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Old 05-14-2001, 11:40 AM #1
bloodsuckingsn
 
 
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my autococker is getting a lot of blowback into the hopper causing it to chop a lot of paint when i fire fast im pretty sure im not short stokeing. what should i do?
thanks
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Old 05-14-2001, 12:18 PM #2
maxpang11
 
 
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Cure Blowback

Blowback is caused by the 4-way activating too quickly relative to the sear releasing the hammer. To cure blowback, you want to create a longer time period between the time the sear releases the hammer and the time the 4-way activates. You do this by 1)turning the hammer lug counterclockwise (thereby shortening it and making the sear release it sooner); 2)lengthening the 4-way rod (thereby causing the 4 way to engage later in the tirgger stroke); 3)doing both 1 and 2 (you'll probably have to do both).

Lengthen the 4-way rod far enough that you can pull the trigger to get the hammer to drop, but NOT have the 4-way activate. From there, its just a matter of shortening the 4-way rod to speed up your firing cycle, but not short enough so you get blowback.

Make sure not to adjust your hammer lug out too far, or else the lug won't catch the sear.
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Old 05-14-2001, 01:50 PM #3
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i think my bolt isnt getting a good seal
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Old 05-14-2001, 04:52 PM #4
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A good seal has very little to do with blowback. Check out the high end bolts like the superfly: they don't have o-rings at all, and the delrin is not a material that forms a seal with the breech. A really tight seal would reduce blowback in an improperly timed gun, but it would really slow down the cycling action because of the friction between o-ring and breech wall. Better to just properly time the gun.
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Old 05-15-2001, 02:55 PM #5
Devaut
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what kind of gun is it

i've shot overhoned guns that have blowback no matter how far appart the timing is.

a delrin bolt usually doesn't have these problems because they are made to take the airflow the right way.

but if the gun is overhoned at all any bolt even one of those slingshot bolts won't help prevent blowback.

-y
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Old 05-16-2001, 02:34 PM #6
Yochinaman
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You guys are right. I have an old STO cocker that has been plated with some brushed nickel or something. The bolt tube is wider and fits the bolt looser than normal. I tried fixing that problem by using tank orings on the bolt to make a tighter seal around the exhaut hole. What happened was i got extreme blowback no matter how I timed the gun. I even manually cocked the gun and there was STILL blowback. Air was seeping pass and around the bolt face and back up my feed tube. My solution was to replace the rear bolt oring with the old original bolt oring so that excess exhaut gas will blow out behind the bolt instead of up my tube. I now get a shot of gas coming out of my sear adjust hole every shot. But blowback is gone and I even have a little suction going on. I did however lose ~20 fps by replacing the oring.

Guess what though. Now I have exhaust port for air assist feeding. ROFL!! Just need to find the right fittings now...

Yochi.
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