Exceed max powder charge in the tables 38 special

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Grizzlie

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TL;DR
My powder charge for 38spc is exceeding max charge in the manufacturer's tables yet I'm not achieving fps/mps (that even the min charge is telling me I should be getting). Solutions (?):
1. Add more powder until desired bullet velocity is attained with repeatable accuracy without signs of overpressure?
2. Seat bullet deeper (staying above min OAL) until getting velocity with repeatable accuracy without signs of overpressure?
3. I'm doing something terribly wrong. Where's my mistake?

More details

Powder: Vectan Ba9
Case: S&B 38 special
Primer: Fiocchi small
Bullet: TMJ 125grains, round nose.
OAL: 38mm

Press: Lee Loadmaster + autodisk + 4 die set (Lee)

At powder charge 6.95grains I'm getting:
Velocity: 215 +/-12 mps (705 +/- 39 fps);
max: 237mps (777 fps)
min: 198mps (650 fps)
ES: 39mps (128 fps)

The standard deviation is the smallest thus yet. My increments were 5.2, 5.6, 6.3, 6.5 grains (using the lee auto disk).

Vectan's tables for a TMJ 125grain bullet (jacketed soft point flat nose - the closest in terms of weight) give a max of 6.5 grains which should give me a max velocity of 325mps (1066 fps). Min charge 5.2 grains should be getting 292mps (958 fps).

I'm swaying toward seating the bullet maybe 0.5mm deeper or perhaps up to 1mm? Or increase the charge? Hmmm
 
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I'd be suspicious of Vectan's tables. If min to max charge is only different by 20 fps, something is wrong. Also the on line table shows barrel length of 1.15 inches -- does anyone make a .38 that short? Last suggestion would be to use a scale when working up loads close to maximum; verify your Lee autodisk is correct with the powder you are using.

Attempting to duplicate a loading table fps by increasing the powder charge is not a good practice since several other variables (such as barrel length) are at work.
 
Ah yes, the gun itself...

Smith Wesson Model 60-9 (~2 inch barrel).

*Correction, I looked at a different bullet for Vectan's Tables for the min charge+fps (I quoted the FPXTP - flat point extreme terminal performance.)
The min charge and fps should be 5.2 grains, 292mps (958 fps)
I've updated the main post

Also, Vectan gives 292mps equaling as 953fps, whereas google converts 292 as 958mps...hmmm (?). Probably insignificant differences, but why the difference in the first place?
 
My initial thought is that to try to get 1000+ fps out of a 2"barrel is really dangerous in a .38 Special. If you are shooting it in a .357 mag revolver it may be marginally safe but the muzzle blast will be awesome as will the recoil.

Why not drop in 5.0 to 5.8 grains of Unique and be done with it? I've used 5.0 grains of Unique behind a 146 grain lead semi-wadcutter for 30 years and had great accuracy with reasonable recoil.

The Vectan Baa9 site says it is about the same as Unique. Start low and work up using Unique loads and see if you can match the 2" barrel reloading book specs.; not necessarily those found on the internet.
 
I checked the Vectan data, but no barrel length or other information was shown on what firearm was used to generate the velocity data. It could easily be a 6 inch test barrel. This would not have a cylinder gap, plus the long barrel will maximize velocity. I agree with the others that trying to get 1000 FPS out of a 2 inch barrel is difficult.

One thing you can do is bench mark your velocity by shooting factory 38 spl ammo through your chrono and see how it compares.


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Coupla questions. Does your bullet have a cannelure for crimping into? If so, how can you legitimately change seating depth? What method are you using to determine "signs of over pressure" ? Like others here, I doubt if you can get 1066fps from your gun.......safely. You're already almost half a grain over max and 350fps short.
 
I have achieved over 1000 fps with a 125 gn bullet from a 38 special 2 inch barrel but I had to slightly exceed max published loads for HS-6 and use a magnum primer.
You really need to be careful doing this so I don’t recommend it. But I would recommend trying a different brand powder and you might see better results.


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I checked the Vectan data, but no barrel length or other information was shown on what firearm was used to generate the velocity data. It could easily be a 6 inch test barrel. This would not have a cylinder gap, plus the long barrel will maximize velocity. I agree with the others that trying to get 1000 FPS out of a 2 inch barrel is difficult.

One thing you can do is bench mark your velocity by shooting factory 38 spl ammo through your chrono and see how it compares.
Click to expand...

Good job. :) Shooting factory ammunition is an excellent basis for comparison. While an imperfect measure of pressure, you know the factory has pressure equipment, and keeping your reloads to less than or equal to factory ammunition for the same bullet weight, should keep you safe pressure wise. Assuming you are using an appropriate powder.


