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PostPosted: Thu Dec 05, 2013 3:35 am 
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Joined: Fri Sep 20, 2013 1:08 am
Posts: 54
Location: Toronto
Hey guys, I purchased a generation 5 Makarov but blew out the CO2 cartridge seal, and would like to have a crack at replacing it myself. I'm not entirely sure why it happened, but basically I had noticed beforehand that the the CO2 tightening bolt had somewhat finnicky threads, and that when it got really far in it wouldn't thread in any further, even though the bolt should in theory be able to thread all the way through. Anyway, it seemed like it was able to go in far enough at least for the CO2 to puncture so I decided to not worry about it and load the CO2 anyways. Well low and behold, the CO2 cartridge for some reason just refused to puncture, and the bolt wasn't going in any further either, so I decided to back out and try to take it out to see what's up. As I loosened the bolt the cartridge suddenly started to leak CO2 very rapidly (I guess it punctured at some point?), and when I took it out I noticed the seal was blown halfway out from its seat.

Baikal was kind enough to include a spare seal (that's sarcastic considering all the goodies they used to pack with their older models :(). I was able to remove the old one, since it was already blown halfway out so I was able to pull it out easily. I notice that the seal is slightly larger in diameter than the socket it sits in so I presume I'll need to somehow press it in or shrink it (someone mentioned heating seals to shrink them)? Or do I need to remove the seat/socket/whatever it's called as well, since it does have slots for a valve removal tool...which I did try with a screwdriver and it was deadly tight.

Some pictures:
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PostPosted: Thu Dec 05, 2013 12:07 pm 
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Joined: Sat May 07, 2011 12:09 pm
Posts: 1677
Location: Waterloo, Ontario
Quote:
assteepee wrote
Hey guys, I purchased a generation 5 Makarov but blew out the CO2 cartridge seal, and would like to have a crack at replacing it myself. I'm not entirely sure why it happened, but basically I had noticed beforehand that the the CO2 tightening bolt had somewhat finnicky threads, and that when it got really far in it wouldn't thread in any further, even though the bolt should in theory be able to thread all the way through. Anyway, it seemed like it was able to go in far enough at least for the CO2 to puncture so I decided to not worry about it and load the CO2 anyways. Well low and behold, the CO2 cartridge for some reason just refused to puncture, and the bolt wasn't going in any further either, so I decided to back out and try to take it out to see what's up. As I loosened the bolt the cartridge suddenly started to leak CO2 very rapidly (I guess it punctured at some point?), and when I took it out I noticed the seal was blown halfway out from its seat.
Baikal was kind enough to include a spare seal (that's sarcastic considering all the goodies they used to pack with their older models :(). I was able to remove the old one, since it was already blown halfway out so I was able to pull it out easily. I notice that the seal is slightly larger in diameter than the socket it sits in so I presume I'll need to somehow press it in or shrink it (someone mentioned heating seals to shrink them)? Or do I need to remove the seat/socket/whatever it's called as well, since it does have slots for a valve removal tool...which I did try with a screwdriver and it was deadly tight.


First of all, unfortunately the piercing bolt you show in slide 2 will never be flushed with the bottom of the magazine. It’s a simple design fault because it is too thick. The bolt on my magazine goes properly inside but still protrudes slightly i.e. is not flushed with the bottom of the mag after piercing the CO2 cartridge. In your case the thread might be slightly damaged (?) so the bolt doesn’t go far enough. So be careful.
Now regarding the seal. I had exactly the same situation. When I was removing the CO2 cartridge after shooting the cartridge tip was embedded in the seal to the extent that it pulled the seal out of the seat. However, the seal was not damaged so I could put it back into the socket by just pressing with a piece of dull soft wood e.g. wooden pencil (you can even use a Q-tip). The seals are quite strong which is good. However, you must be very careful when tightening the bolt for piercing the CO2 cartridge. Do it slowly in the beginning and then when you hear the first hiss rapidly make a half turn to seal escaping gas. This is not so easy because you need a large screwdriver for turning the bolt. Also, I noticed that the bolt is made of quite soft steel and the material around the slot where the screwdriver is inserted easily deforms plastically. The manufacturer should have made the bolt harder by appropriate heat treatment. Also, it would be much better if the bolt was operated using an Allen key (hex key). I have two other MP 654K model 2008 and 2009 that have piercing bolts with a small loop-type handle on them so I’ll mount one of them into the Generation 5 MP 654K and see whether it works better for CO2 piercing.
By the way, I reviewed the Generation 5 MP 654K in the Equipment Reviews section of this forum.


