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totalh
02:08:28 Tue
Jul 20 2010

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Re: Metal breech gasket modification

Has anybody else ever tried this mod to see what it gave them?

Would anybody happen to have the pictures that went to this mod?

zaitsev?



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windage
06:58:13 Sun
Feb 21 2010

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Re: Metal breech gasket modification

Thanks for the suggestions guys. I am not doing the full gasket mod. I am only trying to hopefully increase accuracy and barrel life by centering the bb's better in the mag head. I will try this again using some of these suggestions.

  
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jkdrozd
06:14:39 Sun
Feb 21 2010

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Re: Metal breech gasket modification

but after every shot, a bb or 2 falls out of the barrel. Sometimes I fire and 2 bb's get shot out the barrel at once.

i had in the past had issues as you describe,,,,i fresh set of batteries solved it for me...i use 10 N sized for 15V,,but i am going to installa watch battery to to increase up to another 3 V to 18v like GD has done


also , as Z said , his mod allows single shot only...which is not why i bought my dorzd...
to shoot high velocity single shot i use raptor pellets and i put one into the exit hole of mag head the best i can to get full charge from air valve...if i geta good shot off it sounds lika a.22 caliber rifle,,,i think the extra 25% free gain of using the lighter alloy allows me to break the sound barrier without the gasket mod..another point to ponder
there is a mod that lets ya achieve mechanical lockout witha longer air valve which also prvents blow by into the bb res tube of the drozd1...i have athread that shows/desrcibes the mods of the maghead to improve air flow and gain fps that way as well
pEACE
jkdrozd

  
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rkr
06:52:25 Thu
Feb 18 2010

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Re: Metal breech gasket modification

You could try greasing a BB heavily and then use that to push the glue (or whatever you are using) to a right form. The grease should protect the BB from sticking and it should come off easily after the glue has cured.

  
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zaitsev
12:24:22 Tue
Feb 16 2010

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Re: Metal breech gasket modification

hi

Yes, it is. Ideally you want to have the mag head off so that you have easier access. You can then make a concave in the material you are using via the BB tube.

I must say again that really these mods are for experienced users of the drozd, and are happy with being able to dismantle it totally, and work confidently. I and others are trying to work past the 1000fps barrier with( zinc BBs).

zaitsev

  
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windage
01:34:05 Tue
Feb 16 2010

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Re: Metal breech gasket modification

I ended up scraping all the glue out. The gun now fires normal and no more bb's fall out during firing. I think the glue didn't form enough of a dimple to hold the bb properly. I would like to retry this mod out but I find it a difficult challenge to properly place some material inside the mag head. It is such a small space to work with.

  
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windage
06:37:03 Sat
Feb 13 2010

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Re: Metal breech gasket modification

Yes, I am using zinc coated bb's. I just thought of something that I haven't done yet. I haven't done the mag position mod yet. I bet that now since I have done the previous mod, I should make sure the mag fits solid and doesn't move so there is a perfect fit between the mag head and the barrel chamber. I am going to experiment a little before I scrape out the glue.

Thanks for your time in responding to my comment.

  
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zaitsev
09:56:56 Fri
Feb 12 2010

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Re: Metal breech gasket modification

This is a critical area of the modification as i said before so
the BB can actually fire from the mag in a straight line. When the hole in the top of the mag head is filled, the force of the spring on the BBs will still look for something to grip on.
If the glue you used left a "tit", this may allow the BBs to come out prematurely.
I finally used a 50-50 mix product that sets very hard.
I have had no problems with this. Do not make a raised
filling of the hole in the mag. Ideally the filling should be slightly concave.
The ideal situation for this would be a a metal rod through the mag with a concave bottom to hold the BB steady.
Its a bad design by Baikal, but i suppose they built the drozd as a fun gun with not having accuracy and lots of power in mind
I presume you are using zinc BBs.

zaitsev

  
Mood:
windage
04:25:52 Fri
Feb 12 2010

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Re: Metal breech gasket modification

