Felt Snappiness: 357 Mag v. 38 Short Colt

[jski]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

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.

So naturally I looked at 9mm load data. Found the Western Powder load data PDF and look at 9mm loads for True Blue. There was no exact match for my 125 gr Berry's FN bullets but for 124 gr Berry's RN bullets it had 5.9 gr. Since these were NOT +P loads and since the 38 SC case capacity is slightly larger, I went with 6 gr. of True Blue.

Went to the range today and was getting an average of 1080 FPS with this load ... but they were "snappy", actually snappier than Barnes 357 self defense loads.

So riddle me this: why would this 38 SC load firing a 125 gr bullets at ~1080 FPS be more "snappy" than a 357 124 gr load?

Attached is a picture of the case heads of the spent 38 SC brass. I don't see of any signs of excess pressure.

 

[ballman6711]

Trying new loads for 38 Short Colt ammo.

So naturally I looked at 9mm load data

My first question is why would you use 9mm data for 38 short colt?

There was no exact match for my 125 gr Berry's FN bullets but for 124 gr Berry's RN bullets it had 5.9 gr. Since these were NOT +P loads and since the 38 SC case capacity is slightly larger, I went with 6 gr. of True Blue.

My second question is ... Is the 5.9gr load a start load or a max load?

chris

 

[Docendo Discimus]

why would this 38 SC load firing a 125 gr bullets at ~1080 FPS be more "snappy" than a 357 124 gr load?

You kinda went off the reservation with this load data combo so I think GRT or Quickload will be needed to answer your question. Any answers you get here would be educated guesses at best.

 

[film495]

uhh, you got 38 Short Colt to go over 1,000 fps? you should look at load data for 38 Short Colt, not 9mm, unless you are loading 9mm. It is probably not that risky if you are firing it out of a 357 revolver, but IMHO, always stick to the data for the case/cartridge you are loading; generalizations and mixing load data can be dicey.

 

[fxvr5]

Just a heads-up for people, the 38 Short Colt is used by competitors and loads can match 9mm ballistics in order to achieve the necessary power factor.

It is discussed in this link:

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

And here, too: (Page 48)

https://www.dillonprecision.com/media/bluepress/2013-2016/August_2014_Issue.pdf

 

[mcb]

Did you Chronograph the 357 magnum ammo. That data would help.

 

[jski]

My first question is why would you use 9mm data for 38 short colt?



My second question is ... Is the 5.9gr load a start load or a max load?

chris

Because that was the usual comparison in loads I found online from what I think are credible sources. The cartridge case capacities are so close and cowboy shooters are looking for something that can move steel plates.

 

[jski]

Did you Chronograph the 357 magnum ammo. That data would help.

Yep, the 357 Barnes ammo was moving at ~1250 FPS from my S&W Carry Comp with a 3” ported barrel. I used the same gun for BOTH.

 

[jski]

Just a heads-up for people, the 38 Short Colt is used by competitors and loads can match 9mm ballistics in order to achieve the necessary power factor.

It is discussed in this link:

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

And here, too: (Page 48)

https://www.dillonprecision.com/media/bluepress/2013-2016/August_2014_Issue.pdf

Excellent! Thanks for this link!

 

[jski]

Did anyone see any signs of excess pressure on those case heads above ?

 

[jski]

Oh yeah, lest I forget, way back when I first thought about using Starline’s 38 SC brass, I called their in-house ballistician and asked if their SC brass could handle 9mm pressures and he responded by saying that “many competitive shooters load it to those levels”. I didn’t push him further.

His first name is Hunter (strangely enough).

 

[film495]

cool. this kind of makes this cartrdige more interesting if you can use 9mm load data. uhhh, to the OP, I'm not a physicist, but if I had to hazard a guess why it feel snappier is you are getting a different peak pressure spike and you feel the difference in the recoil even though likely the 357 has more nrg into the recoil, felt recoil is weird. Maybe, to hazard a guess, the peak pressure might be reached sooner, and feels snappier as a result.

 

[jski]

cool. this kind of makes this cartrdige more interesting if you can use 9mm load data. uhhh, to the OP, I'm not a physicist, but if I had to hazard a guess why it feel snappier is you are getting a different peak pressure spike and you feel the difference in the recoil even though likely the 357 has more nrg into the recoil, felt recoil is weird. Maybe, to hazard a guess, the peak pressure might be reached sooner, and feels snappier as a result.

Sounds reasonable.

 

[GeoDudeFlorida]

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.

