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Moe T Vator

RELOADING 38 SPL VS 357 MAG

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Howdy All,

 

background:

I am loading 38spl with 2.7 grains of claydot and federal primers to push a 105 grain SWC (pistol)

and

I am loading 38spl with 3 grains of claydot and federal primers to push a 125 grain RNFP (rifle)

 

What, if anything, can I expect to happen if I use the same bullet, powder, and primer but load a 357 case vs a shorter 38 spl case?

 

If you have a reference or manual I would appreciate it so I can check as well.

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What will your OAL be with the 125 gr FNFP loaded in the .357 case.

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I would think the rounds will be a lower pressure due to more space in the case.

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Generally the velocity will be lower due to the larger volume of the larger case.

As the volume increases, the pressure of the load decreases.

 

So you normally need to sightly increase the power used in the Magnum case to get the same velocity.

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I load 2.7 gr of Solo 1000 in 38 and 357, behind a 125 rnfp, Fed sp primers and crimped in the groove. I only bother since my 73 likes the 357 length for feeding and Jersey Bratt's 94M wont hold 10 of 357 length. I can interchange the ammo in pistols and not tell by recoil or POI which case length I am shooting. Both loads come in low but legal on PF and are easy on the hands, ears and nerves.

 

Imis

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Posted (edited)

I'm not sure why you want to shoot 357 if you are shooting 38 now. It would be much cheaper to stay with 38 and get the gun fixed if the OAL is an issue. 357 brass is more, harder to find and it takes more powder so a little one time gunsmith tab will save you a lot of money over the years. 

 

Plus if you forget ammo, need to borrow a knock down load 38's are everywhere......357's not so much. 

 

Last your empty cases won't screw me up when I'm loading my 38's...……..lol

 

I'm not skirting the answer just trying to help a little. They'd probably shoot but they would be really light. 

Edited by Cowboy Junky
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There’s a five dollar difference per thousand from Starline between .357 and .38 Special cases so I gotta push back a leetle bit on the “much cheaper” aspect, and it’s always in stock so it’s not harder to find. And I’ve never been to a shoot that I recall where someone else wasn’t shooting .357, and push comes to shove I can always run some borrowed .38 Special if I have to, but I’ve never had to. Personally I think the cost differential between .38 and .357 is greatly exaggerated. I acknowledge that it exists but once you buy your brass, at an extra five dollars per thousand for the most expensive case option, it’s relatively insignificant.

 

Respectfully submitted.

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Posted (edited)

Moe, If I remember correctly, this is your second post about 38 v 357. I think that the 1st was because you had a problem with a rifle feeding .38's. If that is the reason, I've got to go with Junky. Mostly because of the extra work changing the dies and possibility of errors.

Edited by Marshal Chance Morgun

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In respect to the OP, only changing to .357 cases and not changing anything else, your performance SHOULD drop off a little, meaning less velocity and hence knockdown power. For what we're doing, probably not a big deal at all. If your guns feed .357 better and you're ok using them, by all means. But in cowboy circles, .38s ARE more prevalent and yes, in the long run, you will save a little in case cost; powder, if your charge remains the same, no difference. As far as different loadings, why would ya? Use one load and never have to worry "which load am I using?" I load .38s with a 125 gr TC bullet (red polymer coated, of course. thanks Scarlett) over 3.2 gr of Trailboss, not picky about the primer and NEVER have to worry (well, my daughter doesn't, I shoot .45s) about which load I should be using and will it work for knockdowns; it works fine. If ya felt that ya really needed a KD load, then have some 158 grainers for that. Happy shooting... and reloading.

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One other thing. As Rainmaker stated, "in cowboy circles, .38s ARE more prevalent." You are not always going to get only your brass back, and others are going to get your brass. Yes, while we are careful, sometimes we don't catch a different case size when they are that close.

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I've been loading 38's for my wifes 357 pistols and rifle with 2.8 grains of Clays. Clay-Dot would be the same by weight. We haven't had any OAL issues with her Marlin crimped in the groove, however if you need a little more length just seat the bullet out a bit. As stated above though you do have to watch out for 357's getting in your brass mix which will be quite evident you start reloading and one finds it way in. One thing I have been doing is marking with magic marker her brass and then when I check them over the ones that aren't hers are easy to spot.

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17 hours ago, Lazy Eeyour said:

This should give you some generalization for your questions.

http://ns.hodgdon.com/PDF/Cowboy Action Data.pdf

This is exactly what I was looking for! than you!!

And from what I am reading its almost a null point.

125gr Lead RNFP in the 38Spl is 978 VEL. fps

125gr Lead RNFP in the 357m is 984 VEL. fps

What I don't know is what the "CUP" is. From 16,900 in the 38spl to 11,900 in the 357m. What does this mean?

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CUP (copper units of pressure) is an older system of measuring pressure in firearms.  Use a search engine and you will quickly find an explanation of this system and the modern system that replaced it.