I was somewhat successful in centering the bb in the mag head. The bb is now perfectly centered but after every shot, a bb or 2 falls out of the barrel. Sometimes I fire and 2 bb's get shot out the barrel at once. I used crazy glue and dropped one drop into the top of the mag head and let it dry upside down. The valve head doesn't look like it is blocked. I might have to scrape it all out and leave it the way it was. The bb's don't fall out as often (maybe once every 3 shots) when I use 14v instead of the standard 9v. I have already done the magnet mod and when the mag is out and the spring is pressurized, the bb in the mag head doesn't fall out, even when I tap it. Only when I am shooting does this happen. Any ideas? Has anyone else had this problem?

  
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zaitsev
19:42:37 Mon
Feb 8 2010

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Re: Metal breech gasket modification

I used a very small screwdriver to apply the epoxy or whatever you use. You dont have to disassemble the mag. Just be very careful to apply just enough to fill the hole.
Look down the exit hole and make sure you can see all of the valve hole, then its ok. If you put too much in it may block the valves path.

zaitsev

  
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windage
06:44:43 Mon
Feb 8 2010

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Re: Metal breech gasket modification

Sorry, I didn't see the follow up link at the bottom of this thread. BTW, how do I change the format of the threads so that it doesn't post oldest at the bottom? LOL, I am sure there is a way to do so.
To do the glue mod, should I take apart the mag head? How did you apply the epoxy? I was thinking a toothpick. I am worried about getting some of the epoxy inside the valve at the back of the mag head.

  
Mood:
zaitsev
20:57:09 Sun
Feb 7 2010

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Re: Metal breech gasket modification


The hole in the underside of the Blackbird mag head
is the same as the 30round mag. The mag heads are the same anyway.
I initially used gorilla glue to fill the hole, but since have used a product that is mixed 50-50 and hardens like metal. The BBs dont fall out of the Blackbird mag I altered.
On the 30round mag , the spring will still push the BB with the same force as before.

  
Mood:
green_dots
19:30:03 Sun
Feb 7 2010

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Re: Metal breech gasket modification

You need to read through all of Zaitsev mod. I believe he used a tiny drop of glue. GD.

  
Mood:
windage
17:03:17 Sun
Feb 7 2010

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Re: Metal breech gasket modification

How did you center the BB in the mag head? The mag head is designed from the factory to not center the BB so then the BB doesn't fall out. I thought of placing a tiny magnet in there but damnnnnn it's a small place!

  
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zaitsev
21:01:30 Sat
Feb 6 2010

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Re: Metal breech gasket modification

Hi all

I have located a strong steel eyelet that is sturdy enough to allow the magazine to be inserted and removed on the Blackbird. It can also be removed from the standard drozd magazine with a little coaxing both ways. The gasket keeps its shape ok. The steel eyelet also came up smaller than the other one so the BB is tighter in the bore. Really perfect for the Lead BB. Not tested this yet but should be as good if not better than the original gasket I made and published on here. Dont forget to mod the mag so the BB sits in the middle of the exit hole as stated before. This is vitally important. Here are a couple of pics of the new gasket and also of it in place. As before, the original drozd gasket fits over the metal gasket and locks into the concave made in the mag head. The new steel eyelet is the one on the right of the picture. The second picture is of it in place. Once the rubber gasket is put back there is about 1mm or so of the metal gasket proud of the rubber gasket.



[1 edits; Last edit by zaitsev at 21:02:47 Sat Feb 6 2010]

  
Mood:
zaitsev
21:21:06 Fri
Feb 5 2010

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Re: Metal breech gasket modification

Quote: totalh at 01:20:29 Fri Feb 5 2010

zaitsev,

It looks in the pictures that you used a rivet for this project is that correct?

My hat is off. What a great improvement to the drozd. I wonder if the percentage of gain greendots mentions increases 17% across the board or if you hit a point of diminishing returns.

Anyway, that is all to be seen with more people testing this out. That being said I want to try this mod out.


