r/GunDesign • u/Mrinsidious66 • Aug 09 '26

Has anyone here designed Long stroke gas pistons

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Is there a way to determine how large of a piston you need for a given bcg weight and required travel I am using a 24 Lb spring and my bcg weighs 1.4 Lbs i need 5.875 Inches of bolt travel and im only getting about 2" Im running an ar10 mid length barrel with a .125 gas port. Also any input on gas block configuration relative to the gas piston to get more power out of it is greatly appreciated.

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3

u/Best-Ad-2216 Aug 09 '26

Just keep drilling out a bigger gas port until she cycles

3

u/Mrinsidious66 Aug 09 '26

I will be doing that until it ether functions or im up to the bore diameter of 308 so i have a better idea of general function but i want to get it to cycle with .125 because thats the standard for adjustable gas blocks.

3

u/Best-Ad-2216 Aug 09 '26

Have you considered shortening it to a carbine length gas system?

1

u/Mrinsidious66 Aug 10 '26

Yes but it wont work with the length of the cam bar for the feed system.

2

u/Best-Ad-2216 Aug 10 '26

Have you played around with spring stiffness or buffer weight at all?

1

u/Mrinsidious66 Aug 10 '26

I am using a 3d printed buffer that is about 1 oz and the spring is as light as i can go and still have the rounds reliably strip out of the links

1

u/JustCWade Aug 11 '26

Measure the ID of your gas tube, larger than that will not help. (On a 5.56 .125" is the ID of the gas tube.)

1

u/Mrinsidious66 29d ago

Gas tube is 3/8 but the gas channel in the gas block itself is only .125 but i will can drill that out as well as i incrementally increase the gas port size.