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piston system drawings

9K views 69 replies 21 participants last post by  chopper 
#1 ·
here are some of my drawings for the piston sys




 
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#4 ·
You made your piston system out of tool steel and titainium. I was planning on making one out of aluminum and stainless steel. If I made one like this since I would use softer aluminum I'd put a little shoulder on the spicket (?) to keep it from being battered into the gas block, and make the spicket a non removable press fit so I wouldn't wallow out the hole from taking it in and out. I figure it would be similar to the mini 14 gas block. Do you think that will work ok, or see any problems with it? and what type of SS should I use?
 
#15 ·
I kinda like the simplicity of the spigot type set up. I had made up some drawings a while back for a piston setup based off of a FAL piston. At the time original ones were cheap on ebay because everyone replaced them with USA made ones for their parts count. I can get enough 6061 for 4 gas blocks if I don't screw any up for $13. But I just noticed the fortal guy is only about 10-15 minutes from me so I might be able to pick it up and save shipping.
 
#17 ·
and prints of the oprod and do you use an original gas key or did you make a new one as most of the kits do? Also is the piston/ oprod or oprod/key pinned or just a .001 fit? I have one more ? sorry but i'm just trying to grasp this all in my head before i buy material ... What does the end of the piston look like i see the dimension but don't know what its supposed to look like....

thanks
Matt
 
#18 ·

i made a new gas key it is hardend o1 tool steel it could have been made from 8620,but i had the o1 on hand.
the oprod to piston is slip fit .
("What does the end of the piston look like i see the dimension but don't know what its supposed to look like...".)
im not shure what your asking? just break all sharp edges
 
#19 ·
okay but is it cupped on the end or flat and what is the .187 dia. specified for is that a counter bore for the oprod or what is that also a question that I myself feel dumb for asking but is the gas block capped at the end of the bore for the piston and what purpose does the hole for the ar rear take down serve

sorry these prints are helping but stumping me at the same time as i don't have much exp. with gas piston systems

thanks again
Matt
 
#20 ·
okay but is it cupped on the end or flat and what is the .187 dia. specified for is that a counter bore for the oprod or what is that also a question that I myself feel dumb for asking but is the gas block capped at the end of the bore for the piston and what purpose does the hole for the ar rear take down serve
flat,
.187 is for the oprod
caped at the end?
if you can mark my drawings were your haveing truble and post it ,it would help me help you
 
#21 ·
I had a Rhino gas piston conversion 20 years ago. The replacement key had a pin portion that went in to the bolt carrier as using the bolts alone would result in sheared bolts. They would get knocked loose first too. The pin was a tight fit in a hole in the bolt carrier between the two bolts. The pin can be part of the key or maybe a separate pin but must fit both the key and the bolt carrier tightly. The gas key bolts aren't strong enough alone to hold up to a gas piston system.
 
#25 ·
When I did the Rhino conversion removing the gas rings resulted in a very loose fit between the bolt and the bolt carrier. I noticed on my AR-10 the bolt is a close fit with the bolt carrier even without the gas rings. In fact my AR-10 will function with the original gas system with the gas rings removed from the bolt. I know 308 makes more gas than 223 but I think a lot of it is the close fit between the bolt and bolt carrier. The Ar-15 seems to leave a lot play with the gas rings removed. Maybe different brands of parts might fit together differently.
 
#29 ·
I've noticed most gas piston systems (apart from the M-14) have a spring to return or hold the gas piston / op rod forward. It might only be a factor when the bolt is held open and I have tried the FAL with the spring and it works. Maybe it's just to keep it from rattling around or to hold it forward when the top cover is the stripper clip type but even rifles without stripper clip loading usually has a spring for the gas system.
 
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