Hi Totalh

I used a metal eyelet cut down to size. The original drozd gasket then can fit over the top and also seal into the concave made on the mag head. The gasket is nearer to the valve head. This just needs a better valve to really take off.
I have just got hold of some stronger steel eyelets that are
5mm so I am going to make gaskets out of these. It may be possible to then insert and take out the mag with out loosening the barrel.
I am no engineer, but my idea works, I put it on the forum now, (although i was still searching for a really strong eyelet) as I got such good results.

Feel free to go on and perfect this.

I have only tested with a 12oz CO2 carts so far and fps tapers off pretty quickly after 10 shots. I think the best gains will come with HPA.

best regards

zaitsev

  
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totalh
01:20:29 Fri
Feb 5 2010

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Re: Metal breech gasket modification

zaitsev,

It looks in the pictures that you used a rivet for this project is that correct?

My hat is off. What a great improvement to the drozd. I wonder if the percentage of gain greendots mentions increases 17% across the board or if you hit a point of diminishing returns.

Anyway, that is all to be seen with more people testing this out. That being said I want to try this mod out.



---
www.drozdmax.com - One stop shopping for all your Drozd and automatic airgun needs.
www.airgunextreme.com - An up and coming airgun site.
 
 
Mood:
howell11
19:28:24 Sun
Jan 31 2010

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Re: Metal breech gasket modification

Hello thanks for the help

  
Mood:
zaitsev
20:37:40 Sat
Jan 30 2010

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Re: Metal breech gasket modification

Here is a clearer view of the current gasket with original drozd gasket on top of it. The idea is to have 2 seals, 1 via the metal gasket and the rubber seal closing into the concave on the mag head.


  
Mood:
green_dots
19:19:59 Fri
Jan 29 2010

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Re: Metal breech gasket modification

Hello Howell11. You need to use the search function for barrel removal. The major problem is getting the old barrel out. Go to search function and don't forget to click and older on the bottom right side. What psi JDS regulator did you buy?As far as magnets this only applies to the Blackbird (BB) and I only have the regular drozds.

  
Mood:
howell11
17:58:46 Fri
Jan 29 2010

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Re: Metal breech gasket modification

Hello GD

1. What do U have to do to put in a new barrel
2. I ordered a JDS air tank what modifacations are there for
this
3. how and where do the magnets install

thats all for now.. I am new to air guns and looking to
have some fun with them Thanks for the welcome

Howell ~ov\o



  
Mood:
zaitsev
10:07:10 Fri
Jan 29 2010

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Re: Metal breech gasket modification

last two for now



  
Mood:
zaitsev
10:01:50 Fri
Jan 29 2010

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Re: Metal breech gasket modification

and a couple more

(pic of my drozd to show I do have the equipment



  
Mood:
zaitsev
09:58:19 Fri
Jan 29 2010

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Re: Metal breech gasket modification

hers some pics to help: i am working on clearer ones, but I think this shows the idea.




zaitsev

  
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Tbkahuna
00:32:52 Fri
Jan 29 2010

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Re: Metal breech gasket modification

Here is the second post from Zaitsev:

#Results

I used a chrono that I know is reliable for the tests. I used a new 12oz cart for each test. I had a silencer fitted on the gun.

I was amazed at the power increase with this idea; I rechecked the chrono on firing the first shot with the metal gasket, as I thought I may have put the wrong BB weight in, but no it was correct.

So, with a zinc plated BB of 5.4grains, firing indoors into a safe backstop and using a 12oz CO2 cart, I got an maximum increase of 106 fps using the metal gasket arrangement. This is over standard gasket and mag head tests. With HPA etc we must surely expect much larger increases.

Standard Mag Metal Gasket and Mag Head Mod

1. 598 fps 1. 704
2. 593 fps 2. 700
3. 595 fps 3. 699
4. 591 fps 4. 699
5. 594 fps 5. 698

I am going to continue testing with slightly smaller gaskets; ideally stainless steel. Maybe an engineer can make up some hardened steel ones!! . These would only be able to be used with zinc or copper BBs. Lead will be too big. However, there is a possibility of further increases in fps with this idea. The key is to have the BB central in the mag head.

