Loading Based on Velocity Results

[Blued Steel]

Hello... I've read about reloading for the 38spl/357mag and a consensus is that pressure signs aren't there until passed the safe pressure level and that loading based on velocity is the way to go. I'm sure that could also be applied to loading for 44 mag, which I'll be doing soon as I have a model 29 on the way.

After shooting 38's in my 357 I've decided I don't want to use 38 brass anymore, nor will I want to use 44 spl brass in the 44 mag. Will only be using the 357 or 44 mag brass.

That being said, I want to load "light target 38 loads" in a 357 case, light magnum loads, and I will also want to load up some heavy hitters for 357 sake. And the same for 44, some light medium and heavy loads all in the mag case.

Can a light 38 spl load (i.e the standard 2.7gr BE 148gr WC) be replicated into a 357 case?
Is it acceptable to load purely on velocity results?
What would be considered acceptable minimum and maximum velocity's in 357 and 44 for light target loads, and heavy but safe loads? (out of 6" barrels)
Bullets to be used for 357 would be campro's copper plated 158's, hard cast 158 SWC, hard cast 148 button nose WC. And for the 44, most likely a 240 plated and/or hard cast lead.

 

[Nevada Ed]

The volume in the 357 case will be under charged with 38 spl data
and it is best to add a little more powder to get near the 38 spl. fps.

A 38 special 158gr lead factory load is around 755fps but with a
357 case my 6" minimum load with Trail Boss is 788fps and a
standard load runs around 900fps for good target accuracy.

You don't want to shoot any plated or copper jacket bullet at too
slow a speed or you might get a "Squib" with the added barrel friction.
My lowest 158 jacket load starts at 1108fps but is under 1" off a rest.
It is also below the factory standard loading, making for a nice target loading.
With proper powders, 1240-1340fps are possible.

 

[BLUEDOT37]

Keep in mind that plated bullets typically have slower MV than jacketed bullets of similar style/weight & using the same amount of powder.

Hard cast bullets will typically be faster than either, all things else being equal.

Whatever is the lowest published MV of a similar style/weight jacketed bullet I'd keep the powder charge at or above that to avoid a squib with plated bullets.

If you already have some favorite loads in 38 Spcl. & 44 Spcl. just increase the powder charge by 10% & 7%, respectively, which is the typical difference in case volumes for 357 Mag & 44 Mag cases over them.

.

 

[Joe4d]

Alliant has separate "Cowboy" loads listed, so do most other manuals.
Basically light loads using 357 and 44 cases.
Id go with a fluffy fast powder, American Select, Sport Pistol, etc and coated cast bullets.
Alliant, Lyman, Hodgdon, all have published data. Follow th epublish data,
Then chrono and adjust for the velocity you want, but u should still stay within published max and min for the components u are using.
Bad things can happen with an undercharge just like an over.

 

[rwsmith]

In the scenario you describe......

To duplicate a .38 load in a .357 case, or the same with the .44, velocity is about the best tool to match loads and you may have to furth tune for accuracy.

I'd expect there to be very little difference in the amount of powder between the shorter and longer cases because the extra volume is very small in relation to the available volume, but if you have any compressed loads, the tad of extra length is probably a good thing.

 

[stansdds]

I've loaded tons of 357 Magnum brass with reduced power loads that duplicate 38 Special. A very general rule of thumb for recreating 38 Special loads in 357 Magnum brass is to use standard primers and add 0.3 to 0.5 grains to the 38 Special load data.

 

[Eddietruett]

I have loaded .38/.357 for over 40 Years. After a lot of trial and error, I now load all "light target" loads in .38 brass and "magnum" loads in .357 brass. Only negatives if you only have one press is adjusting dies from one to another and shooting .38s in .357 cylinders will leave a ring that can make magnums hard to insert but with regular cleaning it is not an issue. I guess if you are going to all .357 brass, once you get the charges adjusted it will be smooth sailing. I have guns chambered in both so one case is not an option. I have one press set up for .38 and one for magnums. Makes life much simpler. One caution as others have said. Be careful with plated at low velocities. They run slower and I had a couple of squibs using light charges of Bullseye that shot great with lead.

 

[scooter123]

IMO 2.7 grains of BE will be a bit "lost" in a 357 case. This is an invitation for Position Sensitivity issues that can potentially lead to a Squib. Since you are using a Magnum case I would suggest that you start your charge weights at the low end if the Magnum recipe for your bullet, if it exists. If there aren't any listings for BE in a 357 Magnum then I would suggest using a different powder. BTW I use Vihtavouri 3N37 specifically for it's complete lack of position sensitivity in my 38 special loads due to some first hand experience with Position Sensitivity.

