do the following figures seem realisticly achievable?:
.30/6.5mmRM 200gn@2700fps
.338/350RM 230gnFailsafe @2600fps
.375/350RM 270gn Failsafe @2400fps

I don't think the 6.5 necked up to 30 would be able to push a 200 2700, more like a 180 gr that speed. Case capacity will be about identicle to the 30-06. I'd opt for the 300 WSM over a 2" belted 30.

The 350 rem mag pushes 225's ~2700, so assuming you loose 100 fps when necking down to 33, you should be able to push 230's around 2600.

The 350 rem mag pushes 250's 2500, so assuming you can either get more speed for the same weight, or more weight at the same speed when necking up, I'd think 270 @ 2400 would be reasonable. I would however likely go with a 260 gr Nosler partition at your more sedate velocities in the .375-350 mag.

Look for data for the same bullet diameters using the 30/06 case as the case capacities are virtually identical,

what DB Bill said.. it's the original short and squat case!!

jeffe

Given that the 6.5mmRm is like an improved version of a 6.5/284 case,(and that we can already achieve 2950fps with 140gn in the 6.5mmRm. Hodgson book I believe)if we were to neck it up to 7mm or .30cal then could we reasonably add say 75-100fps for the improved feature and 75-100fps for the cal. increase for the same weight projectile. would that not sensibly give us 2950-3000fps for a 160gn/7mm-165gn/.308cal bullet?

Woodjack,
HUH?

You do understand that
1: the 350 rem mag is a far smaller case than the 7 rem mag, right?
2: 160gr 7mm going your project 2950-3000fps is a TOP load for the 7 rem mag
3: getting a 160gr 7mm at 2950fps from a 350 rem necked to 7 would be a SERIOUSLY dangerous pressure, that could result in body injury

... let's assume a 284 and a 350 remmag case...

Measure the remmag ON the case wall, just above the belt.. and then do the same with the 284...

the 284 has the 404 jeffery as a parent case (same as wsm/rum) and was designed to have about the same case capacity as a 30-06

the 350 rem mag was design to be a 35 whelen in a short action, nothing more or less. Necked to 30 cal, it's nearly also exactly the same case capacity as the 3006 (it's the same as the 35 whelen in it's normal format)

let's walk through this, please
1: 284 and 280 rem have the same case capacity.
common ground, 280 is based from the 30-06

2: 350 rem mag and 35 whelen have the same case capacity. common ground, 35 is based from the 30-06


Therefore.. ANY thing that you neck the 350 remmag to will be exactly the same as a 3006 necked to the same caliber, or a 284 done the same.

there is NO increased velocity, especially not 75-100 fps in an already high pressure load, that can be done safely.

can a 30-06 get 165gr bullet to 3000 fps?

jeffe

If you really want to do strange things on another case and go "absolutely wildcat" consider the 376 Steyr case. It has the capacity to get where you want to go.

Jeff,

Actually the 284 win is a slightly smaller case than a beltless 6.5 rem mag, as I recall it measures .500" at the head vs .510" at the head for a beltless H&H case.

If one wants 165's @ 3000 fps from a 30 cal, the 300 WSM is the answer for a short action.

Jeffosso,
something does not sound right in your post.
If as you say that the 284 is same capacity as 280, then what does that tell us about the 6.5mmRm case when its length is the same as the 284 but has a .010" wider base and .020" wider shoulder Dia. So it is more or less an improved version 6.5/284 or.284win in capacity right?
I hear people telling us on this forum that they are getting 2850-2875 with 160gn in their 284win and 280s. Now given that the 7mm/6.5mmRm is an improved version of that .284 case(same length,but .010" wider head dia. and .020"wider shoulder dia.) Does not that extra capacity offer us more?? So if typically we get 75-100fps increase when we Ackley something on a 280 capcity case, does that not give us 160gn.2925-2950pfs on a 7mm/6.5mmRm. Maybe more.(3000fps)on a 165gn .30cal/6.5mmRm. Given that we run them all about the same pressure? this is also taking account that we get an increase in velocity for a given bullet weight if we go up in calibre as in the case of the .308/6.5mmRm

Woodjack.

