Interpolate new FPS & NRG per barrel length?

[PT7]

Would like to find out if there is a formula to determine certain ammo stats based on a longer-length barrel? I have a .357 Magnum round that shows testing done with a 10" barrel. I'd like to see if stats are much different for use in my Henry AW with a 20" barrel.

Here are the stats I've found for this ammo:

Caliber: .357 Magnum
Weight (Grains) 158
Mzl Vel (fps) 1560
50yd Vel (fps) 1434
Mzl NRG (ft.lb) 865
50yd NRG (ft.lb) 722
Barrel Length 10"

PT7

[GunnyGene]

A general "rule of thumb", is 25fps per additional inch of barrel. I'm not aware of any broad formula that will give an exact number, since there are many other factors that are specific to the individual firearm. Also see this: http://www.ballisticsbytheinch.com/

[PT7]

Appreciate the "rule of thumb," Gunny. I'm looking mainly for an estimate.
Thanks for the BBTI link. Looks like there is some interesting stuff there...will check it out for sure.

PT7

A general "rule of thumb", is 25fps per additional inch of barrel. I'm not aware of any broad formula that will give an exact number, since there are many other factors that are specific to the individual firearm. Also see this: http://www.ballisticsbytheinch.com/

[wingnut]

Approximation done with QuickLoad & QuickTarget. BTW, that is a very hot load even with Win 296 & A2400, ~37.6K psi vice 35K psi SAMMI.

Code: Select all

10 in bbl
Gun / Ammunition : .357 Magnum (SAAMI)
 Bullet Type      : .357, 158, Nosler JHP 44841
 Bullet Weight    : 158 grains or 10.24 Grams
 Muzzle Velocity  : 1564 fps
 Twist Length     : 38.0 in.  (RH)
 Gyro.  Stability : 0.61
 Crosswind Speed  : 10.0 Mph 
 Ballistic Coefficient(s) (G1) :
 C1_1=0.182@V>0 fps;

 Optimum trajectory information : 
 Optimum sight-in range (X) = 120 Yds. 
 with max. ordinate above LOS at range (M)= 66 Yds.
 and max. point blank range (P)= 141 Yds.
-------------------------------------------------------------------------------------
 Range  Velo Time of  Energy   Path   Spin / Wind-  Total  Sight correction  Target
        city  flight            to     dage, Wind    drop   for setting new   lead
                                LOS    of 10.0 Mph             zero range     33 fps
-------------------------------------------------------------------------------------
·Yards   fps     s    ft.lbs.   in.    in.     MOA     in.   Clicks     MOA     yds ·
-------------------------------------------------------------------------------------
|    0  1564  0.0000    858    -0.8    0.0   -----     0.0   ------    -----    0.00
|   25  1478  0.0487    767    +1.1   -0.1   -0.48     0.4    -11.6    -4.00    0.53
|   50  1399  0.1008    686    +1.9   -0.8   -1.59     1.9    -10.3    -3.54    1.10
M   56  1380  0.1139    669    +1.9   -1.1   -1.86     2.4     -9.3    -3.21    1.25
|   75  1325  0.1562    616    +1.6   -2.1   -2.67     4.5     -5.7    -1.95    1.71
X  100  1257  0.2141    555     0.0   -3.8   -3.62     8.2      0.0     0.00    2.34
-------------------------------------------------------------------------------------
M = Peak vs. L.O.S, X = Set Zero, P = Max. Point Blank Range
Elevation above Angle of Site (0.0 deg.)  = 0.1431 deg.


20 in bbl
Gun / Ammunition : .357 Magnum (SAAMI)
 Bullet Type      : .357, 158, Nosler JHP 44841
 Bullet Weight    : 158 grains or 10.24 Grams
 Muzzle Velocity  : 1749 fps
 Twist Length     : 11.0 in.  (RH)
 Gyro.  Stability : 7.56
 Crosswind Speed  : 10.0 Mph 
 Ballistic Coefficient(s) (G1) :
 C1_1=0.182@V>0 fps;