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Posted (edited)
22 hours ago, Lead Friend, SASS #53635 said:

There’s a five dollar difference per thousand from Starline between .357 and .38 Special cases so I gotta push back a leetle bit on the “much cheaper” aspect, and it’s always in stock so it’s not harder to find. And I’ve never been to a shoot that I recall where someone else wasn’t shooting .357, and push comes to shove I can always run some borrowed .38 Special if I have to, but I’ve never had to. Personally I think the cost differential between .38 and .357 is greatly exaggerated. I acknowledge that it exists but once you buy your brass, at an extra five dollars per thousand for the most expensive case option, it’s relatively insignificant.

 

Respectfully submitted.

It's not just the new brass cost.....that's only part of it. It's easier to find once fired 38 brass and much cheaper. You use less powder for the same power factor and it's easier to shoot a lighter bullet due to case volume which is again cheaper....and IMO for SASS better.

 

Then you times that times thousands of rounds you shoot in a month and it will add up. If you shoot alone and once a month it's not a big deal.....but if you shoot every weekend and load for 2 or more it does save you money. It won't finance a new home or nuttin' but it does save you money and if the gun is setup right there are no drawbacks to it. 

Edited by Cowboy Junky

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Posted (edited)

All of your points are valid and I agree with everything except “much cheaper.” I’ll meet you at Cheaper and I’ll even go farther to Marginally Cheaper but I’m still going to respectfully disagree with “much cheaper.” Yes pennies add up to dollars but in the end they are just pennies and it takes a vast amount  of them to add up to anything.

 

Respectfully submitted. 

 

 

 

 

 

Edited by Lead Friend, SASS #53635

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Alright, you two. Don't make me send you to your rooms. Winter is over.  It's official Spring. Get out there and shoot and have fun.  

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And when it comes down to it, it's YOUR money, spend it how ya want to. If you're ok spending more, that's up to you. 44-40 and 38-40 aren't cheap to shoot, but many do.

Shoot what ya want and have fun.

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21 hours ago, Edward R S Canby, SASS#59971 said:

CUP (copper units of pressure) is an older system of measuring pressure in firearms.  Use a search engine and you will quickly find an explanation of this system and the modern system that replaced it.

nope, would never have gotten to that one :Dlol. Thank you!

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34 minutes ago, Moe T Vator said:

nope, would never have gotten to that one :Dlol. Thank you!

 

22 hours ago, Edward R S Canby, SASS#59971 said:

CUP (copper units of pressure) is an older system of measuring pressure in firearms.  Use a search engine and you will quickly find an explanation of this system and the modern system that replaced it.

seems like CUP is out dated and not the standard anymore, now that we have digital PSI piezoelectric transducer systems. well someone does.

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On 3/20/2019 at 6:34 PM, Moe T Vator said:

Howdy All,

 

background:

I am loading 38spl with 2.7 grains of claydot and federal primers to push a 105 grain SWC (pistol)

and

I am loading 38spl with 3 grains of claydot and federal primers to push a 125 grain RNFP (rifle)

 

What, if anything, can I expect to happen if I use the same bullet, powder, and primer but load a 357 case vs a shorter 38 spl case?

 

If you have a reference or manual I would appreciate it so I can check as well.

 

It's been my experience that, with all other things equal, changing to a longer case, can have some rather interesting ramifications.

 

Obviously, or intuitively, velocity will be less, and pressure should be less as well. 

 

Less obvious or intuitive are the creation of poor ammo. IOW, the same charge, now in a larger container, becomes position sensitive and produces erratic velocities (large Es/Sd). Cowboy loads are generally at or sometimes below the normal starting load. They can take on a mind of their own. Sometimes they are completely predictable, more often they are not. 

 

Low loading density Cowboy loads can be very tune-able with a primer change. Different brands of primer make less of a difference in mid to high end loads, and become a factor again at the top loads. 

 

I am using light loads, similar to your loads, about 3.5 gr of AA-452, a CCI 500 SP primer, with a 147 gr bullet, OAL of 1.5" for my '66 Yellow Boy. As the chamber in this one is a bit bigger than the chamber in my hipguns, I wanted to keep the brass separated. An easy way to do this was to load 357 for my hipguns. I loaded the 357 mag brass with the same load, and testing found it to be position sensitive. Increasing the charge to 4.1 gr helped but the biggest improvement came with a primer change. With this combo a WSP primer worked well. OAL was 1.6".

 

The '66 is chambered in 38 Spl, so I pretty much need to load 38 Spl for it. I was able to find a brand of brass that is a wee bit thicker immediately ahead of the web, and it come out of the '66 chamber looking more normal, so this year, I'll be using 38's in my 357 hipguns and my '66. 

 

I test new loads over a chronograph, and I follow a procedure that was listed here of ??? I shoot 5 shots, powder against the primer, and shoot the second cylinder powder against the bullet. In other words, for the first 5, I hold the muzzle up then slowly lower the muzzle onto the rest and shoot over the screens, the next 5 start from the muzzle pointed towards the ground. 

