammo releases.

Frequently asked questions

What is the SAAMI maximum pressure for .300 Remington Ultra Mag?
SAAMI lists a maximum average pressure of 65,000 psi for .300 Remington Ultra Mag, measured by transducer, in ANSI/SAAMI Z299.4 (the table shows 650 in psi/100).
What grain is .300 Remington Ultra Mag ammo?
In our tables the bullets run from 150 gr to 220 gr. Check your firearm maker's manual for what your rifle is set up to shoot.
How fast is .300 Remington Ultra Mag ammo?
In our tables, listed muzzle velocities run from 2,910 fps to 3,450 fps, and muzzle energies from 3,964 ft-lb to 4,221 ft-lb. Test barrels vary, and some maker pages list none. See the test barrel section of this guide.
What does test barrel mean?
It is the barrel length the maker used to measure the listed velocity. A shorter barrel will likely give lower velocities than the box.
Do you list prices or stock for .300 Remington Ultra Mag ammo?
No. We link only to maker pages. Where a maker page shows a status, such as "Available" or "Currently Unavailable," we copy it as of Nov. 5, 2026. Hornady's pages show none.

Sources

  1. Remington: Remington Core-Lokt .300 Remington Ultra Mag 180 gr Pointed Soft Point Core Lokt, item 27641 (checked Nov. 5, 2026)
  2. Remington: Remington Premier Scirocco .300 Remington Ultra Mag 150 gr Swift Scirocco Bonded, item 27950 (checked Nov. 5, 2026)
  3. Remington: Remington Premier Scirocco .300 Remington Ultra Mag 180 gr Swift Scirocco Bonded, item 27936 (checked Nov. 5, 2026)
  4. Hornady: Hornady Outfitter .300 Remington Ultra Mag 180 gr CX® Outfitter®, item 82084 (checked Nov. 5, 2026)
  5. Hornady: Hornady Precision Hunter .300 Remington Ultra Mag 220 gr ELD-X® Precision Hunter®, item 8209 (checked Nov. 5, 2026)
  6. SAAMI: ANSI/SAAMI Z299.4 centerfire rifle standard, .300 Remington Ultra Mag drawing (checked Nov. 5, 2026)

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