CRF M-70 416 Rem Feeding

[intj]

I purposely left the magazine of this rifle unmodified to ensure reliable feeding. I swear the ones I have opened up and installed the Wyatt's 3.825" mag box work better than this factory Winchester.

This rifle started as a stainless synthetic 375 H&H. Many years before I had my own lathe and mill I had a very good gunsmith install a new chrome-moly M-70 416 Rem takeoff barrel. I then put in a 416 Rem magazine box. In prep for upcoming cape buffalo hunt this Aug I had my shop cerakote the barreled action in elite black. I then bedded it in a McMillan Supergrade stock. I had also acquired a steel one-piece floor plate to replace the aluminum one.

I started load development, and quickly wished I had went ahead and chambered a new barrel myself. Now I am continuing to tell myself this isn't one of my LRBR rifles, and it's not even a LR hunting rifle, and that sub 1.5 MOA is fine with a 6x scope with 55 ft lbs of recoil. Any yes, in a addition to shooting off the bench for load dev, I have been shooting off sticks as well as offhand--in addition to dry fire practice. That whole paragraph is irrelevant to my upcoming issue, but I need to keep telling myself that I DON'T need that Krieger barrel Bruno's has in stock, so please humor me. Besides, the Bruno barrel is a 14 twist and I really want a 12.

The issue is the left side round from the magazine will sometimes pop out. I have used Winchester magazines #1460 and #1450. The 1450 seems a little better and is what is in it now. Both mag boxes look and measure the same, but I still had to mill a little on the one-piece floorplate to get a stress free fit with the 1450.

With the 1460 mag box, I could duplicate at home what I was seeing at the range. With the 1450, I absolutely cannot get the left side round to pop out at home. It still will on ocassion at the range while shooting. For this rifle, all load dev shooting is done from the magazine so I can test feeding.

Now I just (like 10 minutes ago) fixed the second issue I was having. The last round in the mag would sometimes nose up when feeding the next to last round, which would bind the round being fed as you push the bolt forward. If I ran the bolt fast it didn't happen, and if I went slow and backed the bolt off slightly when it bound then pushed forward again it would chamber fine. However, that needed to be fixed.

The magazine spring on these rifles always winds up sliding all the forward in it's slot in the floorplate. I have fixed M-70s with the long Wyatt's box by sliding the spring aft per Kevin Wyatt's instructions, so I did that here. I slid the spring aft in the floorplate (about .150") and put a piece of double-stick tape to keep it there. It the last round doesn't nose up anymore. Maybe that will also fix my left side round popping out when shooting issue. I will strake the magazine spring in it's new location to make sure it stays.

Anyway, if anyone has had the left side round popping out issue and fixed it, please share what you did. I can think of a bunch of things to try, but I would rather let someone else's expereince be my teacher.

 

[Ruraldoc]

Had the same problem. Sent to smith. He cut the solder at back of mag box. Widened slightly. Problem solved. Then he soldered it back together at new width.

Perfect

 

[Ontario Hunter]

Base and rim are the same for 416R and 375 so I don't think it's the aft end of box or rails.

You have changed to 416 bottom metal but still have 375 action. The significant difference between those two cartridges is the shoulder thickness. How does the shoulder width opening on receiver where it mates to the box compare to shoulder width of new box? I'm thinking it must be much narrower otherwise the narrower former 375 cartridge bullets in magazine would have been pointed into side of loading ramp and feed rough. You need to open the shoulder area of action UNDERNEATH the feeding rails where receiver meets mag box.

Are you using the Mauser cos 30 formula for determining mag box and receiver opening widths?

 

[Ontario Hunter]

To add some explanation to my above post:

Remove metal  underneath the feeding rails ... for starters. The rails  may be okay as is. Cartridges should be up into bolt face by the time they arrive at shoulder area of rails. Widening the bottom of receiver at shoulder area to match width of 416 box while leaving rails alone will create an increased ledge underneath the rails to hold the fatter 416 cartridges which are now jumping the rails prematurely.

 

[intj]

The magazine boxes designed for the 416 Rem, parts 1450 and 1460, fit into magazine and bottom metal with no issue. There is no metal under the rails other than the mag box. The metal under the rails is already wider than the magazine box. I can fit wider RUM boxes into the receiver with no issue.

While it makes sense that a too narrow forward part of the magazine could cause the left side round to pop out, both mag boxes I have tried are Winchester parts for 7mm STW, 300 Wby, 375 H&H and 416 Rem.

Winchester also made a mag box 1420 that is for 375 H&H and 416 Rem that looks wider. Maybe that one was made in response to feeding issue with the one size fits all approach.

If In haven't resolved this pop out issue with by sliding the mag spring aft, I guess I'll be modifying mag boxes.

 

[Ontario Hunter]

So what exactly is the difference between 416R and 375 mag box dimensions?

 

[intj]

Best I can measure they are the same.

 

[PanhandlinPat]

Is the follower different? I had to modify one pretty heavily building a 404 Jeffery. With the follower in received form you’d stick that third cartridge in and all rounds would spit out the top. It wasn’t pushing the rounds to the side enough I guess, reprofiling it to match the fatter 404 fixed it.

This of course is on a sporterized 1917 enfield but the concept is still the same. I also did some work as Ontario Hunter describes, but it still “worked” with just the modified follower. Opening up the inside of the action made it feed like butter.

 

[baxterb]

I had this isssue with a 375 - the follower was one of the cut-out style. It simply did not hold the lefty round far enough 'into' the rails. I think they were still figuring things out. I replaced it with an older, non-cut out follower and that was that. Inb my case only the last round would pop out - the 3rd round was fine. I simply looked for a follower that looked more like a 375 case than the weird cut out one.

