MAX Velocity of 357 158gr cast bullet in a 4-inch barrel?

[gilgsn]

Hello.
I am trying to determine a maximum do-not-exceed velocity for a cast & coated 158gr bullet in my 4" 586. Note that I am well aware that a certain velocity doesn't necessarily mean a safe pressure... Surfing YouTube, I find values between 1250 and 1434fps (for Underwood & Buffalo Bore), the later seemingly very high for a barrel that short. I wonder what kind of powder they use...
Just for information, I have only access to French powders and Vihtavuori:
Vectan Ba9: Very close to Unique (not used for heavy loads).
Vectan SP3: Very close to 2400.
Vectan Ba6-1/2: Very close to N110/H110.
My test loads (not shot yet) do not exceed 15.5gr of both SP3 and Ba6-1/2, slightly below Vectan's max published data.
My light load is 5.5gr of Ba9, and my medium load is 13.5gr of SP3. I use Starline 357 cases with regular primers.
For those of you guys who own a chrono, what kind of max velocity did you settle on with your 4-inch barrel?
Thank you.
Gil.

 

[Alaskamike]

About 1300 to 1350 fps for me. I don't shoot many loads that hot anymore though. Most of my .357 loads now are 1000 to 1100 fps probably.

 

[.38 Special]

As a teenager, I loaded everything as hot as I could. 158 cast SWCs were loaded with enough H110 to get them over 1400 fps in a 4" gun. Cases had to be pounded out of the chambers.

These days anything above 1350 fps starts to make me wonder, and I normally keep it in the 1250 fps range.

 

[gilgsn]

Thanks. A couple weeks ago a guy at the range was shooting a Dan Wesson 357. I don't remember his ammo brand, but his primers were flattened and he even had a split case. He had to pound the empties out with a brass rod. The range officer told him to stop shooting. No idea how fast they were going, but I certainly don't want to over-stress my revolver like that guy did. It takes way over safe pressure to flatten a primer.. Even if the cylinder doesn't give immediately, there is no telling when it will. It just baffles me that he seemed to find those pressure signs normal. When I told him it seemed excessive, he just said "It's 357 Magnum." As if ammo manufacturers can't make mistakes...
I wouldn't have shot a single round of his ammo. Even worst, I was in the lane right next to his, separated by a thin sheet of plexiglas.
If I see the slightest primer flattening, just the edges not being nice and round, or a sticky extraction, I stop and back off one notch. The chrono is a great help, as too fast a bullet for the powder used might be the first sign that something is wrong.
Right now I am considering 1300... Hoping for more inputs...
Gil.

 

[AJC1]

N110 will get you max speed. Cip standards are 40kpsi and Sammi 35k. You should get more than most here unless they just don't follow manuals.

 

[Jim Watson]

I don't know what your top loads might be with domestic powders but I do have a bit of French humor on the subject.
The GTV - Grand Tres Vitesse - ammunition fired a hollowbased copper projectile so heavily loaded that there was powder up into the bullet base. Chamber pressure was ca 50000 psi, excessive by CIP and SAAMI standards.
To which the developer responded: "But Monsieur, it is only for the minutest fraction of a second."

Buffalo Bore claims
➤ 4-inch S&W L frame Mt. Gun
c. Item 19C/20-158gr. Jacketed Hollow Point = 1485 fps

But they SAY this is with Secret Sauce powders and I think at excessive load levels.

Lyman shows 158 grain velocity up to 1100 - 1300 fps in a 4" vented test barrel.

 

[Hartkopf]

Flat(ish) primers are not always a problem. Sticking cases worry me more than primer signs.

 

[GRIZ22]

I don't go over about 1250 fps. That's what most factory loads go to when chronographed. The same loads go about 1800 fps in a lever action.

 

[armoredman]

Just for clarity's sake, are your bullets gas checked as well, or just coated?

 

[tightgroup tiger]

I don't go over about 1250 fps. That's what most factory loads go to when chronographed. The same loads go about 1800 fps in a lever action.

