Martini Cadet in .357 Magnum

[Murphinator]

I just picked up a .357 Magnum Martini Cadet and I wanted to know what the maximum pressures these rifle can sustain. I know off the shelf ammo will be useless for my application as I want this to be a deer hunting rifle. I was thinking about getting some Buffalo Bore Ammo but I know those loads can be quite hot so I wanted to make sure the cadet rifle can handle it. I also thought about handloading some .357 mag and working up a good powder load. Anyone know offhand what the maximum muzzle energy in ft•lbs a .357 mag could produce. Buffalo Bore states that from a 24" barrel at 50 yards their 180gr ammo is pushing 1257 ft•lbs and at 100 yards is 1089 ft•lbs. If anyone here has a Cadet could you share your load info ? Thanks in advance for any help that can be given.

[M-Tecs]

I cannot directly answer that but they do chamber Cadets in fairly high-pressure calibers

https://www.go2gbo.com/threads/martini-cadet-caliber-conversion-question.19584/

[stubshaft]

I have a converted Cadet myself in 357 mag. too. I've shot 180 grain RCBS silhouette bullets ahead a case stuffed with 296 with NO problems.

[john.k]

The likely problem with a Cadet is primer deformation,unless the block and firing pin has been modified...........if your application does not crater the primer in your rifle ,then you will have no problems .....it would also be advisable to use rifle primers in reloads ,for a bit more resistance to cratering.

[indian joe]

The likely problem with a Cadet is primer deformation,unless the block and firing pin has been modified...........if your application does not crater the primer in your rifle ,then you will have no problems .....it would also be advisable to use rifle primers in reloads ,for a bit more resistance to cratering.

Back in the day there were heaps of martinis converted to 222rimmed bushing the firing pin was part of the deal.

[Jedman]

I have several in higher pressure cartridges, 22 zipper, 256 win. mag., 357 Max. and there are no worries about the action but they all have had the breech block bushed and firing pin fitted close.
With the 357 magnum if your chamber will allow you to chamber bullets seated out long you have more room in the case for powder. I have several 357 mags in single shots that I can shoot a OAL of 1.730” with 200+ gr. cast bollits.

Jedman

[Rapier]

The Cadet, like the AR-15 and Contnder is rated as a 50k action. However, the Cadet will handle 65k without issue, with a bushing for the firing pin and a reduced firing pin diameter, both alterations are necessary for high pressure cartridges.
I have a 225 Win Mag, and two 357 Super Mag Cadets. The 225 and 357 SM cruise at 50k. I built the 225 as the calculated largest diameter case to fit the Cadet due to the minor thread cuts. Factory ammo works just fine in that chamber.
The 357 Mag in gun that has a block with a bushing and a turned firing pin, in good condition should be loaded like the rifle it is. I use 200-180 grain cast, with rifle primers and a righteous amount of H-110 or 296. Best accuracy, no crimp, just straighten the case mouth, 200 gr RCBS style sized to groove, 14.6 to 15 grains 296, 205m primers. The chamber walls on a 357 Cadet are much thicker than the chamber walls a model 19 Smith, just for example..
You just need the chamber lead setup for a rifle, not a revolver. This will allow a 200 to be set out to the crimping groove on the bullet.

[John Taylor]

I have converted more than a few Cadets. Have had some come into the shop that were re-chambered to 32 Special with no other alterations. As stated by a few here, the firing bin will need to be bushed and the firing pin turned down. The action can be locked up if the primer flows into the firing pin hole. The cadet can be chambered to 357 MAX but the top of the breach block will need to be carved out a bit. Bottle necked cartridges with a little taper to the body don't seem to have the problem like the long strait case.

[john.k]

The Cadet rechambered to 32 Spec is an awesome gun........once fired ,not forgotten.......I always wondered how the 22in twist stabilized a 165gr bullet......but it did ,and otherwise they worked OK.

[Murphinator]

Is 23 grains of H110 a too hot load for .357 Mag? I was thinking on a 180-200gr bullet and 23gr of H110 with a rifle primer instead of a pistol primer.

[gnoahhh]

Out of curiosity I checked a couple sources, including Hodgdon's web site, and 14 grains seems to be maximum. (Hodgdon lists 13.5 grains with a 180 bullet as maximum.) So yes, I would consider 23 grains H-110 as too much, waaaaay too much!! Lyman manual lists 18 grains/180 as max in the .357 Maximum and that's a much larger case.

Begs the question, where did you come up with this load?

[Murphinator]

A guy I work with says he uses 23grs on H110 in his .357 Magnum Ruger BlackHawk and a 190gr bullet.