Felt Snappiness: 357 Mag v. 38 Short Colt

[fxvr5]

What's the case capacity of the 38 SC brass vs 9mm?

That information was noted in the first post. The OP writes: "Trying new loads for 38 Short Colt ammo. The 38 SC brass is slightly more voluminous than 9mm brass with a slightly larger case diameter and case length ... but close nonetheless."

That information is also in the article that has been linked to: "Case volume is an important factor in determining chamber pressure. Measurements of case capacity showed that Starline’s .38 Short Colt brass have a little more capacity than the typical 9 mm brass. I trimmed virgin cases to the same length of 0.748 inch and measured (three times) how much Accurate #7 powder they would hold. Starline’s .38 Short Colt case held an average of 14.62 grains. Starline’s 9 mm case held 14.28 grains. For comparison, a Lapua 9 mm case held 13.97 grains, and a Winchester nickel-plated 9 mm case held 14.32 grains. When loaded with the same powder and bullet to the same overall length, the .38 Short Colt case should produce slightly less chamber pressure than a 9 mm case. This is handy to know when using 9 mm load data for Starline .38 Short Colt cases."

The link again:

An NRA Shooting Sports Journal | Handloading The .38 Short Colt For Competition

Modern competitive revolver shooters use .38 Short Colt for its short case, which is faster to eject and reload than the more common .38 Special.

www.ssusa.org

 

[Ethan Verity]

A cartridge originally designed for black powder has the same case volume as a cartridge original designed for smokeless, so you use the smokeless cartridge load data in the black powder round? To me, this sounds like the same line of thinking as saying 38Spl has similar case volume to 357Mag, so you use 357Mag load data in the 38Spl case... that's a recipe for disaster!

I would hate to see what would happen if one of these hot 38SC rounds were inadvertently shot through something like a cartridge conversion 1851 Navy.

 

[reddog81]

That information was noted in the first post. The OP writes: "Trying new loads for 38 Short Colt ammo. The 38 SC brass is slightly more voluminous than 9mm brass with a slightly larger case diameter and case length ... but close nonetheless."

That information is also in the article that has been linked to: "Case volume is an important factor in determining chamber pressure. Measurements of case capacity showed that Starline’s .38 Short Colt brass have a little more capacity than the typical 9 mm brass. I trimmed virgin cases to the same length of 0.748 inch and measured (three times) how much Accurate #7 powder they would hold. Starline’s .38 Short Colt case held an average of 14.62 grains. Starline’s 9 mm case held 14.28 grains. For comparison, a Lapua 9 mm case held 13.97 grains, and a Winchester nickel-plated 9 mm case held 14.32 grains. When loaded with the same powder and bullet to the same overall length, the .38 Short Colt case should produce slightly less chamber pressure than a 9 mm case. This is handy to know when using 9 mm load data for Starline .38 Short Colt cases."

The link again:

An NRA Shooting Sports Journal | Handloading The .38 Short Colt For Competition

Modern competitive revolver shooters use .38 Short Colt for its short case, which is faster to eject and reload than the more common .38 Special.

www.ssusa.org

The capacities are basically identical. Saying it's slightly more voluminous doesn't really mean anything. Starting with a 35K PSI max charge as a starting load because the case capacity is 2% larger doesn't make sense to me. Depending on bullet being used or how deep you seat the bullet will have a much more significant impact than 2% extra case capacity. The 38 SC load probably felt snappier because the pressure was higher than the .357 Mag load.

 

[Mr_Flintstone]

I am, by no stretch of the imagination, an expert on all things reloading, but I do understand the concept and desire to load shorter cases to .357 magnum pressures to achieve a faster reload time for competition. With that said, I’d like to touch on a couple things here. First is that a load that falls within the pressure limits of the .357 magnum “should be safe” regardless of the length of the cartridge case, so a 38 Short Colt case loaded with some data 9mm loads should fall within that range. I say some because even though the load shows a usable pressure in the books doesn’t necessarily mean that they are in actuality safe when you start changing components from what was actually tested. While 9mm cases and 38 short colt cases share virtually the same volume, you can get into trouble quickly with seating depths. Most 9mm bullets don’t have a crimp groove, but most 38/357 bullets do. The actual tested seating depth on a 9mm load might be less than what would be expected by crimping a .357 bullet at the groove. While this might not be a big difference in depth, that difference in a case as small as a 9mm can cause a big difference in pressure. For example, on Hodgdon’s website 38 short colt shows a 135 grain bullet with an overall length of 1.135” while the 9mm shows an overall length of 1.15”. This small difference could be responsible for several thousand psi difference in pressure. With the relatively cavernous capacity of the .357 magnum this small of a difference in depth would still make a difference, but not nearly as great. That’s why when working with small capacity cases, definitely start on the low end and work up.

 

[Docendo Discimus]

GRT gives an output for recoil force and recoil velocity. I imagine Quickload does as well, I don't know for sure because I haven't ever used it. Either way I would plug this into the program and get some numbers to look at to see what is going on.

