Jamming Ruger MkII

[bernie]

I have a Ruger Mk II with a jamming problem. This is the jam, every time:



I had this 5.5" MkII threaded to be a suppressor host for a Dead Air Mask HD. When the suppressor is not on it, it runs like a top, with the suppressor on, this happens every couple of mags. I happens with 1995 era Remington Target ammo and new Blazer ammo as well. I have replaced the extractor with a Volquartsen extractor and no change. It has a Volquartsen recoil spring assembly and I have tried all three spring strengths, with no change. Do you guys have any ideas?

 

[George P]

Well, it seems you answered your own question when you said

When the suppressor is not on it, it runs like a top, with the suppressor on, this happens every couple of mags

 

[bernie]

Except I know that Ruger MkII's are capable of functioning while suppressed.

 

[mokin]

It seems the only time my MkII would jam was when I let it get dirty. Really dirty. Do you notice an increased rate of crud build up while shooting with the suppressor?

 

[film495]

interesting. someone might know how the supresson changes the physics of the ejection, beyond me.

 

[edwardware]

Check extractor tip (sharp & shape), spring, plunger, and notch for schmooze. It might be gummed to the point it can't retain the brass quite well enough. This is common, and you must disassemble it to get it really clean.

Then check ejector length vs reference.

 

[Blue68f100]

Sounds like it needs detail cleaning and a light lube.

My MKIII has the LCI, after 1200-1500 rounds it's gummed up and time to detail clean it. The MK II does not have the LCI.

I want even buy Rem 22 ammo. It's so dirty and leads up my guns so fast it's not worth trouble. Haven't tried Blazer, so may try some CCI or Federal ammo if you can find any.

 

[bernie]

It is clean, I am pretty anal about that. I have had it apart several times and the extractor stuff is all clean as well.

 

[jmohme]

I don't know about your Mark II or how it reacts to being suppressed, but I will say that Remington ammo will FFT in my Mark III almost any time I tried it. Since I quit trying that garbage ammo, my Mark III has run like clockwork.

 

[243winxb]

If the round in the magazine is riding to high, it can knock the fired case off the bolt face.

Do all magazines do it? Number each mag

 

[bernie]

The Remington Target ammo is circa 1995, much better than the recent stuff. I had not thought about the mag. I will try a different one.

 

[Slamfire]

I suspect the residual breech pressure is being affected, and it may be too high with a suppressor on. Take the suppressor off and leave it off.

 

[Riomouse911]

Hmmm...If it jams with other ammo brands while suppressed, but runs 100 pct when unsuppressed, there is a mis-match between your gun and the suppressor. I think it could be the spring rate not keeping up with the extra pressure against the bolt from the suppressor. I would first try well up and down the weights with your chosen ammo to see if it stops.

If it only jams with this ammo and the suppressor, either change ammo to a more reliable brand because they’re not compatible, or continue fiddling with the spring rate and the same ammo to find its happy place.

I have one each of my 6 Mk IV and one of my 8 Mk II mags that have the same issue: they both will jam on the 3rd to 4th shot consistently. I culled those mags out. I mark them and it’s easy to ID which mag us acting up. If you have more than one mag, go ahead and mark them. Be sure to note if one or two keep being the ones that jam and if so, leave them home.



Magazine 5 of 6 for the Glock 43X, I use metallic sharpie markers to id which is which using dots. When they start to wear I re-dot them. Just an idea.

Stay safe.

 

[greyling22]

My mkii runs fine with and without the suppressor, ( dead air mask) regardless of ammo. Now, it gets dirty fast and jams when dirty. But that's a dirty chamber issue. Are you sure the extractor groove is clean?

 

[4v50 Gary]

Try hotter ammunition. It is blowback operation.

 

[entropy]

As edwardware said, extractor, ejector, magazine. Looks to me like the ejector is the most likely culprit.

 

[Milt1]

I used to have a MK II and it was very accurate. The ejector wasn't reliable and my understanding at that time was Ruger's ejectors left a little to be desired so I replaced it myself but don't remember with what? The replacement ejector worked great and I never had a problem after that.

