Home Forums Hunting & Shooting Hunting Rifles The "best" 7mm magnum

My 7 weatherby never fails to impress..Lots of guys go outta their way to match what it does.

Dogshooter-

What's wrong with 65k pressure in a MODERN rifle?

We get good case life (with quality brass), no sticky bolt lift, tight primer pockets and 7 Mag vel? Never made sense to me to be happy w/280 vel.
Might as well get a 280!

What's to run from ??

I only own one 7mm mag and I waited along time before deciding to buy one. When I finally found the one that "talked to me" . . . turns out it was a SAKO AIII Finnbear Deluxe.

I have a 7 WSM shooting 160gr factory Winchester Accubonds as well as 140gr loaded Barnes T-TSX. The have been great from an accuracy, trajectory, killing performance, etc. standpoint. I am probably just biased. It has done well from whitetail to elk for me.

No personal experience with it, but I sure like the looks of the 7 Dakota.

With brass at $2 a pop, I'll probably never buy one, but I REALLY do want one.

Anybody running one?

My thoughts as well. If we were starting at square one and no rounds existed I think the Dakota line-up would be the end all.

It's a great cartridge,and from a standpoint of capacity and actual velocity delivered,it "performs".From that standpoint I consider it one of the two "best". I spent a lot of money to build one and find out how good it was.

But eventually the luster wore off.The brass is nice, but I got intermitent but repeated longitudinal cracks at the shoulder/neck junction on the second firing,despite using good dies and watching headspace...at $2 a pop, that shouldn't happen.Never seen that with WW brass of any sort.

Because of the head size, you can't form it from any other brass. Don Allen designed it that way,without a rebated rim, to avoid function problems in the CRF Dakota 76.And the same head size problem precludes rebarreling the rifle to anything else if you change your mind down the road.Plus, the cartridge holds no advantage over a wildcat from the standpoint of available factory ammo....lose your ammo in Canada or Alaska and you are just as screwed as you would be with a wildcat......Scratch the Dakota from my list.

Personally I could never wrap my head around how the 7 Weatherby gets its velocity....just hold it side by side with a 7 Rem mag and its apparent it is no larger,and holds no more powder, yet loads are faster and it takes larger powder charges.Building several long throated 7 rem mags had me nudging 7mm Weatherby data and velocities from 24" barrels.I could only conclude the cartridge gets its velocity from a combination of high pressures,26" barrels,and the Weatherby free bore.A custom barrel might or might not show those big velocity gains,as Bob Hagel proved working with the 7mm Weatherby.

To me a 7mm magnum is about 160 gr bullets at 3150-3200 fps,and a 175 gr bullet at over 3000 to 3100 fps from a 24" barrel.Once you get those velocities, lighter bullets are a moot point(yes I know they work).I don't want to lean as hard as possible to get those velocities,and I sure don't want a factory cartridge loaded to 65,000 psi to get it...you are operating on the ragged edge for reliable function IMO and I have seen the bolts of factory 7mm WSM's frozen from factory ammo that is too hot,give sticky extraction.Its' a good cartridge just not my cup of tea.I'm not into seeing how much velocity I can squeeze from small cases.

The only cartridges I'd trust to deliver those velocities, repeatedly and reliably, are the STW, the Dakota, and the Mashburn.The 7 Rem Mag will not do it,but is off by only 100-150 or so fps...brass is easily available and good factory ammo is everywhere, maybe not loaded to the same velocities, but this alone will save a hunt if you lose your ammo.


Over all the best 7mm magnums? Out of those I've worked with personally,the 7mm Mashburn Super followed very closely by the 7mm Rem Mag.

Bob HAGEL -- is my HERO

Honestly I've never had any problem using his procedures of load development.

I have seen L-L variation BUMP pressures to 2 blown primers (H450) & slight bolt stick.

That tells me I WAS at the limit for those powders & I BACKED down.

