1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

.357 load in .38 Case

Discussion in 'Handloading and Reloading' started by Hungry1, Nov 18, 2012.

  1. Hungry1

    Hungry1 Well-Known Member

    Hello, I have question.

    I shoot Speer 158 gr SWCHP over 6 grains of Unique in .357 cases. I'm happy with the load.

    What is the danger of putting that same amount of powder in a .38 case?

    My Speer manual lists 5.2 as max for .38+P

    Every once in a while, when shooting from a LCR, the recoil will knock the round out of the case and prevent the cylinder from turning. This could be eliminated by using the shorter .38 cases.

  2. Chuck Perry

    Chuck Perry Well-Known Member

    With the bullet seated identically in either case, the 38 will have less capacity than the 357. This will have the effect of higher operating pressure in the 38 case. There are some that will use 357 powder charges in 38 cases, but it's not something to be taken lightly.
    If you' re only concerned about the problem you detailed in your post, you should be able to solve that by re-examining your reloading process. Better case tension and a firmer crimp should solve the bullet jump issue you're experiencing. I'd first look at how much you're belling your case mouth; too much will negatively effect your case tension. If you shoot a lot of cast, try a Lyman M die. This is an expander die made exclusively for loading cast. I use them on all my revolver loads.
  3. beatledog7

    beatledog7 Well-Known Member

    You're missing a very important point--internal pressure. If the manual says 5.2gr is max for a +P, why would you consider upping that to 6.0gr? It might not hurt your revolver, but it will ply havoc with your brass.

    If you're getting bullet jump in your .357s it's because you don't have enough neck tension and/or insufficient crimp. Failure to alleviate these issues with the .38SPL cases will not solve your problem, and you'll be in an overpressure situation to boot.

    In short, don't do it.
  4. mdi

    mdi Well-Known Member

  5. CraigC

    CraigC Well-Known Member

    No it won't. :rolleyes:

    I've used standard .38Spl brass for .38-44 loads in the 1300fps range 20 times without issue a single loss. I just stopped counting.
  6. Hungry1

    Hungry1 Well-Known Member

    Okay. I figured it must be a over-pressure issue.

    I'll address the neck tension.

    Can anyone explain the advantage of the M-Die over the expander die in the RCBS set?

    I do have a Lee expander die that I've used for cast rifle loads. Is one better than the other?

    Thanks again.
  7. jmorris

    jmorris Well-Known Member

    My old IDPA "minor" loads were over 38+p book loads, to make power factor. I only used them in 357 revolvers and kept good track of them.

    The danger is having a 357 load in a case that can fit into a 38 revolver. Do that and you could be one of the folks starting a kaboom thread.
  8. rsrocket1

    rsrocket1 Well-Known Member

    If your rounds are being knocked out by the recoil you might want to try working on your roll crimp technique. Yes, it takes some practice, but a good roll crimp without overdoing it should hold the bullet in place. Here is a thread with good pictures on roll crimps. Yes, the OP is about 38 specials and the Lee FCD, but it progresses into a good thread on proper roll crimps.

    As for loads with > 38+p pressures in a 357, I'd keep it below the recommended 5.2g Unique. I personally like 5.0g Unique under my cast 158g RNF bullets. It pushes the bullet into the mid 990 fps with a 4" barrel and makes you feel like you're really shooting something and not firing a starters' gun :)
  9. Chuck Perry

    Chuck Perry Well-Known Member


    The image shows the M die in use. The M die first expands the case to just under caliber(image A). It then creates a very slight, squared off expansion (image B). It then slightly flares the case mouth (image C). When you have it set up just right, the bullets actually snap into place when you fit them into the case for seating. The M die promotes great case tension on the bullet, plus it really helps seat your bullets perfectly straight.
  10. Walkalong

    Walkalong Moderator

    You need better neck tension, along with a good roll crimp.

    Your load would be dangerous if it found its way into a .38 Spl revolver, especially some older ones.

    +1 for the M die. They are nice.
  11. blarby

    blarby Well-Known Member

    Is generally a bad idea, if you have any 38 specials hangin around the house.
  12. tightgroup tiger

    tightgroup tiger Well-Known Member

    I'll say, neck tension comes from the resizing die. If you push the neck sizing die to far into the case you undo everything the resizing die just did.

    First off start using your .357mag cases for .357mag loads again and back off the neck sizing die until you can't get a bullet to start or even to sit on the top of the case without falling sideways. Screw it in about a 1/4turn at a time until you can get a bullet to stick in the top of the case. This is where you will get the best neck tension. Don't try to physically flare out the case until it looks like a funnel, just enough to get the bullet to start without shaving copper. This will get the best neck tension your dies can produce.

    You've heard us all say that we won't trust someone elses reloads, putting .357mag loads in a .38spl case is one of the reasons why. Not a good idea.
  13. GLOOB

    GLOOB Well-Known Member

    The 357 case is as long as it is because it was designed to take black powder. So yeah, you can load 38 special cases with 357 data, minus a tiny smidge. The danger comes if you accidentally put that round into a gun that isn't rated for 357.
  14. Hungry1

    Hungry1 Well-Known Member

    Thank you. That's what I was looking for.

    I've decided against doing this though.

    I'll work on the neck tension and carry factory ammo in the LCR. I'll keep the cast loads for range use until I can get the neck tension correct.

    Thanks for all the responses. Some very helpful info. :)
  15. CraigC

    CraigC Well-Known Member

    Hold the phone there boss! The .357 is NOT long because it was designed for black powder. I don't know where this info comes from but it is absolutely untrue. The .357 debuted in 1935. It was developed with and designed for smokeless powder. Never was blackpowder ever a consideration, whatsoever.

