Which powder for .38Spl-.357Mag /rifle/ for subsonic 158gr cast

[Kestrel4k]

I'm reloading for my suppressed 77/357, so am looking for a /subsonic/ rifle load - and there's certainly less data for that particular area.
I will be shooting the Penn 158gr TCBB (http://www.pennbullets.com/38/38-caliber.html), sized to 0.358" (my bore slugs 0.3565")

The most applicable powders in my inventory are:

Bullseye
Red Dot
Unique
800x - poor metering is of no concern for this application; all charges will be trickled

I was wondering if folks might have any suggestions for subsonic loads in .38Spl OR .357Mag rifle - I have plenty of cases for either and both lengths feed well from my magazine.

I have been developing subsonic 158gr jacketed & 230gr cast loads from scratch for this rifle throughout the summer, but hitting the 1000-1080 fps window from a 16" bbl takes quite a bit of work even prior to accuracy evaluation. I have some experience with QuickLoad but its velocity predictions are less accurate than I'd like when using straight-wall pistol cases.

Thanks in advance,

[jcren]

Have you considered the new Lee 200 rf bullet loaded long in 38 cases? Don't have one yet, but have been researching 357 lever loads, and that bullet over unique in on my must try short list.

[GhostHawk]

I have very good luck with .358 158 gr round nose over 4.6 of Red Dot in my Handi Rifle.
It has a rather long lead so the most accurate ones are actually loaded into .360DW cases. Yes they fit, just. Bullet is maybe 1/6th of a hair off the rifling. And it will shoot cloverleafs farther than I can hold it.

I also have an for hunting recommend the Lee .360 200 grain gas check wide meplat round nose.
But it is a bit more than I really need for punching holes in paper.

I tried IMR 4227 but it was no more accurate than the Red Dot and used about 5x as much powder at a corresponding higher cost.

I also recently picked up a .358 124 gr which I hope to test soon. Works great in my problem 9mm's.
It would significantly lower lead use if it can hold reasonable accuracy. Time will tell.

[dannyd]

I would use Unique best all around powder

[Ed_Shot]

+1 for Red Dot/Promo for 120~160 gr. boolits in .38/.357. My Marlin and Handi like the Lee 358-158-RF and Lyman 358156 over Red Dot/Promo 5.0 gr in a .357 case. If I want more power I use 2400.

[RickinTN]

I've used mostly Clays in 38 special with good success in handguns as well as a Rossi 38/357. Since you don't list that powder my vote would go to the Red Dot as being the closest you have.
Good Luck,
Rick

[Kestrel4k]

Sounds good, thanks for the recommendations. Getting good accuracy hasn't been a huge challenge with this rifle - good accuracy at subsonic velocities has been very difficult however.

My first test will be 4.0/4.3/4.6/4.9 grs of Red Dot in .38Spl cases (matched for headstamp & case weights), with a subsequent test in .357Mag cases (adding 0.3 grains for the increase in case capacity).

Unique can be my backup choice if I don't get good results with Red Dot - I have tried Unique with 158gr JHP XTP's, but did not get good accuracy until 1260 fps was reached.
800x gave me better results in that test - maintaining good accuracy down to ~1100-1150 fps.

[wiljen]

4.5gr of unique is about max with a 158 to stay under your 1080 mark. I would think some of the fastest powders like red dot might lose accuracy in the 16" barrel as it is entirely burnt in the first 6 inches. To me, finding a powder that burns in 12-14 inches would be about the best bet. 4.5gr of Unique shows complete burn at 11.9 per QL. 4.5g of Bullseye shows complete burn at 6.2 inches for comparison.

[fecmech]

With 158 gr bullets 4.2/Bullseye or 5.0 Unique are just over 1000 fps out of both my Rossi rifles with 20 and 24 " barrels. Accuracy is very good.

[Kestrel4k]

4.5gr of unique is about max with a 158 to stay under your 1080 mark. I would think some of the fastest powders like red dot might lose accuracy in the 16" barrel as it is entirely burnt in the first 6 inches. To me, finding a powder that burns in 12-14 inches would be about the best bet. 4.5gr of Unique shows complete burn at 11.9 per QL. 4.5g of Bullseye shows complete burn at 6.2 inches for comparison.
What you're saying makes some sense; however I did comparable load development for my 16.5" bbl 77/44 and got the best results with Red Dot & 240gr XTP's: 1/2" to 3/4", 5-shot groups @ 50 yds.

So I'm not sure what will happen, but I bet I'll get a mix of results. :)

[Kestrel4k]

With 158 gr bullets 4.2/Bullseye or 5.0 Unique are just over 1000 fps out of both my Rossi rifles with 20 and 24 " barrels. Accuracy is very good.
Thanks for that info; w/ .38Spl or .357Mag cases?

[Scharfschuetze]

Has anyone mentioned Tight Group yet? It's one of the few "modern" non legacy powders that I've come to use routinely.

At subsonic velocities in straight wall cases from the 32 S&W to the 45/70, it provides very uniform velocities, sometimes bordering on or beating black powder spreads. Accuracy is the equal of any of the other fast pistol powders.

[fecmech]

Thanks for that info; w/ .38Spl or .357Mag cases?
That is with .38 cases but mag cases aren't much different, if anything a touch slower.

[Walks]

Scarf is right. Titegroup is the way to go.
I've been shooting 3.2grs behind a Lyman 358665/158gr in .38spl cases 4 20+ yrs 4 Cowboy in Colts & a Marlin 1894css without a problem.