The Rem 7 Mags are the only 7s I've worked with & I feel it ( Rem 7) performs plenty GOOD NUFF for me. If I want more PUNCH I have an 8 Rem Mag.

1. 7mm Weatherby
2. 7mm Mashburn
3. 7x61 S7H
4. 7mm Rem Mag.
This in no way indicates which cartridge is really the "best". It's just a list of my own preferences. I rate the Remington at the bottom mostly because of the short neck compared to the others. The 7x61 won't perform with the others but it's just a nice cartridge which fits standard actions real well. GD

Bob, are you familiar with the Jarrett 284 mag ? If so, what are the differences between that and the Mashburn as it appears to be close to the same. Always thought that the 300 WM case was the perfect candidate to neck down due to it's capacity and length for most long action bolt rifles. Seems like most cases bigger only get small increases in velocity relative to the increased amounts of powder needed.

RD you nailed it on both counts....Never had the Jarrett but it is nothing more than a modern rendition of the Mashburn.Same/same from what I recall looking into the cartridge a year or so ago.And it seems your analysis of the bigger jugged 7's is correct as well...depending how thin we want to slice the pie.

Years back Bob Hagel did an article on work he did with the 7mm/300 Weatherby(really just an STW)and concluded it held an advantage over the 7mm Mashburn only with the 175 gr bullet and even then it was not great.

Also keep in mind that Art Mashburn developed a cartridge similar to the 7STW but the Super was the more "efficient" and the one that we know today.Layne Simpson was by no means the first guy to use a 7mm on the full length H&H case;many preceeded him but he popularized it.

Study some of the Nosler Manual data seems to corroborate what Hagel said....and the thing that becomes apparent is that the STW and the Mashburn are virtually identical with 175 gr bullets if barrellengths are the same...even the powder charges are close.The 7RUM is about 100 fps faster than either with the 175 gr but you have to burn 10-20 gr more powder to get it there...and these numbers are for 26" barels in both the STW and the RUM.

Four Mashburns that I know of(Dobers, mine, my friends,and another fellow from Texas)all do 3040 to 3090 with 24" tubes and 175 gr bullets.

I think in my case,the fact that I load to a 3.5+" OAL,rifle throated for that,brings my useable capacity up to about the same as an STW with its' longer case, but deeper bullet seating.I don't know whether this makes it more efficient than the bigger case or not,but it works and my powder charges are in the 73-74 gr range for those velocities.

I'll take the lesser velocity from the Mashburn,and the 24" barrel, instead of 26" and the extra 10-20 gr of powder for the RUM any day. Somethng along he lines of the 300Win Mag case may indeed hit the real sweet spot for a 7mm magnum with heavy bullets.Far as I know,the Mashburn and the 300 Win mag are the only two cartridges to have that case length.

The best one is the one is one I just had built. M-70 classic action- blueprinted with a Hart 1-9 lightweight barrel bedded in a McMillan edge stock. Haven't shot it yet, but its at home waiting for me.
Haven't figured out the scope for it yet though.

rgr: That sounds nice!

Used a 7 Rem Mag for years. Shot a truck load of game with it up to and including elk. Been playing with a couple 7 STWs over the last few years and have been much impressed in not only accuracy but performance on game. It really shines with the 160s. It is now my go to long range deer rifle. 163bc

The one for which ammunition is available almost anywhere...presuming of course we're talking about real hunting rifles, ones that go on hunting trips.

I like the shape of the 7mm Wby Magnum better, the Mashburn the same, but the 7mm Rem Magnum wins for me.

Bob.... I'm not sure about the actual Mash. Sup. case.... but the STW is larger in case capacity than the .300Win (6.03cc vs. 5.62cc). In fact, the STW is .4cc larger than the .300 win..... the .300 Win is .35cc larger than a 7 Remmie case.....