    It is generally a fine idea if you have a .38-44HD or any .357 with a cylinder too short for the Keith bullet loaded in .357 cases. There are plenty of easy methods for insuring that they don't end up in inappropriate guns. No different than loading Ruger .45Colt's to 32,000psi when you have Colt SAA's in the house.
    Last edited by a moderator: Nov 18, 2012
  16. Lost Sheep

    Lost Sheep Well-Known Member

    After you minimize the case mouth flare (to maximize the bullet retention provided by friction between the cartridge case and the bullet) and increase the crimp you can test the adequacy by doing this:

    Load 9 rounds. Mark one with a felt-tip marker. Measure its overall length.

    Load five

    Fire one (unmarked) round.

    Measure the marked round

    Fire another (unmarked) round

    Measure the marked round

    Repeat until all 8 unmarked rounds have been fired.

    Examine the measurements on the marked round.

    If measurements 1 and 8 are the same, your bullet retention is adequate.

    If measurements 1 and 8 are not the same, you could improve things a bit.

    If 1 and 2 are not the same, but 2, 3, 4, 5, 6, 7 and 8 are the same your roll crimp is probably in the wrong place. The bullet is moving to where the roll crimp stops further movement and you are probably OK, but could do better. Make sure the roll crimp goes into the crimp groove and the lead meets the brass (inside the case mouth - hard to see, of course, but clean the lube off a bullet, seat and crimp and use a magnifying glass). Also, your friction retention is contributing little and could be improved substantially. If your bullets are properly sized, usually this involves moving to a thicker-walled brass or polishing down your case-mouth expander a little.

    If 1, 2 and 3 are showing increases but 3, 4, 5, 6, 7 and 8 are the same, then the same situation holds as above, but your friction retention is working somewhat. Just not enough. The cure is the same as above.

    And so forth

    If 1, 2 and 3 are the same but later measurements show lengthening, then start another thread, please. There will be a lot more questions.

    If there is ever shortening between measurements 1 to 2, 2 to 3 and so forth, you have me stumped.:confused:

    Note: It is better to depend on friction as much as possible for bullet tension. Roll crimping works the brass and makes it brittle, leading to cracking of the case mouths unless you anneal the brass periodically, which is barely worth it with handgun brass.

    Aside: Your original assumption, that starting out with shorter brass would mitigate the problem, while dimensionally correct, does not address the underlying problem. It gives you an extra 1/8", true. But it does nothing for the crimp jumping.

    Thanks for asking our advice.

    Lost Sheep
  17. Steve C

    Steve C Well-Known Member

    The .357 mag was made a bit longer so they wouldn't fit into .38 spl chambered revolvers and not because of any need for more volume. While it is a bad idea to load magnum pressures in .38 cases for the simple reason one could get used in a .38 spl pistol be it yours or somebody else its not exactly dangerous per se specially when used in a magnum handgun. Using .38 spl cases was common practice in days long ago when magnum brass was in short supply but its not something that's an issue today so its better to use magnum brass for magnum loads.

    Regarding your specific load, 6.0grs of Unique behind a 158gr lead bullet is just barely under the old 6.1gr maximum Hornady data for the .38 spl published in 1973 before there was such a thing as +P. Instructions said to "use max loads in heavy frame revolvers only" in an era where people where expected to be able to read, understand and follow directions. This loads didn't blow up any .38's at that time and will not now but they'll ruin a light frame .38 quicker than more moderate loads. In a .357 mag they will certainly be safe. At that time I only owned .357 mags and shot 158gr lead SWC .38 spl loads using 5.5 to 6.0 gr of Unique without issue or worry. After all I was following the manual of that time.

    If you want to experiment with jacketed bullets do your work up and don't just dump in max loads to start out. Use common sense and don't wind up compressing a load in .38 spl cases that wouldn't be compressed in .357 mag cases.
  18. GLOOB

    GLOOB Well-Known Member

    Yeah, ok. But the 38 special was. And then smokeless powder came around, and they figured out you could shoot a 38 special to higher speeds with the same case volume... as long as the gun was made stronger to contain the pressure.

    So, as Steve pointed out, they made the case even more needlessly longer so it wouldn't fit in 38 special revolvers.

    There are a few powders where you can get "an advantage" with the extra case volume. Like with super wimpy powders like Trailboss, or for really slow powders that maximize velocity out of a rifle. But for the most part, it's completely useless out of a pistol. That extra space just wastes a fraction of a grain more powder and creates more muzzle blast to do the same thing that could have been done out of a 38 special case. Or even shorter, for that matter.
    Last edited: Nov 19, 2012
  19. CraigC

    CraigC Well-Known Member

    Hogwash! Keith's and Sharpe's heavy .38-44 loads at the time didn't go much over 1300fps and pressures were very high. Keith reported his loads tested at 42,000psi. Factory loads for the .357 with Hercules 2400 and Sharpe's bullet topped 1550fps. Remember, the factories were producing .38-44 ammo so if that were enough, they never would've introduced the .357Mag.

    The same powders yield the highest velocities regardless of barrel length. Powders are chosen for the cartridge and its pressure range, not barrel length. That means H110/296 or Lil Gun, revolver or rifle.
  20. helotaxi

    helotaxi Well-Known Member

    Ordinarily, I would heartily agree with you, but in the case of the .357 you can coax a little extra out of the round from a rifle with a slightly slower powder. A full case that makes max pressure is usually what defines the limit on the slowest powder that makes practical sense in a particular cartridge. A max load of H110 doesn't fill the case. A slightly slower powder can use that extra bit of case capacity to generate a slightly different pressure curve that peaks just a bit later in the bullet travel and keeps the pressure up. The difference is a slight reduction in velocity in a short barrel and a slight increase in a rifle barrel. The difference isn't huge, but it is there and is only made possible by the over-capacity nature of the .357 case.

Share This Page