Scaling up/down cases

[MFG_BOP]

Hello there.
I was wondering here that a scaled down version of the 6PPC comes close to the 20 VT with .378 head. Just around 0.109" shorter (with some other differences) and it is a very accurate cartridge. If we scale it up, it comes also close to the 300 WSM with .535 head. Again, length and some other differences and accurate as well. I know it is a very simplistic idea (extremely simplistic), but lets suppose we scale them up or down to match the existing case heads so we can have some wildcats to play with. Do you guys think it would be possible to make them shoot accurately? .378 head to shorter ranges and the .535 heads to longer ranges with proper propellants, bullets, case prep and so on?
Sorry guys, I just had a brain fart after a long working day before going to bed.
Cheers

edit: the image is a 3d idea of what I am talking about.

 

[artbosco]

The two most accurate cartridges in the world are the 6PPC and 30BR. The science is already there / has already been worked out. Go back to sleep.

 

[Eddie Harren]

Don't go back to sleep! Keep forging ahead.


And before that it was the 222 Rem and different variants thereof. Staying "stagnant" is not the way of the true benchrester. If so we would not have the PPCs and the 30BR. I'm sure glad Msrs. Pindell, Doc Palmisano and Robinett didn't think like you. I, personally am waiting to see what is next.

 

[dkhunt14]

I don't exactly see the PPC or 30 BR winning any 600 or 1000 yard shoots. So how can you call them the worlds most accurate cartridge. Yes they might be forgiving and win a lot of 100 yard Br shoots but that is not all the shooting people do. I also saw a few Dashers and 6 BR's that would hang with a PPC especially at 200 yards when windy. Matt

 

[spclark]

Scaling works for cartridge cases as well as for bullet shapes! The predictability associated with those operations is pretty well established, it's with case manufacturers that things tend to get bogged down. Unless there's already a parent case easily available a wildcatter can work with to develop a new case profile from, it's an expensive proposition well beyond the resources of most of us.

6PPC is a good example having started life as the 220 Russian. 6HAGAR is another more recent, or the 6.5 Grendel that was developed off the 6PPC. Add the 6Dasher or 6BRX, both based off the established 6BR & better capable of reaching out farther than the smaller volumed cases.

One has only to compare the 223 REM, 308 WIN & 50 BMG cartridge silhouettes to get a good impression of just how well accurate case shapes can be scaled up and down and stay accurate.

 

[357Mag]

MFG -

Gidday on ya !

While I do agree w/ your basic premise, I look @ it more from an " expansion ratio " and case capacity points of reference.

A " BR-sized " case capacity is not the best choice for all calibres.
Scaling-up the case dimensions is a vehicle towards adjusting the final case's capacity.

Wildcat experimentation:
If you have a good idea of the case capacity that would address your shooting need(s), then.....
you can see what " parent brass " has things like a base diameter and perhaps rim diam you
could work with.

When using the scale-up method during wildcat design, one can and will encounter gaps in the parent case line-up; where no existing ( common ) case will feature very case diameters you seek.

Go find 'em.


With regards,
357Mag

 

[357Mag]

MFG -

Please check your PM's.


With regards,
357Mag

 

[mikecr]

You can 'scale' cartridges up & down, but results do not follow. It just isn't that simple.
Scale applies to more than dimensions on paper.
Different bullets, powder, and capacities change the whole ball game, not just with the cartridge but the shooting system in it's entirety.

There was someone on another forum asking if he could scale up a 6PPC/30br for 1kyd shooting. Well he could, maybe(although a 300WSM is nothing like a 30br), but it couldn't be loaded like and therefore couldn't shoot like a 6PPC/30br at any distance.

Everything in ballistics begins with a bullet. Start there, build from there, and see viable for yourself.

 

[BCoates]

I agree with the statement above. Accuracy has much to do with the bullet, then the barrel. Look at results from recent IBS or NBRSA matches. You will see aggs for 100 yds = 0.170s", 200 yds= 0.205 MOA, 600 yds = 0.272 MOA, and 1,000 yds = 0.4 MOA. The short range is probably 6 PPCs. The 600 and 1,000 yd matches were won by 6 Dashers with 300 WSMs close behind (and better in the wind). Almost all of the winners are shooting custom (boutique) bullets or Bergers that have been sorted, trimmed, and pointed. They also put significantly more time into case prep vs. other long range shooting sports.

I believe some cartridges are inherently accurate; however, the cartridges that are the most accurate are because people built bullets, brass, and chambering reamers to maximize the accuracy.

