Starting to Load 357 Mag
- Thread starter Poconolg
- Start date
I pay attention to which powder is mentioned in the load book as the most accurate during the tests. If I want target loads or am loading for a smaller gun that would be a beast with full power, I look for a powder that is common to both 38+p and .357 minimum data and try something in between. Lighter loads of Unique then work nicely, but serious magnum loads have too sharp an impulse with faster powders, including Unique. I look to IMR4227 as the most shooter-friendly of the magnum powders. When loading hotter stuff, I will be using 158 gr bullets except for the smaller guns.
buck460XVR
New member
My experience with IMR4227(and I use quite a bit of it), is that it is a poor choice small cases like .357, especially with a light for caliber bullet like 125gr. In bigger cases like .44 and my .460 it works well, especially in long pipes and heavy bullets. Being as the OP is going to be using plated bullets, I'm gonna guess he needs to keep his velocities down. In that case, I'd be looking at Unique, Hp38/W231 or Bullseye. Maybe one of the latter two since the OP is new to reloading and those two meter better than Unique.
.357 is a very easy and very forgiving cartridge to reload as long as one sticks to published load recipes(and there are a ton of them out there). The OP should be able to use starting to mid range loads for jacketed bullets for his plated projectiles. Not knowing what brand they are and not knowing whether they have a cannelure to crimp into, I suggest he keep velocities below 1200 fps.
I load/shoot a lot of 357 Magnum. Been doing so for decades.
It would be helpful if you told us the purpose of the ammo you intend to load.
Since you have a 125gn plated bullet, I'm going to assume you are looking for basic range shooter ammo.
Plated bullets are not nearly as sturdy as jacketed bullets and are not a substitute for jacketed bullets. They are an alternative for straight lead bullets. In the case of 357 Magnum, a plated bullet can easily be over-driven, leaving the inside of your barrel with a nice bright shiny orange (copper) coating. I know. I've done it.
Most plated bullets' manufacturers print a velocity limit on their box. It's a bit misleading. Really, the issue is pressure - not so much velocity.
I don't load 125 plated bullets for 357, but I do load a 158 plated SWC. My current recipe is 7.0gn Unique. It yields 994 f/s 3"bbl; 1058 f/s 4"bbl; 1087 f/s 8"bbl; & 1251 f/s 16"bbl (carbine rifle). I believe this loading is at the edge of a plated bullet's capability - regardless of the printed velocity limit on the box.
Although I'm not a fan of Unique, it's nice and fluffy, so the fill level is good. And it's not so spunky-fast, so the pressure curve is gentle enough for plated slugs. Both of these characteristics are good for what you're doing and manifest even more so when moving to your lighter 125's.
I'm out of Unique (intentionally), so subsequent loadings will likely be with AA#5 - I still need to do the workup. AA#7 and AA#9 were mentioned. AA#7 would be a good choice; as the pressure curve will be soft. AA#9 might be too slow - depends on how much unspent powder you want to deal with while shooting/cleaning. Loading up AA#9 to the point where it runs clean, will likely bring pressures/velocities up to the point where plating breakdown becomes an issue.
Point is, with plated/357, you'd want to stay away from fast powders like Bullseye, W231, TiteGroup, etc. They will develop a sharp pressure curve that doesn't bode well for plated bullets. Move to an intermediate burn rate propellant like Unique, AA#5, AA#7, BE-86, Power Pistol (turned down a bit), etc. -- propellants in that range. Using slower powders would be ill-advised because it would be hard to get them to run consistently before pressure AND velocity becomes an issue. They should be reserved for jacketed bullets (IMO).
It would be helpful if you told us the purpose of the ammo you intend to load.
Since you have a 125gn plated bullet, I'm going to assume you are looking for basic range shooter ammo.
Plated bullets are not nearly as sturdy as jacketed bullets and are not a substitute for jacketed bullets. They are an alternative for straight lead bullets. In the case of 357 Magnum, a plated bullet can easily be over-driven, leaving the inside of your barrel with a nice bright shiny orange (copper) coating. I know. I've done it.
Most plated bullets' manufacturers print a velocity limit on their box. It's a bit misleading. Really, the issue is pressure - not so much velocity.
I don't load 125 plated bullets for 357, but I do load a 158 plated SWC. My current recipe is 7.0gn Unique. It yields 994 f/s 3"bbl; 1058 f/s 4"bbl; 1087 f/s 8"bbl; & 1251 f/s 16"bbl (carbine rifle). I believe this loading is at the edge of a plated bullet's capability - regardless of the printed velocity limit on the box.
Although I'm not a fan of Unique, it's nice and fluffy, so the fill level is good. And it's not so spunky-fast, so the pressure curve is gentle enough for plated slugs. Both of these characteristics are good for what you're doing and manifest even more so when moving to your lighter 125's.
I'm out of Unique (intentionally), so subsequent loadings will likely be with AA#5 - I still need to do the workup. AA#7 and AA#9 were mentioned. AA#7 would be a good choice; as the pressure curve will be soft. AA#9 might be too slow - depends on how much unspent powder you want to deal with while shooting/cleaning. Loading up AA#9 to the point where it runs clean, will likely bring pressures/velocities up to the point where plating breakdown becomes an issue.
