357 barrel length and velocity ... again

[Warhawk]

The new issue of GUNS magazine showed up yesterday, and on the back page is an article about the .357 Magnum and barrel length. He gives velocities of various loads in barrel barrel lengths from 2.25 inchs to 6 inches in revolvers, and the 18.5 inch barrel of a Ruger 77/357.

Bottom line is that with full power 357 loads, there is only about 100 fps difference between a 2.25 inch and a 6 inch barrel revolver, but the carbine barrel shoots those loads about 500 fps faster than the 6 inch revolver.

Unfortunately he didn't test any loads will bullets heavier than 158 grains.

[O.S.O.K.]

Slower burning propelants like H110/W296 will generally give bigger gains from revolver to carbine length barrels in my experience. What load or bullet weight gave 500 fps more? I don't recall ever seeing that much gain. But then again, I don't shoot the lightweight bullets much and that may be what did that - like 125 grain bullets...

[FatJackDurham]

That makes sense, sort of. If you think about the gas expansion and pressure, I would not expect to see much difference between two and six, but given a longer barrel to all full expansion of gas, a high velocity would be achieved for rounds whose powder load can continued to discharge through out the length of the barrel.

However, I have to think a six inch barrel would be more accurate than a two inch barrel.

[Warhawk]

Slower burning propelants like H110/W296 will generally give bigger gains from revolver to carbine length barrels in my experience. What load or bullet weight gave 500 fps more? I don't recall ever seeing that much gain. But then again, I don't shoot the lightweight bullets much and that may be what did that - like 125 grain bullets...

My mistake, it was in AMERICAN HANDGUNNER magazine, I get both.

American Eagle 158 JSP was one. The other was a Remington 158 gr load and a Buffalo Bore 140 grain load.

[Old Savage]

Go by the percentages and it will probably be close.

[3leggedturtle]

Dont have my notes with me, but 180gr RFN GC hardcast bullet does 1600fps with a less than max charge of H2400 out of my 20" Puma. Havent chronoed them out of my 6" Security Six yet. The 125 Golden sabres are only doing abougt 1750gps but really cant use more than that with open sights cuz of getting "old eyes". But they will "mist" a 2 litre pop bottle of water. 3leg

[madman4570]

Wondering if it's kinda of a catch 22 deal ?

The slower burning powder will achieve say more velocity in a longer barrel but in the short barrel the velocity is way down.
The faster powder sure it's faster in the short barrel but maxes out not fully utilizing utmost potential in the long barrel.

I would like to see apples to apples----
What load/powder provides the max velocity in say a 4" barrel and what load/powder provides max velocity in a 18" barrel.
Also what even one with these loads/lengths in both Slow/Fast powder loadings.


If I recall right my max loads for my Dan Wesson 8" 158gr Hot Loads were around 1600fps ???????
(16.7grs of H110) I think(don't quote me on that)

What was the velocity from that 18" Ruger???????

Slow/Fast powder(who cares)what's the best result for given length.??

[COSteve]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

[madman4570]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

Now that's more like it(thanks Steve)
Big gain from 2-6"
Little gain from 8-18"

[BAGTIC]

The load that gives maximum velocity in a carbine will almost always give the maximun load in a handgun. The same heavy charge of "slow" powder that gives maximum velocity in a long barrel will also give the maximum velocity in a short barrel. It has nothing to with burning rate. It is because the slower powders permit larger powder charges. Larger charges generate more gas to expand. One can not get energy by expanding gases that did not exist in the first place.

[Charles]

The problem with test like those is they use different firearms and that alone skews the results and make the whole thing not dependable. Some years back the American Rifleman folks. Took a 8 3/8" Smith Model 27 and cut the barrel back an inch at a time. they found it lost 35 fps per inch with factory ammo of the time. That test is more valid.

[madman4570]

Interesting stuff guys!

[Warhawk]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

Nope, the author actually fired live ammunition through real guns over a functioning chronograph and wrote up his results. No websites or ballistic calculators involved.

[Warhawk]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

Now that's more like it(thanks Steve)
Big gain from 2-6"
Little gain from 8-18"

You've got it backwards.

