P700w breech block is loose

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Raden1942

Raden1942

Member
Feb 15, 2018
1,757
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California, United States
Hey guys I recently did a conversion from 177 to 22 on the mrodair mk2. Somehow the breech block got a few thousands off and air shoots out the side of the oring. I can visibly see it and its not the orings fault. Anybody know how to tighten it up? I haven't seen any vids on youtube adressing the block. Also if anyone has instructions on drilling out the transfer port that would be awsome. 
 
Your valve must have rotated counter clockwise a little. You are really testing my memory because I am at work and don't have my gun. There should be a little grub screw on the right side of the gun. It keeps the valve from rotating. Yours must be loose. Whatever, loosen it and rotate the valve clockwise until it stops then tighten the grub screw to lock it in place. Drill out the hole that is behind the pellet with a drill. The aluminum is soft so it takes no effort. Run the screw in the top of the breech block down until it is even with the top of the TP hole. Something tells me that the .22 pistols have a 4.5mm hole. There is no use in making it bigger than the hole that comes up the breech block from the valve. If I were you I would start with a hole that a .177 pellet will just fit in and see what it gets you.
 
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I figured it out ty! I had two problems I fixed at once. After degassing the cylinder it would just blow air out the barrel. I spun the valve off after taking off the set screw you mentioned.it was as you suspected. it had gotten loose. Anyway the inside of the valve has a spring inside with a flathead adjustable screw that adjusts pressure on the tophat. It was too loose. I took it out. Polished the flat ends with 1000 grit and went on adjusting the valve to work properly. Im getting 545fps with cph 14.3. I feel the reg cant open up anymore and the transfer port doesn't show any gain to fps as i turn it either. That leaves me to hammer spring or going back into the valve and backing off the valve spring a bit. I was really hoping to get 650fps out of this but I think 600 might be all i can manage out of this without drilling out the 177 sized transfer port to proper factory spec 22 size. Have you ever taken the regulater out and seen how much power you gain? Im kinda trying to make this my kids squirrel hunting rig. Maybe i need to just buy another one lol
 
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With that small of a tank, unregulated it might only have a 5-7 sweet spot on the ever descending curve. I played with the valve screw and found that setting it 4mm deep gave me the best balance of efficiency and fps. If you back that screw out to only 3mm deep you will pick up 20fps. If you back it out too far you won’t be able to fill your gun from empty without cocking the hammer. I have a shorter tube and barrel on my gun so I put efficiency over power but found a nice balance. Just use a digital caliper and measure the depth of that screw from the edge of the valve. I couldn’t get my stock reg to go over 110b without bypassing it. When that happens, after you fill the gun, every shot just gets slower and slower. Just put a Huma in it. Then your not tip toeing around a crappy reg.
 
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I have my hammer spring set to the max I can go with a flat blade screwdriver. Some guys break out a wrench and go tighter for more velocity but I like not running everything maxed out. My trigger pull feels very good at my hammer spring setting also. I made my TP for .177 9/64”. If I were you I would make yours 5/32” if you are committed to .22.
 
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