.357 Mag /.38 Special carbine loads ?

[BigSlick]

Lookin for info on runnin a 16" barrel with .357 Mag or .38 Special.

Gonna go with cast at ~ 12 BHN, unless that proves futile.

Any things to watch for or skip doing ?

I'm thinking a 158 or a 180, but I'm open on weight/style at this point.

I *might* also run something like the (new) Hornady bullets based on the Leverevolution or maybe an XTP just for grins, but *really* prefer to run cast.

[DssG19]

My Marlin levergun does'nt like SWC. I shoot 90% .38 spcl cast 158gr RN. No problems at all. Missouri bullet has a 158gr RNFP for tubular magazines, I ordered 1k to try em out. You can shoot SWC, but they sometimes get hung up....

[4eyes]

Make the length of twist a higher priority than make/model. Second the "don't like SWC bullets".

[BigSlick]

I'm thinkin what... maybe 1x16 ?

[4eyes]

I checked the Marlin site and the 357 is 1/16. Don't know if anyone else makes a slower twist. I have a 44 with 1/38. Thought 1/38 was crazy until I started pressing the lead loads. Accurate and consistant 1800 fps easy with non checked 240 gr. lead with no bore leading. Shoots cowboy loads with swaged bullets fine also.

[BigSlick]

I'm gonna be workin with a Winchester. I *think* they're 1x16, but I ain't 100% sure about that.

I been thinkin about your comment about watchin the twist rate. After some study on it, now ya got me wonderin if any of the data (even for rifle) is based on 1x16 or ???

I would really like to get a chance to work with somethin like the 1x38. I don't recall ever workin with a twist that slow before, but, I can see how it would definitely open up some good potential... like maybe somethin in da 200 grain + range - which would tickle me like nothin else for this application.

I'm gonna be wondering about Winchester twist rate until I find out for sure now.

This could turn out ta be a helluva lotta fun :supergrin:

[4eyes]

My supposition on the 1/38 is it allows easy lead entry into the rifling; less stripping.

The 1/16 ( good old pistol twist) should be better for heavy bullets.

[BigSlick]

My supposition on the 1/38 is it allows easy lead entry into the rifling; less stripping.

The 1/16 ( good old pistol twist) should be better for heavy bullets.

I realize the faster twist will stabilize heavier bullets better than a slow twist, but in a .358 over 200 grains I'm wondering if the slow twist might allow running the bullet without it completely whackin out the accuracy with such a heavy bullet.

Any idea about how to correlate the 'limitations' of twist rate vs bullet weight vs fps ?

.44 Mag runs a slower twist with much heavier bullets, I'm wondering if running a slower twist in .357 might allow for running bullets heavier than the caliber is typically loaded with.

I'd really like to see if I could run a 250 gr bullet. Maybe just not possible, but I think running that weight bullet (even though it would be slow) might give the gun a little more useability, and alleviate some of the potential issues with outrunning the alloy.

I've been reading accounts of the carbines running 158gr cast bullets in the 16-1700 range with undocumented data. Some folks get away with it fine, but they are in the minority where leading or accuracy issues are concerned.

I know, ya can't make a .357 into a .41 Mag, but I'd sure like to run some heavy bullets without worrying about wearing out a case of Chore Boys or working with pressures above the limitations of the caliber.

I can see a lotta use coming from say a 250 gr bullet running in the 1050 range or so.

Not a typical load for a .357 Mag, I know, but running 158gr cast with book data in the 12-1300 fps range just doesn't jazz me. It ain't bad, but it sounds kinda boring.

I can get a mould cut from Mountain in the weight I'm talking about and see what kinda of results I get, but, I don't want to venture off into an excercise in futility if the twist rate just prevents it from being wholly feasible.

Can ya tell I been bored outta my skull the past week an a half ?

[CZ93X62]

Slick--

1-16" and 1-18.75" twist (Colt and S&W respectively) run Lyman #358430 (195 RN plain base) VERY well at 1200-1250 FPS.

If you take a look at Greenhill's Formula (web search), it can point out the "optimum" twist rate for a given bullet fairly closely. Dan's software at Mountain Molds has the Greenhill function built into it, in the lower end of the text on the design-your-own page.

Most pistol-caliber bullets are best served by a twist rate of 1-20" to 1-30". The 1-38" twist is a leftover from the Winchester '73 in 44-40 WCF, the 200 grain round flat-nose bullets weren't much longer than they were across. They are stable at 1200 FPS in the '73, but I think the only reason the 44 Mag and 444 Marlin do well is the extra velocity they impart to their 240 grain bullets. 240 grainers don't shoot worth crap at 1000 FPS out of my '73. Velocity is part of the program when it comes to the twist rate/bullet length equation--the "constant" in the Greenhill Formula changes as the muzzle velocity increases--from 150 to 180 at the 1,800 FPS point. (Rinker, Understanding Firearms Ballistics, pp. 141).

[4eyes]

Nice to see a note from someone that is educated on the subject. Thanks CZ.

Know anyone with a 357 Desert Eagle? ? the twist--prolly 1/16. Cut the mold and try it there prior to buying a rifle.

[CZ93X62]

A gas check is a wonderful device, and to paraphrase Mark Twain--they can cover a power of sins. They are pretty much a requirement for cast bullets in a rifle at about 1400 FPS, and while I might be full of it--I believe they assist a cast bullet in taking the rifling without undue skidding, even in a twist like 1-16".

I'm wondering if you're being overly concerned with this "fast" twist question, Slick--I routinely run cast bullets in 243 (1-10"), 250 Savage (1-14"), 30-30 WCF (1-12"), 30-06 (1-10"), and 9.3 x 62 (3 turns/meter, about 1-13.1"), between 1600 and 2000 FPS. I can shoot all of these calibers with castings to 1.5 MOA at 100 yards, and some loads/calibers are in the 1.0 MOA's toll-free dialing area. No exotic alloys, just 92/6/2 and stock Hornady gas checks on mostly commercial moulds. I designed the 9.3mm critter on Dan's software at MM.

Twist rates and castings start getting froggy at about 1-9". At this rate and faster, cast bullets start losing the ability to shoot well at higher velocities. 6.5 x 55 milsurps are noted for this, the cast bullet speed limit is about 1600 FPS in their 1-7.9" (5 turns/meter) twists. Same story in my Win 94 with its 1-8" twist--to 1600 FPS, it does well with castings--push it past that, and things go to hell in a handcart.

Hope this helps.