M77/357 magazine problems

Is anybody else having any problems with the magazine in their 77/357? I am now on my 4th from Ruger and it still won't feed. Bullets hit the rear of the barrel because the nose doesn't raise up enough to let it enter the chamber. The back of the barrel has a fairly substantial bevel at the lower edge. I can get one or two from a 5 cartridge load to feed. Same with only putting 4 in the mag. I have tried every bullet shape I can find and nothing is any better than another. I even tried Lyman 9mm 356402's, the pointy little 9mm in some dummy rounds. The front of the cartridge just doesn't come up high enough to clear the rear of the barrel and enter the feed ramp. Anybody got any ideas cause Ruger doesn't seem to have any. They just keep sending the same mags out with the same problem. It seems like the spring pressure is not enough to "kick" it up.

Sounds like the mags are binding up. They need to break-in. Try loosening the mag up by turning the plastic nut on the end with an Allen wrench. You might also try some dry lube like graphite or maybe some spray silicone. When you push the rounds down in the mag they should pop up into place. From time to time they may need cleaning or adjusting.

Don't take the mag apart they are a PITA to re-assemble. 8) 8)

I would occasionally get rim-lock on the first magazine that came with my 77/357 but they still fed. Called Ruger and they sent me another mag and so far no rim-lock and it too feeds fine.

After being frustrated with myself for not be able to figure this mag thing out, I enlisted the help of one of my shooting buddies who has extensive experience in all things "gun". He is the retired CO (full colonel) and master armorer of one of the military marksmanship units. We started in one the none feeding mags and discovered some problems that were easily corrected. I got chastised a little that I hadn't done some of this myself. The comment went something like "you designed ICBM's and you can't figure this out".

So here is what we found. The screw/shaft that holds the mags together was slightly bent in one and caused the rotor to bind on the wall of the mag after inserting 3 rounds. The last two rounds just sort flopped around. Fixed that and tightened it back up and the rotor wouldn't move until the screw was backed off almost a full turn. This made the back wall of the mag sit away from the main part so the mag did not enter or eject form the gun without difficulty. So now we took the mag apart and started measuring to see who was the problem. Turns out that when the screw is tightened up fully the inside from front to back of the mag is .030" smaller than the length of the rotor. Removing .020" of this amount of plastic .005" at a time from the front or round end of the shaft on a Unimat mill until the rotor spun freely when the screw was tight did the trick on that part. We did not reinstall the spring to do this. We made it so the rotor spun freely in the mag body minus the spring. We also found that .010" must be removed from the little 1/4 moon shaped part of the rotor shaft at the rear of the mag. This we found after assembling one mag. The pressure from the spring made this necessary. The next thing was to remove the mold "flash" from the anywhere we found it on the rotor. We found this on 4 of the 5 mags I have. This flash is a very thin bit of plastic at the mold parting line and on two rotors was enough to make a swishing sound as the rotor was spun in the mag. That came off with a sharp knife and a small file. When all the rotors would spin freely when the screw/shaft was tight, we quit.

Next came assembly. After years of figuring out this sort of thing for a living, it was actually easy. I put the mag together by putting the spring back on the rotor and getting the two prongs to go into the hole on the mag body and the one on the rotor. Have the screw/shaft in position as you do this. Tighten the screw/shaft just enough to hold the back end plate on. One or so threads is enough. This makes the mag loose. Hold the mag tight together with on hand and tighten the rotor spring two turns and hold it in place low in the mag with a small screwdriver or awl. Now the tricky part, the feed lips. I used two jeweler's screwdrivers to hold the rotor as I slip the feed lips into place. You have to slide the lips in and then take the second screwdriver and put through the opening in the feed lips to keep the rotor down. The lips will pop into place and then you can tighten the screw/shaft until it bottoms in the "nut" on the back side of the mag. The mag is now tight and will not not hang up in the mag well and will feed 5 shells very smoothly.

One of my friends has the same rifle and it needed a slight amount of work on the feed ramp at the rear of the chamber. His was not centered so our armorer friend used a flex shaft machine and a green Cratex abrasive point to remove enough metal to center the feed ramp. Mine needed none of this to now feed 5 shells as fast or slow as I choose to cycle the bolt. He did polish the feed ramp on mine and my friends to a very shiny smooth finish.

I now have 5 mags that all function perfectly. The hardest part of the whole thing is getting the feed lips back in but you will figure it out quick.

Great job with fixing a quality control problem with those mags. Thanks for the update.

I gotta try this on my old magazine. Thanks for the wright up!

I called Ruger about my magazine problems & they told me to send my magazine in for a replacement. so my gun sits empty while I wait on a replacement mag. that sux. plus I have to pay shipping to them.

I hope our "cure" helps anyone with these mags. Let us know how it goes for any who give it a try. As I said the only hard part is getting the feed lips back in and with a little patience it becomes easier each time you do it. You don't need a Unimat or any kind of milling machine to do this. We did because I have one and my friend is so used to using machines and not files to do this sort of thing. His shop has more CNC and manual machines than any gunsmith could even dream of having. A fine tooth file will work just great. Just make sure the ends of the rotor are kept square. Have fun.

