Short fatties vs long slender ones...

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07-03-2021, 12:25 PM
Stocky

Out of pure interest i just ran a 20 inch barreled 7SAUM against a 20 inch barreled 280AI in quickload with capacities being averaged to the same 73Grains and seating depths of the 180 eld m to the same depth to keep useable capacity identical. The results where all the same powders and same loads to reach identical pressures however interestingly the Saum alway leads in velocity at that pressure by 19-20fps. Im guessing this if due to the extra half inch of effective barrel length.
Obviously this isn't a real test but its based on a program based on lots of testing.

The issues (not to discredit it but maybe why they cant be taken as gospel) I see with the 300wsm vs 300H&H test are as follows:
-There is higher case capacity (a few grains) on the 300H&H.
-We dont know what seating depths were and whether they where kept consistent.
- How was the extra barrel added?
- Without seeing the test there appear to be quite a few uncontrolled variables including how to determine actual pressures etc as by feel isn't accurate at all.

I feel there may be an advantage by shorter cases but i imagine its minimal. The consistency of burn leading to a more efficient burn appears to be true so wouldn't a more efficient burn lead to more velocity? Also your half inch shorter the second you drop to a short action anyway so could run a half inch longer barrel for same overall length.

I dont think we will ever see a proper answer but velocity probably shouldn't be the only factor.
07-03-2021, 12:36 PM
grandpamac

Quote:

Originally Posted by Stocky

Out of interest how was barrel added?

Greetings Stocky,
Somehow I managed to get this test scrambled with a previous test comparing the .30-06 and .30-06AI. In this test the barrel section was attached with locating pins and bolts. They also wrapped the join in tape to detect any gas leakage, there was none. I think the extension may have been smooth bored. The idea of the extension was to test 24 and 26 inch barrels. The result of the test showed the extra velocity was minimal, as would be expected for the small capacity increase.
Getting back to the .300 H&H .300 WSM test the same throat was used but the barrel from breech face would have been .75 inches shorter, perhaps a 20 fps velocity difference. Interesting point in John and Charlies limited tests although the H&H showed higher pressure differences on average the ES was largely the same. The accuracy from the H&H was better than the WSM.
Regards Grandpamac.
07-03-2021, 12:52 PM
csmiffy

mmmm 300 H+H
The 308 P14 rechamber project would be a classic in one of these but a Norma/300 win mag probably easier
07-03-2021, 12:54 PM
grandpamac

Quote:

Originally Posted by Micky Duck

so the good old 22hp savage rimmed cartridge would be awesome in a single break open if given a fast twist 224 barrel it wouldnt be giving buggerall away to the modern flash cartridges with similar case size...and be heaps easier to extract....
one day when win lotto....reminds me must get around to buying a ticket one day LOL

Yes Micky quite true. The continentals have been turning out break open rifles in 5.6 x 52R for about a century. They use them for shooting Roe Deer. 5.6 x 52R is just their name for the .22 Savage High Power. Wish I had one too.
Regards Grandpamac.
PS I think that Bergara makes a .223 which should give the same performance but no retro cred.
07-03-2021, 01:00 PM
Micky Duck

Ive thought for awhile now there is LIMITED niche for clever person with lathe to make barrel extensions out of something light,like alloy...say 10" with internal hole of say 10mm and bit threaded to fit barrel with maybe 2" over barrel...so the guy who has chopped barrel to say 16" wants to do tops trip but dont want to carry suppressor...for whatever reason...or going to use mild loads for plinking.....the longer barrel will take muzzle blast away from shooter by enough to make big difference to sound...may even allow more of burn to happen pre new muzzle.....
not a lot more silly than running suppressor and muzzle brake on same rifle....
07-03-2021, 01:00 PM
Stocky

Quote:

Originally Posted by grandpamac

Greetings Stocky,
Somehow I managed to get this test scrambled with a previous test comparing the .30-06 and .30-06AI. In this test the barrel section was attached with locating pins and bolts. They also wrapped the join in tape to detect any gas leakage, there was none. I think the extension may have been smooth bored. The idea of the extension was to test 24 and 26 inch barrels. The result of the test showed the extra velocity was minimal, as would be expected for the small capacity increase.
Getting back to the .300 H&H .300 WSM test the same throat was used but the barrel from breech face would have been .75 inches shorter, perhaps a 20 fps velocity difference. Interesting point in John and Charlies limited tests although the H&H showed higher pressure differences on average the ES was largely the same. The accuracy from the H&H was better than the WSM.
Regards Grandpamac.

