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MP153 owners please help (Gas system seal for MP153)

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spcamno

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Discussion starter · #1 ·
Recently pick up an used MP153 upon inspection and cleaning noticed there is a gas seal (part #19 on the diagram) and I remember my previous one (had one about 3 years ago sold it by mistake and thought I will like something better but its not) doesn't have and according to the previous owner it has some sporadic cycling issue.

So my question is yes I know it shows on the diagram but my previous one doesn't have but have no cycling issue and would like to know if this part (#19) is a critical and important part or its not necessary on different model years.

Both my previous one and this one has a cutout / lightened shell lifter (I know some older models has a solid (no cutout) shell lifter.

Any help will be very much appreciated.
 
#2 ·
All the MP-153's should have an "O"-ring at the muzzle end of the gas chamber (the cylinder welded to the barrel). The "O"-ring sits in a groove around the inside perimeter of the chamber, and it can often seem as though there is nothing there, as the ring is nearly the same diameter as the inside of the chamber, and with some fouling can appear the same color as the chamber metal.

You should be able to find a replacement from a very good hardware store (Ace sometimes) or certainly from McMaster Carr. I don't know the size off hand, and I can't measure mine as the gun is currently not with me. You might PM "humpty dumpty" a SGW member that surely is the resident expert on the Baikals.

I hope this helps.

Good luck and safe shooting.
 
Discussion starter · #3 ·
Thank you Trapperjohn01 for your post.

The gun came like this and I remember my last one (several years back) I did not notice the extra small ring (gas seal?) in front of the gas piston.



The small ring (gas seal?) in question:



The gas chamber came like this and it appears to has a grove that the small ring (gas seal?) can fit into:



This pic show I managed to seat the small ring (gas seal?) inside the chamber (notice the gap on the ring just below the gas holes).



However, with the small ring (gas seal?) in place I can't get it to fit over the mag tube (its too small for the mag tube to go pass that ring) so there is no way I can assemble the gun with the small ring (gas seal?) in question seated in the chamber.

So my question will be first of all is the gas seal suppose to be inside the chamber or not?

And if the gas seal is the right size (previous owner took this gun in on trade not long ago I bought it cheap and he did disclosed it has some sporadic jamming issue) so I suspect someone before him did some home gunsmithing and probably don't know what he's doing and mess up the gun.

I haven't test fired the gun yet so don't know how bad it jams and would like to give a good clean / inspect before doing so.

Any help will be very much appreciated.

Cheers
 
#4 ·
Ah. Well that is certainly different than the "O"-ring that I thought you were referring to!

I'd still pm Humpty Dumpty and ask him, but in the meantime I'll get to my MP-153 and take a look at it and see. I honestly don't think I've ever noticed this extra split ring, but maybe mine appears solid, or maybe there are in fact differences in various iterations of the gun.

I'll get back as soon as I can.
 
Discussion starter · #5 ·
Trapperjohn01 said:
Ah. Well that is certainly different than the "O"-ring that I thought you were referring to!

I'd still pm Humpty Dumpty and ask him, but in the meantime I'll get to my MP-153 and take a look at it and see. I honestly don't think I've ever noticed this extra split ring, but maybe mine appears solid, or maybe there are in fact differences in various iterations of the gun.

I'll get back as soon as I can.
Click to expand...
Thanks John,

Yeah, according to my memory my previous MP153 does not has this split ring on the mag tube as well.

However, I never pay attention before if its something seated in the chamber or not that's why I'm confused coz its looks like there is a grove or channel where this ring can fit into the chamber but the gun won't assemble when the ring is there so if you can take a look at yours it will be great.

I did sent Humpty Dumpty a PM hopefully he will chime in soon.

Thanks again!

Cheers
 
Discussion starter · #7 ·
Humpty Dumpty said:
Hi there.
I got the PM; unfortunately, I'm not too much into semiautos, and cant' answer this question offhand. I'll have to do some research, that might take some time.
Click to expand...
Hi,

Thank you for your prompt reply.

No problem please take your time and thanks for checking for me.

In the mean time may be John or other MP153 owner may chime in for more info on how the gas system looks like and where the split rings belongs or should it be there in the first place.
 
#8 ·
Well, I took a look at my MP-153, and have to first apologize for my original post - I was confusing my 153 with a Weatherby SA-08 semi-auto I also have. The SA-08 has the "O"-ring as I mentioned, but the 153, being built simply and like a tank, does not have any whimpy "O"-ring whatsoever.

