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Mk III Inconsistent Feed Issue

4K views 15 replies 4 participants last post by  Bullseye 
#1 ·
Before I start, I apologize for the lengthy description ... but I am out of ideas.
I have a Mk III Competition. I use it to compete in bullseye competition and have fired 35,000 - 45,000 rounds without any major issue. The only modification that I have done is the Volksquartsen trigger upgrade, which was done when the gun was first purchased (less than 100 rounds fired). Recently, I have started to experience the following inconsistent loading issues.
  1. After firing a round, the bolt cycles and a new round loaded into the chamber. However, the trigger does not completely reset. I have tried resetting the trigger stops, but the problem continues. It does not happen every round ... actually with no consistent frequency. When I eject the live round, there is a slight gouge in the bullet.
  2. I have inspected the spent casing from the round which was fired and the trigger failed to completely reset, and have discovered a slight dent in the casing.
In an attempt to solve the problem, I have done the following:
  • rebuilt all of the magazines with new internals
  • replaced the mainspring housing assembly (Ruger part)
  • replaced the bolt coil assembly (Ruger part)
I completely clean the pistol after every 100 - 150 rounds. The magazines are stripped and cleaned at least every 4 months.

I have noticed some "pitting" on the ramp-like structure at the breach of the barrel, which guides the bullet into the breach during the reloading cycle.

So, my question: could it be that the ramp is worn to a point where the round is not consistently being loaded into the breach?
 
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#2 ·
This sounds more like a trigger reset issue than a feeding problem. Areas I would inspect would include the VQ target trigger adjustment screws (ensuring that they are properly thread locked with sealant once adjusted as they can vibrate out of position and cause intermittent failures like you've described); the trigger return spring and plunger in the top of the trigger (check for powder residue interfering with the operation of these components, especially since this is an area prone to heavy blow-back deposits); the disconnector lever and frame interaction (ensure that there is no residue behind the lever to cause an undue amount of friction which would prevent the lever from operating normally). The disconnector lever is an area that also receives a fair amount of powder blow-back and if the disconnector has never been taken out and thoroughly cleaned behind could also still have some of the original factory shipping preservative that tends to harden over time and can attract enough powder residue to gum up the operation of the disconnector lever and prevent the sear/trigger reset.

R,
Bullseye
 
#4 ·
Bullseye,

Thanks for the insight. The Mk III is such a reliable firearm and I was beginning to wonder if there was some pathway that I had not thought of. All of the possible causes are the same ones that I have come up with. Keeping any firearm clean has been ingrained in me during my 21 years in the military.

I will continue to resolve this current issue and keep my post updated as I progress.

Brere Bear
 
#3 ·
I concur with Bullseye.

From the OP's description, this sounds like a trigger reset issue.

As for the dents in the spent casings, if the dents are ONLY appearing on the rounds that initially failed to fire, you may have a magazine problem. The issue wouldn't be with the follower or spring but rather the feed lips. If the top round isn't held at the proper angle the casing could be dented during feeding. My first guess would be to go with what Bullseye said but if that doesn't fix the issue, try a replacement magazine just to see if the issue continues.
 
#5 ·
Petrol & Powder,

I have ordered two replacement magazines. All of the other inputs from you and Bullseye are already in motion. The fingers area of the magazine that I have not yet found any specifications on. Being a mechanical/marine engineer, I am going to try to compare the spread on the existing magazines with that of the new ones. I am not sure how much tweaking can be done, but will pass any learnings on.

Brere Bear
Cdr. USCG
 
#6 ·
Is the disconnector lever in good condition? Are there any signs of wear, especially around the top angled edge where the disconnector rides along the underside of the bolt? Any damage here would cause a hang-up and failure to reset, and some of the factory disconnectors in the past have been prone to peening damage along the top, angled edge like the one depicted in this picture.



I have also seen some of the factory disconnectors fail, especially around the location where the trigger pivot pin is pressed into the disconnector lever, a good inspection here for component integrity may be called for with a detailed stripping of the grip frame. Any looseness on the pivot pin and lever joint is a sign of failure.