[Warhawk]

Had to take it down, copyright... You can see it on-line...

http://fmgpublications.ipaperus.com/FMG ... er/AHMA12/

[COSteve]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

Now that's more like it (thanks Steve)
Big gain from 2-6"
Little gain from 8-18"

You've got it backwards.

I doubt it because Ballistics By The Inch is a website that's been around for years. The story you show is dated March 2012. You do the math.

[madman4570]

Same answer I gave you on AR15.com.

Ballistics By The Inch for 357 Mag. However, he too stops at 158grn but goes from 2" up to 18" in 1" increments. I'm guessing that's where American Handgunner got their information.

Now that's more like it(thanks Steve)
Big gain from 2-6"
Little gain from 8-18"

You've got it backwards.

Da! MY Bad (absolutely right)
Sometimes don't read after I type!
That American Eagle 158 JSP -------------88 fps from 2.25" to 6.5" (that surprised me)
But from 6.5" to 18.5" (over 500fps)
Roughly 20.7 fps per inch shorter length and 43.5 fps gains per inch in the longer barrel (12" difference) ?????????
More than double per inch
Weird thing--------check the fps on the 3" compared to the 4" and then 6.5" on that brand?? (difference in guns??)

[El Chivo]

you know, something on this occurred to me today that I haven't seen addressed yet.

I've rarely shot revolvers but did so recently and when I got a little casual with the way I was holding it I got a hot dose of powder and gas on my fingers. I was amazed at the amount of flash and blast. I also remember standing next to a guy at the silhouette range who was shooting a 50 caliber revolver. Every shot pelted me with particles of hot powder coming out the side, from 8 feet away.

In other words, revolvers have a cylinder gap that lets a lot of stuff out - gas, heat, sizzling particles of powder. If you were able to keep that stuff bottled up you'd have more pressure and velocity, right? Well, carbines do that.

And doesn't the jump in velocity hold true for other revolver cartridges, such as 44 mag and 41 mag? I know the Remington 44 mag load exits a carbine at around 1760 fps, that is at least as fast as most .357 loads. So it's not just the .357, or is it?

Perhaps a true test would be to compare a closed handgun, like a Contender, to a carbine, and see what the difference is. Perhaps it would be more like the difference between 9mm pistols and 9mm carbines, i.e., not much?

In a recent thread, someone mentioned that revolvers are inefficient. So we're comparing inefficient revolvers to efficient carbines and surprised that there's a big difference?

[Leverdude]

44s will do the same thing. The ones that dont benefit much at all from a longer barrel are calibers like 9mm, 45 etc because they dont have room for larger charges of slower powders. The 158 Federal AE comes from my 20" Rossi @1700fps and though I never chronied it its likely about 12oo fps from my Vaquero or GP. We need t remember that even high power rifle calibers reach top pressure within a few inches of the chamber. So I'm not very surprised that revolvers barrel length doesnt show as much gain as a rifle length barrel. Plus as already noted a rifle contains the pressure much better than a revolver.

[earlmck]

This post got me to thinking -- although I have a S&W 38 stubby revolver with 1 3/4" bbl, a Ruger 6" bbl .357 revolver, and a 24" Rossi .357 rifle I've never chronographed the same load in them. So today I had some range shooting to do and took these along with some different loads. Here's what I found with mine:

A 38 load with 5 grains of Unique and 160 gr. Cast: Stubby revolver -- 650 fps. ; 6" Revolver -- 800 fps; 24" Rifle -- 1100 fps.

A 38 load wit 5 gr. Green Dot and 125 gr. Cast G.C: Stubby -- 860 fps. ; 6" Revolver -- 1070 fps. ; 24" Rifle -- 1250 fps.

A 357 load with 12 gr. H108 and 183 gr. Cast: 6" Revolver -- 1160 fps. ; 24" Rifle -- 1460 fps.
(H108 is a no-longer available Hodgdon powder just a bit faster than H110)

As always happens to me when I gather real data rather than make assumptions, this came out a little different than I would have "assumed".
No, I would not have guessed that the rifle would gain approximately the same fps. with a light load of Unique as it did with a medium .357 load of slow ball powder. I would have guessed somewhat less gain with Unique and considerably more gain with H108.