 

[SGW Gunsmith]

Reads to me as though some are confusing the "extractor" with the "ejector". The extractor is what's supposed to pull the spent case backward until the rear face of the spent case hits the ejector,
Make sure the "pocket" in the breech face is clean. Both brands of .22 rimfire you are using, are indeed quite dirty. Try some CCI Standard when suppressed. Magazines feed ammunition and have nothing to do with extraction, so if the jams are not occurring during the feeding of rounds, it's probably not the magazine(s). Pull the bolt out and try exercising the extractor by pulling it sideways and letting it snap back into place. If that doesn't happen quickly, those three parts are gunked up and need to be sprayed with some "brake & parts cleaner", or better yet, pull those parts out of the bolt and clean the bolt where they reside and all three parts thoroughly.
Ditch the Blazers and the Remington ammunition and go with some CCI "Clean" Sub-Sonic, .22 Long Rifle if you can find it:

 

[bernie]

SGW, I appreciate you pitching in. The one thing that I can assure everyone reading this, is that the sidearm is CLEAN. I have detail stripped and cleaned it three times in this process. The extractor recess is clean, as it the extractor spring tunnel and the associated parts. However, I can understand why that is most peoples first recommendation. Most people are not as anal about their firearms being clean as I am.

I have replicated the problem with Remington Target(circa 1995, it is truly better than the stuff has been lately), Blazer, Aguila SuperExtra Standard Velocity, and CCI Standard Velocity. FInding anything else in my area right now is a fool's errand.

It hit me that I put a red dot on it at the same time that I got the suppressor, so I have taken it off and will try it again today. The Tandemkross pic rail overhangs the ejection port a little bit, but I do not think that will be the problem. However, I am not going to assume it.

I am also trying with a third magazine to see if I have two magazines that may be causing the problem.

What truly has me baffled is that it runs flawlessly with the suppressor removed.

 

[SGW Gunsmith]

The picatinny rail brings up another possibility. The rear mounting screw is the ONLY screw that goes through and into the receiver. You might consider if that screw is a tad too long and just might be rubbing against the recoil spring in the bolt.
You bring up a good point. Without the suppressor, there's no problem. Interesting.

 

[bernie]

I fired it again today, without the pic rail mounted. It was impeccably clean when I started, but jammed on round 23 with the suppressor on. I took the suppressor off and it worked perfectly for 80 more rounds.

 

[greyling22]

I don't know then. Suppressor should increase back pressure a little. When firing, extractor doesn't really pull the case out in a blowback pistol. It just holds the case to the bolthead until it hits the ejector and then directs the angle the empty flys off at.
A common issue is the extractor groove building up enough crud that the extractor won't hook over the rim of the case. Then, when you fire the gun, the bolt and case move rearward and hit the ejector, but instead of the extractor pinning the case to the bolt and causing the empty to be flung out of the gun, the empty just gets knocked off the bolt and stays in the gun, causing a jam. Some symptoms are stovepipes, reverse stovepipes, etc. It often looks exactly like your original picture.

Extractor does work as an extractor when manually cycling bolt on a live round. You might try loading a round in the chamber, empty mag in the gun, and pulling the bolt back and see what happens: does it extract and eject properly? Try chambering an empty and doing the same thing.

 

[SGW Gunsmith]

Have you given any thought about contacting the maker of your suppressor? Doesn't really read like the pistol, or magazines are the issue, but as was mentioned above, the suppressor just might be the culprit.

 

[SGW Gunsmith]

Just curious. Have you reached any conclusions as to cause, when the suppressor is in use?

 

[mcb]

The suppressor increases the duration of the back pressure and since it's a blow back operated firearm it is almost certain that your suppressor is increasing the bolt speed. Since the gun runs well without the suppressor but jams with the suppressor this increased bolt speed is the most likely cause of the jams. You have to figure out how to slow the bolt speed down. There are three ways to decrease bolt speed in a blow back gun. Reduce the pressure, increase bolt mass, increase spring force (thru preload and or stiffness).

The easiest way would be to shoot lower power ammo. Dedicated subsonic ammo would probably help reduce bolt speed. Buy a bunch of different ammo types and try them, your setup might like one better than the rest.

Add mass to the bolt would be the next most effective option but that is hard to do with a Ruger Mk II. There are bolt racker accessories for the Mark II that attach to the bolt to make getting ahold of the bolt for manually cycling easier this would also add mass to the bolt slowing it down. You might see if you can find one made of steel or brass to add to your bolt. If you replace the hammer with a light target hammer put the OEM hammer back in.

Springs don't have a huge effect on bolt speed but it will have some effect, especially if combine with the two previous approaches. Put the heaviest recoil spring in you have. You might also see if you can replace the hammer spring with a slightly heavier hammer spring or at least a new spring as that will also slow the bolt down.

-ramblin