Tip, if you ever have a 38 special, or any caliber of similar or greater energy and have a recoil that feels like a 22 short with a report volume DO NOT FIRE ANOTHER SHOT. Stop, open the cylinder, and either shove a pencil down the barrel or shine a penlight down the barrel and make 100% certain that the barrel is clear. I would also suggest just packing up an heading home because that lot of ammunition isn't safe to use. Remember, a single squib in a barrel is simply inconvenient, multiple squibs into that first one can mean purchasing a new handgun or a trip to the ER.

I know, you are wanting to load light. What I am saying is that to be safe doing this with a 38 special load in a 357 Magnum case means that you go against the common wisdom and Work Your Load DOWN while testing for velocity and position sensitivity. I expect that your final result will likely end up between the Max for 38 Special and the lower half of the 38 +P range. Because that 1/8 inch will increase the case volume Which will reduce both peak pressures and the rate of pressure increase immediately after ignition.

Note, I have a 1972 vintage 2 1/2 inch model 19-3 that is a real favorite that I wanted to develop a specific "light" Magnum for to protect the forcing cone. While I could have used 3N37 to do this I chose to use Accurate #5 because it is easier to find and less expensive. Final result is a load featuring 7.4 grains of #5 with a 158 Grain plated FP at 900 fps. While it's not a Magnum it has energy in the 9mm parabellum range so it's a fun to shoot "light" Magnum that won't do any harm to the forcing cone on my model 19. It's also a charge that falls between 38 +p and the start of 357 Magnum so going "off the charts" can be safe if you approach doing this properly and chronograph your loads so you know what you are getting.

Final tip, testing for Position Sensitivity. What you to is Position the powder charge in the case by either pointing the barrel straight UP or straight DOWN, tap the cylinder lightly to settle the charge, and slowly bring the barrel horizontal and fire a shot. If you see a swing of ~50 fps or more due to Powder Position you have a Position Sensitive Powder. BTW, I have personally observed a 300 fps swing in velocity when testing IMR SR7625 in a 38 special case with a 125 grain plated FP. After that I changed to 3N37 for all of my 38 special loads after testing a couple of powder I had on hand.

 

[gwpercle]

Keep an eye out for high pressure signs and keep an eye on velocities.
Both will tell you when something is wrong so don't disregard "signs" and look only at velocity.
High pressure maximum loads and extremely light loads are the ones that can get you in trouble.
Use every safety precaution and warning sign you have at your disposal....you can't be too safe or too cauautios in this hobby.
There is no real reason to not load target rounds in 38 special cases, just clean the cylinder after shooting. I've been doing it now for 51 years with no ill effects to my 357 magnum.
Gary

 

[WR Moore]

Going from Special to Magnum brass and back is easy. Redding and others sell spacers to make the adjustment. You set the dies for the Special length brass and put the spacer between die and press for the Magnum brass. At least one of the die companies includes the appropriate spacer with the die sets.

That said, after the nightmare I had cleaning the carbon/lead ring from the chambers in a .357, I've never used Specials in a .357 again. Oddly, never had that problem in .44, possibly because the .44 slugs were all hardcast rather than swaged (softer). I'll also note the .38 use was extensive.

 

[Protocall_Design]

Lots of good advice here. If you think about it, pressure = velocity, so a chronograph is the reloader's friend. Also, every gun is an individual. What is 800 fps. in one gun may be 840 or 750 in a seemingly identical gun.

 

[dave1918a2]

lot's of replies, but No one mentioned reloading for accuracy. Most reloaders load for $ savings and accuracy. Do not forget accuracy. Velocity is fun for sure, but accuracy and velocity is much better. Play with loads until You achieve both.

 

[rwsmith]

I did......

lot's of replies, but No one mentioned reloading for accuracy. Most reloaders load for $ savings and accuracy. Do not forget accuracy. Velocity is fun for sure, but accuracy and velocity is much better. Play with loads until You achieve both.

I did say that with the slight change in volume and a slight addition of powder would probably need to be retuned for accuracy.

 

[rwsmith]

In one long range session........

Going from Special to Magnum brass and back is easy. Redding and others sell spacers to make the adjustment. You set the dies for the Special length brass and put the spacer between die and press for the Magnum brass. At least one of the die companies includes the appropriate spacer with the die sets.

That said, after the nightmare I had cleaning the carbon/lead ring from the chambers in a .357, I've never used Specials in a .357 again. Oddly, never had that problem in .44, possibly because the .44 slugs were all hardcast rather than swaged (softer). I'll also note the .38 use was extensive.