The differences between the stubby revolver and the 6" bbl are about what I would have expected. But I did find a surprising (at least it surprised me) result with the Unique in the 38 case: in the stubby revolver this gave a huge (135 fps) velocity spread; in the 6" revolver it still produced a rather large (90 fps) velocity spread; but in the rifle it gave a very small (15 fps) velocity spread. With large velocity spreads like that I really needed a lot more shots than the 4 I used to get a decent average for the revolvers. So I guess we shouldn't take that Unique data too seriously. But what a nice January day to shoot: low 40's and almost no wind. That's a wow for Central Oregon.

[retmech]

I don't have a short barreled revolver but I have chrono'd a lot of .38/.357 pistol loads in both 6" pistols and 20-24" rifles. Five grains of Unique behind a 158 gr cast bullet runs right at 900 fps out of both my 6" revolvers and 1100 fps out of the rifles. With 296 I use 15 grs behind the Lyman 358429 170 gr "Keith" bullet and out of a 6" it's 1250 fps and out of the rifles it's 1600-1650 fps. Using that same bullet the "classic" load of 13.5/2400 gives 1291 fps out of the 6" and 1689 fps out of the 24" rifle. All of my data is 10 shot strings. Basically fast powders like Bullseye and Unique gain 200 fps going from pistol to rifle. Blue Dot gains about 300 fps and the slower stuff like 2400, AA9,296, H110 gain about 400 fps in a rifle. Also going from 20" to 24" barrels in pistol caliber rifles is meaningless as far as velocity gains. I have 2, 20" rifles and with a given load 1 is the fastest and the other the slowest, the 24" is in between. They are all within 50 fps of each other. My 2 centavos!

[COSteve]

Like retmech above, I've chrono'd the same 357mag loads in a pistol: 7.5" 1873 Peacemaker clone made by Uberti as well as in my 20" Rossi carbine and 24" Rossi rifle. It's clear from the data below that my full charge 357mag loads utilize more of the charge energy when fired in a rifle length barrel than the same loads fired in even my long barreled pistol.

The velocity increases are most noticeable when using slow burning powders wherein the longer barrel gives the powder to burn completely. There is less velocity growth when using fast pistol powders like TiteGroup or Unique, in fact, lighter charges will actually slow down during their flight through the barrel because the gas expansion has dropped off considerably with the fast burning powders.

Uberti SA 7.5" barrel:
38Spl+p ..... 158gn Zero JSP ..... 14.0grns of H110 ..... 1,181fps
357Mag ..... 158gn Zero JSP ..... 16.5grns of H110 ..... 1,332fps

Rossi 20" carbine:
38Spl+p ..... 158gn Zero JSP ..... 14.0grns of H110 ..... 1,551fps *
357Mag ..... 158gn Zero JSP ..... 16.5grns of H110 ..... 1,789fps **

Rossi 24" rifle:
38Spl+p ..... 158gn Zero JSP ..... 14.0grns of H110 ..... 1,521fps *
357Mag ..... 158gn Zero JSP ..... 16.5grns of H110 ..... 1,822fps **

* Note that even using slow burning powder like H110 in the 38spl+p load, the charge weight is not sufficient to keep accelerating the bullet in a 24" barrel so the 20" carbine actually produces slightly higher velocity.

** Note the full power 357mag charge can still accelerate the bullet in the last 4" of the rifle length barrel because it produces 33fps higher velocity than the 20" carbine.

[Paul105]

Here are some more actual chronograph results with a heavier bullet.

Beartooth 185gr LFNGC (yes 185gr not 158gr)
New WW Cases
Fed 200 Mag
14.7gr Lil'Gun
1.595 OAL
Chron 4 Paces fr Muzzle
Temp 75 Deg


Marlin 18" 1,713 fps
Ruger BH 6.5" 1,388 fps
Ruger SP101 3+" 1,161 fps
S&W M60 3" 1,175 fps
S&W M360 Ti 1 7/8" 1,023 fps
S&W M340 Ti 1 7/8" 1,007 fps


Paul