 

[dkhunt14]

The 308 Baer, 6.5-284, 300 Weatherby and the 30-378 have all but disappeared in the 1000 yard BR game. The 6 Dasher and 300 WSM pretty much dominate the line. They are the right capacity and are efficient. The Williamsport 1000 yard club has been shooting since 1968 and has had a lot of shooters over the years. Some of these guys spent money hand over foot and had the best barrels bullets and everything else available. They had custom bullets for a very long time. JLK, Cartiruchio and others have been making custom bullets for a long time. Some of them even made their own. The biggest thing is the 300 WSM is just easy to tune and doesn't change from day to day like some do. The Dasher is the same way. They are a case full of powder and give you the velocity to be in a range where the bullets perform. Matt

 

[BradY]

Would like to know if there is a "magic formula" in working out the right case capacity? Or were the 6PPC, 6 dasher and 300WSM the result of many people just trying to modify things so they would work or if they were just plain lucky when they came across it.

 

[dkhunt14]

I believe the 6PPC and dasher came about by trying to modify to make better. I believe that when Winchester made the 300 WSM they just wanted Magnum velocities in a short action. I don't believe they any idea it would at 1000 yards the way it did. I believe it was more of a luck thing, Many guys have tried to make the 6.5 and 7MM short mag work and they just weren't competitive. The one guy got the 6.5 to compete but he shortened it twice before it worked. He told me he thought it needed shortened one more time to be good. Matt

 

[Raythemanroe]

I'm new to this game and a wildcatter I am not. I have noticed the Dasher (which has multiple reasons it performs well) 300wsm and 30 br's and 6br's along with the PPC have in common, They have short fat cases in comparison to it's overall stature. They eat up intermediate powders and are efficient powder burners.. In my opinion the OP is on to something because I believe the WSM is a scaled up version of the short fat cases used before in BR.. Someone should try that with the .50 BMG, Fatten and shorten up the case and make it a more efficient cartridge or the 338 Lapua..


Ray

 

[MFG_BOP]

Thanks for the reply guys. I really like the idea of modifying existing brass to make them shoot better.
I did some work on a 20VT http://www.nzhuntingandshooting.co.nz/f53/forming-221-fireball-20-vartarg-brass-14410/ if you guys are interested in taking a look.
As I said, it was a very simplistic idea, so, again, thanks for the answers.
Cheers

 

[mikecr]

Would like to know if there is a "magic formula" in working out the right case capacity?

There is no formula or rule of thumb.

Point blank BR would settle into something out of pure probability. It happened to be 6PPC, as this is the right capacity for filling powders similar to N133, with light bullets & slow twist short barrels.
6Dasher is a good all around design. Can't think of anything but good about it.
The WSM case is a better design than any other factory 30cal cases I'm aware of, and given success of 30cal bullets, it doesn't surprise me that a WSM case would be popular.

There are enough capacities in each cal to spot highest efficiency among them -for purpose. From there many wildcatters know just what to do. This is 6Dasher.
There is also plenty of evidence as to bad capacities in cal, like a 260, which should be improved to viable ~3000fps w/140gr bullets. This is 260AI.
Bunch of folks working on 28cal wildcats. One of these could be special.

 

[Toolbreaker]

Someone should try that with the .50 BMG, Fatten and shorten up the case and make it a more efficient cartridge or the 338 Lapua..


Ray

It's been tried with a .50, but I don't know how much it's been pursued...

http://www.6mmbr.com/compcartridges.html

Scroll down about 3/4 of the page to the picture of the 50 Bat & the 50 Fat Mac.

 

[MFG_BOP]

I would like just to make a correction here. The cartridge that approaches more to a 6ppc with .535 head is the 300 SAUM and not the 300 WSM. Sorry guys! Correct if I am still wrong. ;D
357MAG, your email has returned.
Cheers

 

[dkhunt14]

I really think the 300 WSM is the best case for the 30 caliber. It is about the right capacity and really accurate. Now for the 7MM it is a little too big and the SAUM case works better. Matt

 

[savagedasher]

I like the design of the WSSM. The reason I stop using it was the brass. Larry

 

[mikecr]

I like the design of the WSSM. The reason I stop using it was the brass.

If you couldn't work with Win reloading brass for WSSM, you let the cartridge down.
I couldn't be happier with my 26WSSM cases from 25WSSM reloading brass. It's as good as any brass in existence.