That would lead one to believe that the STW should be equally better to the Mash.... than the Mash is to the 7RM. Now, we all know it don't work out that way in the real world.... but I'm wondering why the jump from 5.3cc capacity to 5.6cc provides a 100-200 fps jump..... but going from 5.6cc to 6cc.... doesn't get you anything?

The above line of reasoning is getting a little .280AI here..... and that ain't a good thing. I know.... this is actual data.... and it's hard to argue. But to be frank, Bob, you've called out quite a few guys on their Ackleys and loads lately..... stating, and I quote: "there is no case design, only capacity and pressure"..... how is that working out with the STW/Mash?

I am just wondering here Bob.... that's all.....

7mm WSM

Forgot to mention it's a 7mm Rem mag with a 24" barrel. I plan on NECG sights to finish it off.

dogshooter, talk about rifles and cartridges long enough and eventually you bump into yourself....especially when things get closely matched.

But I'm not talking about the difference of 150-200 fps in this instance....I'm talking about two cartridges being very closely matched,and a manual showing very little difference with 175 gr bullets in the STW vs a lot of istoric data from the past,and what a few of us today are experiencing.....And I am not prepared to tell anyone what pressures are being run in either case.

I am only reporting what the manuals are showing,what others have done and reported (Hagel with the 7mm/300 Weatherby. That article is back there somewhere in Rifle or Handloader and I am working from memory), and we can see for ouselves what happens.I really an't say why Hagel found what he did back then, but my memory on it is pretty clear.

In pure terms the STW should be faster because it holds more powder,and maybe it is in longer barrels....why it does what it does I have no idea.Maybe the fact that the STW is a bigger case but you have to seat bullets deeper due to magazine constraints, has something to do with it? I don't know.....

And of course we really don't know what pressures are actually being run when we see these results.

Here's an example....back in the 80's I had a 300 Weatherby and a 300 Win Mag throated "long". Both had 24" barrels,and both built on M70 H&H length actions.What I found was that the 300WM was so close to the Weatherby with 180's that there really was no difference.The Weatherby did around 3150 with a 180 gr bullet,and the 300 WM did about 3125...they were seperated by about 30-40 fps or so....BUT,later work with other 300 Weatherby's with 26" barrels showed the cartridge to have a significant edge and it was not unusual to see the 300 Weatherby kick up its heels and leave the 300 Win Mag in the dust with a 26" barrel.

Since I have not done as much work with the STW,I really can't say.Might be worth reading back on what Hagel had to say about it;what Art Mashburn discovered himself with the full length cartridge,, and what the Nosler manual shows us with the 7mm Weatherby, the STW,and the 7mmRUM...I think we know enough about the Mashburn at this point to know it is capable of getting over 3000 fps with a 175,and being right in the middle of that group somewhere....same with the STW.

Also remember that Art Mashburn felt the middle cartridge(Super) struck the best "balance"...maybe he got more velocity from the longer case, but felt the two were so close that the extra powder in the full length case was not worth the trouble.

How much more is the STW capable of in absolute terms over the intermediate length Super??

I don't know.

Hell man.... I don't know either. I suppose with any bore size there truly is a correct maximum relationship betwixt bore and case.... once you get past there.... it takes a lot of boom to make things move a little quicker. IME, once you get past RM/Roy capacity (as they are equal).... the noise and recoil seem to go up disproportionately to the increased performance. I know I notice it even when leaning on heavy pills in the 7RM. Everyone is willing to tolerate different levels of recoil/report/efficiency.... I recon that's why we have a veritable cornucopia of 7mm 'magnums'....

I do see the Mash as a great platform for 180 Bergers at 3100ish... quality .300 Winny brass is plentiful and the extra boom-room would come in handy trying to launch those t-posts over 3k. I have a Sendero Special (remember those?) in 7mm Rem Mag en-route.... thinking a Mash punch would give it a little more attitude... and the extra 2lbs would absorb the additional punishment..... hmmmmm....