I shoot all .357 cases in .357 because at the range I start out with .38 and usually shoot a lot of them. The crud ring messes up the chambering when I try to load .357. Rather than clean it at the range, I just load .38 in .357 cases. If caught short, I can always shoot regular.38s. If I could get through a long range session without cleaning, I'd use the .38s and clean when I got home.

 

[Wise_A]

Lots of good advice here. If you think about it, pressure = velocity, so a chronograph is the reloader's friend. Also, every gun is an individual. What is 800 fps. in one gun may be 840 or 750 in a seemingly identical gun.

You do realize that this is self-contradictory, right?

Pressure doesn't directly equal velocity. Where it matters is when you start getting erratic velocities at the top and bottom of the data range. It's a sign that the powder is starting to burn inconsistently, and a good sign that you should consider stopping.

If the max load in the book lists 1200 fps, and the same load in your gun only gives you 1000 fps, that's not a good reason to keep shoveling powder in.

PS--You don't need consistent velocities to get good accuracy, either.

 

[Protocall_Design]

Normally the erratic velocity is above and below the book loads. The laws of physics dictates that more pressure will give more velocity. For every action, there is an equal and opposite reaction. Erratic velocity means erratic pressures, which indicates a problem, all the more reason to use a chronograph.

 

[MichiganScott]

Normally the erratic velocity is above and below the book loads. The laws of physics dictates that more pressure will give more velocity.

Up to a point you are correct. It falls apart when your bore is of a different condition than the bore on a test gun. Take a well eroded rifle barrel that looks like a bad road. The friction from the eroded barrel will give less velocity than a smooth barrel at the same pressure.

 

[Blued Steel]

You do realize that this is self-contradictory, right?

Pressure doesn't directly equal velocity. Where it matters is when you start getting erratic velocities at the top and bottom of the data range. It's a sign that the powder is starting to burn inconsistently, and a good sign that you should consider stopping.

If the max load in the book lists 1200 fps, and the same load in your gun only gives you 1000 fps, that's not a good reason to keep shoveling powder in.

PS--You don't need consistent velocities to get good accuracy, either.

What is a good reason to start shoveling powder in?

If the book says 15 grains at 1200 FPS, and without pressure signs I am getting 1400 FPS, should I be backing off? If I am getting 1000, is it not safe to up my charge?

What is a good approach to loading "off the books", and basing the charge on velocity?

What velocity in a 357 is starting to get questionable? (low or high) For simplicity, base it off a 158 gr bullet.

 

[WR Moore]

Now you're getting into really gray areas. I once had a ballistic tech tell me that: "If you're not getting the velocity, you're not getting the pressure." That's not entirely true, there are variables like very rough bores etc., but other signs can support that.

Remember, the load data & pressures in the source you're using is with that particular test barrel/firearm. The big BUT is that we don't have pressure gauges. Working with new, unfired rifle brass, one can use case head/web expansion as a clue. Some of the manuals explain this in detail. I've never seen such information on pistol cases. Cases marked with soot area definite sign of low pressure and suggests that the loads can go higher.

This is one very good reason to have multiple manuals and data sources. That Hodgon is now the source for IMR, WW and Hogdon powder data kind of dilutes variety, but there are still others. Get a variety of sources, check the data and get some idea of the range where the maximum loads might be.

I've never seen a ~20% velocity advantage over published data. In fact, it's rare to match it. If you see that, I'd back off, there's something strange going on (maybe your chrono). A difference in bullet material, bearing surface of the bullet or other factors might get you a very slight change. Remember, loading at maximum effort really isn't a good idea. The MAP of factory load specs are designed to make over pressure loads virtually impossible.

Making a velocity estimate without knowing the bullet/powder combination would be a wild guess. Per the most recent Hornaday manual, figure 1000-1200 f/s for jacketed 158 using multiple powders, up to 1400 f/s with one powder IN THEIR GUN. Swaged lead, 750-900 f/s (to avoid excessive leading) with multiple powders, hard cast linotype lead 900 to 1200-1300 f/s with the right powders. Plated bullets: go with the velocity limits posted by the vendor, use lead bullet data-unless there's specific load data like for the Speer Gold Dots.

To give you some perspective, one of my sons asked me to reload some .303 British for him. Checking with some folks with extensive experience with that round, I was told that BL-C2 was THE powder to use. I gathered load data from several load manuals and the Hogdon and Alliant websites. I started with a load that was about mid range in the most conservative data and chrono'd it. Several hundred foot seconds low, sooty cases. I worked up to the max load and the cases were less sooty and I was about 300 f/s low on velocity from what "the book" said I should be getting. The Hogdon data showed I might be able to go up about 4 grains in charge weight. With this as a green light, I was able to make factory duplication while still ~2.5 gr short of Hogdon's max load.

