[wendellcrain]

So I have been lurking here for a bit now, but had to join in order to post. I am the original owner of a bull barrel Mk II that I got in the late 80s. It was always extremely finicky about ammo brands. If it wasn't CCI Mini-Mag, it was jamming continuously.

Fast forward to this week. I had not shot this for a couple of years (life, COVID, moving from the country into the city, etc.). But my son and I have been making time to go to the range once a week lately. I grabbed this out of the safe and thought I'd give it a go. I had a 100 pack of CCI Mini-Mags. Out of 40 rounds, I had 7 jams. For 6, it was the same as before where the nose would impact the end of the feed ramp and split the bullet. One did the attempt to chamber at an angle.

The gun was cleaned the night before we went. I am stumped. There are no modifications whatsoever to the gun.

Any suggestions?

Thanks in advance!

 

[SR40Ohio]

I would look at the magazine. My MKII likes just about any type of ammo but I have noticed a feeding problem every so often with the original mag (1 out of 100?) but shot 300 rounds without a failure out of a mag I picked up 2 weeks ago and that was with cheap Remington bulk ammo. I haven't looked into the old mag yet so I can't say what the problem is.

Good luck.

 

[wendellcrain]

I would look at the magazine. My MKII likes just about any type of ammo but I have noticed a feeding problem every so often with the original mag (1 out of 100?) but shot 300 rounds without a failure out of a mag I picked up 2 weeks ago and that was with cheap Remington bulk ammo. I haven't looked into the old mag yet so I can't say what the problem is.

Good luck.

Thanks!

When you say look at - are you talking about for damage or do some of the adjustments I have seen? Rounding back portion of the lips, making the follower be the same height as the edge, smoothing the follower button track, etc.?

 

[TestEngineer]

The bullet jamming on the bottom of the feedramp is a dead giveaway that your mag is not sitting properly in the mag well. It's either sitting too low or is tipped too far forward. Don't modify your mags until you get past this issue.

First, check your mag release spring. Unlikely, but if it's weak or bent, your release may not lift the mag all the way to the top.

Second, lock the bolt open and insert an empty mag. Check for play/space behind the top/rear of the mag. It should butt up against the receiver cross bar that the ejector is riveted to. My bet is there is extra space there. I shimmed the mag well in both - my mk2 and mk3 to make the mags sit correctly. Now they both feed really smooth without dragging or jamming.

 

[wendellcrain]

The bullet jamming on the bottom of the feedramp is a dead giveaway that your mag is not sitting properly in the mag well. It's either sitting too low or is tipped too far forward. Don't modify your mags until you get past this issue.

First, check your mag release spring. Unlikely, but if it's weak or bent, your release may not lift the mag all the way to the top.

Second, lock the bolt open and insert an empty mag. Check for play/space behind the top/rear of the mag. It should butt up against the receiver cross bar that the ejector is riveted to. My bet is there is extra space there. I shimmed the mag well in both - my mk2 and mk3 to make the mags sit correctly. Now they both feed really smooth without dragging or jamming.

Thanks for the ideas. I will investigate after work today.

 

[SR40Ohio]

Thanks for the ideas. I will investigate after work today.

Not to leave you hanging but I agree with TestEngineer.

 

[bubba68]

Not to leave you hanging but I agree with TestEngineer.

Yes. Plus I would also take the mag apart and give it a good cleaning they tend to acuminate a lot of unburnt powder in them. Also make the mag button slides freely in the channel and doesn't catch or hang up as it goes up and down. If it does take some fine sandpaper and smooth out the channel until the button slides smoothly.

 

[oldster]

As TestEngineer said. Also, if the bullets have nicks or gouges, they are being slammed against the top edge of the chamber. Also a magazine issue.

 

[wproct]

You say that the pistol has had some feeding issues since new, I presume that you have been using both magazines that came with it, did both of them give the same feeding results?

 

[wendellcrain]

You say that the pistol has had some feeding issues since new, I presume that you have been using both magazines that came with it, did both of them give the same feeding results?

Yes, both magazines will cause the feeding/jamming problem.

 

[wendellcrain]

The bullet jamming on the bottom of the feedramp is a dead giveaway that your mag is not sitting properly in the mag well. It's either sitting too low or is tipped too far forward. Don't modify your mags until you get past this issue.

First, check your mag release spring. Unlikely, but if it's weak or bent, your release may not lift the mag all the way to the top.

Second, lock the bolt open and insert an empty mag. Check for play/space behind the top/rear of the mag. It should butt up against the receiver cross bar that the ejector is riveted to. My bet is there is extra space there. I shimmed the mag well in both - my mk2 and mk3 to make the mags sit correctly. Now they both feed really smooth without dragging or jamming.

Pulled apart both magazines again. The springs are straight and I think they have excellent tension.

Putting the magazines in the well, they are positioned forward when the bottom latch catches. There is approximately 1/32” (.03) of play at the rear. I am looking at the bar where the extractor is and cannot visualize how to shim that. Can you give a bit more detail, if not too much of a problem?

I am adding a couple of pictures showing the magazine in position. Just in case it might help.

Thanks!

 

[HIghstandardguy]

You inspected the magazines, but did you clean them? Anytime I personally have had a feed problem with a Mark pistol it's been caused by a gummy magazine.

 

[wendellcrain]

You inspected the magazines, but did you clean them? Anytime I personally have had a feed problem with a Mark pistol it's been caused by a gummy magazine.

I did. Surprisingly, they were not really dirty. But I had cleaned it fairly decent when I put it away there a couple of years ago.

 

[TestEngineer]

Thanks for posting a pic. Your mags definitely sit much further forward than mine do. I believe a shim will help with your feeding problem.

I sent you a PM with pictures of the shim installed in my mk2. Not a permanent (or expensive) change, but changing the angle of the mag position makes a huge difference in how good/bad they feed. Let us know if it helps with your problem.

 

[sarge912]

I have found that replacing the extractor solves many feeding problems of any of the Mark series Rugers. Also, inspect the chamber and feed ramp for any nicks.

 

[wendellcrain]

Finally was able to find some quiet time to disassemble the pistol. That was a learning experience. Shim is in place and feeding with me manually cycling worked. Need to get it to the range and see if it worked. The magazines do not have the free play as before. As a bonus, I found that field stripping and cleaning leaves a lot of places that do not get cleaned.

 

[TestEngineer]

Looks like you did a good job! It doesn't take much change to go from jam-o-matic to feeding like a champ.

Looking forward to your range report.

 

[wendellcrain]

Took the Ruger with me to the weekly pistol league. After the league shoot was done, got on an empty lane and loaded up 3+ magazines. Nary a FTF in the lot. I had only CCI Mini-Mag with me, but after having it jam on just about every magazine before this was even better than before. The last magazine of 10, just kept the muzzle pointed towards the target and did a magazine dump. 10 rounds as fast as I could pull the trigger.

Thanks TestEngineer for the suggestion and the pictures! It was a huge help and greatly appreciated.

Next time, I will grab a box of .22 that I bought on sale and see if they feed OK. I will still be pleased even if they don't, It always has had a preference for the CCI.

 

[TestEngineer]

You're very welcome Wendell. I'm glad it's working for you.