Velocity Loss With Shorter Barrels

[John18]

My .458 Lott has a 22” barrel. I get 2300 fps with federal factory ammo topped with 500 gr TBBC bullets. I have checked this with 2 different chronographs.

My .375 H&H has a 21” bbl. If you are interested I can dig out the chrono results but I can assure you that any velocity loss was insignificant for shots at Reasonable hunting distances.

I am interested in the chrono results for the 375 if you can find them

 

[Bob Nelson 35Whelen]

Wow! That’s almost no velocity loss! But I would have kept the barrel at 24”. I personally like longer barrels. Better sight plane? I also like 28” vs 26” barreled shotguns. Just personal preference?

CoElkHunter
At my age with my eyes sight plane isn't an issue as all my rifles are scoped
Cheers mate Bob

 

[Bob Nelson 35Whelen]

Maybe a SMLE conversion to a .350 Remington Magnum? Always thought it was an underrated cartridge before it’s time. One can make it from 7mm Rem Mag brass.

CoElkHunter
I like your joke converting an SMLE NUMBER ONE or No4 would be very difficult. With the pressures the 350 mag run at the only thing it would be good for is putting the bolt thru your eye, ripping your forearm off and generally rearranging various parts of your anatomy. It would not be a pretty site.
Cheers mate Bob

 

[WAB]

I am interested in the chrono results for the 375 if you can find them

Well deer season went out last night so if I can’t find them I’ll wander down to the range and lob a few over the chrono.

 

[edward]

i dont believe any animal will complain about the difference.

 

[CoElkHunter]

CoElkHunter
I like your joke converting an SMLE NUMBER ONE or No4 would be very difficult. With the pressures the 350 mag run at the only thing it would be good for is putting the bolt thru your eye, ripping your forearm off and generally rearranging various parts of your anatomy. It would not be a pretty site.
Cheers mate Bob

Well I’m not a pretty sight anyway, but I still need my eyes and various body parts for now. And what makes you think I’d be the FIRST one to shoot it? I maybe ignorant, but not stupid! Ha! Ha! Anyway, I just looked up some maximum cartridge pressures:
.375 H and H=62,300
.350 Rem Mag= 53,000 CUP Saami
.303 British= 49,000 CUP Saami
.405 Win= 46,000
.444 Marlin= 44,000
I’m sure there are additional suitable cartridge candidates out there for a SMLE?
And how do we know the steel receivers are still strong enough in these rifles for these conversations after all these years? How would one test the steel’s strength?
CEH

 

[Bob Nelson 35Whelen]

Well I’m not a pretty sight anyway, but I still need my eyes and various body parts for now. And what makes you think I’d be the FIRST one to shoot it? I maybe ignorant, but not stupid! Ha! Ha! Anyway, I just looked up some maximum cartridge pressures:
.375 H and H=62,300
.350 Rem Mag= 53,000 CUP Saami
.303 British= 49,000 CUP Saami
.405 Win= 46,000
.444 Marlin= 44,000
I’m sure there are additional suitable cartridge candidates out there for a SMLE?
And how do we know the steel receivers are still strong enough in these rifles for these conversations after all these years? How would one test the steel’s strength?
CEH

CoElkHunter
I would only use a No4 action these are stronger than the old No1 mk111.
Any good gunsmith can test it. The No4 was converted to 7.62x51 NATO without any issues. Any reasonable rimmed cartridge could be used. I used to load the 444 up a bit. The book give the 280grainers 2,100 fps , I was up close to 2,400fps, it made a big difference on what it hit.
If you could safely work up the 405 Winchester a couple of hundred fps with a Barnes bullet. My my that would put some serious hurt on game. Just my ideas don't under estimate the old No4.
Cheers mate Bob

 

[Tanks]

That is why I like the .458 B&M in an 18" barrel. Very maneuverable while:

258 grain tipped raptor @ 2850 fps for plains game
420 grain HP @ 2240 fps for buffalo
450 grain solid @ 2200 fps for anything than requires a solid.

If something requires more oomph then I step up to 20" barrel .500 MDM which gives me.

335 tipped raptor @ 2850 fps
450 grain HP @ 2500 fps
500 grain solid @ 2350 fps

This August I will be carrying the .458 B&M to Zim.

 

[Ray B]

There are computer programs that calculate the differences where everything is the same except barrel length. I use an old cardboard Powley computer, which bases the difference with barrel length using the expansion ratio, that is, the ratio of powder space to bore space.

 

[Bob Nelson 35Whelen]

That is why I like the .458 B&M in an 18" barrel. Very maneuverable while:

258 grain tipped raptor @ 2850 fps for plains game
420 grain HP @ 2240 fps for buffalo
450 grain solid @ 2200 fps for anything than requires a solid.

