Ok fellas, I have a funky predicament, so bear with me.

I’d like to try a couple loads for 357 or 38 in 357 brass. I only have 357 brass and a few 357 maximums I could trim down to 357 mag length. And I don’t have any small pistol primers, but have small rifle primers.

Bullets, I have roughly 75 hard cast lead 157gr, and a box of extreme 158gr copper coated. Powder is unique, bullseye, 2400, and h110.

So, from what I’ve read, loading 38 in 357 brass, I need to add 10% to the powder, but using srp, I need to cut 10% from the powder. I’m just looking for around 800-1000 fps tin can fun.

Is this achievable or do I have such a Frankenstein brass primer setup, I’m asking for trouble? I can wait if primers are a huge problem because I’m not paying it right now.

Do not trim down the 357 MAX, it will probably have smaller case capacity than 357 Mag

This is fine for the Unique and Bullseye. I only use Magnum primers with H110 and H110 only works well at Max or near Max loadings. I do not use 2400 so I can not comment on non-Magnum primers

Unless the Lead projectiles have gas checks, they are not suitable for use with H110. I would not even use plated bullets with H110 as most should be kept under 1200 FPS according to their manufacturers

You only need to increase the powder charge if your goal is to hit that published estimated velocity.

In other words a 38 powder charge in a 357 Magnum case will have a slightly lower velocity.

You do not need to do anything for the primer changes unless we are talking a MAX load, then it need to be re-worked anyway


Now for a few suggestions. For decades I have been shooting 5.5 grains of unique with a 150-158 grain hard cast SWC. Depending on your barrel length, this runs just under 1000 FPS when loaded into 357 cases

That same load can be used with your plated projectiles

Save your 2400 and H110 until you get a small supple of Jackated projectiles

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"Acta non verba"

That’s wild about the maximum brass, thicker wall maybe?

I’m not looking for maximum power, just some fun and not risk sticking a bullet.

5.5 or so on unique sounds good to me. I load 7gr in 44sp, works wonders there.

2400 will work with Winchester primers, the primers that say both magnum and standard, done that in 44 mag and special both.

H110 seems about impossible to use other than hunting or a desert eagle,lol. I have a partial can of it and have about zero use for it, just trying to get rid of it.

Thank you for the tips, I’ll load a couple cylinders worth and see.

Forget any "formula" for 38 Specials in 357 Magnum brass. Yes the pressures will be lower in the longer brass, but as with any reloading using new/different components, use starting loads and do a load work up, and I've even used 2.9 gr of Bullseye under a 150 gr DEWC in 357 Magnum brass. Never stuck a bullet in my 6" 357. I have used hundreds (thousands) of Special loads in Magnum brass, both 38/357 and 44 Special/44 Magnum. From mild to wild, just do a load work up and review, watch for problems...

I've gone both ways Special loads in Magnum brass and Magnum loads in Special brass. Just think about what you're doing, understand more powder means more pressure and K.I.S.S.

The major "problem" using rifle primers instead of standard primers increase in pressure. Rifle primers are often the same as Magnum primers and are "hotter" so again, start low and work up. Also rifle primer cups are "harder" and light firing pin strikes may cause misfires, but I've never had that problem in a revolver...

In the 44 Special, that is a Large Pistol Primer and Winchester makes just the one for Magnum and Standard loads

In a Small Pistol Primer, Winchester makes both a Standard and a Magnum

Funny,
I LOVE H110. That big orange fireball and that deep throaty KABooooom . I have hand loaded well over 100 pounds of it

I use it for max loads in 357 Magnum and 41 Magnum

21.7 grains of H110 under a Winchester 125 JHP is a long time favorite of mine

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"Acta non verba"

I would not trim the Maxi cases..........for safety reasons.

For light loads go with the Bullseye or Unique powders, in the .357 Mag cases.

Rifle primers: starting loads and work up to be safe.

Being a .357 Magnum revolver............
you should not have any problems at the beginning with light loads
plus there is a lot of data on the "Net" or your manuals, to help out.

A 5.0 gr load of Bullseye in my 686 6" with a lead 158gr gets around 918fps. Medium load of Unique at 1133fps


Stay safe.

CCI has long maintained that THEIR small rifle primers are equivalent to their small pistol magnum primers... There should be no real problem with any BRAND "X" except the afformentioned potentially harder cup.

If the O/P has 357 Maximum brass it might logically follow that he also has something to shoot them with...? I would imagine it would give any primer a good WHACK!

Cheers!

P.S. Where Bullseye is concerned in 357 Magnum, 4.5 to 5gr ought to be OK even with the plated stuff.

I had a super 14” contender barrel in 357 maximum, it was an excellent shooter, but the contender and the barrels are long gone. XP100 took its place, I like the xp much better.

I understand start low and go up, I’ve never blown up a gun and don’t plan on starting now. Overall, sounds like treat them as a magnum primer, but I’ll start not at rock bottom, but bottom quarter of the power scale and hopefully find something that works.

Only one I’d somewhat be concerned with is the cimarron saa replica, but it’s the one I’m most wanting to shoot. The other two 357’s, I have no concerns with. But, non of them are going to have barn burners in them as long as I own them. The cimarron is brand new and I don’t want it dismembered.

H110 and 2400 are all I’ve ever got to work reliable in the eagle, 2400 is more accurate, it’s dirtier than h110 though. But, I clean whether one round or a hundred goes through.

Doubtful that ANY reputable manufacturer of firearms would design and sell a revolver chambered in 357 Magnum that was not capable of safely firing factory ammunition...