 

[rwsmith]

Higer pressures DO equal more velocity....

..BUT I DON''T THINK THAT THE RELATIONSHIP IS LINEAR. A point comes where a lot of extra powder DOESN'T get a lot of extra velocity. After this point is reached, pressures can soar above the allowable very easily. And most publishers leave out data that is erratic in performance.

Just like a big cargo container ship. They can pour on more engines and fuel to get a couple of extra knots, but it's a lot of expense for a very small result.

If they learn how to run a container ship up on plane, though, that limitation may go out the window.

 

[Joe4d]

Normally the erratic velocity is above and below the book loads. The laws of physics dictates that more pressure will give more velocity. For every action, there is an equal and opposite reaction. Erratic velocity means erratic pressures, which indicates a problem, all the more reason to use a chronograph.

Not quite, more pressure doesnt equal more velocity. Look in a loadmanual,, Its more a pressure over time. I could load rounds that blow your gun up but barely launch the bullet, or fast bullets with low pressure.
Your gun will come apart due to an instant peak, Powder burns and pushes all the way down the barrel.
Thats why slow burning powders generally launch bullets faster at the same peak pressure.
So a slower burning powder with lower pressure peak, but it holds that peak longer,, or actually the pressure wave is flatter will result in more velocity.
Any time I have ever done a ladder.. ( same everythign just load 5 rounds of incrementally more powder) You usually have a sweet spot in Standard deviation, which generally means a more accurate load.
To light and I suspect its a case volume issue, usually the increase in velocity is pretty linear and a direct ratio,, as u get higher the velocity starts flattening out with increase in powder.
I suspect the pressure spike is increasing but not much velocity gain.. ur SD tends to fall apart around there as well.

 

[fredj338]

Hello... I've read about reloading for the 38spl/357mag and a consensus is that pressure signs aren't there until passed the safe pressure level and that loading based on velocity is the way to go. I'm sure that could also be applied to loading for 44 mag, which I'll be doing soon as I have a model 29 on the way.

After shooting 38's in my 357 I've decided I don't want to use 38 brass anymore, nor will I want to use 44 spl brass in the 44 mag. Will only be using the 357 or 44 mag brass.

That being said, I want to load "light target 38 loads" in a 357 case, light magnum loads, and I will also want to load up some heavy hitters for 357 sake. And the same for 44, some light medium and heavy loads all in the mag case.

Can a light 38 spl load (i.e the standard 2.7gr BE 148gr WC) be replicated into a 357 case?
Is it acceptable to load purely on velocity results?
What would be considered acceptable minimum and maximum velocity's in 357 and 44 for light target loads, and heavy but safe loads? (out of 6" barrels)
Bullets to be used for 357 would be campro's copper plated 158's, hard cast 158 SWC, hard cast 148 button nose WC. And for the 44, most likely a 240 plated and/or hard cast lead.

Well no. Vel variation can be enormous in revos. I have 5 diff 4" 357mags. They can vary as much as 125fps with identical loads. So trying to chase a given vel would certainly put me over pressure in one vs another. There are over pressure signs to watch for, like diff extraction or excessive case head pounding, all over pressure events, regardless of vel achieved.

 

[Wise_A]

Normally the erratic velocity is above and below the book loads. The laws of physics dictates that more pressure will give more velocity. For every action, there is an equal and opposite reaction. Erratic velocity means erratic pressures, which indicates a problem, all the more reason to use a chronograph.

Well, pressure doesn't create velocity, pressure over time does. You can have a high-pressure load with a fast-burning powder that generates less velocity than a lower-pressure load with a slower-burning powder.

The rest, you're agreeing with me. I'm not saying chronographs are dumb. I'm saying that it's dumb to load over max because your chrono results were lower than the book velocity for a load.

Perhaps you meant to say more or less the same thing, except whenever one starts mentioning "pressure = velocity", it's possible to interpret that as a license to go hog-wild if your gun doesn't duplicate the rather optimistic velocities listed in manuals.

What is a good reason to start shoveling powder in?

There really isn't one.

If the book says 15 grains at 1200 FPS, and without pressure signs I am getting 1400 FPS, should I be backing off? If I am getting 1000, is it not safe to up my charge?

If the book says 1200, and you're getting 1400, I'd be shocked. In fact, my first order of business would be to pull and weigh my bullets, verify the powder charge I'd dropped, and then check that my scale was working properly.

If the book says 1200 is the max, and you're getting 1000, no, it's not safe to continue. Your gun isn't going to explode if you go .1 grain over, but there's no percentage in pushing things, and the fact of the matter is that you really have no idea what's going on in the chamber.