A little background here, it takes very little extra friction to cause failures to reset. The trigger return spring and plunger only impart about 4 to 6 ounces of upward force on the disconnector lever to cause it to rise upward and engage the sear. If the disconnector lever is bent, just a little bit, or if a residue has built up in any or all of the places I've indicated earlier, this combination of drag can overcome the trigger return spring tension and cause intermittent reset failures. One way to totally eliminate the VQ trigger from the cause of the problem would be to reinstall the factory trigger and then run a live fire test session. How does the disconnector lever function with the receiver off of the frame, mainspring housing assembly installed, and the hammer cocked? When you push down on it does it pop back upward freely? Or does it seem to act sluggish?

Another question, do you have an operational factory magazine disconnector safety lever in your Mark III pistol?

The denting you described on the spent cases can be coming from the ejection sequence, where the spent casing is being thrust against the edge of the ejection port as it is exiting the pistol. If you are seeing any slight malformation on the soft noses of the unfired bullets, this is not an abnormal indication and can be caused by the bottom edge of the chamber mouth scraping the bullet nose, where the top of the feed ramp meets the chamber during the feeding phase.

R,
Bullseye
 
#7 · (Edited)
Bullseye,

Thanks for the additional insight. It gives me confidence in my problem solving process, since you hit all the areas that I have.

The factory bolt stop assembly is a definite weakness in the Mk III. Each time I clean the pistol (about every 100 - 150 rounds), I have learned to check the bolt stop ... and have found the factory version (which is stamped out rather than machined) to exhibit the wear shown in your picture. The peaned-over leading edge is a definite problem, which can be solved by filing off the bad area until the disconnector needs to be replaced. After replacing the disconnector many times (at least 6), I have gone with the VQ replacement (which is a machined component). This was done long before the loading issue surfaced and did not cause any problem. Oh, by the way, I only use the slingshot method for releasing the bolt.

When I clean the firearm, I do a complete cleaning ... short of completely removing all the internals. All areas are cleaned with a bore patch, soaked in Hopes and held with a surgical tweezers. I checked to ensure that there are not gritty areas. As you point out, I pay special attention to: the areas between the disconnector and frame, the disconnector piston frame, the trigger disconnect and frame, the trigger spring-plunger, the trigger-pivot retainer spring, and the sear-spring/safety assembly area. Finally, I then put several drops of Hopes in all the areas and use compressed air (the canned type used to clean computer keyboards). When done, all the areas are clean and dry.

I had replaced the magazine disconnector assembly with the Tandem-Ross bushing (over 2000 rounds ago) and had not experienced any issues. However, until I get the current mystery resolved, I have re-installed the factory magazine disconnector assembly.

I have ordered two factory magazines, which should be coming in this week. In the mean time, I've done some additional research and found the discussion about tweaking the MK II magazine by changing the angle on the rear lips. This was specific for MK II's ... but am wondering if this may also help with the MK III magazines?

I continue to learn more about this firearm ... and still am impressed with its reliability. Some of the Ruger supplied components should be redone by Ruger (such as the Bolt stop assembly). My next step is the new magazines and will let you know how much this contributed to the final solution.

Brere Bear
 
#8 · (Edited)
That is good to hear, I'm just following my typical troubleshooting process to reduce the possible factors and get down to the source of the problem. The big question needs to be checked out, i.e. what does the disconnector lever do with the receiver off the frame and all the necessary internal components installed to cock and release the hammer? Now that you've reinstalled the old mag safety lever in the place of the Tandemkross hammer bushing, the possiblility that the aftermarket bushing was forcing the disconnector lever over at an angle and potentially causing a binding situation which could lead to your hang-ups may be tested. That change also tells me that your old mag safety disconnector was not hanging up on the top of the sear, as has happened in the past to cause similar symptoms of failure because the factory component wasn't installed at the time of the failures to fire. TandemKross makes good products, but I would also inspect the aftermarket bushing for any sharp edges that could have been hanging up on the squared hole in the disconnector lever and causing a bind that would also result in a failure to reset the sear with the trigger.

You now can see why I am asking some very particular questions about the configuration of your pistol, as it initially appeared to me that you hadn't replaced anything other than the factory trigger from your original posting. Now I know that you have also replaced the disconnector lever and the factory hammer bushing. Is there anything else? Please be specific so I can take any other aftermarket parts into consideration as I contemplate your issue. Also, the picture I posted earlier with the peening damage was a view of the top of the disconnector lever not the bolt stop. Are you also experiencing signs of abnormal wear on your bolt stop? Right now I am not focusing on your magazines, as you may be experiencing multiple problems and I'm just trying to focus on the trigger reset issue. Once that is solved then any other pending problems can be addressed in a logical order. Trying to do too much at one time, just potentially clouds the results and could lead down a rabbit hole.

