Marlin 1894C (.357) Max Loads

[Groundhog92614]

I have read of different max pressures for the .357 round and the Marlin 1894C (.357) in different reloading books and from experts. The variety of comments and opinions have left me with two key questions:

(1) Is the Marlin 1894C designed for more (Paco et al) than the ind. std. of 35 kpsi? The owner's manual is silent on this critical point.

(2) Why do reload manuals listing max loads in CUP generally show a higher max powder load than those in psi (i.e. Hodgdon 158gr H110 is 16.7 gr vs. 15.5 gr. from Speers?

References:
Speers Manual #14: Normal industry pressure for 357 rifles: 35,000 psi
Paco (a): Marlin...rifles will easily take 40 to 42,000 psi
Alliant Power (pistol loads 357): 33,600 psi
Hodgdon Manual 2008 (pistol loads 357): 43,200 CUP
Lyman Casting 3rd Ed (pistol loads 357): 42,000 CUP

(a) See www.leverguns.com/articles/paco/357_magnum_and_the_literature.htm

 

[rcmodel]

The 1894 action is also chambered for .44 Magnum at 36,000.

The larger .44 case gives more bolt thrust then the smaller .357 case.

The 1894 is not considered strong enough to be chambered for .454 Casull at 50,000.

So draw your own conclusions.

Regardless, you are not going to gain a whole lot by loading over-pressure rounds specific to the Marlin 1894.

If you want deeper penetration, load 180 grain Cast SWC.
If you want much flatter trajectory, shoot Hornady Lever-Revolution plastic tip spitzer ammo.
If you want much more then that, Marlin makes a very nice 30-30.

CUP measures only max chamber pressure with a copper crusher.

PSI electronically measures not only max, but also "peak" pressure spikes, which can spike higher, faster, then a copper crusher can measure it.

You also have to consider that Hodgdon and any other testing source are all using different barrels to arrive at their data.
No two barrels are the same.

BTW: SAAMI pressure for the .357 was dropped from 40,000 to 35,000 several years ago, in difference to all the little bitty 5-shot .357 revolvers coming out, and damage to Model 19 S&W's with 40,000 PSI 125 grain loads.

rcmodel

 

[Vicious-Peanut]

I too am curious about this. Hodgdon list most of their rifle loads in CUP and many of them are around 40,000 CUP, I know there is no conversion, but from what I've seen there are very rough 'conversions' and sometimes a 40k CUP load is a 50K PSI load and some times a 50K CUP load is a also a 50K PSI load. This leads me to be extremely confused. The only conclusion I can draw from this is that all of Hodgdons 'rifle' loads would be safe in modern rifles chambered for the .357 magnum since they are published loads.

 

[rcmodel]

Typo in my other post you quoted. CUP & PSI were reversed. Sorry!

It should be:

CUP measures only max chamber pressure with a copper crusher.

PSI electronically measures not only max, but also "peak" pressure spikes, which can spike higher, faster, then a copper crusher can measure it.

Copper Crusher, (CUP) will, or at least may, peak higher then the actual max pressure measured.

rcmodel

 

[ReloaderFred]

+1 to what rcmodel said. I've got four of the Marlin .357 Magnum rifles and have put thousands of rounds through one of them in Cowboy Action Shooting, and my wife has put thousands through one of the others (actually her rifle that she stole from me).

With Hodgdon's Lil'Gun and 185 grain cast gas check bullets in the .357, I'm able to exceed the energy of the 150 grain .30-30 round, without exceeding the pressures the rifle was designed for. There's no need to blow up your rifle by trying to exceed it's limitations, but there are ways to make it a heavy hitter, if that's your goal.

Hope this helps.

Fred

 

[Vicious-Peanut]

I'm not out to hotrod any loads, I simply want to know if Hodgdon's loads are too hot for the 1894C. I don't imagine they are since most of the .357 rifles floating around are Marlins and I doubt Hodgdon would publish something that is potentially dangerous.

 

[rcmodel]

Yes, Hodgdons loads should be safe in your rifle.

As always, you need to start out low, and work up to max while watching for pressure signs.