This might come over a little funny.
Biggest difference is PRESSURE in like cases, not capacity

Ya'll tell me... it's not exact spot the same, but the differences are trivial... in fact, i've found some cases to be greater and lesser capacity, and all of them overlap ( for example, 300 win brass can br from 89 to 93gr, depending on maker)

there's no apreciable difference from the x284, x06, and x350 rem mag cases. Especially not enough to justify 400 bucks in custom reamers and dies.

here's the case capacities of the stuff i have in quickload based off the 284, 30-06, and 350 rem mag.

25/284 65gr, 25-06 66gr, ave 65.5

6.5x284 norma 66gr, 6.5-06 66gr, 6.5rem mag 68gr, ave 66.67

284 66gr, 280 67.50 ave 66.75

30/284 - 67gr , 30-06 68gr 30x350rem 72 ave 69

35x284 68gr, 35 whelen, 70.5gr, 350 rem 72gr ave ~70.15

To compare with the WSM cases (either wsm or jamison data will be used, which ever i have)
25 81gr (j)
6.5 81 (j)
280 81 (j)
30 80(w)
35 84gr (j)


The differences you are discussing on brass are mostly within the SOLID parts of the brass, not the capacity parts. Belted brass is heavily constructed. ..

As for an improved version... well let's take a look at the BEST of all the improved rounds, and see the change in capacity
257 roberts 59.5gr
257 roberts ACK 63gr

and now you might want to point out what a "huge" difference those 4 grains make. They DO, but the 20% increase in pressure makes MORE of a difference.

For example - load them both to the same pressure 48k then 58k with 24" barrel, 120gr nos part.
257 rob. ~2870 ~3000
Imp ~2930 ~3070

Then take the SAME thing with the 25-06 (66gr)
25-06 ~2920, ~3075

280 rem (67.5g h20) vs 280 ackley (74gr)
58k psi
160 gr nos part
24" barrel

280 - ~2850
280 ack ~2920

at exactly the same pressure.

+70 FPS..
VERY nearly 10fps per grain h20.

more speed then equals more pressure. Since i can't control what pressure others load to, i can't tell you what safety factors they are using. if you picked up another 80fps on this, you are in a red zone for danger/

jeffe

Jeffosso,

going on what you have said,would you say that the idea of a 9.3x68s Improved (as posted earlier) would barely be any different to a 9.3x64 brenneke, because the 68s brass is thicker?

Woodjack,
that's not really what I said...
the 284 and 6.5rem are about the same INTERNAL volume, which defines case capacity.

the 68, if it has the same INTERNAL diminsions, except longer, would have a greater capacity.

tell ya what, get a 284 case and a 6.5 rem case, and weigh the water capacity.. and a 280 rem...

then weigh a 7 rem mag...

aebe, the larger capacity, with the same pressure, results in a faster bullet.

this is why a 7x57 is slower than a 280 or 284, or 7x6.5rem, which is slower than a 7 rem mag, all loaded to the same pressure.

the simple fact is that a grain or 3 of water can be within the various factory brass of these rounds... and the loads are taylored for them.

the 350 rem mag was designed to be a 35 whelen in a short action.

there's only TWO ways to get there correctly
lower pressure in a bigger case
same pressure in the same size case.

think of it as pints... pints come in all shapes and sizes, but the weight (in water) is always 16 oz of water.

jeffe

Jeffe and Woodjack,

I may be able to add a little bit of info. I have a 338-350 Rem mag. I just finished measuring and comparing some case capacities. All were measured in fired/not resized RP cases. Cases were filled to the top of the neck with H2O.

Std 338-06 70.3 gr.
338-06 AI 72.8 gr.
338-350 72.6 gr.

I am just starting to work up loads for the 338-350 but so far I have topped out at about 2700 fps with 225 gr. bullets.