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PostPosted: Fri Dec 06, 2013 10:15 pm 
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Joined: Fri Sep 20, 2013 1:08 am
Posts: 54
Location: Toronto
rav wrote:
First of all, unfortunately the piercing bolt you show in slide 2 will never be flushed with the bottom of the magazine. It’s a simple design fault because it is too thick. The bolt on my magazine goes properly inside but still protrudes slightly i.e. is not flushed with the bottom of the mag after piercing the CO2 cartridge. In your case the thread might be slightly damaged (?) so the bolt doesn’t go far enough. So be careful.
Now regarding the seal. I had exactly the same situation. When I was removing the CO2 cartridge after shooting the cartridge tip was embedded in the seal to the extent that it pulled the seal out of the seat. However, the seal was not damaged so I could put it back into the socket by just pressing with a piece of dull soft wood e.g. wooden pencil (you can even use a Q-tip). The seals are quite strong which is good. However, you must be very careful when tightening the bolt for piercing the CO2 cartridge. Do it slowly in the beginning and then when you hear the first hiss rapidly make a half turn to seal escaping gas. This is not so easy because you need a large screwdriver for turning the bolt. Also, I noticed that the bolt is made of quite soft steel and the material around the slot where the screwdriver is inserted easily deforms plastically. The manufacturer should have made the bolt harder by appropriate heat treatment. Also, it would be much better if the bolt was operated using an Allen key (hex key). I have two other MP 654K model 2008 and 2009 that have piercing bolts with a small loop-type handle on them so I’ll mount one of them into the Generation 5 MP 654K and see whether it works better for CO2 piercing.
By the way, I reviewed the Generation 5 MP 654K in the Equipment Reviews section of this forum.


Ah I really wish I tried pushing the seal back in! I was thinking about doing it but it looked like it was putting alot of pressure on the puncturing pin so I took it out to make sure it wouldn't break that too. I didn't realize the puncture pin is so short anyway there's no way it could've been damaged. The seal was very slightly cracked though. So I wonder if maybe I could just manually press the fresh seal in then...

And yes I read your review before I bought the gun, it was very helpful. I knew it had plenty of quirks and it wasn't as good as the previous generations. But I still just really wanted one. Don't get me wrong, I think it's such a cool gun and really like it, but there are some peculiar design decisions. Like having a massive flathead slot for the CO2 bolt. I had to use a specifically shaped key. Ironically they put the flush bolt in because people were asking for it, and now I wish I had a bolt with the ring instead. Also the insane slide spring which I'll definitely replace because it takes way too much effort to even rack the slide and nigh impossible to field strip it. I also noticed with a CO2 cartridge inserted in the magazine it's incredibly tight to insert and remove it from the gun, probably having something to do with the lack of structural support at the bottom of the frame's grip area.


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PostPosted: Sat Dec 07, 2013 5:31 pm 
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Joined: Sat May 07, 2011 12:09 pm
Posts: 1677
Location: Waterloo, Ontario
Quote:
assteepee wrote
seal was very slightly cracked though. So I wonder if maybe I could just manually press the fresh seal in then...


Yeah, if it’s cracked it’s a piece of garbage. You can manually press the fresh seal using some soft pusher e.g. Q-tip. But do it slowly, don’t rush. At least, the spare seal is supplied with the pistol.

Quote:
Ironically they put the flush bolt in because people were asking for it, and now I wish I had a bolt with the ring instead
.

They should have made a bolt which one could turn in with a hex key. The slotted bolt for a screwdriver is really a very stupid idea particularly because it is soft steel.

Quote:
I also noticed with a CO2 cartridge inserted in the magazine it's incredibly tight to insert and remove it from the gun, probably having something to do with the lack of structural support at the bottom of the frame's grip area.


When you remove the mag do NOT hold the pistol by the grip in your palm or grab it very, very lightly. When you squeeze the grip even slightly when removing the mag, due to the lack, like you say, of structural support at the bottom of the frame's grip area, the mag gets squeezed by the grip frame and gets stuck.
I agree that the MP 654K is a very cool handgun and a must have for collectors. I also found that it is surprisingly accurate with 8.2gr Gamo round lead balls at 25 feet. The only problem is that even if I put the steel BB first and then 10 lead balls into the mag the ball sitting directly on a steel BB is getting heavily deformed and eventually jams the breech when it is shot. I read that this is a recommended procedure for the MP 654K to avoid jams but still there is a problem because Gamo lead balls are unfortunately very soft and deform easily. Now I’m trying to reduce the number of lead balls and it seems to me that loading only 7-8 on a steel BB (which is loaded first) reduces lead deformation such that the lead ball sitting directly on the steel BB doesn’t jam the breech. Although I have to make a few more experiments. Shooting with Gamo lead balls gives around 3 J of muzzle energy which is higher than that obtained with 5.3gr steel BBs. Pretty devastating for solid targets like pop cans, glass bottles, clay etc. up to 25-30 feet.
And always remember about a drop of Pellgunoil on the tip of a CO2 cartridge!!!


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