That said, there certainly is a marked difference in the construction (and anticipated life?) of a S&W J-frame, a typical K-frame, an L-frame or N-frame, as well as something in an alloy, titanium or scandium designation in this caliber.

I personally wouldn't hesitate to shoot factory 357 Magnum ammo in a Cimarron 357 Magnum revolver: probably not the hottest Underwood or Buffalo Bore rounds or MAX handloads ON A REGULAR BASIS, though!

Just like with my K-frames it would likely be mostly 38 Specials at the range...

Cheers!

P.S. I don't shoot "RUGER ONLY" 45 Colt loads out of my Cimarron, either!

Good, I’d like to have fun with the cimarron as long as possible.

I’ll load a few and see what happens, I’ll probably try them in my ruger first, it’s supposed to be a tank. Same routine I go through with 44 mag, srh first, then the 629 next, but I don’t load barn burners there either.

You don't 'have' to increase .38 loads 10%. The .357 is designed to shoot ordinary .38 ammo and that small addition of length to a .357 magnum case has no function other than keep the .357s from being loaded into a .38. The extra volume is miniscule compared to the interior volume of a .38/.357 case.

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"He was kinda funny lookin'"

<<I LOVE H110. That big orange fireball and that deep throaty KABooooom . I have hand loaded well over 100 pounds of it>>

I bet! 100 pounds would be well over a 357 max load.

It went in here

Not even a compressed charge but I did use a heavy roll crimp

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"Acta non verba"

Hey! Check out the Speer web site, under Reloading.

I have found this a very good Resource for me, and
the very good Posters here.

The Best to you and your Endeavors.

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SD social distanc'n since 1889

Tried the cimarron out today, shoots high at 50 yards with zero 158gr magnum ammo. After figuring out where to hold,it hits soda cans and bottles nearly every time , so I guess that’s good. And I’m not steady at all freehanded. Recoil is pretty low, so no flinching or any of that nonsense. Overall, I like shooting it though, think I’ll keep it.

I’m used to the 629 and srh hitting golf balls every time at 50 yards, so I’m a bit spoiled, the xp100 hits gnats at 200yds, but that’s a different animal all together.

Anywho, I’m going to load a few tonight and try them after Christmas.

You may want to try a lighter weight bullet to get the POI down.

It seems more often times than not with S/A revolvers that my POA and POI need tuning.

My first stainless Vaquero chambered in .357 simply wouldn't cooperate. I was so disappointed that I couldn't get the POI down enough to work for me.

I love S/A's. I looked at very nice Uberti 12 round 22lr earlier this week.

Enjoy!

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Real Eyes Realize Real Lies

Brass isn't all that expensive so why not just buy 100 pieces? It will cost you under $20.

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Freedom is never free!!
SWCA #3437

You are over thinking it. Just load 38sp max loads in mag brass, done.

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NRA Cert. Inst. IDPA CSO

Well, no luck on finding small pistol primers, what a surprise huh.

Anyway, I loaded a few rounds to try in the gp100. 11.5gr 2400, xtreme 158gr flat nose plated, federal 205 srps. That’s the starting powder charge in my hornady book. My Lyman book showed 12.6 as a starting load, but the hornady book has never steered me wrong.

From what I’ve read, it should at worst just be dirty, as low 2400 loads tend to be, but I’ll find out. I’m hoping I don’t have the flame etching or whatever from the primer not sealing to the case.

You shouldn't have any problems with the sm rifle primers in your pistol cases. They are the exact same size as a pistol primer, so you won't have any problems with blow by in the primer pocket, And I load sm pistol primers in my 22 Hornet brass as it's supposed to be more accurate in the Hornet than small rifle primers; no problems there either.

I load SRPs with 6 grains Unique in .357 brass with a 358477 150 grain bullet. Shoots real nice, just over 1000fps in my 4" 686.

Well, made it to the range.

All of the ones I tried went off. Something odd I noticed, I had the lightest load of 2400(11.5gr), there was no powder residue issues, I shot 18 rounds and figured there would be some nastiness, but the gp100 wasn’t very dirty at all. Wonder if the hotter primer had something to do with that? No pressure or sticky case issues either.

The first cylinder full got zeroed in, and at 50 yards, it was constantly hitting soda bottles and cans. I’m happy with that, just being I’m out there for fun. Recoil wise, it’s snappy, but I could shoot all day with it, surprised me it had as much as it did.

357 magnum load - standard pressure - midrange load .
in 357 magnum case
157 / 158 grain cast lead or plated bullet

the following were developed for max. accuracy and are my "pet loads"

7.0 grs. Unique (1089)
4.8 grs. Bullseye (910 fps)
16.5 grs. H110 (1240 fps) (magnum pistol primer)

Use what primers you have/can get and see how they perform.
During these times you have to use whatever components you can get .
Gary

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Certified Cajun
NRA Member

7gr unique 210gr gdhp is what works for me in 44 special. That’s a golf ball at 50 yard load.

Once I finish the can of unique, I’ll try the bullseye powder, I’ve never tried it but hear nothing but praise.

I have a partial can of H110, after beating myself up trying it in the srh, it’s been banished to desert eagle duty. I fired 3 rounds, pulled the other 9, no fun at all.

I was trying 2400 first for 357 as I have more of it than unique or bullseye, it worked great, wasn’t hard recoiling, and surprisingly wasn’t nasty. The special and magnum 44 loads I have for 2400 are dirty as ****, but are accurate.