125gr HP 357mag Loading Data Help

RUSigX

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I'm just getting into loading 357 mag on my Dillon 650. I have 1,000 Rainier 125gr HP 'plated' bullets along with new and used brass. Rainier claims these bullets should not be loaded over 1,500 fps although I've read you shouldn't go over 1,200 fps. For the life of me I cannot find any loading data on these bullets for 357 mag. From reading I have learned that I cannot push these plated bullets at magnum velocities, I'll need to purchase 'jacketed' bullets in order to do that.

I have an array of powders (Bullseye, CFEPistol, 296, 2400, Unique, and TiteGroup). I also have regular and magnum powders. I've read that you should load plated bullets using lead loading data or use 10% less powder than what is published for jacketed bullets.

I'm really lost as to what to do as all the 357 loading data that I see doesnt even list a 125 gr lead bullet. I'm also guessing I should never use 296 for anything other than magnum bullets. If I had some jacketed bullets I'd probably load 21gr of 296 using a magnum primer.

Can someone help me with some loads for the powders I mentioned above, I seem to be really struggling with this and making these plated bullets work in a 357 mag casing.
 
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You do not need load data for that specific plated bullet since you have no intention of going for a full magnum load.

Choose any 125 grain bullet and look at the load data that puts you in the 1200 FPS category.

8.5-9.0 grains of unique should get you there.

I load my Winchester 125 JHPs over 21.6 grains of H110 and a magnum primer.
 
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Hodgdon has data online for 125 gr jacketed and lead for 296 and CFE Pistol. Go to Hodgdon Powder web site and look up the data. Hodgdon uses a 10 inch test barrel for their data so you will not get the claimed velocity out of a 4 or 6 inch barrel.
 
colt_saa, that's a good idea didnt really think of looking at fps for other loads for some reason. Every 357 smith I have is 7" or less. I may have to try the Unique, I dont think I'll be buying plated bullets for magnum rounds anymore due to the limitations, these seem to be better suited for 38/38+p applications.

3five7, looks like I could only use CFE Pistol according to their website and I've also read you cannot download 296.

I should use a light taper crimp?
 
Groo here
For factory spec 125gr hp 1450fps is about normal.
The plated bullets are fine for "mid" range loads.
158gr HP loads are about 1200fps making the plated bullet just fine.
[except in a rifle]
Don't right off the bullet unless it is not accurate in your application.
Many of us down load some for range use.
 
According to the Lyman 49th edition looking at 125gr 'jacketed' HP I should be fine to use the minimum load for just about any powder except H110/296 which shows 21 gr at 1357 fps. 13 gr of 2400 gets me 1159 fps and 7 gr of Unique gets me 990 so using 8.5-9 as suggested previously should get around 1200 fps. Max Unique of 9.7 gets 1359 fps which would probably be pushing it on a plated bullet even though Rainier claims 1500 fps max.
 
Look into hard cast....

Cheaper alternative to jacketed. Look into HARD CAST COATED bullets from some of the casting outfits. Penn, Missouri, Bayou bullets and many more. Anybody you see recommended here is probably good. They can be pushed to magnum velocities and beyond. They usually start around 135 to 140 grains. Penn makes bullets starting around 100 gr in cowboy bullets but many places will work with you on specs, sizing, etc.

2400 is a great powder for magnum loads.
 
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For my hotter Magnum Rifle loads I use Hornady XTP bullets in either 140 or 158 grain varieties in combination with H110/W296. Loads are on the light side but the 140 grain bullets leave the barrel of my 20 inch Winchester at 1875 fps and the 158 grain bullets clock at 1600 fps. Accuracy is simply splendid, even with just a peep sight on the rear tang.

I've also experimented with using H110 for 125 grain XTP's in my 4 inch model 620 and didn't like the result. The flame front erupting from the B/C gap (0.006) and barrel completely obscured the target. In addition the sound blast riveled a 500 Magnum. Got home and during cleaning noticed a distinct deepening in the flame cutting in the top strap of my 620 and I don't care what is claimed about flame cutting being self limiting, I've cut steel with a cutting torch and do not believe that myth about "self limiting" one bit. My handgun Magnums are now constructed using Accurate #5, 7, or 9 depending on what I want in terms of velocity. Because I've found using what is really a Rifle powder in a Handgun load only results in excessive wear to the handgun with not much gain in velocity. My 158 grain Accurate #9 loads clock 1200 fps out of my 6 inch Dan Wesson and the one time I tried the 158 grain Rifle load in the Dan Wesson it only made 1250 fps.

So, what should you use for your 125 grain plated bullets? IMO it would either be Unique or CFE Pistol. Having used both powders and having tested both for consistency in a powder measure the CFE Pistol wins hands down. I will also point out that there is a large span available between 38 +P and Magnum start that goes unexplored by many because you won't find listings for this particular "desert". However for lite shooting Magnum Lites with energy levels closer to a 9mm Parabellum this is an area well worth delving into. Because these Magnum Lites are plain fun shooting plinkers that are quite accurate and gentle on the forcing cone on our treasured K frame Combat Magnums.
 
As mentioned, the plated bullet (no cannelure) will do a LOT better at target to medium speeds with just a taper crimp in the 357 Magnum.

If you do get setback or bullet jump you can drop down to the 38 special case for even a lighter load if needed.

CFE is the powder I would pick for the 357 loads.
Good luck with those smooth bullets.
 
Doubtful I will go with these smooth bullets going forward but I'm sitting on 1,000 of them at the moment. The coated lead bullets look nice and the price is t too bad especially since you can push them like a jacketed bullet. I really like how Accurate Powder clearly calls out loads for the 125(P) HP, that's very helpful. Looks like RamshotZip would be a good powder if I can find it.

Looks like 6.6 grains of CFE Pistol would be 1375 fps? Probably less out of a 7" barrel.

Flame cutting with the 296 does scare me a little as I treasure all of my S&W revolvers. I do want to get into loading 44 mag at some point and may save my 8 lbs of 296 and 8 lbs of 2400 for that. I also want to pick up a lever gun in 44 mag, will flame cutting be an issue with 296 in my 44 mag revolvers or a lever gun?
 
IMO Flame cutting will always be a present potential with any revolver except that sliding cylinder Nagent. I personally wont use a power slower than 2400 in any of my handgun loads. Because when compared to AA#9 or 2400 the velocity gain is so slight it's just not worth the flash and boom. However used in a rifle for a magnum handgun caliber or 300 Blackout H110 is just perfect.

As for that 6.6 grain charge for CFE Pistol, you may want to double check that data. Because I'm using 3.8 grains of CFE Pistol for my 380 ACP loads with a 100 grain Berry's plated. With the much larger case capacity of the 357 Magnum 6.6 grains seems way light. I can also tell you that Hodgdon's velocity data is pure smoke and mirrors. I've seen Hodgdon claim velocity figures I can't match out of a 20 inch rifle much less the 10 inch revolver they claim to use. I would expect that 6.6 grain charge will only yield something in the 800 fps range out of a 6 inch barrel.
 
I just loaded up 50 125gr plated HPs behind 9.0 grains of Unique. I can already tell that Unique doesn't meter all that great in my Dillon 650 and the vibration from the press causes some grains to jump out of the casing. Going to head to the range this evening and I'll report back.
 
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