R,
Bullseye
 
#9 ·
Bullseye,

Sorry about the misinterpretation of your last picture. The disconnector lever has never shown any kind of peening ... even with the factory mag disconnect assembly in place.

As far as replacing any other factory components, nope. I will be going to the range today to try the pistol with the factory mag. disconnect in place ... just to see if the TR bushing might be the cause. The bushing looks brand new and never had any signs of rough edges.

The magazines are the originals ... so this might be the culprit. The new magazines should be showing up by the end of the week, so I will be able to see if the old magazines are just betting tired.

As mentioned in my previous reply, I was wondering if the magazine modification (see the attached picture) discussed for Mk II's might also be a potential solution for the Mk III magazines. The rational discussed for the modification seems to make sense.

Thanks. I will keep you updated with the results of today's range visit.

Brere Bear
 

Attachments

#10 ·
Bullseye,

Per my latest, the re-installation of the Ruger factory magazine disconnect assembly may have done the trick. I fired 75 rounds with no mishaps. The only issue (which is not a new one) is that the magazines did not always release cleanly ... necessitating an assist with my thumb in the breach as I pushed the mag release button. The problems with the trigger failing to reset and the inconsistent feed issue appear to have been resolved.

I have not yet received the new magazines, but three that I replaced the springs in worked without a hitch.

I will continue to exercise the pistol to make sure that the original problems have been resolved. My next step will be to contact TKR to see if they have had any similar situations with the swap out of the magazine disconnect assembly with the TKR trigger bushing. I'll followup with more updates.

Brere Bear
 
#11 · (Edited)
The results of your "live fire" testing is potentially good news in isolating the source of the trigger reset issue. I suspect either the dimensions of the hammer bushing are slightly off and is causing some binding of the lever, or the edges of it are chafing and hanging up on the disconnector lever resulting in the same outcome. I have heard of this rare situation before from some owners of TK bushings, but I have also equally heard them from the other aftermarket suppliers as well. I can say that those folks who've contacted TK customer service about the problem promptly received fully functioning replacements. If you want to PM me a pic of your aftermarket bushing I will examine it to see if there are any areas that could be cleaned up to aid in proper functioning. You may want to carefully inspect around the bushing hole on both sides of your disconnector lever to see if there are any chafe marks which would indicate where the source of the friction is located. As I mentioned before it doesn't take a whole lot of additional friction to overpower the capabilities of the trigger return spring and plunger and lead to a failure to reset the sear and trigger.

The factory mag safety hook and bushing is the current reason why your magazines will not drop cleanly anymore. The aftermarket hammer bushing was designed to eliminate the mag safety hook which depresses on the back side of the mag body and prevents a clean gravity release. That issue is why I originally designed those replacement bushings when the Mark III first came out back in 2004.

The magazine modification you have shown an interest in involves slightly modifying the rear feed lips by rounding, this procedure was designed to solve a problem of failure to eject the spent cartridges (stovepiping) cleanly. Once one has replaced the factory extractor claw and still experiences ejection failures this modification reduces the profile of the rear feed lips to minimize the chance of the spent casing striking them and getting dislodged off of the bolt face prior to the case reaching the pistol's ejector pin. Your problem is not of this nature, as you've described it earlier, and unless you are experiencing failures of ejection (like the one picture below) I would not personally invest the time to perform the magazine modification.



Here is an example of why the rear feed lip modification works for some people. Take a look at this picture.



In a normally functioning pistol there is an approximately one sixteenth inch gap between the ejector pin and the top of the rear feed lips. In some pistols the magazine is positioned much higher and virtually eliminates that gap causing the rear of the case rim to actually strike the feed lip prior to the casing hitting the ejector pin. Rounding the front edge lowers the profile of the angled rear feed lips back to one where the 1/16th inch gap is regained. If your pistol has the proper gap between your mag's rear feed lips and the ejector pin then performing the modification serves no real purpose.

Hope this helps.

R,
Bullseye
 
#12 ·
The idea of rounding the rear feed lips is BAD. I know - I did it to 9 mags and now all 9 can only load RN bullets without the round popping up and cleaving into the top of the chamber mouth.

True, it can reduce stovepipes - but there's a better way.