My 77/357 feeds fine with the .357 and .38 ammo I have tried so far, but I do have a devil of a time getting the magazine out of the rifle. It won't drop out. I have to depress the magazine latch with one hand and push down on the top of the magazine through the ejection port with the other to get the magazine to release. if there's a fix for that, I'd like to hear about it.

I am also having problems. My K77/357 is the first Ruger I owned. It will probably be the last. First I had to send the rifle back due to jamming issues, which were resolved by adding more bevel to the barrel. They also fixed the creepy trigger. I bought a couple of extra magazines, but tomorrow I will be sending back another bad one, making it the fourth magazine I have returned.

This last one had a problem due to a weak spring and a rough finish on the end plate. On the last couple of rounds the rim would catch on the rough surface. Usually pushing the magazine eject button would allow them to pop up.

The other three magazines the rotor would bind. My thanks to Lo_Tek for the work he has done (I design rockets too). But really, why can't Ruger fix this problem? If we fix it then Ruger will continue blindly making unreliable arms. I believe we need to write letters to Ruger an have this looked into. What good is a rifle which may not work when you need it? For that matter, why not design a banana mag like the one you can get for a 10-22?

I also found the metal used for the rotor shaft bends really easily, so you may find after reworking the magazines, and pushing more rounds into the magazine, that it might bend again.

I want to see Ruger be successful. I like many things about this rifle. Many of the issues were fixed in the American model, like the 90 degree bolt lift and floating the barrel. But in the year 2012 to design a rifle with a magazine which has a part which bends easily, isn't reliable, and doesn't drop free when the eject button is pushed just doesn't cut it. I have to pry my magazines out with a awkward push the button while grabbing the magazines by both ends.

Warthog

Warthog and wildhobbybobby

The problems you are having are all the same ones I and a friend had with ours. If you work the magazines over as I outlined and be patient and remove all the flash and rough places, you will have useable mags. I found the center shaft/screw to be soft also, so my friend, the armorer, and I did some serious looking at that part. First we did some measuring and found that all 8 of the mags we have played with to this point, have the exact same length shaft/screw. It appears to be designed to bottom out in the nut at the rear of the mag when the rotor is trimmed to fit. This way the rear end plate is up tight and allows the mags to drop out of the gun. We decided to see if the shaft/screw was heat treatable so I sent one to a local lab to see what the steel is. It is a heat treatable steel and can be made much tougher. We are working on that tomorrow or Wed. Making it so it doesn't bend so easy is our goal. I will post when we get that figured out.

I also found that rounding the corners of the back plate helps the mag to fall out easier when the release is pushed. It seems Ruger did not spend anytime de-horning, for lack of a better word. The mold they used for the back plate leaves a very sharp edge.

In the meantime it is raining around here for the next two days so the range will be a mud hole until at least Thurs., so I have time on my hands to tinker. Retirement is great.

Lo_tek
Thank you for your help. I wrote a letter to Ruger and referenced you work. I don't know if it will bare fruit.
Warthog

Well things got dry around here finally yesterday afternoon so maybe by tomorrow the range won't be a total mud hole.

We got the screw/shaft heat treated to a place we like but it not a process not easily done at home. A small temperature controlled oven that will reach 2000 degrees is a must. We used some temp indicator crayons from McMaster-Carr at http://www.mcmaster.com to get the proper temper after hardening the screw/shaft by heating it to nice cherry red and dropping it in quenching oil at my friends shop. This makes the unit very hard and brittle. I think he used a 1800 degree crayon for that. I was not there for that part. We then found that if we heated the hardened unit to 450 degrees and then quenched it we wound up with a tough screw/shaft that was not brittle. We used the 450 degree temp crayons to make sure of our temperature. When the crayon color turned brown, out of the oven it came and into the oil. We did ruin two screw/shafts in the process. One we had too brittle and the other we are not sure what went wrong. Both broke.

On Friday I turned down a couple of Allen head cap screws to the correct diameter and length and then threaded them on my Unimat lathe. It was raining hard so I had more time on my hands. They did not need heat treating as they were already tough enough.

The heat treating process we did was very precise and is easy if you have the right equipment. Without it, it would a guessing job and I am not sure how that might come out. I have done things like this with an oxy/acetylene torch in a pinch and the crayons will take some of the guess work out. I just worry about someone not getting it right and ruining a screw/shaft and having to buy a new mag. I have access to stuff at home and my friend has everything else that I don't and then some. He is even thinking about making a batch of screws for club members and beyond. Again, retirement and too much time to play.

In the end we now have 8 very nicely functioning mags. When things dry out, I plan on going up to the range and running a few dozen rounds through my 5 and see what happens. They so far they work very slick with dummy rounds, so I am pretty confident they will work nice and slick with live ones. Recoil is the only wild card my friend can foresee.

Looking forward to reading your results.