Tim

Forgot to add that I saw about 75 to 100 fps gain for the 338-06 AI over the std 338-06.

I thought that short fat cases that have equal capacity to longer thin cases perform better because they are more efficient. Isn't that what the advertising for the short magnums say? They claim less recoil too. At the very least, if two cartridges share the same powder capacity, say one a half inch shorter than the other, all other things being equal (such as barrel length) then the shorter cartridge should have a slight edge because its barrel is effectively a half inch longer.Isn't that the case?

If you want less recoil either use less powder, have a lighter bullet, or a heavier gun. An 8# gun shooting a 140g bullet at 2700 fps will have more or less recoil solely based on how much powder it is ejecting. Nothing else. If the short rounds are more efficient, and can safely reach X fps with less powder then there will be less recoil. Bear in mind, the WSM's are pretty high-pressure rounds. And TINSTAAFL. Bolt thrust rises with casehead size. Efficiency is a very loaded term at best.
How's this for a 6.5 Rem wildcat:
H&H case cut to 2.33" and necked to .264", COL of 3.1" and blown out like a trailer park pimp.
140g at 2900-2950fps from a 24" bbl.
Caes are everywhere, chambering is simple.

quote:

Originally posted by 1Ruger3:
I thought that short fat cases that have equal capacity to longer thin cases perform better because they are more efficient. Isn't that what the advertising for the short magnums say? They claim less recoil too. At the very least, if two cartridges share the same powder capacity, say one a half inch shorter than the other, all other things being equal (such as barrel length) then the shorter cartridge should have a slight edge because its barrel is effectively a half inch longer.Isn't that the case?

Don't ever believe advertising claims! Despite all the hype, the new short mags, that have less case capacity than the existing mags, don't match the performance of the old mags! Let's look at the most popular of the short mags, the 300 WSM. In the real world, it falls between the 30-06 and 300 win mag in performance. As far as less recoil, yes burning slightly less powder and getting slightly less velocity will produce less recoil, but, the short mags are typically built in lighter guns, so the recoil will be the same if not more.

In a 20" or longer rifle barrel, velocity gain/loss is approximately 30 fps/inch, so having a 1/2" longer barrel gains a wopping 15 fps!

Hey Paul,
we both shoot 500 jeffe'ry right?
the original short/fat case...

other than the 577/450, i think that's the oldest short fat case!!!
jeffe

Yep, I too have a 500J. I gueess in relation to the over 3" NE rounds it's short, and no doubt it is fat.

So have you ever loaded it up to see what it's potential is with modern powders? Mines still in it's temporary stock and I haven't put the barrel recoil lug on it, so I've refrained from any more full power loads. I also need to make the magazine and work the feed rails. 600's @ 2200 were suprisingly shootable, but I'm thinking if I get 2400 or more it would be a different deal.

I'd still like to take a moose with the 570 gr X @ 2400 fps, thus answering my long held question about moose not reacting to being shot.

Paul
with deiter's brass, ANYTHING that a 510wells or 500 asquare can do, ours can do at lower pressure.. the case is just that much bigger!!

jeffe

Page 475, "Cartridges of the World" 10th edition.states that,
Gun writer Nick Harvey necked up the 6.5mmRm to 7mm (7mm HarveyMagnum)and achieved 2995fps/ 160gn with top loads.
Go to 30cal and 165gn3000fps and all should be fine and safe.

I have a McGowan XX CM barrel in 7mm/6.5 RM that I put on a Mauser 20 + years ago. It shot the 140s at about 3075 or so and very accurate. It was just another "project" that was abandoned along the way. I have the barrel [threaded for Lg ring 98 and chambered] and loading dies for sale for 110.00 if anyone is interested.
Aloha, Mark

I've been using a .30x6.5 RM on a 600 Rem for about 4 years now. I use .30-06 load data and with the 18.5" barrel it give me velocities comperable to a .308 with a 22' barrel. A handy little rifle to carry and not bad at all to shoot. Accuracy is about 1" to 1.25".