Very cool. Some ingenious buggers out there.
07-03-2021, 01:17 PM
Pushover

Quote:

Originally Posted by zimmer

No sure why the writer of the article chose 300 H & H except of course for comparable capacity with the WSM.
THE 300 H & H certainly meets the long and thin criteria but it's design was such to allow early days loading of cordite strands.

I'm picking he had impeccable taste and a yearning for simpler times
07-03-2021, 02:07 PM
grandpamac

Greetings Micky,
While we are waiting for our Lotto winnings to arrive I thought I would do some research. Krieghoff offers something that might suit. The Hubertus model single shot looks nice, only 6.5 pounds and only $US 7,500.00. Should I order two just in case.
Grandpamac.
07-03-2021, 02:34 PM
zimmer

Quote:

Originally Posted by Pushover

I'm picking he had impeccable taste and a yearning for simpler times

Ah, I get it, the good Olde days and nostalgia (usually cockeyed due to brain fade).

I thought it was supposed to be a clinical comparison not an old versus new theme.
07-03-2021, 02:50 PM
grandpamac

Quote:

Originally Posted by csmiffy

mmmm 300 H+H
The 308 P14 rechamber project would be a classic in one of these but a Norma/300 win mag probably easier

Greetings Csmiffy,
A friend lusted after a .300 H&H Mag years ago. Unfortunately no one seemed to have a reamer and he had to settle for a .308 Norma Mag. It had a 1 in 14 inch twist barrel and shot the 130 grain projectiles at a speed I probably should not mention.
Regards Grandpamac.
07-03-2021, 03:05 PM
gonetropo

Quote:

Originally Posted by dvk-kp

Long and thin goes too far in, short and thick does the trick...

long and fat, the wife likes that :P
07-03-2021, 03:07 PM
zimmer

Lifelong 2 firearm lusts - 375 H & H and a 308 Norma Mag.
The NM has faded but the 375 H & H is still strong as ever.
Would be a total waste of time and money though as I no longer tramp the hills.

Sorry OP, getting OT here. (It's an old age thing....)
07-03-2021, 03:08 PM
Mr Browning

Quote:

Originally Posted by dvk-kp

Long and thin goes too far in, short and thick does the trick...

Or,

Long and thin goes all the way in, short and fat, cant do much with that. :thumbsup:
07-03-2021, 03:43 PM
GWH

Quote:

Originally Posted by Stocky

Out of pure interest i just ran a 20 inch barreled 7SAUM against a 20 inch barreled 280AI in quickload with capacities being averaged to the same 73Grains and seating depths of the 180 eld m to the same depth to keep useable capacity identical. The results where all the same powders and same loads to reach identical pressures however interestingly the Saum alway leads in velocity at that pressure by 19-20fps. Im guessing this if due to the extra half inch of effective barrel length.
Obviously this isn't a real test but its based on a program based on lots of testing.

The issues (not to discredit it but maybe why they cant be taken as gospel) I see with the 300wsm vs 300H&H test are as follows:
-There is higher case capacity (a few grains) on the 300H&H.
-We dont know what seating depths were and whether they where kept consistent.
- How was the extra barrel added?
- Without seeing the test there appear to be quite a few uncontrolled variables including how to determine actual pressures etc as by feel isn't accurate at all.

I feel there may be an advantage by shorter cases but i imagine its minimal. The consistency of burn leading to a more efficient burn appears to be true so wouldn't a more efficient burn lead to more velocity? Also your half inch shorter the second you drop to a short action anyway so could run a half inch longer barrel for same overall length.

I dont think we will ever see a proper answer but velocity probably shouldn't be the only factor.

Yes most people dont realise that for the exact same barrel length a saum or wsm type cartridge will have a greater length of rifling compared to a longer case such a a 7RM etc.

This has to give a slight increase in velocity for the powder burnt.
07-03-2021, 03:50 PM
grandpamac

Quote:

Originally Posted by GWH

Yes most people dont realise that for the exact same barrel length a saum or wsm type cartridge will have a greater length of rifling compared to a longer case such a a 7RM etc.

This has to give a slight increase in velocity for the powder burnt.

John Barsness calls the 7mm RSAUM a .280 double improved due to its identical capacity and ballistics. Just don't try and convince a .280 AI fan on this though and especially don't mention a superiority due to the shorter and fatter case.
Grandpamac.

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