 Optimum trajectory information : 
 Optimum sight-in range (X) = 132 Yds. 
 with max. ordinate above LOS at range (M)= 74 Yds.
 and max. point blank range (P)= 155 Yds.
-------------------------------------------------------------------------------------
 Range  Velo Time of  Energy   Path   Spin / Wind-  Total  Sight correction  Target
        city  flight            to     dage, Wind    drop   for setting new   lead
                                LOS    of 10.0 Mph             zero range     33 fps
-------------------------------------------------------------------------------------
·Yards   fps     s    ft.lbs.   in.    in.     MOA     in.   Clicks     MOA     yds ·
-------------------------------------------------------------------------------------
|    0  1749  0.0000   1073    -0.8    0.0   -----     0.0   ------    -----    0.00
|   25  1656  0.0446    962    +0.7   -0.3   -1.01     0.4     -7.9    -2.73    0.49
|   50  1566  0.0913    860    +1.4   -0.8   -1.59     1.6     -7.7    -2.64    1.00
M   58  1538  0.1066    830    +1.4   -1.1   -1.77     2.1     -6.8    -2.33    1.17
|   75  1480  0.1400    769    +1.2   -1.7   -2.15     3.6     -4.4    -1.52    1.53
X  100  1400  0.1920    688     0.0   -3.1   -2.93     6.6      0.0     0.00    2.10
-------------------------------------------------------------------------------------
M = Peak vs. L.O.S, X = Set Zero, P = Max. Point Blank Range
Elevation above Angle of Site (0.0 deg.)  = 0.1172 deg.

I hope that is close enough. Different bullet shapes will produce different bullet BC's that will produce different elevation drops, V drops at range & E drops at range.

[GunnyGene]

Appreciate the "rule of thumb," Gunny. I'm looking mainly for an estimate.
Thanks for the BBTI link. Looks like there is some interesting stuff there...will check it out for sure.

PT7

A general "rule of thumb", is 25fps per additional inch of barrel. I'm not aware of any broad formula that will give an exact number, since there are many other factors that are specific to the individual firearm. Also see this: http://www.ballisticsbytheinch.com/

You're very welcome. Also, what wingnut posted is a better estimate than the "rule of thumb". Ballistics is a very complex subject, but if you're interested, here's a couple video's from TiborasaurusRex in his Sniper 101 series, beginning with Part 25. His primary focus is on ELR (Extreme Long Range) shooting, but the basic principles apply across the board.

https://www.youtube.com/watch?v=F39yUEM ... ex=26&t=0s

1. Internal Ballistics -- and all the possible factors that cause variations in either MV or in Point of Aim as the bullet begins its motion and how to correct for them. • We will discuss the nature of propellants and how they affect projectile movement / pressures • We will discuss different factors that can affect the MV of a projectile o Variations in ammunition / reloading tips / non-uniformities -- propellant moisture, primer seating, bullet seating, case dimensions, powder weight, orientation of grains in a case, projectile weight/profile, etc... o Tolerances in different weapons o How bore wear affects muzzle velocity o Propellant Temperatures o Projectile and Bore Temperatures o Coppering o Powder Fowling o Bore conditioning and barrel memory • We will talk about how other factors can cause the axis of the bore at the breech to differ slightly from the axis of the bore at the muzzle o Muzzle Jump variations due to inconsistent rifle deployment -- bipods vs sandbags, deployment and marksmanship techniques o Whip action - harmonics o Deflections due to muzzle break pull-off. o Other tips

2. Intermediate ballistics -- we will mention how suppressors effect the transition of the projectile from internal progression to external flight '

3. External Ballistics -- is the science of all the factors that affect the flight path of the projectile after its exits the muzzle. • We will discuss everything you will need to know: how changes in ambient air temperature, humidity and barometric pressure affect the bullet. We will talk about wind, how to set up Microsoft excel to make corrections for coreolis effect, how and why spin drift occurs and much much more.

4. Terminal Ballistics -- is the study of what happens once the projectile arrives at its destination.

[PT7]

Thanks to both.
Yeah, complex is the word for it.

Cannot imagine the computer work and effort needed to create a bullet for a specific purpose, e.g. the Hornady ELD-X bullet created three years ago. And their initial offerings came in three calibers with 7 bullet weights across those calibers. What was needed to achieve their goal is beyond me. To think those basic stats of weights & calibers were only the tip of the tip of the tip, etc....of the iceberg.

Appreciate all the info you sent.