 

[Riomouse911]

I do wonder if there also may be a little bit of “expectation bias” in action with the OP. This would be expecting that the smaller cased round would recoil lighter, even though the operating psi of both the handloaded .38 SC and .357 Mag rounds is similar.

Just wonderin’ out loud…

Stay safe.

 

[jski]

This is from the NRA article referenced above:

When loaded with the same powder and bullet to the same overall length, the .38 Short Colt case should produce slightly less chamber pressure than a 9 mm case. This is handy to know when using 9 mm load data for Starline .38 Short Colt cases.

This was my consideration when adding the additional 0.1 gr of True Blue and also that these are not +P loads. I wanted to duplicate the 9mm performance.

I will say I seated the bullets to the crimp groove just like I'd seat a 38 Spl or 357 Mag round.

 

[reddog81]

Hodgdon has a a wide variety of load data for True Blue in 9mm and 9mm +p. There is load data for a 124 grain Berrys bullet with a starting load of 4.6 grains and max of 5.5 with pressure of 34,900 PSI and velocity of 1,074.

All the 124 & 125 9mm +P data is for lead bullets or jacketed HP's. Only one of 6 loads of the +P data goes above 6.1 grains. 3 of the Max +P loads are below 6.0 grains and the max pressure of all of these is above 38K PSI.

 

[Mr_Flintstone]

OK. I just measured some Berrys 125 gr plated flat points, and they measure exactly the same as 125 gr XTP bullets. So I entered the 5 grains Hodgdon 9mm max of True Blue into GRT with a 125 gr XTP at the Hodgdon seating depth and got just below the pressure value given by Hodgdon. The difference was negligible. I then entered the 125 gr XTP and True Blue at 6 grains with the same OAL and got well over 40,000 psi. Extending the OAL to that of a 124 gr XTP I got right at 40,000 psi. Being curious, I tested again with Short Colt cases and the differences in pressures were negligible.

Thats as close as I can figure without knowing the exact measures for overall length and case volume for the loads in the original post, but my guess is that the loads in question were well over .357 Magnum SAAMI specs.

 

[jski]

The Western Powder PDF has the following for 9mm with True Blue:

BERRY RN 124 gr
min: 5.2 & 987 FPS
max: 5.9 & 1,115 FPS
PSI 34,012

And these case heads show no signs of excess pressure:


I always defer to empirical data … assuming Western Powder numbers are measurements from actual tests. Certainly the case heads are empirical data.

 

[Walkalong]

Certainly the case heads are empirical data.

They look good, but are not empirical data.

 

[jski]

They look good, but are not empirical data.

They’re not? Then what are they?

 

[Mr_Flintstone]

They’re not? Then what are they?

It is empirical data in a sense. You have tested the rounds and they proved safe over the course of fire. Where it falls short is in whether it will continue to be safe over the long run, and in that it doesn’t really test the pressure of the rounds in question; and in order to compare the snappy recoil in your original question with that of .357 magnum, you would need to show that the pressure of these rounds fall within the specified parameters of .357 magnum pressure. What you really have is anecdotal evidence in that your primers weren’t flattened, and I’m going to assume that there were no extraction issues. The problem with that type of testing is that you’re not likely to get really flattened small pistol primers until well over 40,000 PSI, and maybe not then. That’s a mistake I made when I first started reloading. The primers in handgun ammunition don’t know what the pressure of the round you’re loading is, and doesn’t miraculously deform when you exceed that pressure. Many times they hold up without deforming until well past their maximum rated pressures. A lot plays into getting flattened primers.

I’m not, and I assume others aren’t either, saying these things to chastise you for what you are doing. Experimentation is part of hand loading. I think what put most people off is that you jumped right past published data and started your testing with a higher charge than what was listed. It may well be that the rounds you have loaded are safe and within SAAMI specs, but this isn’t something we can just assume when extrapolating a published load to another type of round. We just want you to stay safe because sometimes experimental loads work perfectly fine… until they don’t. I still believe that the rounds exceed 35,000 psi, but that doesn’t necessarily mean they aren’t safe. Many factors play into whether a round can safely and consistently be used including the strength of your brass, the strength of your gun, and the number of increased pressure rounds fired before increased wear becomes a problem.

I have pushed past published data in the past without harm. Sometimes it was accidental, and other times it was intentional, but I was using a stronger firearm than what was being tested. Because I like my fingers and eyes though, I always trim back my loads to where I’m fairly certain they are within safe standards.

Whatever you do, stay safe. A few extra fps isn’t worth a trip to the er or worse.

 

[mcb]

They’re not? Then what are they?

Because those primer would have look pretty similar even if they had been put in 327 Magnum at 45,000 psi or 30 Super Carry at 52,000 psi.

I also get much flatter primer in relatively moderate pressure 40 S&W in my 610 as there is a touch more head space with the 40 S&W on moonclips and the primers have a habit of blacking out slightly at primer ignition and then they get driven back into the case when the powder ignites and the case slams into the breach face. Looks like serious pressure signs with flat primers that are sometime even mushroomed slightly but no other pressure signs, the velocity is right where it's expected and in a semi-auto that same load shows no pressure signs on primers.

