357Magnum w/1 in 18 3/4" twist

[smokeater]

Sorry if I'm in wrong section but what's is the heaviest/lightest bullet for 4.2" barrel with twist of 1 in 18 3/4"? Have 150/158swc and 165HP and 170 WFN cast bullets.
Thanks for any help offered.

[megasupermagnum]

There isn't really a lightest. I've gone as heavy as 220 grain in that twist, but it needs to be pushed really hard for good accuracy. 200 grain is a good practical maximum.

[NSB]

I’ve owned quite a few custom built handguns and rifles in 357mag. I have never got great accuracy with any of them that had a 1:18 twist. Bill Davis and Dan Coonan recommended 1:16 which will shoot all bullet weights well (I owned two of each). I purchased two MGM barrels for my Encore, one with 1:18 and one with 1:16 and there was a profound difference with the best groups shot with the 1:16 by a wide margin. My current favorite is an SSK premium barrel for one of my Encores that shoots five shots 1moa or less at 100 yards. If you can, get a 1:16 or a 1:14 barrel.

[missionary5155]

With our Dan Wesson 18 twist it would shoot 3" near cloverleafs at 100 yards with 180's or 200's GC and pushed very fast wit 296 powder.
That is with me laying on my back in the "pistol Creedmore" position.
It is about "rotational speed" of the slug. Been well discussed here at Castboolits. The formula escapes me but a search will turn it up.

[jdgabbard]

I'm admittedly no ballistitian... But my experience, and observations of recommended twist rates, has always been that the heavier the load the fast the required twist. That said, I have a S&W Model 65 that I have put 10s of thousands of rounds downrange out of. Matter of fact I was just last night marveling at that pistol and the fact it's never, to my knowledge, required a rebuild. But that said, I have attempted to shoot RanchDog 190grs out of it, and it just really didn't like them. Accuracy was nowhere close to what I get with 170gr Keith bullets, or even others such as the 358477 and 358156. And this mimics the performance I have seen in other 38 and 357 pistols. So I would say in most 4" pistols the 170-180gr is most likely upper limit of weights that will give good accuracy. But every gun is different, and there are exceptions. Many people shoot that same RD-190gr bullet out of lever guns and they really like it. But I found in my Model 65 it just doesn't make sense.

[smokeater]

Thanks Gentlemen for your insight/experience. Really gave barrel twist no thought when I bought. My new MP 173 Hammer mold with my alloy throws a 168gr solid and a 163gr cup point. So actually weight wise still in the realm of the 358156 and the 358429. I also have the usual 158gr swc (gc) and the Lyman 358477 which I am getting fonder of the more I shoot it. Never having a 357 revolver before, was kinda wondering what the optimum bullet weights were for the 1in18 3/4" twist. Finding out that developing a good load for a handgun is totally different than for a rifle. Again Thanks.

[megasupermagnum]

Thanks Gentlemen for your insight/experience. Really gave barrel twist no thought when I bought. My new MP 173 Hammer mold with my alloy throws a 168gr solid and a 163gr cup point. So actually weight wise still in the realm of the 358156 and the 358429. I also have the usual 158gr swc (gc) and the Lyman 358477 which I am getting fonder of the more I shoot it. Never having a 357 revolver before, was kinda wondering what the optimum bullet weights were for the 1in18 3/4" twist. Finding out that developing a good load for a handgun is totally different than for a rifle. Again Thanks.

As I'm sure you know, it's not the weight that matters. Just because you use a cup or hollow point and they are lighter, doesn't mean they will stabilize easier. The bullet is still the same length. You would be changing the balance point of the bullet which may help or hurt, probably won't see any difference with a cup point. I hate saying there is an ideal bullet weight or length for a twist rate since there are so many factors, but I can assure you 150 to 180 grain bullets are perfectly suited for 18 3/4" twist barrels.

[smokeater]

That's good to hear. Not really hung up on heavy for caliber bullets but would like one heavy bullet/load combo for woods walking and for "what if" circumstances. The LEEC358-158gr swc and the 358477 will meet 95% of my shooting/hunting needs. Around here we have a healthy coyote population and not uncommon to see 2, 3, sometimes even 4 together and we're also sitting between two known hog areas and this area is well known by the Conservation Dept as one of only 2 areas in the state that has a breeding population of black bear. Not really concerned about bears as I don't tend to traipse in the woods during the summer cause of a couple of other slithery critters plus the chiggers and ticks. I'm pretty sure either of the two previously mentioned bullets would do fine, just liked the idea of a heavy flat nose bullet. if it works out fine if not I'll put it up or sell. I really appreciate your interest and sharing your experience.

[NSB]

Here’s how it works…generally. When using heavy bullets for caliber, you need a faster twist. A 1:18 twist in a .357 cartridge will require a faster twist rate to give you your best accuracy. There may be some exceptions, but for the most part you’ll do much better with a faster twist rate for bullets weighing more than 158g in a .357. The best gun builders and the best shooters will tell you that a 1:16 twist is the preferred choice. Do a bit of research on this to verify.

[megasupermagnum]

Here’s how it works…generally. When using heavy bullets for caliber, you need a faster twist. A 1:18 twist in a .357 cartridge will require a faster twist rate to give you your best accuracy. There may be some exceptions, but for the most part you’ll do much better with a faster twist rate for bullets weighing more than 158g in a .357. The best gun builders and the best shooters will tell you that a 1:16 twist is the preferred choice. Do a bit of research on this to verify.

Yeah, except there is nothing he can do about it without spending an arm and a leg. At 4.2", I'm sure it's a Ruger GP100. He will be fine. They shoot better with 180s than 125s.

[PP-67]

looking for an answer to this question,
I found a blog from one of your
http://357shooter.blogspot.com
I found the answers.

[smokeater]

Yes it is a 4.2" GP100 357Magnum. And Thanks for the 357shooter link.

[smokeater]

Putting in the required data asked for with the JBM Ballistics calculator software, my Stability rating for my 357 bullets range from 3.243 to 3.406 thus according to calculations should be plenty stable. Lots of good stuff on the 357Shooter link. Thanks to everyone. This is why I only belong to Cast Boolits Forum. Someone inexperienced can ask a question or seek help with a problem and they are not treated as dummies.