I will also use the Blackbird mag for further testing on HPA and 1250-1500psi.
Currently my testing is on single shot only; I don’t see why it won’t work on burst fire.

This gasket arrangement in these instructions should allow the firing of lead BBs also, as on the standard rubber breech gasket. They were not tested at this time. The Blackbird mag needs some alteration to allow the easy flow of lead BBs. I think the mag head mod should allow easier firing of the lead BB in the 30 roun

[ Continued ]
View Rest Of Post

  
Mood:
Tbkahuna
00:31:17 Fri
Jan 29 2010

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Re: Metal breech gasket modification

From Zaitsev on MP661K.com

Metal Breech Gasket idea for the Drozd 1 and Blackbird

For some time now I have been trying to solve the poor breech gasket to magazine (mag) head seal on the Drozd ,which is losing it power. Some air is lost down the BB tube, but mostly it’s around the inadequate rubber breech seal (especially at high psi).
I have a Yunker 3 AK74 air rifle and fitted a metal breech gasket to it that “locks” into the mag head; this via chamfering the BB exit hole with a large drill bit (by hand). This breech arrangement, and also fitting a larger capacity expansion chamber, gave me a 200fps increase in power (using a 12grm cartridge). I have since fired the gun with a standard expansion chamber, and the metal gasket, and still got a 90fps increase.
I have decided that this is the way to go with the drozd to drag a bit more power from it. I have experimented with many metal gasket prototypes with close tolerances to the BBs calibre, and got poor reliability. This was mainly due to the odd BB hitting the edge of the gasket and bending it. I have now got a metal gasket working reliably. I also realised that the BB sits unaligned in the mag head (this will be dealt with). This gasket is cheap to obtain, although many people may be averse to chamfering the exit hole of their drozd/blackbird. If you want to get the maximum power from your gun however, then this is a modification you can try. Maybe it would be worth buying a spare mag head from EAA to interchange as you wish.
I wanted to make this modification without great expense, and so that everyone can benefit from it that wants to.

Randyhub on MP661k kindly sent me a mag in pieces so I could experiment with my ideas. I have a working prototype metal gasket now in a drozd 1 mag.
I did remove the metal Co2 mesh screen in the expansion chamber.
I used a Drozd Blackbird with a JimC 23 inch barrel and a drozd mag with 12grm CO2 cartridge for the initial tests, with 1

[ Continued ]
View Rest Of Post

  
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Uncle_Teddy
23:00:38 Thu
Jan 28 2010

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Re: Metal breech gasket modification

Any chance someone can post the report on this forum. I don't have access to the other and VERY interested in this.
thanks,

  
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zaitsev
21:34:59 Thu
Jan 28 2010

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Re: Metal breech gasket modification

Quote: SONYtec at 20:59:59 Thu Jan 28 2010

Need to take better photos, out of focus!!


Yes, Sir. Does this get me detention? I need to try better :lol:

Seriously, I will try replace the fuzzy pics.

  
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SONYtec
20:59:59 Thu
Jan 28 2010

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Re: Metal breech gasket modification

Need to take better photos, out of focus!!



---
10/02/08 Black '05 Drozd STOCK.
3/13/08 YELLOW '03 DROZD, 9/17/08 full auto mod, 1, 3, Full. ROF mod soon.
07/07 Black '05 Drozd, 8/3/07 resistor mod, 9/20/07 full auto PCB. More to come! (Adjust pot. and solenoid)
Accessories: 8/24/07 PMI HPA tank, remote hose, 9/03/08 JimC barrels and QD adaptors, 10/01/08 JimC CAR stock adaptor. NEED HI-CAP MAGS!!!
 
 
Mood:
green_dots
20:28:00 Thu
Jan 28 2010

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Re: Metal breech gasket modification

Welcome to the forum Howell11. Be more specfic. What info do you need. GD.

  
Mood:

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