 

[jski]

It is empirical data in a sense. You have tested the rounds and they proved safe over the course of fire. Where it falls short is in whether it will continue to be safe over the long run, and in that it doesn’t really test the pressure of the rounds in question; and in order to compare the snappy recoil in your original question with that of .357 magnum, you would need to show that the pressure of these rounds fall within the specified parameters of .357 magnum pressure. What you really have is anecdotal evidence in that your primers weren’t flattened, and I’m going to assume that there were no extraction issues. The problem with that type of testing is that you’re not likely to get really flattened small pistol primers until well over 40,000 PSI, and maybe not then. That’s a mistake I made when I first started reloading. The primers in handgun ammunition don’t know what the pressure of the round you’re loading is, and doesn’t miraculously deform when you exceed that pressure. Many times they hold up without deforming until well past their maximum rated pressures. A lot plays into getting flattened primers.

That is a good point. Primer are a “sign” of excess pressure but not a pressure gauge. But they’re the best “sign” I have. I fired a total of 18 rounds and carefully examined each 6 after having shot them.

I’m not, and I assume others aren’t either, saying these things to chastise you for what you are doing. Experimentation is part of hand loading. I think what put most people off is that you jumped right past published data and started your testing with a higher charge than what was listed. It may well be that the rounds you have loaded are safe and within SAAMI specs, but this isn’t something we can just assume when extrapolating a published load to another type of round.

As we’ve established, there is no SAAMI spec for the 38 SC.

Many factors play into whether a round can safely and consistently be used including the strength of your brass, the strength of your gun, and the number of increased pressure rounds fired before increased wear becomes a problem.

With S&W and Starline, I believe I’m in good shape with that. Both the gun and brass are new.

Whatever you do, stay safe. A few extra fps isn’t worth a trip to the er or worse.

If I thought I was risking that, I would never have pulled the trigger.

 

[jski]

Because those primer would have look pretty similar even if they had been put in 327 Magnum at 45,000 psi or 30 Super Carry at 52,000 psi.

Aren’t .327s notorious for flattening primers?

 

[W.E.G.]

Are these cartridges both being fired in the same gun?

If so, enjoy your fouling ring.

 

[fxvr5]

jski, we're missing information that is important in evaluating your load.

We have your bullet as a Berry 125 grain FP. What we need is: What OAL did you seat them to? What primer did you use?

 

[Mr_Flintstone]

As we’ve established, there is no SAAMI spec for the 38 SC.


With S&W and Starline, I believe I’m in good shape with that. Both the gun and brass are new.


If I thought I was risking that, I would never have pulled the trigger.

No, there isn’t a SAAMI spec for 38 SC, but if you are shooting them from a 357 magnum, you need to stay within the 357 magnum pressure range, but I’m sure you already knew that.

 

[jski]

jski, we're missing information that is important in evaluating your load.

We have your bullet as a Berry 125 grain FP. What we need is: What OAL did you seat them to? What primer did you use?

 

[mcb]

Are these cartridges both being fired in the same gun?

If so, enjoy your fouling ring.

The fouling ring is way overblown by the internet. I ran 1200+ rounds of my 38 Short Colt in my 627 without cleaning and someone told me I would have a bad fouling ring. I grabbed a moonclip of 357 Magnum drop it into the cylinder no problem. Fired all eight rounds and ejected with no problem.

I am not saying the fouling ring can't happen, but you really have to be shooting very large quantities of really poor quality ammo with no maintenance for the fouling ring to really cause functional issues.

 

[fxvr5]

Your OAL of 1.025 is mighty short. Shorter than what's in the load manuals for a 124/5 gr. FP bullet in the 9mm, which usually don't go below 1.060" or so. That will increase pressure.

 

[jski]

Your OAL of 1.025 is mighty short. Shorter than what's in the load manuals for a 124/5 gr. FP bullet in the 9mm, which usually don't go below 1.060" or so. That will increase pressure.

Keep in mind, the bullet has a larger diameter and is consequently shorter for a given weight … but not much shorter.

 

[fxvr5]

Keep in mind, the bullet has a larger diameter and is consequently shorter for a given weight … but not much shorter.

Your theory does not hold up. Berry's 38/357 bullet is longer than the 9mm bullet. From Berry's website:

9mm 124 gr. FP, length = .512

38/357 125 gr. FP length = .518

124 Grain 9mm Bullets | Flat Nose Bullet | Reloading Bullets

Berry's 124 Grain 9mm bullets for reloading are flat nose bullets & can be bought in bulk. Shop our 9mm plated bullets for unbelievable accuracy!

www.berrysmfg.com

125 Grain 357 Bullets | 38 Special Bullets for Reloading

The 38 Special 125 Grain bullets sold and manufactured by Berry's Bullets are some of the best 38 special bullets you can buy for consistency and precision.

www.berrysmfg.com

 

[jski]

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