PT7

Approximation done with QuickLoad & QuickTarget.
I hope that is close enough. Different bullet shapes will produce different bullet BC's that will produce different elevation drops, V drops at range & E drops at range.

You're very welcome. Also, what wingnut posted is a better estimate than the "rule of thumb". Ballistics is a very complex subject....

[GunnyGene]

Thanks to both.
Yeah, complex is the word for it.

Cannot imagine the computer work and effort needed to create a bullet for a specific purpose, e.g. the Hornady ELD-X bullet created three years ago. And their initial offerings came in three calibers with 7 bullet weights across those calibers. What was needed to achieve their goal is beyond me. To think those basic stats of weights & calibers were only the tip of the tip of the tip, etc....of the iceberg.

Appreciate all the info you sent.

PT7

Approximation done with QuickLoad & QuickTarget.
I hope that is close enough. Different bullet shapes will produce different bullet BC's that will produce different elevation drops, V drops at range & E drops at range.

You're very welcome. Also, what wingnut posted is a better estimate than the "rule of thumb". Ballistics is a very complex subject....

And to think the basis of modern ballistics started with Niccolò Tartaglia in 1531, although he continued to use segments of straight-line motion, conventions established by Avicenna and Albert of Saxony, but with the innovation that he connected the straight lines by a circular arc. Then followed up by Galileo in 1638 (parabolic motion), and Newton in 1687 with his Principia Mathematica which gave us the laws of gravity & motion. We've come a very long way since then. Gives an appreciation of what goes into making a shot @ 3 miles as was done recently.

[North Country Gal]

What I've found over the years shooting revolver/pistol rounds in my Contenders is that the velocity gain/loss is not consistent across a wide range of barrel lengths, so formulas based on fps loss for each inch of barrel can only be carried so far. In the case of the 357, you're only going to squeeze so much velocity out of the cartridge, beyond which add more barrel length has no effect or even begins to show a velocity loss.

Here's great resource on the 357, for instance, showing that the velocity gain by going to a 20" barrel from a 16" barrel is not that much.
http://www.ballisticsbytheinch.com/357mag.html

For an autoloading pistol cartridge like the 45 ACP, which I shoot in both a 10" and 12" barrel on my Contender, note how little is gained over shooting the 45 ACP in one of my 1911s with a 5" barrel.
http://www.ballisticsbytheinch.com/357mag.html

[North Country Gal]

Those of us who have been shooting Contenders for years know very well that cartridge design is the biggest factor in which cartridges do well in a 10" barrel and which cartridges need a 14" barrel to be most effective. In fact, in the early days, some cartridges were actually invented to be best used in a 10" barrel.

A classic example of a rifle cartridge being a mismatch for a 10" barrel is the 222 Remington. When Remington shocked the world with their revolutionary XP 100 bolt action pistol, back in the mid 60s, the prototypes were originally chambered in the 222. What Remington quickly discovered was that the 222 was a very inefficient cartridge in the 10" barrel of that first XP. Simply put, that 10" of barrel length was not enough to burn all the powder in a 222 case. Remington then shortened the 222 case, little by little, reducing the powder capacity until they found the most efficient capacity in a 10" barrel. This "222 Short", so to speak, was given the name, the 221 Fireball. Interesting cartridge, the 221. In a 10" barrel, I get the same velocity with the 221 as I get with my 10" 222 Contender barrel, even though the 221 Fireball (222 Short) uses less powder. On the other hand, when I go to a 14" 222 barrel on my Contender, the 222 is much more at home.

[clovishound]

The easiest and most accurate way to determine this, is to get a friend to let you use their chronograph. A couple shots through the crony will give you the skinny.

FWIW, I ran a 158 grain soft point American Eagle through my 20" BBS. Box said 1240 fps out of (presumably) a revolver barrel. Chrony said it was 1800 fps. I'm sure the burn speed of the powder in a .357 will make a big difference in the change in MV from a short barrel to a long barrel. I doubt I would gain much from a fast Titegroup load vs a slow H110 load. I'm sure most of the .357 factory loads are going to use slower powders to maximize MV in revolvers. There may be a few out there that are optimized for short barrels, but will probably be advertised as such.

BTW, Hogdgon has data for both pistol and rifle in .357. If you want you can compare the difference of the same load from a short barrel, and a long barrel. Again, without knowing the powder used in a factory load, you will still be making a WAG.