So naturally I looked at 9mm load data. Found the Western Powder load data PDF and look at 9mm loads for True Blue. There was no exact match for my 125 gr Berry's FN bullets but for 124 gr Berry's RN bullets it had 5.9 gr. Since these were NOT +P loads and since the 38 SC case capacity is slightly larger, I went with 6 gr. of True Blue.

Went to the range today and was getting an average of 1080 FPS with this load ... but they were "snappy", actually snappier than Barnes 357 self defense loads.

So riddle me this: why would this 38 SC load firing a 125 gr bullets at ~1080 FPS be more "snappy" than a 357 124 gr load?

Attached is a picture of the case heads of the spent 38 SC brass. I don't see of any signs of excess pressure.
View attachment 1165404

F=ma. What is the difference in acceleration between the two?
Acceleration is the derivative of velocity. You can’t just swap velocity for acceleration and get anything meaningful.
Remember also that felt recoil is perceptive, not objective.

 

[SingleActionAndrew]

Did anyone see any signs of excess pressure on those case heads above ?

Which primers are those?

 

[Walkalong]

My guess is a much faster powder in your short Colt loads vs our .357 load.

 

[AJC1]

Short colt was not designed for 35kpsi, like 9 and 357. The Sammi pressure rating is 13kpsi. Now you may be shooting them in a 357 and using 9mm data, but that meets the requirements for the heavy loads disclaimer. I hope your doing these loads with intense study and understanding because just about everyone here is deeply concerned with my 38-44 loadings, and all of those concerns would be way more at 35kpsi of your loads, not the 20kpsi loads I work with....

 

[dannyd]

I you want more information on the 38 short being used in competition this is the place.

https://forums.brianenos.com/forum/72-9mm38-caliber/

 

[jski]

Short colt was not designed for 35kpsi, like 9 and 357. The Sammi pressure rating is 13kpsi. Now you may be shooting them in a 357 and using 9mm data, but that meets the requirements for the heavy loads disclaimer. I hope your doing these loads with intense study and understanding because just about everyone here is deeply concerned with my 38-44 loadings, and all of those concerns would be way more at 35kpsi of your loads, not the 20kpsi loads I work with....

I don’t believe there is a SAAMI spec for the 38 Short Colt.

 

[jski]

F=ma. What is the difference in acceleration between the two?
Acceleration is the derivative of velocity. You can’t just swap velocity for acceleration and get anything meaningful.
Remember also that felt recoil is perceptive, not objective.

The only thing I can measure is muzzle velocity and assume a constant rate of acceleration from the time it was fired to moment it exits the barrel.

 

[GeoDudeFlorida]

I don’t believe there is a SAAMI spec for the 38 Short Colt.

All of the relative safety factors aside, the felt recoil discussion comes down to the individual and their perception of how “snappy” something feels compared to something else. There’s other factors, like how fast the bullet accelerates down the barrel, not how fast it’s going when it exits, the effects of expanding gases, and the heat of the burn of one powder vs another but those are relatively small effects - normally. You’re shooting a revolver with a compensated barrel.

S&W Carry Comp with a 3” ported barrel

In this case, the powder which was still making expanding gas after the bullet left the barrel would have the least felt recoil.
Without knowing the powder used by Barnes it’s impossible to compare directly. However, your experience points to the powder used by Barnes to be better suited to a ported barrel than True Blue.

 

[Ru4real]

Case headstamps and primers look fine. I’d say you are pretty close to ideal @jski.

This class, is how you make educated guesses, based on reading, experience and talking with a balistician.

 

[tmd16556]

Wasn’t there a short-lived 9 mm Federal load that did this same thing. Like the 45 auto rim. The problem was it was backwards compatible to 38 short (colt and or s&w).

If the brass didn’t split, it worked alright. It may be the powder that made it snappy. Felt recoil is a lot more guess and check than recoil energy calculations are.

 

[fxvr5]

The only thing a can measure is muzzle velocity and assume a constant rate of acceleration from the time it was fired to moment it exited the barrel.

Acceleration is not constant. Speed gets a big jump as the bullet leaves the case. The acceleration rate declines as the bullet travels down the barrel.

From: https://robrobinette.com/Gun_Recoil_Calculator.html

 

[jski]

Acceleration is not constant. Speed gets a big jump as the bullet leaves the case. The acceleration rate declines as the bullet travels down the barrel.

From: https://robrobinette.com/Gun_Recoil_Calculator.html



View attachment 1165469

I have no doubt that the rate of acceleration is changing constantly. All I’m saying is that I have no means to measure it.