Every gun is different.

rcmodel

 

[ReloaderFred]

I wish I had the article from about 20 years ago that showed that some loads for the revolver in .357 Magnum were actually too hot for rifles, since the revolver is vented between the cylinder and barrel, which alleviates some of the pressure. It wasn't by much, but the crux of the article was to be careful and just not assume that a maximum load in a revolver would be a light load in a rifle. That's why most loading manuals list separate loading data for rifle and revolver in this caliber, as well as the powder company websites.

Hope this helps.

Fred

 

[RMc]

Old Topic New question:

"SAAMI pressure for the .357 was dropped from 40,000 to 35,000 several years ago, in difference to all the little bitty 5-shot .357 revolvers coming out, and damage to Model 19 S&W's with 40,000 PSI 125 grain loads."

rcmodel

Could you provide some detail as to when the PSI standard for the .357 Magnum was dropped from 40,000 PSI to 35,000 PSI?

Within the context of the .357 Magnum cartridge only, do you have any information on what a cartridge of this caliber loaded to the older 45,000 CUP standard would rate on the current PSI standard?

I am aware of general correlation problems between these two systems, however, there would be no such problem in the context of a particular cartridge.

Thanks RMc

 

[rcmodel]

No, I can't give you an exact date.

In general, the Speer #10 manual published in 1979 lists the industry standard for .357 Mag at 46,000 CUP.

The Speer #13 manual published in 1998 lists it at 35,000 PSI.

All loads were reduced between the two manuals quite a bit.

*** = Above current SAAMI standards. DO not use. ***
For instance, using the 158 JHP bullet:
*** #10 shows 17.8 grains 2400.
#13 shows 14.8..

*** #10 shows 17.8 grains H110.
#13 shows 15.5.

*** #10 shows 13.0 Blue Dot.
#13 shows 11.5.

rc

 

[MCMXI]

Could you provide some detail as to when the PSI standard for the .357 Magnum was dropped from 40,000 PSI to 35,000 PSI?

rcmodel,
My Speer No.11 manual published in 1991 states ...

"The maximum loads are slightly under the 46,000 cup working pressure of this cartridge".

... so it had to be after 1991.

Also, the max load given in the No.11 manual for the 158gr JHP and 2400 is 15.9gr and not 17.8gr as you mention. So was this 15.9gr load an interim load between the initial 17.8gr load and final 14.8gr load? It does list 17.8gr of H110 and 13.0gr of Blue Dot as being the maximum loads for that particular bullet.

*** = Above current SAAMI standards. DO not use. ***
For instance, using the 158 JHP bullet:
*** #10 shows 17.8 grains 2400.
#13 shows 14.8..

*** #10 shows 17.8 grains H110.
#13 shows 15.5.

*** #10 shows 13.0 Blue Dot.
#13 shows 11.5.

 

[rg1]

It's not the rifle but the "thin" brass case that limits the pressure that is safe. If a rifle caliber is rated for 35000 psi or cup it's not likely to blow up the rifle at a few thousand psi or cup more. There is a safety margin built into any rifle or handgun that's more than 3 or 4 thousand psi or cup. The manufacturers pressure test their designs to make sure that they are safe with all normal loads. Now a double charge, overcharge, blocked or clogged barrel, or using the wrong powder can exceed the pressure limits of any gun. Again, it's the case that is the usual limiting factor as to how much pressure the caliber can handle and not the rifle. I've shot my Marlin .357 with max loads of Win 296 and AA#9 from different sources but best accuracy in mine was slightly below maximum published data. Some companies bullets have changed in the last few years which could cause more or less pressure. Different bullets, overall lengths, primers used, cases used, all can change pressure. I understand there is no conversion table converting cup to psi. The latest psi testing is more accurate than older cup pressure testing. Electronic transducers to read psi pressure versus crushing a copper pellet with the older cup method.

 

[rcmodel]

It's not the rifle but the "thin" brass case that limits the pressure

Actually, its not.

The weak point in any lever-action is the barrel shank/receiver threads.

The .357 Mag case itself will easily handle 50,000+ in a T/C single-shot.
The same load would likely blow the barrel off of a Marlin 1894.

rc

 

[justashooter in pa]

i had one of these paired with a ruger single action in the new model. the new model fared well with my experimsnts, while the headspace on the marlin suffered. keep loads within standard or you will ruin a good gun.