Short Cases And Pressure ?

[Johnch]

I took a quick trip to the range
As I wanted to do a 50 shot group test out of my Sig 229 with cast bullets out of a loaner mold
Not bad , about normal
So I will cast up a bunch to try


But not what I was wondering about

One of the older members was shooting a 6" S&W 686 357 Mag
His loads sounded like a normal 357 Mag factory load
On the plastic ammo box the label read Hornady 158 gr HP , 16.6 gr H110 , CCI SP and 1.58" OAL
Nothing out of the norm
But the bullets were sticking WAY out of the brass
Also he was using Winchester 38 Special brass

I have heard of doing this before , never tried it
We talked and he said the OAL is what affects the pressure
Not the length of the brass

So if I understood him
Crimping a bullet in a case at the proper OAL for a 357 mag will give him the same pressure
As if he used the longer 357 Mag case and the same 1.58" OAL

Is he right ?
Or what

John

[Rp-]

Maybe the pressure would be a little less since there's not as much bearing surface of the bullet dragging against the brass. Sounds like a test for the Mythbusters.

Sent from my SM-G991U using Tapatalk

[shortlegs]

I would think its the space under the bullet that effects pressure. Same space, same pressure.

[Winger Ed.]

Is he right ?

I wouldn't do it, but yeah, he's pretty much OK as far as pressure and chambering goes.
Also, like that- they shouldn't wander off and find their way into a 38Spec. chamber.

[jsizemore]

Operating pressure of 38 special is 17,000 psi. 357 mag is 35,000. My Hornady manual shows that bullet max load in mag brass is 15.8 grains and OAL of 1.59". I hope he stays at the opposite end of the firing line from me!

I got some load data that is only fit for a Contender. 17.1 grains of H-110 shooting 158 grain Sierra bullets. It will take down a 55lb steel hard set Ram at 200 meters. Doesn't take them down at 500 though.

[racepres]

I wouldn't do it, but yeah, he's pretty much OK as far as pressure and chambering goes.
Also, like that- they shouldn't wander off and find their way into a 38Spec. chamber.
Used to be done alot, back when 357 Mag Brass was Scarce, not to mention expensive.. I still do it, but with my 38/44 loads so they don't accidently end up in a "lesser" 38 Special firearm...
Powder space is Powder space... Period... No One seems to mind seating Deeper....Which is Much more Deviant IMO

[BK7saum]

No issues at all. case volume mimics .357 as long as seating depth is same as .357. Can be done with .40s in a 10mm chamber as well. .40 cases will headspace on the extractor.

[Frosty Boolit]

I know for sure it is the powder space that matters. I remember the way the primers looked when I took some bad advice from a gunshop about bullets are bullets as long as they are the same weight. It was a .357 with 170gr sierras that got me in trouble, just crimp at the canellure, right!

[georgerkahn]

So if I understood him
Crimping a bullet in a case at the proper OAL for a 357 mag will give him the same pressure
As if he used the longer 357 Mag case and the same 1.58" OAL

Is he right ?
Or what

John

To my feeble knowledge base -- he IS! Waaay back a half-century or so I got into Bullseye shooting with a S&W Model 52. Using the "standard" Bullseye loading all was great. I then bought/cast/loaded/used the same weight (148 grain) wadcutter -- only difference to my eyes being this was MY mould, rather than the borrowed one I had used prior. I experienced flat-as-a-pancake heads, with the primers totally even with rest. HUH? A sage at range suggested that MY mould cast wadcutters with a button on end. Seating bullet flush -- required for the S&W 52 -- lowered the bullet into the case -- which is what RAISED the pressure such to result in the clear high-pressure affect. For kicks & giggles, I loaded a box -- same bullets, primers, and cases -- with the wadcutters "upside down" -- button on bottom -- and guess what? No more "hi-pressure" indication.
This all is 100% vis my personal experience; no stress or other gauges, or similar. Just observation.
From it, again, I am a believer that the less space there is in a cartridge -- all else being the same -- the GREATER the pressure.
geo

[45_Colt]

This is why bullet/boolit set-back is dangerous. Drives up the pressure to who-knows-where as the amount of set-back is unknown.

45_Colt

[racepres]

So if I understood him
Crimping a bullet in a case at the proper OAL for a 357 mag will give him the same pressure
As if he used the longer 357 Mag case and the same 1.58" OAL

Is he right ?
Or what

John

To my feeble knowledge base -- he IS! Waaay back a half-century or so I got into Bullseye shooting with a S&W Model 52. Using the "standard" Bullseye loading all was great. I then bought/cast/loaded/used the same weight (148 grain) wadcutter -- only difference to my eyes being this was MY mould, rather than the borrowed one I had used prior. I experienced flat-as-a-pancake heads, with the primers totally even with rest. HUH? A sage at range suggested that MY mould cast wadcutters with a button on end. Seating bullet flush -- required for the S&W 52 -- lowered the bullet into the case -- which is what RAISED the pressure such to result in the clear high-pressure affect. For kicks & giggles, I loaded a box -- same bullets, primers, and cases -- with the wadcutters "upside down" -- button on bottom -- and guess what? No more "hi-pressure" indication.
This all is 100% vis my personal experience; no stress or other gauges, or similar. Just observation.
From it, again, I am a believer that the less space there is in a cartridge -- all else being the same -- the GREATER the pressure.
geo
And...You just explained why the 32S&W Long, became Anemic... At least, and thankfully, in 38, the Target ammo was Not the Majority

[Larry Gibson]

.........

So if I understood him
Crimping a bullet in a case at the proper OAL for a 357 mag will give him the same pressure
As if he used the longer 357 Mag case and the same 1.58" OAL

Is he right ?
Or what

John

He is essentially correct/right. Probably even a little less psi as the absence of that extra lenght of case in the chamber increases the chamber volume just a bit.

Not guessing, actual pressure testing of 38/44 and 357 Magnum level loads in 38 SPL cases tells me so.

[rbuck351]

If you took a loaded 357 round and could trim the case to 39spl length, would it then change the pressure? If anything,it should drop the pressure slightly. It will reduce bullet release grip and increase cyl volume ahead of the case. There may be some 38 spl guns that will chamber a full length 357 round and if you have one and a 357 you may want to label these rounds so they don't end up in a 38 spl.

[Mk42gunner]

So if I understood him
Crimping a bullet in a case at the proper OAL for a 357 mag will give him the same pressure
As if he used the longer 357 Mag case and the same 1.58" OAL

Is he right ?
Or what

This is the reason why the Lyman 358156 (among others) has two crimping grooves.

Some of the old time honored loadings are very brisk with the modern pressure testing methods and limits.

Robert