What it does have is just what you found: one outside diameter snap ring on the piston, and one inside diameter snap ring inside the gas chamber, just above (toward the muzzle) the taper where the gas ports are (and below the pressure adjusting spring). As my gun is seriously in need of a cleaning, I could not tell EXACTLY how far up the ring sits, but it appears to be just at the bottom of the spring. I'll try and clean my gun soon and see if i can tell more detail.

In the meantime, I wonder if the groove that your spring sits in is perhaps not completely clean, preventiing the ring from deating fully and allowing smooth passage of the mag tube (as it IS the mag tube that pases this ring, not the piston).

You might also check the ring for burrs, but what is most likely is that the ring has been compressed somehow (which is how it came out of the groove in the first place) and is no longer of the correct diameter to spring back fully into the groove. You MIGHT be able to sort of flex it outward, in an attempt to return it to its original diameter and then reinstall into the groove.

I'll also try and take some photos of this area of my gun once it's clean and more easily seen.

Good luck and I'd be interested if you learn anything more.
 
Discussion starter · #9 ·
Hi John,

Thank you so much for your prompt reply!

I did tried using a nylon brush to clean the chamber before I insert the split ring into the gas chamber and don't think anything or crud to prevent the ring from seating.

Since the ring was lose (away from the chamber and just sliding on the mag tube when the gun arrives) my concern will be may be someone put an incorrect size seal or may be that split ring doesn't belong to there.

I never looked into the gas chamber on my previous one and didn't notice there was a split rings (may be it was covered by carbon / build up) so never pay attention so if you don't mind please some pics on yours so I can see if mine is missing or there is something doesn't belong there.

Thanks so much again!

Cheers
 
Discussion starter · #10 ·
Some update after weekend.

I was brain storming one night and took everything apart again and looking for clues where that mysterious split ring belongs to and found this:

There is a grove on the gas piston inside the inner channel that goes over the magazine tube and appears the same size and diameter as the split ring so I insert that into the inner walls of the gas piston and appears fit and look like this:









John,

If its not too much trouble do you mind to check your gas piston and see if that split ring should seat in there?

You can see from the pictures it appears a perfect fit and makes sense as well because the piston ring seals inside the gas chamber (or some refer to gas block) and the inner ring seals between the piston and the magazine tube.

However, this inner ring never was mentioned in the schematic diagram (I have attached a pic below) so I am not certain and if you can take a look at yours and confirm if the split ring does belong in there I think we have the puzzle solved.

Thank you very much in advance!

 
#11 ·
spcamno - the assembly drawing helps a lot. It does indeed show the split ring that I mentioned I saw in the gas chamber in my gun (below the pressure adjusting spring) IN ADDITION to the ring that you show inside the piston. In fact, they are the same size and type ring, as evidenced by the same item number on the drawing.

I have checked mine more closely, and it does indeed show the second inner split ring in the piston, just like yours.

I really need to clean this gun more often - I have forgotten these details that I should know off the top of my head!
 
Discussion starter · #12 ·
Yes John my bad (lol)!

After reading your post and check the diagram again and you are right about the split rings (part #18).

It appears it has one exactly where you mentioned before inside the gas chamber below the valve (part #6) and one inside the piston.

It does makes perfect sense now since the piston need seal both inside the gas chamber and over the mag tube (the two split ring (part #18 serve this purpose).

So I guess the gun appears to be complete and assembled in proper order now so my next step is to test fire and will report back hopefully soon (we got hit by a snow storm gotto wait for the weather get a bit milder before head out).

Thanks so much again for your help!

Cheers
 
Discussion starter · #15 ·
Humpty Dumpty said:
Hey, glad you could work it out and sorry I couldn't help.
Click to expand...
Hi Humpty Dumpty,

No worries as I haven't test it yet but possibly this weekend so it may or may not work but will see.

This forum is awesome with members like you and John so eager to help and wealth of knowledge.

Will keep you guys update once I test it.

Cheers
 
Discussion starter · #16 ·
I am pleased to report back the gun cycle all three different shell length (2.75" up to 3.5") shell mixed without any hiccups.

Thanks everybody specially John for your help!

Its confirmed 100% working will be cleaned and waiting for its next mission when the waterfowl season open again.

Cheers
 
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Trapperjohn01
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