Relative strength, Marlin 36 vs. 336?

[Bill in Oregon]

Brent's moose rifle build on a square-bolt Marlin got me to wondering about the relative strength of this rifle vs. the later round-bolt 336. Anyone have data, or lacking data, an opinion?

[Pete44ru]

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The round bolt Model 336 is demonstrably stronger than the square bolt Model 1936/36.

Those Marlins lock the bolt into battery at the rear - where the square bolt Model 1936/36 is lacking a RH receiver wall (connecting the top to the bottom) to support the bolt lock.

That's the reason that Marlin re-designed the Model 1936/36 into the Model 336.


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[Bill in Oregon]

Pete, I had a hunch that this was the case. Thanks for confirming.

[Chuck 100 yd]

The 36 was/is strong enough to handle their original calibers and loads. I would handload cast bullets and shoot,shoot,shoot.

[Pete44ru]

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Maybe the Marlin engineers had amazing prescience in 1947-48, anticipating the higher pressure .356 & .375 Winchester cartridges they chambered the Model 336 for, some 30+ years later.


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[hayabusa]

No doubt about it Pete44ru.
I think that Pete44ru is correct!!!
I sure like those calibers in my Marlins.

hayabusa

[7.62 Precision]

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Those Marlins lock the bolt into battery at the rear - where the square bolt Model 1936/36 is lacking a RH receiver wall (connecting the top to the bottom) to support the bolt lock.

That's the reason that Marlin re-designed the Model 1936/36 into the Model 336.

The Marlins only lock at the lower part of the bolt, not up both sides like a '86/'92 Winchester does, so I'm not sure how much of an advantage the change was for the lockup itself. I also don't know how much stronger the round bolt receiver is, but I'm pretty sure there are some here who know. I can guess that if nothing else the receiver flexes less, with the internal shape changed a bit and a little more meat around the bolt in places.

However, at the time they were not chambering the things for any kind of really hot cartridges, nor planning to, that I know of, and the square bolt rifles were fine for the cartridges they were chambered for.

I can guarantee there was one overriding reason they went to a round bolt - the design greatly reduces cost of manufacture. I would even guess that this was likely the only reason they went to a round bolt.

[KWK]

I've never had a square bolt Marlin apart. My guess is the round bolt's strength comes from the way in which the locking bolt is supported. I imagine the locking bolt in the square bolt models is supported by the receiver analogous to an 1885 Winchester Low Wall; all the support from the receiver is below the contact area to the breech bolt. In the round bolt models, the receiver sides wrap up both sides of the contact area of the breech bolt onto the locking bolt, as in a High Wall. On the other hand, the breech and locking bolts probably don't have as much contact area.

Another benefit of the round bolt is the support of the top rear of the breech bolt is on both sides. The locking bolt is at an angle, and there may be some up lift of the breech's rear into the receiver's top.

A disadvantage of the round bolt is the two piece firing pin starts to overlap when only the round bottom of the breech bolt has begun to overlap the locking bolt. A few years after the round bolt was introduced, they introduced the trigger block; my hunch is this was a fix. Also, the square bolt was likely better at not ingesting dirt, as blown on to the sides of the round bolt at the ejection window.

To my eye, the square bolt models are far more pleasing, and they are strong enough for any cartridge I'd really want.

[Chuck 100 yd]

IMHO , The fit of the contact area and the strength of the steel is more important than the size or the contact area. A large contact area that does not mate up properly is not good either.
I am sure the 336 is made of better steel than the 36. Also look at a typical bolt actions locking bolts,the surface area there is quite small but most have great great strength.

That said,the 36 is strong enough for it`s intended use for sure.
I also like the looks and style better than the 336.

[Griff]

...I also like the looks and style better than the 336.

I'll certainly agree with that! But... those pesky handloaders were/are always looking to push the envelope of safety in search of a few for fps... and that's why the engineers at Marlin decided it needed some "enhancement"!!! I have no doubt that the 336 action is stronger than the 36...

[6pt-sika]

I've played with a pretty fair amount of 1893's , square bolt 1895's , a 1936 , a 36SC and several early 336's to say nothing of the multitude of later manufacture 336/444/1895 guns . And to be honest I shot cast in 75% of them . My cast loads for all of the 1893 , square bolt 1895 and later 336's were all medium at best cast bullet loads with no problem . Only thing I came anywhere close to running warm are my present cast bullet loads for the 444's .

So to kinda answer your question anything I shot in the 36/1936's I had was also used in the 1893's and early 336's I owned at the same time .