Low Flash Powder for the .357 Magnum


March 1, 2008, 01:58 AM
I have been working on a replica round to mimic the Speer 135gr .357 Magnum Short Barrel round. I have found a powder and charge which closely mimics the round but the flash is large.

Speer in a data release recommends 3 powders and charges for their 135gr GDHP SB bullet. They are Power Pistol, Unique and VihtaVuori 3N37. Anyone who has used Power Pistol knows the flash is huge and Unique isn't a low flash powder either. Has anyone used VihtaVuori 3N37? If so can you tell me if it produces a lower flash than most powders on the market? I would hate to buy a lb. only to find out it's no better than the others.


If you enjoyed reading about "Low Flash Powder for the .357 Magnum" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
March 1, 2008, 02:38 AM
This may not be of much help, but I use VV N340 powder in my .357 mag loads and it seems that there is no visible flash from my 5" revolver. That was a real surprise. There is also an almost complete lack of soot, flakes, dirt, and fouling that I usually get from W-231 and H-110.

Hopefully 3N37 will leave you with similar results.

March 1, 2008, 02:54 AM
3N37 flashes--but much less than the others in the GDSB 38+P loads. I haven't tested the 357 Magnum level loads yet.

Ramshot Silhouette, in preliminary 38+P tests looks good for low flash--very good. I have the 357 rounds built, but haven't shot them yet--and I suspect it may be slower velocity.

Jim H.

March 1, 2008, 03:32 AM
Haven't tried it at night to check the flash yet, but I always thought the feel of the SB GDHP round in my Taurus 605 was best duplicated by Bullseye.

For reference, 16gr of 2400 definitely isn't low-flash (http://kd5nrh.blogspot.com/2008/01/more-muzzle-flash.html) :D

March 1, 2008, 05:41 AM
AA9 shines in 357, and doesn't have anywhere near the flash of 2400 or 296.

March 1, 2008, 06:59 AM
Don't know if that is possible though. Blue Dot, AA9, 2400, 296 are all flame throwers to a degree. I think Blue Dot, might be the worst offender (as magnum primers are used in the really slow stuff) which seems to help a little, subjectively, at least. I have fired AA9 in 125 grain loads with a light crimp and standard primer. This creates a fireball almost as big as BD. Then I switched to magnum primers and a very heavy crimp and got less flash. So, is AA9 the best compromise?

Bullseye is fine for lighter loads with light bullets, but I am not a big fan of massive doses of the stuff (seen too many guns destroyed that way). 231 is also too fast. AA7 might work, but you will lose some velocity over the slower powders with heavier bullets.

So, I want to know too. What has a burn rate like 2400 with no flash out of a snub???? Is the VV as slow as 2400?


March 1, 2008, 07:08 AM

March 1, 2008, 09:54 AM
I've never used 3N37, but the lowest flash powder I've ever seen is Winchester WAP/Ramshot Silhouette.

Finding data for WAP and .357 is difficult and the only source I know of is Steve Ricciardelli's data (http://stevespages.com/page8c.htm). Also, a call to Ramshot might gain some insight.

I have used True Blue and it also seems to be relatively low flash. I also have some .357 loaded with WAP, but haven't had the chance to shoot/chrony them because of the weather.

Steve's data doesn't list a 135gr bullet for .357, but he does list this:

125gr: 9 to 10gr WAP
137-140gr: 8.1 to 9gr WAP

Please let us know what you decide on and give us some data of your results.

I believe 'CZ57' may have posted about this in the past, and maybe he'll drop in with some info...

March 1, 2008, 11:44 PM
My shooting this winter has been at an indoor range--satisfactorily lit, but hardly bright. Flash is pretty obvious--particularly since my 38/357 shooting is point / laser shooting, and I can see the flash pattern well in my peripheral vision.

Power Pistol flashy, period.

AA#5 has flash and even some 'sparking'

True Blue's flash is definitely there, but subdued.

Silhouette--in a few shots to check subjective recoil--had much less flash than the others.

I won't be able to chrono for at least another month to six weeks--but, yes, Ramshot's ballistician will provide data for you for 38/357 loading.

Jim H.

March 2, 2008, 02:37 PM
Are you sure about HS-6 being low flash? If that's true it would make me very happy since I already use HS-6 for several rounds including my FBI load replicas. I will have to fire off some of the rounds I already have loaded with HS-6 at Dusk for a test.

I thank you Sir.... :)

Thank for for your input. You know I value your information...

If you enjoyed reading about "Low Flash Powder for the .357 Magnum" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!