 

[intj]

I talked to Andy of Sunny Hill today. He said that cartridges like the 416 Rem, 300 Wby, etc were a problem for M-70s because they were wider in the front than the 300 and 375 H&H cartridges. Because they couldn't make the front of the magazine any wider, Winchester narrowed the back of the magazine instead. Those narrowed read magazines are the ones I have. The idea being that keeping them more parallel would prevent the nose from pushing inward and popping out or jamming.

Andy agrees with my assessment, that since the left round only pops out when cycling after firing, it must be because the round gets pushed forward under recoil and then angles inward. When it angles inward is when all the problems happen and that angling inward is what Winchester was trying to fix with the narrowed rear magazines.

So no doubt my moving the magazine spring aft helped the problem by making it harder for that round to angle in. In fact, that may have resolved it completely. I won't get to shoot the 416 again for at least a week to know for sure.

However, the idea of the wider follower does make sense. it will allow the cases to stack wider and hopefully better keep them under the rails.

I'll update here when I get this sorted out. The info my help the next guy with a similar feeding issue.

All this has shown me how I want my 416 to be configured. After the hunt it will get a new 12 twist barrel that I will chamber and fit myself. I will get a Sunny Hill drop floor plate and then an appropriate stock. I will also mill the action for a Wyatt's 3.825 inside length magazine box. I will make a custom follower if needed. This increases options with bullet choice.

I'll shorten the LOP to 13-13.25" so I can reach the bolt handle better with the rifle shouldered, and I'll move the scope forward the same amount I shorten the pull.
I might be able to shorten the pull and move the scope forward now with the current stock.

 

[Ontario Hunter]

Be careful. Unless you are a short person, you may find a shortened LOP combined with heavy recoil will punch your nose with your thumb. Been there!

A while back we had quite a lively debate on here about the benefits or not of cycling a DGR from the shoulder. I pull skeet targets with my gun at port arms or sometimes muzzle even pointed to the ground. Acquire, mount, fire, all in one instinctive fluid movement. I can shoot skeet high gun (targets pulled with gun shouldered) but I won't shoot it as well. Of course, this requires a shotgun that fits perfectly. Short LOP and I will have trouble (occasionally I'll forget my slipon recoil pad for perfect fit extended LOP). I shoot my perfect fit rifle at moving targets the same way. And very effectively. Five years ago my second morning hunting in Africa I shot an incoming gemsbuck twice through the heart at very close range. My rifle was not cycled on the shoulder. I would not know how to attempt it. Get the gun out of the way while cycling so the target is not lost. Then remount, acquire, and fire instinctively. Stay focused on the target, not the gun.

Very interesting what Winchester did, or rather didn't do, to their 416 mag box and rails.

 

[Ontario Hunter]

When I built my 404 on standard 98 Mauser, I bought new bottom metal from Swift. Because they don't make 404 bottom metal, I chose 416 Rem mag. The intention was to widen it at the shoulder to meet Paul Mauser's cosine 30 formula for stacked magazine dimensions. Before I did that I tried it as is. But first I widened the receiver underneath the rails to meet the 416 box. That's all I needed. Even though the shoulder width is a bit narrow, the rounds stay in the box and cycle very smoothly. But of course I had to trim back the 8mm rails ... actually only one side as it turned out.

Anyway, it sounds like Winchester bottom metal was a mess front and back. Why couldn't they simply widen the shoulders of the box? Not enough wood in the stock? Or just too cheap to redesign? I am surprised there aren't more complaints about this. Interesting.

 

[intj]

I just checked feeding again here at home. I cannot get any kind of failure, regardless of how I work the bolt. Fast, slow, slam it, go soft--it works perfectly.

I won't know until I get back out and shoot it, but I think moving the mag spring to the rear helped the 416, just like it did with the 33-28 Nosler--with the lengthened magazine well and 3.825" Wyatt's box.

What is interesting is that the M-70s do not remotely meet Paul Mauser's idea on mag width. The widest box I have is still too narrow, and the 416 box is narrower still. Had I not talked to Sunny Hill I wouldn't have known the narrowing was actually a fix to the feeding. Then again, they did keep the very far aft of the magazine full width, they just narrowed it in front of the belt.

I don't think it was a matter of being cheap as to why Winchester didn't widen the magazine box. It is expensive to make those kind of changes, and the market demand just isn't there. I am the only guy in my shop that is even interested in DG hunting. One of my fellow employees (and now a friend) is the owner of what I understand to be the largest firearms related forum on the Internet. The hunting market nowadays is driven toward shooting deer and elk at 800 yds and even beyond.

DG hunting has been a niche of a niche for a very long time, just like my chosen shooting competition--long range benchrest.

 

[intj]

I think I my current approach to working my bolt is fine. I shoot, keep the rifle on my shoulder, lift my head, and work the bolt. I have done it enough now so the action is smooth and it feels natural. I am 5'10, but the pull still feels a little long. I think a 1/4" less would be better.

However, just like I tell my customers who call in and want a custom rifle built before hunting season, I am going to have to hunt this season with what I have and then work on a build for next season.

 

[Ontario Hunter]

Glad you got it figured out! I also discovered Paul Mauser's formula isn't carved in stone. In theory, the box in the 416 Rem bottom metal I bought for my build is too narrow for 404J. But it works fine.

 

[intj]

I got to the range this past weekend. My feeding issues are completely solved. In my case, moving the magazine spring aft in the floor plate was the solution. I have seen this work before. I wanted to post that here so if anyone else finds they have this issue--or I forget, they would have a potential solution.