The widely unknown and forgotten marlin mr-7 - building a mountain rifle in .270 sherman

codyadams

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So my cousin has a Marlin MR-7 chambered in .270 win. The Marlin MR-7, while a fine rifle, is not a well known rifle. It was produced only from 1995 through 1999. This is not the optimal set up to build off of, but we enjoy unique rifles, and it was also my cousin's first rifle, a gift from his father, so he wants to keep it around and get more use out of it for sentamental reasons. We are going to be building this rifle into a lightweight mountain rifle chambered in .270 Sherman, but doing so is going to require some ingenuity and outside the box thinking. And since this rifle was only made for 4 years, I will give you a little more info on it.

The bolt face and race way are essentially an exact copy of a Remington 700 design, with the action footprint, 3 position safter, and trigger components being essentially, or very close to that of a Winchester model 70. While the footprint of the bottom metal is also close to a model 70 type, the design is shared with a Browning A-Bolt, with an internal box mag that detaches from the hinged floor plate. The scope base is also that of a Winchester model 70.

Our first challenge, was to see how to go about replacing the walnut stock with a light weight composite for the back country hikes. Not knowing much about the rifle at the time, it was challenging. I had recently bedded a Winchester 70, and when I took the marlin out of the stock, it resembled the Winchester very much. So I grabbed another Winchester 70 out of the closet, and it nearly dropped in to the Winchester stock, and would only take minor relieving in one location to get it to fit. The bottom metal of the marlin was only about .010" larger in all locations, but otherwise same screw hole spacing, and same shape. So that solved the stock delima, just get one for a Winchester 70!!

After further inspection, I realized that the box magazine would have issues with the .270 Sherman running 170's, as it only allows 3.350" OAL!! Well that's a problem.....

To resolve this, I grabbed a Remington 700 out of the closet to see what it would take to switch this over to a Remington Mag box.....and it nearly fit without any modification......nearly.

The floorplate has an arm that extends up to hold the detachable mag in place. This is going to have to come off for it to close. Also, the remington mag box must sit deeper in the action that the reciever allows. So a small amout of metal will have to be removed.

Then when function testing with just pressure holding the follower and mag spring in place, the feed rails on the marlin (designed to feed from the detachable magazine) are too wide. Well.....looks like we are going to have to modify a remington mag box to be a center feed!! I will update this more as this build continues.

I will add - this build is not about being efficient, and taking an easy rout to the quickest final design. We both already have outstanding long range rifles, we do not need this finished now. This is for fun, and to get more use out of a sentimental rifle. When it's done, it will likely be the only rifle of it's kind in existence. Also, if there is someone out there that has one of these rifles and wants to do some work with it, but aren't sure where to start, this will hopefully help them out. I know I was unable to find ANY real information on modifying these rifles or finding aftermarket parts for them.

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You bet rich!! For this season we are going to run it as a standard .270, but after this season I believe he is going to rebarrel it, so we will be hitting you up for reamers for .270 Sherman and probably my .270 SS build about the same time ha ha!!

Blake did just purchase a suppressor, and he is going to be getting a scope and stock for this rifle too, so funds probably won't be regenerated for a little bit ha ha, but it's going to be pretty cool when it's done. Being its a combo of remington and marlin parts (as well as others), we decided to call it, "The Remlin" ha ha
 
You bet rich!! For this season we are going to run it as a standard .270, but after this season I believe he is going to rebarrel it, so we will be hitting you up for reamers for .270 Sherman and probably my .270 SS build about the same time ha ha!!

Blake did just purchase a suppressor, and he is going to be getting a scope and stock for this rifle too, so funds probably won't be regenerated for a little bit ha ha, but it's going to be pretty cool when it's done. Being its a combo of remington and marlin parts (as well as others), we decided to call it, "The Remlin" ha ha
Love it!
 
If the action screw spacing is the same as a model 70, then there are plenty of options for a detachable mag set up. Then you wouldn't need to grind on the action. Just inlet for new bottom metal.
 
If the action screw spacing is the same as a model 70, then there are plenty of options for a detachable mag set up. Then you wouldn't need to grind on the action. Just inlet for new bottom metal.
Because that would add wieght over a bdl type set up, we are trying to go as light as possible. Doesn't look like it's going to be too hard to do!!
 
I think you'll like the 270 sherman. I really like mine. That's a cool project for sure! I built mine off a model 70 crf 25-06 that had the boss bbl. did a Wyatt's box to get more length out of the Winchester action and a 27" 8 twist for a little speed. I've had some feeding issues but once I got a little better understanding of the whole feed cycle, I think I've gotten it dialed in nicely. Going that far off the beaten path, I'd be half tempted to do a 7 twist and try the biggest hammers. I haven't shot any of their bullets yet but you don't exactly see any bad reviews.
 
I owned an MR-7 in 30-06 way back when.

Shot dang good and I wish I had never let it get away from me.

Should be a nice heirloom rifle when done.
 
I was driving to work today and saw a truck carrying a beautifully
re-constructed Sherman tank. I know this is neither here nor there.
It was very nice though.
Zeke
 
Hello,
I admire your ingenuity, but it seems to me in all this modification, you may run the risk of some malfunction in feeding, when hunting, which can be catastrophic at the time. You know the complete factory rifle performs well, so consider this: skeltonizing the original stock in which everything worked perfectly in the first place! I am a huge fan of Elkaholic designs.!

Wildcat westerner
 
Hello,
I admire your ingenuity, but it seems to me in all this modification, you may run the risk of some malfunction in feeding, when hunting, which can be catastrophic at the time. You know the complete factory rifle performs well, so consider this: skeltonizing the original stock in which everything worked perfectly in the first place! I am a huge fan of Elkaholic designs.!

Wildcat westerner
The thing is, the modification we are doing will not make the original design not work, we already ordered a bottom metal from Numrich to modify, and will leave the original as is. As far as the small amount of reciever opening, it never contacted the magazine in any way, and the rails did not work as feed rails, the detachable magazine did. Also, we are not touching the feed ramp. So if for some unforseen reason the rem 700 internal box does not work out, we will still be able to return to the original design with the simple switch of the bottom metal
 
Well got a little update on this rig!!

My cousin got the stock ordered in, and it turns out it needed a little more fitting than we initially thought, though its nothing a dremel and a router bit/attachment couldn't handle!!
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Here, I had to take the inletting about .300" deeper and widen it about .025"

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Here is the result!!!

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On the trigger guard area, I had to take it about .030" deeper in the rear, lengthen it behind the rear action screw about .045", and in the front deepen it another .200" or so to allow the trigger guard to fit properly. Also, I had to widen the square notch you see there in the deeper part of the inletting.
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Final result....
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And a couple rifle pics!!!

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The action needed some minor inletting, mainly just widening in the bolt area of about .150" or so, and squaring off the inletting under the tang, as it had radiused edges for the Winchester vs the square edges of the Marlin. Bare rifle wieght is still 7.6 lbs, finished with rings, bases, scope, pillars and bedding, it will be right around 9.3-9.5 lbs, so not ultralight, but not too terribly heavy either. I also think it helps when a rifle is balanced, and this one feels pretty good.

We could take about a lb off if we went with an ultralight stock, but we didnt want to dump $500+ into a carbon stock when we were unsure of what inletting would need to be done. Knowing that it's not too bad now (with a dremmel and router attachment), it may be an option for the future, but I think the $150 boyds will be on it for quite a while, my cousin seems to really like it.
 

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