Things were fairly dry at the range this morning and so I gave my 5 "fixed" mags a run through. I am up here still using the WiFi at McDucks. All 5 performed perfectly. No jams at all. The only bullet style I had even a small hick-up with is the few semi-wadcutters I had left. They still hit on the driving band but went in with a small shove. I am going back to the range as soon as the sun moves a little more in the sky. It was in my eyes and the 77/357 doesn't have a sun shade on the scope. I wasn't able to see the target real well so I have no real idea how well the gun grouped.

Sun moved to a better position and I got a chance to really shoot the 77/357. All the magazines worked beautifully. No jams or mis-feeds with 250 rounds fed thru them. I was amazed at the accuracy the gun delivers. I don't shoot much past 25 to 50 yards as these old eyes don't see things as clear as they used to much past that distance. I use 9 power at 25 yards so you can see I have lousy eyes. I got some 5 shot groups of 1" at about 35 yards. The load was Winchester brass, Winchester WSP primer, 7 gr. of IMR 4756 and an Xtreme Bullet Co. (http://xtremebullets.com/) 125 gr. plated flat point w/cannelure. With my eyes that is awesome. I am a happy camper and with 5 mags that work without jamming and are smooth feeding, what more could a guy want.

Lo_Tek said:

On Friday I turned down a couple of Allen head cap screws to the correct diameter and length and then threaded them on my Unimat lathe. It was raining hard so I had more time on my hands. They did not need heat treating as they were already tough enough.

Click to expand...

Sounds like someone could make money whipping out some shafts for the rest of us. Are you interested?

I am realizing that even if a take the magazines apart and make the changes you suggest (filing), it's just a matter of time before I insert a round too hard and bend the shaft.

Why isn't Ruger working on this?

Warthog

I bet Ruger is working on the quality control issues of the mags, but remember one thing, cost drives most business decisions.

As far as making screw/shafts for sale, the problem is getting them to modify. Ruger does not sell the screw/shaft as a separate part. I called after my friend and I ruined two in our heat treating trials. Turning them from Allen head cap screws does work, but the screws I used were left over from some space craft or missile I worked on a hundred years ago. We all took home some of the left over bolts and stuff after we were done as our company generally threw them out after the production run was over. Never understood the mentality of that. They were not something you would find at the local bolt and nut supply house. They started out 2 7/8" long and are a #5 bolt size, which is not a stock size. I only have a 1/2 dozen left in my bolt cabinet. I have actually never seen a #5 in a catalog or the local bolt and nut supply. It was something Uncle Sam spec'd for whatever we we working on at the time. When i turned them down and re-threaded them, I started with a screw diameter that was pretty close to what I needed. The screws I used also were not threaded very far down the shaft, only a 1/4", and I cut that off to get the length right. That would make for a problem on stock Allen screws as they are threaded at least 1/2 their length. You could use a #6 but length will be a problem. The screw/shaft is just under 2 5/8" total length. I looked in a catalog from Allen and in a #6 they don't list anything long enough. I found regular #6 machine screws with various heads long enough, but they are all soft steel and the heads are the wrong shape. The head is part of the mechanism to hold the mag in place.

If you are careful and don't get ham handed, I bet you won't bend any of the screw/shafts loading the mags. Stuffing the rounds in with hard pressure could do it, I suppose.

Warthog

One of the other members of the gun club I belong to asked me to fix his 77/357 mag for him and I found he had bent the screw/shaft very badly. I had him come over to the house and show me how he loaded it and sure enough he jammed the rounds in hard. He held the round he was inserting at about a 70-75 degree angle to the mag and then shoved down real hard to push the rotor down. If there was a round already in the mag, he shoved even harder. He had the screw/shaft so bent the rotor would only turn by hard pressure. I did my thing on his mag and straightened the screw/shaft using my drill press chuck to apply pressure. That big 3/4" Jacobs chuck straightened that thing out in two good hard tightening's of the chuck key. The chuck is a huge old 6 jaw chuck that was made before WWII. It is on a 1960's vintage Colchester drill press I got out of the salt caves in Kansas where all the great surplus machinery is stored for sale. Huge chuck on a nominal 1/2" size drill press. Acts like a great big six jaw vise for something like that screw/shaft. I told him to quit being so ham handed and I hope he listened.

You were very right in your guess about shoving too hard when loading the mag. Once they are fixed it doesn't take much pressure to load them. My friend , the retired armorer, showed me how to load them like a 22 RF mag by just sliding the rounds down with thumb pressure not holding them in between my fingers and thumb. They slip right in very easy that way.

Lo_Tek said:

Warthog



You were very right in your guess about shoving too hard when loading the mag. Once they are fixed it doesn't take much pressure to load them. My friend , the retired armorer, showed me how to load them like a 22 RF mag by just sliding the rounds down with thumb pressure not holding them in between my fingers and thumb. They slip right in very easy that way.

Click to expand...

Lo_Tek
Thank you for your help. The 77/357 would be a handy rifle if it was reliable. Ruger needs to get in front of this. How difficult would it be to make a quality shaft? They get enough for the magazines. I wish someone would make a normal magazine for this rifle. I am very disappointed in my first Ruger.


Warthog