[PT7]

Agreed on how2get the skinny, Clovishound.

Pretty certain your American Eagle 158gr SP at 1240 fps was tested in a revolver, probably using a 4"-5" barrel. Most times when the manufacturer has identified the firearm used, it is close to that. Also noticed that almost never is a .357 round marketed as "rifle" ammo; always as handgun ammo. So that makes sense, too.

Your comments on "fast vs slow loads" adds to the complexity, which Gunney noted. There definitely are many factors involved. I'm limited in that my "reloading" is solely done by using manufactured off-the-shelf ammo, which comes with limited info (specs) on the cartridge's build and capabilities. That has always made ammo selection challenging, and yet interesting at the same time.

Appreciate your suggestion on the chrony. I'll check with a couple of friends, who might have one.
PT7

...most accurate way to determine...couple shots through the crony will give you the skinny...
FWIW, I ran a 158 grain soft point American Eagle through my 20" BBS. Box said 1240 fps out of (presumably) a revolver barrel. Chrony said it was 1800 fps.

[GunnyGene]

Agreed on how2get the skinny, Clovishound.

Pretty certain your American Eagle 158gr SP at 1240 fps was tested in a revolver, probably using a 4"-5" barrel. Most times when the manufacturer has identified the firearm used, it is close to that. Also noticed that almost never is a .357 round marketed as "rifle" ammo; always as handgun ammo. So that makes sense, too.

Your comments on "fast vs slow loads" adds to the complexity, which Gunney noted. There definitely are many factors involved. I'm limited in that my "reloading" is solely done by using manufactured off-the-shelf ammo, which comes with limited info (specs) on the cartridge's build and capabilities. That has always made ammo selection challenging, and yet interesting at the same time.

Appreciate your suggestion on the chrony. I'll check with a couple of friends, who might have one.
PT7

I don't reload either. You might want to take a look at Underwood ammo https://www.underwoodammo.com/ . I've been using their .41 mag 210 gr XTP for several years with great results in my Blackhawk, and recently in my BBSC (although I did have a minor extraction issue at first which I took care of by polishing the chamber). The numbers Underwood advertises for their ammo are pretty dependable, so if you have questions about the test barrels they used they will gladly provide that info if you call or email them. They do load at +P pressures to obtain this performance. For the .41 mag, they used the same model Blackhawk I have (6.5").

[PT7]

Good reminder to me, Gunny....I'd forgotten about Underwood Ammo. I have a box of .357 Magnum 140gr Xtreme Penetrators, which I carried in my Ruger SP101 snubby revolver (for SD). For this Henry AW rifle, I think I might get a box of their .357 Magnum 158gr JHPs to try. They make those with Nosler JHP bullets. Sounds like another possibility for me. Thanks again.

PT7

...take a look at Underwood ammo...

[GunnyGene]

Good reminder to me, Gunny....I'd forgotten about Underwood Ammo. I have a box of .357 Magnum 140gr Xtreme Penetrators, which I carried in my Ruger SP101 snubby revolver (for SD). For this Henry AW rifle, I think I might get a box of their .357 Magnum 158gr JHPs to try. They make those with Nosler JHP bullets. Sounds like another possibility for me. Thanks again.

PT7

...take a look at Underwood ammo...

What's your take on the Penetrators? I've never shot any and have been wondering about them. My wife has a pre-Hillary hole S&W 60-10 and they sound like they might be good for her carry. Specifically recoil wise. She's 73 and arthritic, so about all she can cope with these day's are .38 SWC and I'd like to get her something better without the full load .357's.

[PT7]

It's been some time since I shot the Penetrators. Recoil was pretty stout for all .357 loads I shot through the SP101 snubby. It was a lighter weight J-frame @ 27 oz. with 3" barrel. The only mod I did was to change out the hard rubber grip with wood insert to a Hogue Tamer. That helped manage recoil. That being said, I'd say the Penetrators might still have too much recoil for your wife, especially as you described her dealing with arthritis. I have a touch of that in my knuckles, too.

Anyway, you can get a 20-round box of Penetrators, which are not that many to try out.

