New SAAMI Accepted Cartridge, 6.5-300 Weatherby Magnum

weatherby_65_300_f

6.5mm bullet development continues apace, this time courtesy of Weatherby, which has championed the SAAMI acceptance of a new loading, the 6.5-300 Weatherby Magnum. SAAMI acceptance is a major step towards the general acceptance of a loading outside of “wildcat” status.

With SAAMI acceptance, the specifications for the chambering are made public, which typically then leads to larger adoptance of the cartridge. By going public, manufacturers of reamers, buttons, broaches, and other firearms components are able to fully understand the loading including critical tolerances to then make compatible offerings. Most critically, ammo and barrel manufacturers are able to make products with little risk of incompatibility across the market.

weatherby_65_chart

Specifically, the 6.5-300 Weatherby Magnum was developed to push super-slick 6.5 loadings to extremely high velocities. To quote Weatherby, “Never has a 6.5mm bullet gone faster!”ย This may be completely true, as the SAAMI spec loading can push a 127 grain pill past 3500 feet per second.

Weatherby has commercial loadings and unprimed brass available. The cartridge is not for the light of wallet. Commercial ammo is $95/box for 20 rounds and the factory-new brass is $42 for 20. (Here’s to hoping that SAAMI acceptance will drive down costs!)

Additional details can be found at Weatherby’s website and through ballistics charts below :

6.5-300 BALLISTICS

 

Velocity

Bullet Type Ballistic Coefficient @ Muzzle 100 Yards 200 Yards 300 Yards 400 Yards 500 Yards 600 Yards 700 Yards 800 Yards 900 Yards 1000 Yards
127 Grain LRX 0.485 3531 3309 3099 2898 2706 2523 2347 2177 2015 1860 1740
130 Grain Scirocco II 0.571 3476 3276 3084 2901 2726 2557 2394 2238 2087 1942 1804
140 Grain A-Frame 0.401 3395 3122 2866 2624 2394 2176 1970 1776 1597 1435 1293

 

Energy

Bullet Type Ballistic Coefficient 100 Yards 200 Yards 300 Yards 400 Yards 500 Yards 600 Yards 700 Yards 800 Yards 900 Yards 1000 Yards
127 Grain LRX 0.485 3088 2707 2368 2065 1795 1553 1337 1145 976 828
130 Grain Scirocco II 0.571 3097 2746 2430 2145 1887 1655 1445 1257 1089 939
140 Grain A-Frame 0.401 3030 2552 2139 1781 1472 1206 981 793 640 520

 

Trajectory

Bullet Type Ballistic Coefficient 100 Yards 200 Yards 300 Yards 400 Yards 500 Yards 600 Yards 700 Yards 800 Yards 900 Yards 1000 Yards
127 Grain LRX 0.485 0.00 -1.68 -6.98 -16.43 -30.63 -50.30 -76.29 -109.64 -151.56 -203.55
130 Grain Scirocco II 0.571 0.00 -1.74 -7.14 -16.68 -30.89 -50.43 -76.04 -108.61 -149.16 -198.95
140 Grain A-Frame 0.401 0.00 -2.04 -8.24 -19.36 -36.31 -60.25 -92.59 -135.13 -190.12 -260.35


Nathan S.

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

Nathan can be reached at Nathan.S@TheFirearmBlog.com

The above post is my opinion and does not reflect the views of any company or organization.


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  • Gorilla Biscuit

    Who cares how long the barrel will last! This will be an absolute laser beam hunting cartridge!

    • Austin

      Maybe a titanium barrel insert could help with lifespan and imagine what a company like Underwood could do pushing it to the limit.

      • Raven

        Stellite or Inconel (or similar superalloys) is what you want to be looking at for barrels.

        • Austin

          Still perhaps it’s time to look beyond steel for these “barrel burners”

          • iksnilol

            Saboted bullet through smoothbore ceramic barrel. Only have a piece of rifled steel at the end (paradox choke) that can be replaced easily.

          • Austin

            If you got the fin stabilization right you might not need the rifling

          • iksnilol

            True, I was thinking using conventional lead or copper projectiles bullets.

          • dave

            the minute you put a proof of concept video of this kind of thing on youtube i will watch it.

          • iksnilol

            I think several people would watch that. But I got a life in the way of that ๐Ÿ˜›

          • Austin

            Taofledermaus has been testing odd saboted rounds for a while

          • Jwedel1231

            Out of a shotgun, not rifle rounds at rifle speeds. Saboted rounds are apparently a thing in artillery these days, so it may work on a shouldered-weapon level. IDK about ceramic barrels and “paradox chokes” though. Time to test my google-fu.

          • Austin

            Its still supersonic flight, which is useful for testing how stable various designs are in flight.

      • Giolli Joker

        Titanium would only get eroded faster.

      • Gorilla Biscuit

        Ferritic nitrocarburizing (meloniting, nitrided) surface finishes POSSIBLY have a lot more going for them, than any barrel insert or sleeve. Something like this (cartridge) would be an awesome test bed to see if nitrided barrels actually keep the surface coating after firing X amount of rounds down the tube. MAC form Military Arms Channel did a vid bringing up this idea. I would love to know if the nitrided surface finish actually stays in the rifling and grooves. A Hawkeye bore scope and appropriate cleaning methods should be able to answer the question. If nitriding is really the answer , then a very overbore cartridge like this, shooting projectiles with very long bearing surfaces would provide beneficial from said coating process.