I don't, much anymore either. I won't go over 1300 in .357mag with 158gr anything. I used to try to get to the magic 1450fps mark but each gun is different and a lot of companies that test loads here in the states are using a closed breach, universal reciever, anyways so that makes it un-obtainable to me when I use a revolver with and cyl to barrel gap that looks big enough I can throw a cat through it.

 

[fxvr5]

Buffalo Bore claims
➤ 4-inch S&W L frame Mt. Gun
c. Item 19C/20-158gr. Jacketed Hollow Point = 1485 fps

But they SAY this is with Secret Sauce powders and I think at excessive load levels.

DOES BBA MAKE AMMO TO SAAMI SPECIFICATIONS?

DOES BBA MAKE AMMO TO SAAMI SPECIFICATIONS?

www.buffalobore.com

 

[gilgsn]

Just for clarity's sake, are your bullets gas checked as well, or just coated?

Just coated.
Gil.

 

[orionengnr]

I recently bought an old .38/44, so have been reading up on appropriate handloads for this cartridge.
Most of what I read says that 2400 provides the best velocities for anything up to and including 4" barrel.
If you have a 6" barrel, W296 will give higher velocity.
So I am having fun loading and shooting 158s with 2400.

 

[gilgsn]

Hello.
I was able to chrono some loads today and the highest velocity obtained for a 158gr was 1325fps out of my 4" using 15.5gr of Ba6-1/2 (equivalent to N110/H110/W296). The same charge of SP3 (equivalent to IMR4227) gave 1148fps. The maximum published data by Vectan for SP3 is 16.2gr, so maybe I ought to try one more load. No pressure signs yet with either loads, though the Ba6-1/2 15.5gr charge had one ever-so-slightly sticky on one chamber, so probably a good sign to sop there with that powder. SP3 seems to be more regular.
Interestingly enough Ba6-1/2 is more regular in .41 Mag than in .357 Mag.
Gil.

 

[Charlie98]

Sounds like you are on the right path. If I was looking for max velocity in a 4" pistol... and I used to own a 4" 686... I'd reach for the H110... or your equivalent. I like powders in the 2400/IMR4227 range, they work exceedingly well in rifle barrels, but if I want max velocity in a handgun barrel... H110, et al, is the ticket. If you are getting 1325fps... and reasonable accuracy... I'd call it a day.

Interestingly enough Ba6-1/2 is more regular in .41 Mag than in .357 Mag.

I would guess that as slow as Ba6-1/2 is, it may not be optimum for some light bullets in .357... something like 110grn or even 125grn bullets. It probably works very well with your 158's. Along those lines... your PC'ed cast bullets should be fine right where you are at, but if you ever get a chance to pick up some gas checked 158's or heavier, I'd give them a try. Slower powders need bullet weight to work efficiently, in my experience.

One of my all-time favorite loads for my 686 was a 180grn cast TC bullet, over H110, or if I didn't want to pound my hand into putty... Unique.

 

[gilgsn]

Dennis, you are absolutely right, as I am finding out. SP3 did produce a muzzle flash, while Ba6-1/2 did not, so a bit of SP3 burned outside the barrel, hence the loss of velocity. I just bought an MP mold, 359-Hammer, which produces either a 173gr WFN or a 158gr large HP. It will be interesting to see the results with the 173gr and SP3. I am thinking of a Rossi 357 carbine too... For my next loads I might get Vihtavuori N110, though that should be equivalent to Ba6-1/2. I even wonder if the powders are the same, since the load data from the Vihtavuori and Vectan sites are literally copy-pasted...
Unique, or rather Ba9 in my case, I use for light loads, 5.5gr @ 877fps, 6gr @ 949fps and 6.5gr @ 1010fps. For anything faster I switch to slower powders. I might try VV N340 instead of Ba9, or 3N37, down to N350.
What is really cool is that I use the same powders for .357 Mag, 300 Blackout, .41 Mag, even .32-20!

Gil.