Loading .357 using .38 data

[kielbasavw]

I got some funky 38/357 lswc's that are 164gr and the crimp groove is in the wrong spot (too low and makes the entire round too long to fit my gun)

A member mentioned on a previous thread of mine I can seat them deeper all the way to the shoulder and crimp over it, and then use load data for .38. So I seated the bullet so I get a max length of 1.518, which makes the seating depth fairly close to .470.

For .38 bullseye using 158gr book tells me 3.8 - 4.2 grains.

I made a few step loads, since I'm using magnum primers and book is using standards, and I'm unsure of what to expect I dropped the first load down to 3.6, then worked my way up 3.8, 4.0, 4.2.

This will be my first 357 loads ever, since I've only done 30/30 so far.

From my pictures, can you tell if crimp will suffice? That is actually the maximum crimp I can get, shell holder hits the die by this point. I could probably raise the overall length a few thou but not sure that would help much with crimp, if more is needed.

Also please tell me if these will be fine to shoot, I tried researching this type of load, but only come up with articles explaining some 357 do not have a crimp groove and must be seated all the way up to the shoulder, but no data was given.

[mrkubota]

I've seen .357/.38 ammo loaded like that before....
The loads aren't excessive and I'm sure they'll be fine.

Why not just use .38spl brass/loads with those bullets?

[kielbasavw]

I'm sitting here working on the 38 brass I have. My better halfs bday is on wednesday and she loves the 357. Was gonna take her out shooting, but looks like shell be stuck with a bunch of whimpy 38s this time around while I test these goofy 357 loads.

Ill prob take out the .45 too she likes the hk

[J-cat]

The 3.6gr load will give you 800 FPS. That should also be the most accurate one. You could drop it to 3.4grs cuz 357 brass is thicker.

[kielbasavw]

How do you come up with those numbers? Some sort of formula to use?

[kielbasavw]

Also how does the crimp look?

[J-cat]

I clocked them out of my Colt. Your crimp looks good.

[kielbasavw]

You used the same powder and load? Interesting, Ill be using a colt aswell, do you have #s for the other loads aswell

[J-cat]

Yes. Bullseye is the powder one should use to begin target load development in any 38/357 revolver application. I don't have the velocities for your higher charges because I stopped at 3.8grs. I really liked the 3.6gr load. It grouped under 1" at 15 yards and had nice mild recoil. Not as light like a HBWC, but nice.

[hermosabeach]

I have never worried about crimping grooves. I always treated them and lube channels on lead bullets.

I load to a correct overall length.

A 38 special should not have enough recoil to move the bullets from the unfired rounds.

A light crimp is all that I use.


There is a fun event called flashover. It is where too little powder causes the powder to burn all over instead from the primer forward and a light load can blow up a gun.

So if you are using the longer 357 cases, I would stick to the minimum .357 powder charge.

You could play the game where you load .357 brass and seat the bullet deeper to give an OAL of a .38 to not have extra case capacity.

But it is for these reasons why I do not shoots other peoples home reloads.

[J-cat]

There is a fun event called flashover. It is where too little powder causes the powder to burn all over instead from the primer forward and a light load can blow up a gun.

So if you are using the longer 357 cases, I would stick to the minimum .357 powder charge.

You could play the game where you load .357 brass and seat the bullet deeper to give an OAL of a .38 to not have extra case capacity.

But it is for these reasons why I do not shoots other peoples home reloads.

Could you explain how seating a bullet in a .357 case to .38 Special OAL is unsafe, a game, or whatever in terms of what you call flashover?

Because what you posted does not make sense.

[M1NM]

I've used 4 grains of Bullseye for my 357 158 SWC loads for years. Wouldn't hesitate at all to use the same mix in a 38.

[Excaliburr]

I don't think it is possible to know what would happen with this guys loads. Heck, there are so many variables that do not conform to books anywhere. Personally, when I was a begginer I stuck to exactly what was in the book so I did not have a problem. As to crimp, it is really only needed for two reasons in a .357/.38 and they are one to fit in the cylinder properly and two to hold the bullet tight enough so it doesn't move during recoil. A lite crimp is all that is needed in my experience. You say the crimp groove is too low, but could it be that you have not trimmed your brass to the correct trim length? I cast my own bullets and if I had bullets that were made incorrect, I would remelt them and make them correctly. Take it from a guy who has stuck a round in a .38, this guessing game is not a good idea. Changing one factor is one thing, but you are talking about a cocktail of differences. I think the earlier poster is speaking of the pressure curve when he is talking about flashover. If you have too low of powder the pressure isn't enough to move the bullet, so the energy has to go somewhere...boom out the side of the brass or more likely at the head. Not good. Sometimes it could be better to have no charge at all....at least all you might have is a squib.

[J-cat]

OK.

Listen to me. When you seat a 158gr SWC in a 357 case to 38 OAL you end up with a friggin 38. You can use .38 data. Why? Because you have what basically amounts to a 38. The internal case capacity is actually a bit less than a 38 because the case walls are a little thicker, so there is actually, get this, less chance of flashover than you would get in a 38 Special case.

[chknlyps2]

OK.

Listen to me. When you seat a 158gr SWC in a 357 case to 38 OAL you end up with a friggin 38. You can use .38 data. Why? Because you have what basically amounts to a 38. The internal case capacity is actually a bit less than a 38 because the case walls are a little thicker, so there is actually, get this, less chance of flashover than you would get in a 38 Special case.

I agree, a .38 case is what, 1/8" less than a .357? The OP is crimping about 1/8" deeper than the crimp grove which basically turns it into a .38. A bullet with a close profile and weight to the OP's in my book has an oal of .130" difference between .38 and .357.