What is a good approach to loading "off the books", and basing the charge on velocity?

I don't think there's any point to it unless you're in a few very specific forms of competition--and even then, I think those instances have been corrected-out by rules changes. There are so many cartridges and powders available, there's no sense pushing it. Another 100 or 150 fps isn't going to solve any real-world problems. I'd pick a different cartridge--either .41 or .44 Magnum, or .357 Remington Maximum.

Is there a method? Sure. Do I know it? You bet. Am I going to tell you how to do it? Christ, no. To be frank, the questions you're asking frighten me. Somebody mentioned to you something about loading based on velocity, and you've extrapolated that in entirely the wrong direction. You simply can't start exceeding book values until you correct that.

What velocity in a 357 is starting to get questionable? (low or high) For simplicity, base it off a 158 gr bullet.

Velocity isn't your limiting factor, erratic powder behavior is. I bet that I could blow up a gun with an overly-fast powder before I hit the maximum velocities achievable with a slower powder. And I can blow up a gun by jamming the bullet deep-enough into the case to spike pressures. And I can blow up a gun by loading it too long and jamming the bullet into the rifling. Similarly, just because I can hit X fps in my 6" 686, doesn't mean your 6" 686 will produce the same velocities. Even if we happened to have consecutive serial numbers.

Velocity means nothing. Average velocity means nothing. The relative consistency of five or even better, ten rounds means a lot.

The path you're asking about is dangerous, especially when you get into .44 Magnum. Things go very wrong very quickly when you get into big-bore Magnums.

 

[LoboGunLeather]

Learned the lesson many years ago. Everything I load is well below recommended "maximum" loads (9X19, .38 Spl, .357, .40S&W, .44 Spl, .44 mag, .45ACP, .44-40, .218 Bee, .25-20, .32-20, .300 Sav, .250 Sav, .308, .30-06, .33 Win, .45-70, .45-90, .45 Sharps Express, and a few others along the way).

Revolver ammo at 90% or so loads provides great practice ammo without undue strain on the gun. Magnum loads at 90% provide excellent performance within reasonable handgun range. Semi-auto pistol ammo only needs to consistently operate the pistol to provide good range service. Hunting ammo at about 90% loads provides excellent results on game animals at reasonable ranges. If I feel the need for more power I can simply change to a more powerful firearm, rather than try to stretch the capabilities of a less powerful caliber.

Works for me. I own several modern firearms from the past 50 years that have never been fired with factory ammo. I also have several 100-plus year old antiques that continue to provide fun at the range and critters for the dinner pot.

YMMV

 

[Protocall_Design]

Up to a point you are correct. It falls apart when your bore is of a different condition than the bore on a test gun. Take a well eroded rifle barrel that looks like a bad road. The friction from the eroded barrel will give less velocity than a smooth barrel at the same pressure.

If you only change one variable, the pressure, then you have the same equation. That means higher pressure in the same barrel. If you change from one barrel to another, you have a different equation and are not comparing apples to apples.

 

[rwsmith]

Hopefully....

Hopefully, one day in the future there will an affordable way for reloaders to measure their chamber pressures accurately.

Do you mind if I expound a bit?/

I'm not a mathematician, but I would think that the total area underneath the time/pressure curve would be total energy produced. If a powder can make this curve wider (longer time) WITHOUT exceeding the maximum pressure, it will have time to impart more velocity to the bullet. Is this right?

 

[Wise_A]

Yes. That's how powders of different speeds work. The number listed is the peak pressure. The manuals don't describe the duration of the pressure.

As per Hodgdon, .44 Magnum, 240-grain JHP:

Titegroup - 10 grains - 1292 fps - 37,700 CUP
HS-6 - 15.1 grains - 1417 fps - 38,200 CUP
Lil'Gun - 24.5 grains - 1582 fps - 38,100 CUP

Hence why slower powders tend to use larger charges. They're converting more mass to gas (et al), at the same peak pressure, by taking more time.

 

[BC38]

The bottom end of the charge range for most 38 special loads is about 10%v under max, and a 357 magnum case has about 10% more volume than a 38 special case (roughly).

In my experience, if you load at the top of the range for a given 38 special load - but in a 357 magnum case - your results should generally be in the same ballpark as what you'd get at the bottom end of the range using a 38 special case. Not exact, but reasonably close.

So, that is where I start when I load 38 special recipes in 357 magnum cases. Same for 44 special in a 44 magnum case. You can bet the power, pressure and velocity will be equal or a little higher than the minimum 38 special load, but WAY below a 357 magnum load for the same bullet