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 TREADMARKS
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Posted: 5/13/2012 11:18:50 AM
I would say maybe on the gas piston dia.
What size gas port and barrel length were you using? |
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TREADMARKS
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Posted: 5/13/2012 10:07:08 PM
I just took a look an an osprey system that may support the need of a bigger piston with it's larger cross section.
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Posted: 5/14/2012 3:16:38 PM
You are probably going to need larger, remember .375 for 5.56, so Pi/4*(.375^2) is the area. I would maybe start with that, again if you have a regulator you can just open up the port and let it decide the pressure. Aluminum gas blocks are maybe good for prototyping but you should go away from that.
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arcticwarrior
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Posted: 5/15/2012 2:14:26 AM
[Last Edit: 5/15/2012 2:16:25 AM by arcticwarrior]
Just my .02 cents, but I'd stay away from POF. Hogan used to make their parts and went into business for themselves. I got seriously screwed by POF, but ymmv. I'm curious to find out the results of the above poster who suggested using an Osprey Defense Piston System. I absolutely love my Osprey Piston that I have.
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TREADMARKS
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Posted: 5/15/2012 12:57:31 PM
Good stuff guys. Here is where I am now.
FAL .430 M1A .496 AresDefense .374 Adams Arms .313 Using an Adams style piston block (gas block) will allow me to build up to a .437" piston. So.....Me thinks since my Fal shorty runs flawless with a .430 that that would be a good place to start. I know that I can build a system that will allow the use of components from Adams or from Ares, however I would like to standardize. The biggest problem I have encountered to date is the lack of straight line access on the AR10 chassis. Both the Ares and the Osprey use an off center approach which I think rules them out in an AR10 application. What I need to confirm is the exact distance from the centerline of an AR10 barrel to the center of the gas tube port on the receiver. I will need to match the distance perfectly in a newly designed piston block (gas block) to eliminate any chance of carrier tilt and or rod wear due to being off center. I have measured a distance of 0,8505" between the gas port center and the bbl center on an AR10 receiver. Can anyone confirm or deny this measurement? |
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TREADMARKS
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Posted: 5/15/2012 12:58:46 PM
Holy Cow!
ONETHOUSANDFIVEHUNDREDFIFTYONE HITS ON THIS TOPIC!!!!! |
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TREADMARKS
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Posted: 5/15/2012 2:02:16 PM
Actually I am getting 0.8520 and the dimension I am searching for based on the following information from Armalite:
Technical Spec Information DISTANCE FROM BORE CENTERLINE TO TOP OF PICATINNY RAIL OF UPPER RECEIVER •M-15 – 1.213” •AR-10 – 1.318” |
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TREADMARKS
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Posted: 6/29/2012 8:05:05 AM
Almost twothousand views and no solution yet???
An armalite SASS gasblock will provide a straight line shot to the gas port on the receiver. The SASS block is for an .875" bbl though, so a shim/spacer would be needed on a 750 bbl to seal the gas port. There appears to be enough meat on the SASS block, to allow it to be recut for an FAL type gas plug and sleeved on the receiver side for a piston/spring combo. Can a straight line gas block, with enough meat on it to be cut for FAL components, be had in .750" size????????? |
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Posted: 6/30/2012 11:32:10 AM
Isn't an SKS piston around .310 in diameter? Also, wouldn't you need a smaller diameter piston rather than a larger diameter one for a short stroke piston to increase piston speed? I don't pretend to know the physics of it, but the short stroke pistons I know of have a have a smaller diameter head than a long stroke. (sks/ak, M1A/Garand)
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TREADMARKS
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Posted: 7/6/2012 10:10:50 AM
I checked the sks, but I think I would really like to go with the FAL type design. Seems others are headed that way too.
I would really like to get my hands on a POF carrier and gas block for some measurements, or to use. POF refuses to sell any piston blocks or barrels or carriers to the end user. What a racket! |
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TREADMARKS
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Posted: 7/31/2012 5:33:31 PM
I purchased all of the gas piston components for a POF.
They are the same diameter and use the exact same piston plug ans the FAL. Go figure. Same as the FAL except that the POF and Hogan systems remove the spring from the op rod. The distance from the barrel centerline to the piston centerline is High, just like the AR10. I looks like the AR10 SASS gas block is also on the same high center and may be a host for a piston mod. |
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