Marlin 95 goes 450 AK question

[charger 1]

I've got a marlin 95 45/70 away right now being reamed to 450 AK. I have been looking at the other 95 45/70 I have and noticed that there may be some feed length issues with the new monster cause I've trimmed a 348 case to length and tried it,there aint much room ahead of it as it makes the transition from magazine to chamber..Now all the smith is doing is reaming(he's busy as hell is hot),so what mods can be done to give the cartridge more room on one of these puppies? Thankyou


*****After MUCH research on this the project has been scrapped and a #1 ruger chose. Without extensive work(basically building the gun from scratch) the 95 marlin 45/70 cannot be re chambered. They have such small diameter threaded areas that they split when any material is removed....People that successfully do it rethread the action and turn the barrel back with new threads at a large cost********

[JFE]

Chargar,

I think this should help :

Maximizing Marlin's New Model - 1895 Rifle
M.L. McPherson
Precision Shooting October 1998

You can't get a back copy of that issue but you can get a copy of the article from Precision Shooting magazine. It costs $2.00.

Still waiting for my copy, so I cant give you first hand experience on the conversion. As I understand it, it is relatively easy to get 2.65" OAL, but a little more involved to go to 2.73", which seems to be the max possible. This would give you what you are looking for and probably a lot more fun out of a 7lb Marlin than you care to have !

You might also want to look up Mic McPherson website and read his recent article "What is possible in a Marlin". www.levergun.com/main_index.php
Joe

[charger 1]

Ya your right,me thinks. I've been fooling with the one I have that is still in 45/70 and letting a cast FN hang out to see what I can get away with and 2.64 does seem to be a number which requires zero mods so I'm glad I went with the non ackleyed shorter version. However the .350" long neck has left me with the delema of how to get my 400 grains.As I've said in another post,I wonder how a fella can go about running cast bullets deeper than neck?

[Newtire]

Wow! $3000.00 for full-package rechambering and modification! That's just a real heap of dough for some of us.

[rockrat]

3K? Wow, that is a bunch. Figure the conversion of my 45/70 xlr to 50 AK , with the rebore, is going to cost me somewhere around $250. Course, I am cheating as I have the 50 AK reamer already! Good luck on your 450 AK

[charger 1]

Wow! $3000.00 for full-package rechambering and modification! That's just a real heap of dough for some of us.



This pup aint payin 3 bizzoos,no way. 200 for chambering ,the rest by yours truly

[JFE]

Charger,
The conversion costs are prohibitive no doubt and normal folks are unlikely to stump up this kind of cash for such a Marlin conversion. However the article is interesting from a technical standpoint. IMO you are far better off starting with a new model 1886 as the platform for a really maxed out levergun, or if you want to be non-traditional, a BLR.

The 450 Marlin and the 308 Marlin Express both use Vee-threading (threading is different to other chambers). This seems similar to what McPherson uses on his maxed out Marlins. I think that Wild West guns also use this threading technique to provide more beef in the chamber area on their souped up Marlin conversions, otherwise steel available in the chamber area looks to be quite marginal.

On the issue of bullets protruding below the neck, I do this on my 375H&H and it works OK. The CB I use seats approx .25" below the neck, however all the grease grooves are in the neck itself. It is reasonably accurate but this does go against accepted theories.
Joe

[charger 1]

Charger,
The 450 Marlin and the 308 Marlin Express both use Vee-threading (threading is different to other chambers). This seems similar to what McPherson uses on his maxed out Marlins. I think that Wild West guns also use this threading technique to provide more beef in the chamber area on their souped up Marlin conversions, otherwise steel available in the chamber area looks to be quite marginal.


To once again reveal my ignorance,what kind of threading does the marlin 45/70 have? There are companies/gunsmiths just rechambering them to 450 ak and 50 ak without incident that I've heard. Their not about to tell me their mods to action which is OK because I've found out that if your going orig 450 ak the mods are non existant

[JFE]

As far as I am aware all other chamberings (other than 450 Marlin and the new 308 Marlin Express) have square top threads.

Below is an extract from Mc Pherson's article.

Quote

These Marlin rifles have what I would deem a design flaw. Perhaps surprisingly, this is not the rear-locking lug. Rather, it is the relatively small diameter of the barrel threads. When chambering modern cartridges, that work at modern pressures, having a case body diameter larger than about 0.47-inch (Mauser and 30-06 related chamberings, an interesting historical accident!) the weakest portion of these barreled-actions is the chamber, under the barrel threads.
Unfortunately, due to close proximity of the magazine port under the barrel, it is not particularly feasible to enlarge these threads. This is too bad, had John Marlin simply moved the magazine tube and loading port 0.050-inch farther below the barrel he could have enlarged the barrel threads by 0.1-inch and eliminated this weakness. The subsequent design would have worked perfectly without any other significant changes! And this does matter; early Marlins, with softer barrel steel, are prone to chamber swelling. Modern guns avoid this fate only because the steel used in the barrels has significantly increased tensile strength.
My solution to this weakness is to modify the Marlin thread, so that the thinnest portion of the chamber wall under the threads is as thick as is feasible without significantly weakening the receiver. To do this, I use a custom tool set built to my specifications by custom reamer maker Dave Manson. My friend, Ben Forkin (Forkin Custom Classics) originally persuaded Manson to make such a tool set. These tools reduce height of the unnecessarily tall square thread and true the factory cuts so that one can install a barrel with precisely fitting threads.
The improvement is significant. With a properly fitted barrel, thinnest portion of the chamber wall is about 0.035 inch thicker. This may not sound like much until one considers that, for example, in the factory 45-70 Marlin the thinnest portion of the chamber is only 0.100-inch thick! Moreover, with precise threads in the receiver, the gunsmith can fit the barrel threads so closely that the receiver can share the load. While such a design is not ideal (most manufacturers would prefer not to rely on the hoop strength of the receiver to support he chamber), it is the best that we can do with the standard Marlin.

Unquote

You might also want to read through the thread below. Tomray is a Marlin production engineer and in the thread he refers to the barrel threading several times.
http://www.marlinowners.com/board/viewtopic.php?t=17104

Joe

[felix]

Joe, what about the win 92/94? Same-o, same-o? ... felix

[JFE]

Felix,
I dont honestly know, so perhaps someone else can chip in. If not you might like to check with Steve Young. He is a guru with 92 Winchesters.
http://www.stevesgunz.com/
Joe

[charger 1]

Well foolishly I'm going to go on the bases that marlin tech tells me every barrel is proofed to 200% of saami standards. In other words 57,600 PSI. That in combination with the fact that a large portion of the pressure is applied in the first inch of rifling engagement as opposed to the thread end (hence weatherby's free bore,not beefier threads)I'm going to go with it and stay under the 40,000. My understanding of how a locked up thread works in a shoulder application which is what barrel to receiver would be, is that the sides of the thread take a vast majority of the strain. Think of it this way. In an angled thread with shoulder in order for a radial flex to happen a linear flex must also happen. Now given that this is proven fact through years of tool work,I struggle to believe that the 30 some thou at the very tips bought a very big increase in strength. Not very big at all..Actually,if any cause given that stretch I talked about and the fact that you havent changed the root dia.,I would say close to zero increase