I made a SD revolver carry adjust after I sold my SP101 .357 magnum. I have a Ruger LCRx .38 Special + P. Have been carrying two ammo types, and practicing with each: Hornady CD 110gr FTX or BHA 125gr JHPs. The Hornady round is a +P, while the BHA is not a +P. They are both good ammo choices for me, and I like the BHA best for a SD round with noticeably lessened recoil than the .357 magnum. Might be sometime your wife would consider.

Hope this helps a little.
PT7

Specifically recoil wise

.

[GunnyGene]

It's been some time since I shot the Penetrators. Recoil was pretty stout for all .357 loads I shot through the SP101 snubby. It was a lighter weight J-frame @ 27 oz. with 3" barrel. The only mod I did was to change out the hard rubber grip with wood insert to a Hogue Tamer. That helped manage recoil. That being said, I'd say the Penetrators might still have too much recoil for your wife, especially as you described her dealing with arthritis. I have a touch of that in my knuckles, too.

Anyway, you can get a 20-round box of Penetrators, which are not that many to try out.

I made a SD revolver carry adjust after I sold my SP101 .357 magnum. I have a Ruger LCRx .38 Special + P. Have been carrying two ammo types, and practicing with each: Hornady CD 110gr FTX or BHA 125gr JHPs. The Hornady round is a +P, while the BHA is not a +P. They are both good ammo choices for me, and I like the BHA best for a SD round with noticeably lessened recoil than the .357 magnum. Might be sometime your wife would consider.

Hope this helps a little.
PT7

Specifically recoil wise

.

It does narrow the field some. Thanks. I might get a box or 3 of different loads in .38 & .357 and have her try them out.

[PT7]

Sounds like a good plan to help your wife. My original question was re. .357 ammo for my 20" Henry AW. You and I moved over to chatting about the well-liked, well-used .357 caliber in a revolver. Plus a reminder and look at the Underwood Ammo offerings. Appreciated the chance to chat with you.

Final thought on my move to the .38 special revolver and .38 special ammo. It's been a good move for me. Easier doing the needed "due diligence" to be in practice with a CCW revolver. But I haven't really "left" my favorite .357 caliber in the dust. It's so easy to shoot any load .357s with the AW Henry. Never have to think about "stout" recoil.

Not least, I very much like shooting .357s in my Uberti Police S/A revolver. Very little recoil impact with that gun because it carries a 5.5" barrel and weighs 2.5 lbs. It is a heavyweight, but does take care of revolver recoil quite well.

I really hope your wife finds a cartridge/caliber that she more likes handling. Will be interested to hear what she decides. Best to her.

PT7

It does narrow the field some. Thanks. I might get a box or 3 of different loads in .38 & .357 and have her try them out.

[GunnyGene]

Sounds like a good plan to help your wife. My original question was re. .357 ammo for my 20" Henry AW. You and I moved over to chatting about the well-liked, well-used .357 caliber in a revolver. Plus a reminder and look at the Underwood Ammo offerings. Appreciated the chance to chat with you.

Final thought on my move to the .38 special revolver and .38 special ammo. It's been a good move for me. Easier doing the needed "due diligence" to be in practice with a CCW revolver. But I haven't really "left" my favorite .357 caliber in the dust. It's so easy to shoot any load .357s with the AW Henry. Never have to think about "stout" recoil.

Not least, I very much like shooting .357s in my Uberti Police S/A revolver. Very little recoil impact with that gun because it carries a 5.5" barrel and weighs 2.5 lbs. It is a heavyweight, but does take care of revolver recoil quite well.

I really hope your wife finds a cartridge/caliber that she more likes handling. Will be interested to hear what she decides. Best to her.

PT7

It does narrow the field some. Thanks. I might get a box or 3 of different loads in .38 & .357 and have her try them out.

Oh, we'll find something she's more comfortable with. Might cost me a bill or 2, tho.

Btw, regarding velocity and pressures between revolvers and closed breech rifles, you also have to consider the gas that escapes thru the revolver barrel/cylinder gap when figuring what the same round will do in a rifle. Just another complication, but worth paying attention to. Luckily BBTI has some info and did some testing on how the B/C gap effects velocity in a variety of ammo & calibers. One of which was with Federal 158 gr .357 JHP. How about that?

http://www.ballisticsbytheinch.com/gaptests.html