        • Austin

          Hell, why not coat a super alloy and double down

          • Jwedel1231

            only change one thing at a time. Doing both would throw into question the usefulness of each.

    • DwnRange

      While I cannot tell you how long a barrel will last with this particular loading I can tell you that my gun builder friend, who shoots 1K matches with a 6.5mm-284 claims he can tell by round 360 that his accuracy begins to fall off in his custom barrel built rifle.

      By 400 rounds he generally removes the barrel and re-cuts the chamber..

  • Blake

    They speak as if anyone but Wetherby will ever chamber a rifle in this…

    • Austin

      If it can hold a group of shooters Savage or Remington will probably chamber something in it

      • Blake

        Fair enough; Lipseys does carry a Ruger #1 chambered in 257 Wby mag…

  • DrewN

    This is pretty cool, but my old .264 WinMag has never left me feeling under gunned and the 100 rounds of brass I bought with it have lasted me 25 years. In fact, it was 2 bags of 50 and one has never been opened I’ll bet. You would run into OAL issues with match bullets no doubt, but for hunting it can’t be beat.

    • dave

      25 years? you must be neck sizing to avoid trimming them to pencil nubs.

      • DrewN

        Eh, 5 rounds a year tops goes thru that rifle. 3 at the range and hopefully 2 at most in the field. And I stay away from max loads, since they don’t seem to work any better.

        • Jwedel1231

          5 rounds a year? Why even reload?

          • Austin

            Quality control

          • Bobb

            And why not move to a barrel burner? At a 1,000 round lifetime of the barrel the gun will last 200 years

          • DrewN

            No reason not to if that’s your thing. I usually only have one hunt a year where I feel the need for the .264 over my .260 or 6.5 x 55 which are more compact and lighter.

    • Jwedel1231

      According to the graph, this new cartridge is .264 WinMag +400 fps, or +13%. I would stick with the gun you’ve got.

      • Austin

        As a interesting side note, if my math is right it only has a +27% advantage over 6.5mm CM

        • Jwedel1231

          True, but those are different classes of cartridge. 6.5 CM is a rifle round, 6.5 WbyMag and .264 WinMag are magnums. Substantial increase is to be expected ๐Ÿ™‚

          • Austin

            I just expected the gap to be bigger given the difference in case capacities

  • Vitor Roma

    This got me thinking about a challenge: To hit a target 1 kilometer away with subsonic ammo. Like a ultra high BC 220gr 6.5 at about 310m/s. Considering that a 9mm can technically reach 800 yards, it seems doable.

    • Austin

      How big of a target?

      • Vitor Roma

        Let’s say…24″ in diamter gong.

        • Austin

          And did you want subsonic the whole way or just when it gets there

          • Vitor Roma

            Subsonic the whole way, out of the barrel. That is the challenge. A 300gr 7.62 or 220gr 6.5. Part of the challenge would be to stabilize such bullets. Or maybe some very heavy .45 ou .50 focused on sheer momentum.

          • Austin

            If there was any hard data on the loads 9×39 might be a contender

          • Jwedel1231

            Is there a trajectory minimum? Like can I point my rifle a full 45 degrees from horizontal, or do I need to keep it under 30 degrees?

          • Vitor Roma

            No minimum. Just reach and hit without going faster than 340m/s.

      • DwnRange

        Doesn’t matter how big the target is you won’t be able to see it due to the incline and the fact that the view thru the scope would be obscured by the rifle barrel……..

        • Austin

          High mounted scope on top of a handguard might be logical for once

          • DwnRange

            2021.45 inches of drop, that’s 168.45 feet, (by my calcs, using parameters given and best 6.5 bullet) = never happen.

    • Goody

      I think the square-cubed law applies to BC, meaning an aerodynamic heavy for caliber 45 bullet might be better. I might be wrong on the rule, but plenty have hit targets smaller than barns with a 45-70…

      • Austin

        Or even a .50-90, see Billy Dixon’s shot

    • DW

      You are thinking the way of Russia, comrade. VKS is a subsonic .50 rifle that is rated to have maximum effective range of 600m.

      • Austin

        Or the .500 whisper

  • William M Durham

    Wonder what the recoil is on this beast? If its not too brutal I might get one

    • Goody

      I reckon the 120s would be less than a 30-06.

  • Does anybody remember the 26 Nosler?

    • Austin

      Its on the bar graph

  • Gorilla Biscuit

    Id also like to know if the propellant is proprietary? The E I (extruded impregnated) technology peak burn rate limiting process, or making the time pressure curve longer/wider on the top portion of the combustion process, thus making more velocity. Has really changed specific rifle cartridge/projectile combos. Reloder 17 is a great example with 308 and 200+gr bullets providing 300ish fps more than any legacy powders in the same barrel length. The Swiss (Nitrocheme) are really smart. But we all get to benefit from it. I just want to be able to duplicate the magic from my own loading bench while staying within SAAMI pressures repeatably.

  • Rnasser Rnasser

    By the time your load development is done, you’ll have about 300-400 rounds left of accurate barrel life…

  • smartacus

    how does it compare to .257 Weatherby?