A " new" 30 Cal

[Newton]

Greetings all and a peaceful and prosperous new year
After some experimentation , some machining , and modifications
What I thought the 300 Win Mag should have been
See images attached
I understand that this might not be anyone else's cup of tea but it is what appealed to me

Some rationale ...
Headstamp is the same as on license - hole in the barrel is the same
NO BELT = easier reloading
Shorter case with COAL to fit long bullets in standard size action ( HOWA )
Without bullet being pushed deeply into powder in case
Longer neck for more bullet stability
Most important of all the re-worked case appeals to me !

A template of the proposed cartridge was drawn up using QuickDESIGN
A simulation was done using QuickLOAD which showed performance close to the original
then
A standard LEE FL die was machined and modified ( a few trines )
It is now to all intents and purposes accurate as to the template diagram
A few sacrificial cases had their belts removed and were then processed - to end up with the final product
Bearing some resemblance to a .30 Newton and a Schuler 8x68
Re-sizing was done on a LEE challenger press ( which coped fine )
A LEE universal de-prime die was used
A 30-06 collet neck size die works fine for neck-sizing
An RCBS seater die was used for seating the bullet ( Berger 175 VLD )
Still some final fine detailed work to do ( accurate neck dimensions )
then
The purchase of a chamber reamer to make up / modify a barrel and test firing
Hoping to get that done this year
I am quite excited

[Againstthegrains]

I thought the 300 Win Mag that should have been was called a 300WSM

[Newton]

I thought the 300 Win Mag that should have been was called a 300WSM

Yes - they took away the belt - a marketing anachronism
Then they made it fit in a - short action , another market driven design change

I do however believe that there is some difficulty in finding brass for the 300WSM ?
Whereas brass for the 300WM is very plentiful
Personally I do not like short dumpy fat arse cartridges
Why do I see so many people battling to feed and chamber the 6mm Dasher ?
I like my cartridges classical - svelte and in proportion - like my woman

I will be doing something similar for the 7mm Rem mag and the 8mm Rem Mag - ALL based off the same 300 / 375 H&H the father of all medium calibre belted magnums
Perhaps the 338 Win Mag as well ?

[Ds J]

Do I get this right?

Take a 300WM case, cut away the belt, shorten the neck, blow out the case to almost AI dimensions?

Then take a 300WM barrel, shorten the chamber, and voila?

[Newton]

Do I get this right?

Take a 300WM case, cut away the belt, shorten the neck, blow out the case to almost AI dimensions?

Then take a 300WM barrel, shorten the chamber, and voila?

Lengthen the neck - shorten the case COAL
Otherwise correct
A standard 300WM barrel will need to be set back a bit and re-chambered ( slightly )
Optimum bullets will depend on the original barrel twist rate ( apparently somewhere around 1/10 is good ? )
As far as I can see no change to the bolt face
Still working out the dimensions for the - throat / leade / freebore / lands etc ( need expert input here )
Will be a slightly longer throat for long VLD / monolithic type bullets

At least that is the intention
The proof will be in the firing ( the simulations are good )
Not looking for anything more than a good accurate easy to reload lower recoil everyday use cartridge

[Againstthegrains]

What twist rate are you going for?

1:10 for hunting or 1:7 for shooting high BC target bullets?

[Ds J]

Which speeds do you want to obtain, with which bullets?

[Newton]

What twist rate are you going for?

1:10 for hunting or 1:7 for shooting high BC target bullets?

Not sure yet
Perhaps similar to the 300 PRC ?
1:9 ?
Going to use existing barrel to test before deciding on final new barrel
Still LOTS of work

[Newton]

Which speeds do you want to obtain, with which bullets?

Simulations indicate somewhere near 3,000fps with a 175 / 180 gr 61,000 psi with @ 65,000psi max pressure
All depends on what powders and bullets are available here
Still LOTS of work and testing

[Newton]

This is a quickly put together QuickLOAD simulation
Image of a screenshot from QL



As a comparison and check

Load data from the online calculator at Hodgdon

300 WM load data

As can be seen the results are very close - with a little less powder
It appears that with nearly all the Magnums the best loads are at or near max

[Newton]

A favour ...

I am trying to find out what the maxCOAL of the HOWA standard length action is on their 300 WM is ?

Anyone with a HOWA in 300 WM that can check and measure what the longest cartridge is that they can fit in the INTERNAL box magazine ( and feed reliably )

HOWA produce a 300PRC in "standard length action" with a 26" varmint barrel
However the COAL of the 300PRC is in the region of 90mm - much beyond the 300WM

HOW is this done ?
Is the 300PRC a completely new action?
or
Is a little machining involved in order to provide the extra space ?

Anyone know ? ( any gunsmiths out there )
Anyone has one and can check

[Treeman]

From what I could find and this is not my "know" only my Google.
Long/standard length actions accept cartridges that are over 2.8 inches in length but under 3.34 inches. The 30-06 and 270 Winchester are popular long action cartridges. Short actions accept cartridges that are under 2.8 inches in length and generally any cartridge over about 2.3 inches.16 Mar 2023

You need a CIP Mag and action.

Dunno if this helps.

[Newton]

Thanks Treeman

My digging around

300 Win OAL (case head to bullet tip) = 3.690? = 93.726
30 Nos OAL (case head to bullet tip) =  3.595? = 91.313

The Howa / Vanguard and traditional Sako (e.g Finnbear) magazine is 91mm or 3.543"

HOWA produce a 300 PRC on their standard action so in that case COAL must be whatever SAAMI is = 93.98

So it appears some modification on the 300PRC action ?

We really need someone to do an actual proper hands on measurement ( surely gunsmiths do this ? )

It will mean I can extend MY COAL from 87mm to something longer - helps with getting longer bullets up out of the powder
Easy enough to have a long throated reamer but not if you are restricted by magazine length ( COAL )

[Againstthegrains]

How does this differ from a 300 Norma Magnum, other than the fact that the 300WM brass used to modify, is easy to obtain?

[Newton]

How does this differ from a 300 Norma Magnum, other than the fact that the 300WM brass used to modify, is easy to obtain?

300 Norma Magnum very different cartridge based on the 338 Norma Magnum - based on the 416 Rigby ( also parent case for the 338 Lapua Magnum )

Perhaps you mean the 308 Norma Magnum ?

308 Norma Magnum

Which is based off the same parent case as the 300WM and came out earlier

This The 300 Norma magnum history and performance should answer some of the questions.

My cartridge is somewhere between the 300WM and the 308 Norma Magnum