 

This gives you data from both extremes. Be warned, I've had a few squib loads with powder forward. Some powders do not like to be too far away from the primer. Interestingly, some primers do not like the powder too close. 

 

Other loads don't care what the primer is, either they work or they don't.

 

So far, I've not been able to run bullets lighter than 135 gr at low velocity, and get consistent Es/Sd, but I'm working on it. 

 

This is the bullet that works for me.

 

vuDFkGn.jpg?1  

 

 

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That bullet is movin’ mighty slow for you to get such a clear picture of it.

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On ‎3‎/‎23‎/‎2019 at 4:58 PM, "Big Boston" said:

 

It's been my experience that, with all other things equal, changing to a longer case, can have some rather interesting ramifications.

 

Obviously, or intuitively, velocity will be less, and pressure should be less as well. 

 

Less obvious or intuitive are the creation of poor ammo. IOW, the same charge, now in a larger container, becomes position sensitive and produces erratic velocities (large Es/Sd). Cowboy loads are generally at or sometimes below the normal starting load. They can take on a mind of their own. Sometimes they are completely predictable, more often they are not. 

 

Low loading density Cowboy loads can be very tune-able with a primer change. Different brands of primer make less of a difference in mid to high end loads, and become a factor again at the top loads. 

 

I am using light loads, similar to your loads, about 3.5 gr of AA-452, a CCI 500 SP primer, with a 147 gr bullet, OAL of 1.5" for my '66 Yellow Boy. As the chamber in this one is a bit bigger than the chamber in my hipguns, I wanted to keep the brass separated. An easy way to do this was to load 357 for my hipguns. I loaded the 357 mag brass with the same load, and testing found it to be position sensitive. Increasing the charge to 4.1 gr helped but the biggest improvement came with a primer change. With this combo a WSP primer worked well. OAL was 1.6".

 

The '66 is chambered in 38 Spl, so I pretty much need to load 38 Spl for it. I was able to find a brand of brass that is a wee bit thicker immediately ahead of the web, and it come out of the '66 chamber looking more normal, so this year, I'll be using 38's in my 357 hipguns and my '66. 

 

I test new loads over a chronograph, and I follow a procedure that was listed here of ??? I shoot 5 shots, powder against the primer, and shoot the second cylinder powder against the bullet. In other words, for the first 5, I hold the muzzle up then slowly lower the muzzle onto the rest and shoot over the screens, the next 5 start from the muzzle pointed towards the ground. 

 

This gives you data from both extremes. Be warned, I've had a few squib loads with powder forward. Some powders do not like to be too far away from the primer. Interestingly, some primers do not like the powder too close. 

 

Other loads don't care what the primer is, either they work or they don't.

 

So far, I've not been able to run bullets lighter than 135 gr at low velocity, and get consistent Es/Sd, but I'm working on it. 

 

This is the bullet that works for me.

 

Very good to know.

Is there any advantage to filling the space in the casing with something like when reloading black powder?

On ‎3‎/‎23‎/‎2019 at 4:58 PM, "Big Boston" said:

vuDFkGn.jpg?1  

 

 

 

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Posted (edited)

With Black Powder any air space is not the desired state. So a reduced load requires a filler to remove any air space. Smokeless is different.

 

So, why not use a bit of ??? to keep the powder next to the primer? Good question, and hopefully someone with a bit more experience/knowledge will chime in.

 

From what I've read and heard, a tuft of Dacron or cattail fluff, or ??? will certainly do that, but sometimes it can create problems. I avoid it because of the tiddly butt job it is. If you're making 50 rounds of ammo that will last you several months, not a problem. If you're loading 500 rounds and it lasts days, too tiddly butt for me.

 

But: for real mouse sneeze loads, probably a required step. I even bought a few square yards of Dacron, used it for testing, that's it.

 

Using a smaller case works better IMO, (more reliable, predictable, easier), ie; 44 Russian in the 44 Rem Mag, 45 Cowboy Special in the 45 "Long" Colt, or 38 Short/Long Colt in the 38 Spl/357.

 

Unfortunately this may introduce some additional stress in a revolver. The cylinder may get an extra knock or kick as the bullet enters the cylinder throat. Some think this may contribute to premature cylinder rattle. I've not seen any scientific testing, but cowboy logic tells me that it, may or could, increase wear. If you load in 38 Long Colt brass for a 357, the bullet has an increased jump to the throat, of app 1/4". Is that significant? That, loading in shorter brass, knocks about 200 fps off, if pressure is kept the same. It's not as dramatic a change as I thought it would make. You do use less powder for the same pressure, and you loose velocity as a result. 

 

As soon as it warms up I plan on chrono testing some 38 Long Colt loads. 

 

BB

Edited by "Big Boston"
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