I have 1 mag that I tapped the front of the rear feed lips downward slightly on. This is the only 1 of my 10 mags that never jams, regardless of using RN or HP ammo.

I wish the guy that wrote grinding the feed lips was a good idea would replace the 9 mags that I did it to!!!
 
#13 ·
Bullseye,

Again, thanks for the explanation of the magazine rear feed tip modification. I wondered about that clearance between the ejector pin and the magazine. I've check mine and it looks good.

I noticed that, with the TK bushing installed, the safety was very hard to engage. With the Ruger mag disconnect assembly, the safety worked easily. I am wondering if I might have one of the TK bushings where the dimensions are out of spec. I am going to contact Tandemkross and see what they think. The actual bushing does not appear to have any flaws ... but trying a new bushing seems like the easiest steps.

My the way, this "search for a solution" is very informative. I really appreciate your help.

Regards,
Brere Bear
 
#14 ·
BrereBear, Glad I could be of some assistance to you. I know that a poorly functioning pistol can be very frustrating at times.

The safety lever engagement difficulty issue you've noticed tells me that most likely your replacement bushing may be actually changing the position of your hammer in such a way that also is skewing the sear face's positioning. This slight movement is why the catch on the safety lever is harder to engage with this bushing installed than the factory ferrule and safety hook. An inspection with the receiver off of the frame would confirm that situation or at least possibly reveal the source of where the additional friction is originating. If the sear face is being re-positioned a bit more forward then that could cause issues with the disconnector lever resetting on the back of the sear and engaging the trigger. The tolerances are very tight between these components in order to provide minimum slack in the trigger take-up, and any slight variation of the front to back positioning of the sear face can indeed have a negative effects on the disconnector lever. Contact the manufacturer is a good next step. I'm sure that they will do everything they can to assist you with this problem.

Hope this helps.

R,
Bullseye
 
#15 ·
Bullseye,

I contacted TR this morning ... a very pleasant experience. They are sending me another bushing, free of charge, and have asked that I send them the other bushing so they can do some inspection.

I also received the two new Ruger magazines. Comparison with the other ones showed no significant difference or wear. I also compared each magazine-ejector gap; all are about 1/16", so I don't think this contributed to any loading issues I have experienced. I fired about 50 rounds with the new mags ... no problem. I am ruling out the magazines as a main contributor to my trigger reset issue.

Progress may be slow, but it is progress.

Regards,
Brere Bear
 
#16 · (Edited)
That is really good news. What I am going to do next is provide some extra info for you.

Here is a picture of a Mark III frame with the receiver off, mainspring installed, hammer cocked, and set up to test the disconnector engagement.



From this view you can also see where the thumb safety hook captures the sear face (Orange Arrow). If the sear face is cammed slightly more at a forward, or rearward, angle the safety notch cannot cleanly capture it to engage the thumb safety.

I also have a few pictures that depict how the sear engages inside a Ruger Mark pistol. These are shown with the hammer removed so one can actually see exactly how the tab on the bottom of the disconnector lever engages the back of the sear to connect the trigger. This is the root of the issue you are experiencing with your pistol. In the first picture the sear and trigger are disengaged (not connected) and the disconnector tab is positioned underneath, in the sear slot, rather than the back edge of the sear.



When this condition happens the top of the disconnector lever is down.

In the next picture the disconnector lever tab is engaged on the back side of the sear and the disconnector tab is positioned up, out of the slot, and on the back surface edge of the sear for trigger engagement.



When this condition is met the top of the disconnector lever is upward and the trigger is connected for firing by a pull of the trigger. If the sear face is not at the exact proper cam angle then the disconnector tab cannot clear the slot in the sear and engage the trigger, which is the problem you have been experiencing with the replacement bushing installed.

When you get the new bushing installed, you should set up your pistol in the configuration of the first picture in this post, to best test the sear/disconnector engagement by cocking the hammer and depressing the top of the disconnector lever downward, then by squeezing and holding the trigger rearward. This will cause the disconnector tab to be contained within the sear slot. Next, slowly release pressure on the trigger and the disconnector lever should click upward when the trigger is engaged. If it doesn't then the sear face is not being positioned at the proper angle to allow trigger engagement. It would also be a good time to check for proper thumb safety engagement with the hammer cocked. If the safety lever is hard to engage then that is another sign that the sear face is not being angled properly when the hammer is cocked.

Hope this helps.

R,
Bullseye
 
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