Marlin M62 256 Win Mag...

[Encore64]

I picked one of these up a few years ago at a local gun show. My love for the small game cartridges made the $200 easy to part with.

Gun is in excellent condition. Stock could use refinishing and one screw is a silver Phillips Head. Obviously the wrong screw, but fits perfectly.

I've always read that these were chambered too deep. Case head separations were the norm. So, I decided to fact check this.

Forming and loading fresh Starline 357 Mag Brass started by setting the shoulder .025" forward. Easily done by setting a feeler gauge between the shellholder and die.

The action would not close on this.

I decreased shoulder by .001" until the action would stay closed with no spring. But, sure enough, the gun is chambered .010" too deep.

But, this is no big hurdle for a handloader. I'll just form and load ammo for this gun. It requires flat nosed bullets anyway due to magazine restrictions.

I'll search for the correct screw and may or may not refinish the stock. This should be a fun one...

UPDATE: Was still getting a little push back when closing the action. I had to set the shoulder back .004" for .010" over maximum. I suspect many chambers are like this. I believe the condition with these rifles is overblown...

[williamiorg]

UPDATE: Was still getting a little push back when closing the action. I had to set the shoulder back .004" for .010" over maximum. I suspect many chambers are like this. I believe the condition with these rifles is overblown...

Believe me, you are in for an Experience in Reloading when working with the .256 Win Mag in the Marlin Model 62 rifle.
As you found the chamber is cut long from rim to shoulder.
The chamber is also cut too large in diameter. Most all lever action rifles have a slight oblong cut at the base of the chamber to facilitate chambering.
The combination of the chamber cut too long with the base too large leaves the handloader in a tough spot. You can use a .357 die to work on the base but then you are unable to bump the shoulder back just a touch to help the rifle lock up in battery.

Not all Thompson Center .256 Win Mag chambers are cut the same. Some TC barrels also give the handloader problems with sizing, tripping the safety and case life.

I quit trying to get anything resembling high velocity from the Marlin Model 62. It has proven to be a reasonable cast bullet rifle with short case life still an issue.

256 Win Mag cases break for me just above the solid head in the pressure ring area. Case strength with high pressure loads is not an issue as you will have short case life with 256 Win Mag cases and 357 Magnum/Maximum cases due to stretching. None of my cases last six reloading cycles at high pressure. There are no issues with primer pockets loosening.

Discussing case life issues with Ed Harris on the Cast Bullet Association forum did not reveal any new tricks with regard to sizing for an over long, over diameter chamber. Ed did suggest making 256 Win Mag rimless cases from 223 cases and this did help some in extending case life. The 223 cases are still worked hard and do not last long. While extraction of the rimless case is not a problem the Marlin extractor will not hold the 223 case securely and will drop the case prior to being kicked out by the ejector.

The Marlin Model 62 will fire with the bolt just short of lock up. I have never seen a picture of this event but I understand firing with the lever not quite locked will break the case and will dump high pressure gas into the magazine.
You can simulate this with a primed case.
The Marlin Model 62 is not unsafe but the handloader needs to be aware of this and be watchful if he decides t experiment with neck sized cases. Just a little familiarity with the rifle gives a good understanding of when the rifles action is fully closed.


Use caution with load data intended for the TC or other single shots as the load data for the 75 grain and heavier bullets is often above the 46,300 CUP limit for the 256 Win Mag.

357 Magnum case rims vary in thickness. This will cause problems as you experiment with neck sizing and setting your dies.
An example of case life: My Marlin Model 62 loaded with 14.5 grains of Alliant 2400 will push the Hornady 60 grain JFN bullet 2,750 fps and I get FOUR loadings after fire forming R-P 357 Magnum cases.

The 75 grain JHP Sierra bullet ahead of 14.0 grains of Alliant 2400 will nudge 2,500 fps with similar short case life.

The 87 grain JSP Hornady bullet ahead of 12.0 grains of Alliant 2400 will deliver 2,075 fps with equally short case life.


Just for fun here is a picture of some broken cases and some 256 rimless cases.
Broken 357 Magnum formed 256WM cases.

256 Win Mag rimless cases

[Encore64]

Good information and similar to what I've read.

I set the dies not to set the shoulder back and never experienced case separation.

Granted, I never used max loads.

[taffin]

postimg.cc/5Y4tGR5x

postimg.cc/6TQ3fF5c

[Encore64]

My gun isn't that nice. It's in decent shape, but has seen some use.

I've been loading mine to mimic the upper end 25-20 Loads.

Cases have been repeated loaded and holding up fine. Not much noise and cases resize with little effort. Assuming pressures are quite low.

Not a bad little gun for $200...

On a better note, I sent Jack Huntington a Ruger #3 today to become a 256 Winchester with a modified throat. The saga continues...

[williamiorg]

Wayne Blackwell wrote a very well researched article on cast bullets for the 256 Win Mag for the Handloader No. 124 December 1986.

Greg Mushial on his GMDR website has some good low velocity data for the 256 Win Mag.

Greg Mushial had a very goodchamber on his rifle and his case life was excellent. I look forward to any information you wish to share from your experiences with the Model 64.

[rjm52]

Those were interesting guns...

One day at a range in Connecticut in the late 1960s I ran into a guy who had one in .256, .22 Jet and .357. He had three sons and was planning on giving them each one.

I looked for a .22 Jet for decades to go along with my Model 53 but didn't find one for sale till a few years ago...and passed it.

Have fun with yours...Bob

[Encore64]

I'm going to bump the loads up in mine. But, the chamber seems to be fine.

Shame the little spitzers and HPs are available anymore. But, I have a huge supply of 60, 75 and 85 grn FPs.

I'll keep working with this little gem until I get it like I want it.

[tonyrumore]

I always wanted a 62, but never ended up with one.

Back in my 20's, I had a Ruger Hawkeye, Universal Ferret, and Contender, all in 256.....but no 62.

Tony Rumore
Tromix

[contender]

I own a few Hawkeye's and a T/C Contender barrel in .256 Win. I solved my case life issues with a few little things. (1) I have a set of Corbin case forming dies. Better than many, and MUCH better than trying other ideas. (2) I built a case annealer just for this caliber. Anneal the brass after forming, and after firing.
I use the Hornady 60 grn JFP bullets.

[williamiorg]

This thread should have a picture. My rifle is not the best example but it shoots well.

I have a 4x scope with post and crosshair reticle. 

Here is a question: this Marlin is a no serial number rifle. I believe the rare/collectable rifles are the ones which were returned to the factory for the addition of the serial number. I have never seen a picture of a rifle with the serial number added to the barrel.


Here are some pictures, lever closed, lever open - with the "spring back" which moves the bolt forward when the lever is released. And then the post reticle. The post is pretty good in low light or when looking into dark places when the racoon or skunk gets under something or out of the porch light.

[Encore64]

My rifle isn't collector's grade either. Then again, I'm not a collector.

Great looking gun and scope you have there. I really like that reticle.

These are fun guns with enough unusual to them to make them fun...