I looked on the web and I don''t know where in the US you can get Vectan powders. I assume you are in Europe. I am absolutely ignorant about the characteristics of Vectan powders. You know, if Vectan has a phone number, you ought to call them and sort this out with a technical representative.

I have a number of 38 Special snubbies and a number of my 125grcast reloads are going 750 to 800 fps out of a 2inch barrel. I did not fire factory 125 grain bullets over the chronograph and I did not note any extraction problems with my reloads. I made my velocity decisions based on leading with the cast bullets. Maybe I could have pushed them faster, but I stopped at 760 fps because leading increased above that speed. I think 1000 fps is very fast out of a 2" snubbie.
 
Grafs has been pushing Vectan powders for a while now. They also have load data as well.

I haven't looked elsewhere.
 
The 2 inch barrel is your problem.

What over pressure signs are you looking for? You won't see any over pressure signs on the primer of brass until you're well past .357 magnum pressures.
 
Coupla questions. Does your bullet have a cannelure for crimping into? If so, how can you legitimately change seating depth? What method are you using to determine "signs of over pressure" ? Like others here, I doubt if you can get 1066fps from your gun.......safely. You're already almost half a grain over max and 350fps short.
Click to expand...

1. No cannelure. Seating depth is set with seating die and measured by hand with calipers. Changes are done by screwing in a 'test/dummy' bullet and measuring by hand until I get the depth I want. So far I've been checking every case for consistent OAL
2. Signs of overpressure that can be viewed with the naked eye - flattened primers, bulged out primers, stretch rings on cases, etc.
 
I checked some factory Geco 38spc 158grain which gave a mean 207+/- 2.8mps (680+/-9fps) , max/min 211/204mps

S&B Magnum 357 gave 324+/-2.7mps (1063+/-9fps), max/min 326/320mps.

So I guess I'm in the area of a factory Geco load. Would it be prudent to decrease grains a bit and seat deeper to eliminate (ever so slightly) the empty space in the brass?

Answers to other questions:

1. I'm in Europe. I currently don't have access to Unique powders...or too many at all. Hodgdon I can get at twice the price of Vectan. I've chosen to start experimenting with reloading with Vectan's line. :(
2. The autodisk powder drop gives an accuracy of +/-0.1 grains for Vectan Ba9 powder as measured with a Lyman electronic scale (for example, measurements come out as 5.2, 5.2, 5.2, 5.3, 5.2, 5.1). I've been checking more or less every 5th bullet and it's been consistent.
 
About pressure signs in straight-walled cases like the .38 Spl....it is entirely possible for a load to be overpressure and for there to be NO signs of such by looking at the case.
The most reliable method of determining whether a load is too hot is to measure case head expansion.
This link is to a fairly succinct discussion of pressure measurement for the handloader:
http://shootersnotes.com/articles/when-are-pressures-too-high/
 
Grizzlie said:
1. No cannelure. Seating depth is set with seating die and measured by hand with calipers. Changes are done by screwing in a 'test/dummy' bullet and measuring by hand until I get the depth I want. So far I've been checking every case for consistent OAL
2. Signs of overpressure that can be viewed with the naked eye - flattened primers, bulged out primers, stretch rings on cases, etc.
Click to expand...

With no cannelure, I'd be very afraid of bullets jumping crimp in a revolver with the heavy recoil you are going to get with over max loads.

As has been said, very difficult at best for the average handloader to see overpressure in revolvers by just looking at cases.

Just, sayin'.
 
You will never get signs of over pressure on a 38 special case until you are past .357 magnum pressures. Same goes for any low pressure round like 380 Auto or 45 ACP. Primers don't have some magical ability to know if they are install in a 38 vs a .357 or a 9mm vs a 380 or a 45 ACP vs a 44 Mag.
 
There is no way you can measure the chamber pressure of your gun with a chronograph.
If a maximum listed load isn't giving you the same velocity listed in the manual there is a reason for it but it likely has less to do with pressure than it has to do with everything else.

You can continue to push beyond the maximum loads until it blows your gun apart and maybe never get the listed velocity. If you want higher velocity than you get with the powder and bullet you are using then switch to lighter bullets or a different powder. there is, as a practical matter, no correlation between velocity and pressure. If there was I could load my 300 Win. Mag. with enough Bullseye to get 3000 fps and only get the same 50000 psi. In reality I would likely get 50000 psi long before I got more than 1800 fps and the gun would become a bomb long before I got close to 3000 fps.
A chronograph only measures the velocity. It cannot measure, or even approximate pressures.
 
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