Point is, with plated/357, you'd want to stay away from fast powders like Bullseye, W231, TiteGroup, etc. They will develop a sharp pressure curve that doesn't bode well for plated bullets. Move to an intermediate burn rate propellant like Unique, AA#5, AA#7, BE-86, Power Pistol (turned down a bit), etc. -- propellants in that range. Using slower powders would be ill-advised because it would be hard to get them to run consistently before pressure AND velocity becomes an issue. They should be reserved for jacketed bullets (IMO).
Jim Watson
New member
If you have a D650, surely you have some sort of pistol powder on hand.
There is probably .357 data for it.
There is probably .357 data for it.
It works great with 158 grain casts bullets, I think it should do about as well with plated 125's. WSF would be good if there was any load data for it.I accept your experience but would point out that Lyman lists IMR4227 as its most accurate with hard cast 150 and 160, while included on the list of every bullet weight shown. I mentioned IMR4227 in the context of my including that for hotter 357s I use a 158 gr bullet, applicable to all bullets except maybe plated with their presumed limitations. I did not feel locked in to the OP's reference to plated 125s, with which he would be following data for those bullets, probably not including any magnum powder except maybe the versatile A2400.
A starting charge of Alliant Power Pistol has worked well for me with 125 gr plated bullets. The down side is generally greater muzzle blast that often accompanies use of that powder. Another possibility would be Hodgdon HS-6, which has worked well for me with 158 gr plated bullets.
BE-86 is versatile in a similar range and includes flash suppressant. You would have to extrapolate loads, since Alliant only shows max loads for their powders. They do cover the range of common bullet weights.
"...poor choice small cases..." Works like hot dam in .30 Carbine though.
I've always found using the powder given for the accuracy load in my Lyman manual(not all manuals give one.) is a good place to start. Usually where I stop too.
With a plated bullet you need to use cast bullet data as plating is not a jacket.
I've always found using the powder given for the accuracy load in my Lyman manual(not all manuals give one.) is a good place to start. Usually where I stop too.
With a plated bullet you need to use cast bullet data as plating is not a jacket.
I would not put tremendous faith in what Lyman lists as their accuracy load being the most accurate in your gun, with your bullets. It is a STARTING point not a definite thing.
It is the most accurate load they got, with what they tested, so you can use that as the starting point to search for what is most accurate in your gun, nothing more.
My old Lyman book lists 8 different "Accuracy loads" for bullets ranging from 121gr to 195gr. Four of those accuracy loads use Unique, two use Bullseye, one is 2400 and the other is SR 7625 powder.
IMR 4227 may be what gave them best accuracy in their latest round of testing, but all that really means is it gave THEM the best accuracy in their latest round of testing.
Plated 125gr slugs are what I would consider light plinkers, suitable for light or midrange loads and so, use a fast or medium burn rate powder. Unique is almost never a bad choice. Slower powders like 2400, H110, W296 and IMR 4227 are a poor choice, and a waste of those powders for less than top end loads, using hard cast or jacketed bullets.
RaySendero
New member
I reload 125 platted bullets for my 357M practice and plinking.
I use Alliant Green Dot.
I'm not surprised. Power Pistol - oddly enough - is a good choice here. Its wheelhouse is for making potent semi-auto ammo (9mm, 40S&W, 10mm, 357Sig, and 45ACP). The good thing about PP is that it's high energy and easily ignited. That translates to consistent burns, even when turned down. So Power Pistol "de-tunes" well, as I like to phrase it.
Power Pistol is flashy. But I don't think it's as bad as Unique when they're both loaded to modest pressures - which is what we're talking about here. Unique gets really flashy when it's not running hot. This is where BE-86 comes in (as Real Gun mentioned). It's basically flash-suppressed Power Pistol - but - the flash suppressant makes it a touch faster in burn rate (close to Unique) and so charge weight recipes are not interchangeable. They are different propellants. But yes, BE-86 would be pretty much ideal in your application.
Yes, another good choice. Very good, actually. As long as you don't mind sooty burns - and the use of a magnum primer. HS-6 seems to only run clean when you drive it real hard (hot) and with heavy bullets (as mentioned).
Have used some BE-86 in a few calibers as well, but haven't found a place where I like it so far. I recently loaded some 125 gr coated bullets in the 357 but haven't fired any of them yet. Also loaded up some 260 gr jacketed "practice" loads for the 454 I've yet to try.
Wasn't real happy with BE-86 in mild 200 gr coated 44 Mag or 200 gr plated in 45 Auto. A few quick loads in 45 Colt 250 gr coated suggested it might be good for that, and I'll be loading more of those soon.
Wasn't real happy with BE-86 in mild 200 gr coated 44 Mag or 200 gr plated in 45 Auto. A few quick loads in 45 Colt 250 gr coated suggested it might be good for that, and I'll be loading more of those soon.
You're declaring the obvious. I did say it was their best result. A reloader with the slightest experience and reading would know that their context is a specific test platform. I used it only to lend credibility to use of IMR4227, which I recall was in reference to higher performance loads.