If something requires more oomph then I step up to 20" barrel .500 MDM which gives me.

335 tipped raptor @ 2850 fps
450 grain HP @ 2500 fps
500 grain solid @ 2350 fps

This August I will be carrying the .458 B&M to Zim.

Thanks
They will put some serious hurt on game, what's it like on the shoulder.
Cheers mate Bob

 

[Tanks]

Thanks
They will put some serious hurt on game, what's it like on the shoulder.
...

Not bad at all. Accurate Innovation does the stocks for these with aluminum bedding. The recoil is more of a push rather than a punch. I'd say by the time it is all said and done about the same felt recoil as a .375 H&H very manageable for a second shot.

From the bench a different story hence why I use a Caldwell lead sled for sighting in and load testing.

 

[WAB]

Well deer season went out last night so if I can’t find them I’ll wander down to the range and lob a few over the chrono.

OK John, here is what I am getting in my 21”
Bbl .375 H&H:

270 gr Swift A-Frame. 2550 fps
300 gr Swift A-Frame 2500 fps
350 gr Woodleigh Weldcore 2300 fps

I use H-414 powder under these bullets. I don’t believe that I have given up anything at practical hunting distances by cutting 3” off the bbl. in my opinion, the profile of Winchester’s .375 bbl is too heavy (I believe it is the same as as their .458 bbl), and the shorter length improves handling tremendously. I should note, all loads shoot sub moa.

 

[HWL]

CoElkHunter
I like your joke converting an SMLE NUMBER ONE or No4 would be very difficult. With the pressures the 350 mag run at the only thing it would be good for is putting the bolt thru your eye, ripping your forearm off and generally rearranging various parts of your anatomy. It would not be a pretty site.
Cheers mate Bob

Take a Mauser M98 - save a SMLE......



HWL

 

[Dr Ray]

Why worry?
The difference is insignificant at hunting distances (but not so with long distance target shooting),
I hate muzzle blast so prefer 24 inch barrels in my bugger calibers.

 

[Dr Ray]

Bigger calibers - fat thumb syndrome strikes again

 

[Rule 303]

The velocity drop with shortening a barrel is dependent on the cartridge ie bore size to powder quantity + powder used. A 45/70 will burn most if not all the powder in an 18" barrel. A 338RUM sure as hell won't. Generally speaking the faster the projectile travels the greater the loss per inch of barrel lost. You can in my opinion go too short with some calibres. Like a bloke I came across who had an 18" barrel on his 375H&H, with a break on it. Every time he fired my chrony gave a false reading, and I had several grains of unburnt powder on my bench.

I can not see the sense in having say a 30-06 with a 20" barrel, you may as well save powder and get a 308. If you are spitting out a fair bit of unburnt powder you need a longer barrel or a different cartridge. Just remember the 375 and 416 Ruger use special powders to get their velocities in short barrels.
One thing is for sure, each barrel will be different.

 

[Dr Ray]

The velocity drop with shortening a barrel is dependent on the cartridge ie bore size to powder quantity + powder used. A 45/70 will burn most if not all the powder in an 18" barrel. A 338RUM sure as hell won't. Generally speaking the faster the projectile travels the greater the loss per inch of barrel lost. You can in my opinion go too short with some calibres. Like a bloke I came across who had an 18" barrel on his 375H&H, with a break on it. Every time he fired my chrony gave a false reading, and I had several grains of unburnt powder on my bench.

I can not see the sense in having say a 30-06 with a 20" barrel, you may as well save powder and get a 308. If you are spitting out a fair bit of unburnt powder you need a longer barrel or a different cartridge. Just remember the 375 and 416 Ruger use special powders to get their velocities in short barrels.
One thing is for sure, each barrel will be different.

Yes good advice.
Actually a magnum needs a 26 inch barrel but then you have to co wider the unwieldiness.

 

[Dr Ray]

Cope with a 26 inch barrel especially in scrub country.
Bugger my fat thumb

However a 24 inch barrel is a reasonable compromise.
I had a 308 with a 20 inch barrel and the blast was something horrendous.
In my Sako rifles the barrel length is around 23 inch in the 270 and 24 inches in bigger calibers.

 

[John J]

Cope with a 26 inch barrel especially in scrub country.
Bugger my fat thumb

However a 24 inch barrel is a reasonable compromise.
I had a 308 with a 20 inch barrel and the blast was something horrendous.
In my Sako rifles the barrel length is around 23 inch in the 270 and 24 inches in bigger calibers.

Blast was horrible on this 16.25" 308. I put on a BRT (Black river tactical) covert comp. It directs blast forwards and works like a charm. Admittedly it may not look the best on a standard hunting rifle.

 

[WAB]

I have no issues with a 21” bbld.375 H&H. I suspect that you would not want to go much shorter.