texasdawg Posted April 28, 2012 Report Share Posted April 28, 2012 Been working on this setup for a week or so off and on between work and family,,, getting close to finished,,, probaley not till next set off will I be able to test it out,,, going to profile the gasblock and put some finish on it today,,,Finished the gasblock and assembled the rifle,,, just barely fit under the handguard,,, the gasblock is 7075 aluminum, the gaspiston assembly is 416 SS, and the spring is an Adams Arms spring. The adjustable gasrod is detented and made of aluminum and SS, eight steps from open to closed. The spring is what I used to figure the stroke and the overall size is what I measured to fit under the handguard. I am not sure if the piston is the right size and if it will cycle properly, but that is the challenge of homeshop made,,, Quote Link to comment Share on other sites More sharing options...
unforgiven Posted April 28, 2012 Report Share Posted April 28, 2012 <munch> Quote Link to comment Share on other sites More sharing options...
IM_JOHNNYV Posted April 28, 2012 Report Share Posted April 28, 2012 Will you be posting more details? Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 30, 2012 Report Share Posted April 30, 2012 Interesting . Quote Link to comment Share on other sites More sharing options...
Jgun Posted April 30, 2012 Report Share Posted April 30, 2012 Impressive!, Can you tell me how you selected your starting dimensions for the parts? Did you take some rough measurements from a commercially mfgd setup? What about your spring and the bolt carrier, what parts are they and where did you source them? Did you modify the gas tube hole in your upper, installed any bushing, or does the piston just pass through the unmodified hole? Quote Link to comment Share on other sites More sharing options...
texasdawg Posted May 1, 2012 Author Report Share Posted May 1, 2012 I ordered a boltcarrier key for a piston gun from Midway. Stuck a rod thru the original holes in upper and handguard barrel nut. I measured the height of the rod where it meet the carrier key and the inside height of the handguard. I wanted it all to fit under neath and it just barely does. No bushings needed, yet, and I believe the next thing to make will be a new buffer weight that has an extenstion on the front of it to mate with the rear of the bolt carrier to prevent carrier tilt. Saw one on the web and it looked like a neat idea. The rod and piston lenghts were determined from the gap between the gasblock and carrier key and the piston spring compressed lenght. Same for the gaspiston vent hole,,,shooting it on saturday weather permitting,,, Quote Link to comment Share on other sites More sharing options...
Jgun Posted May 1, 2012 Report Share Posted May 1, 2012 Very resourcful of you, I'll be eager to hear how the gun runs for you, please take the time to post your range results. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted May 1, 2012 Report Share Posted May 1, 2012 As far as "tilt" is concerned... I use an Adams Arms piston in my 5.56. I put in the carrier weight and an H2 buffer with the standard carbine buffer spring. That slowed the BCG down enough to prevent any noticeable wear. Just my $0.02 Quote Link to comment Share on other sites More sharing options...
texasdawg Posted May 6, 2012 Author Report Share Posted May 6, 2012 Good news, Bad news,,,had a chance to shoot the rifle and the gaspiston system didn't break, but it also didn't fully cycle. Wasn't sure the two piece rod would hold up, but it did. The alignment was spot on, and nothing was dragging that I could tell. Just seems to have been a case of the piston not being sized right? Or something else? I have included some pics as they came off the rifle to see if anyone has any comments or suggestions. I will start on making a larger diameter piston as soon as some metal that I ordered comes in,,, will eather have to make an offset piston rod assembly to fit under the DPMS freefloat handguard I have or find a larger hanguard. Ideas??? As an aside, I closed the ejection door after I loaded a round and it was kicked open after firing, but the bolt didn't cycle enough to load another round. Maybe I'm close,,, Quote Link to comment Share on other sites More sharing options...
unforgiven Posted May 6, 2012 Report Share Posted May 6, 2012 My question brother,from a mechanical standpoint if you incorporate an offset wil it want to twist on you or she might just seat herself and run true? <dontknow> Quote Link to comment Share on other sites More sharing options...
survivalshop Posted May 7, 2012 Report Share Posted May 7, 2012 Are you using a std. gas port in the barrel for a DI operated rifle ? Did you paint the gas block or is that all fouling from firing ? If a lot of it is fouling , could be too much bypass gas to operate piston effectively. Quote Link to comment Share on other sites More sharing options...
texasdawg Posted May 7, 2012 Author Report Share Posted May 7, 2012 The gas port thru the gasblock is bigger than the hole in the barrel; originally due to helping if I missed the alignment up slightly. Could I have gone too big? The ports in gas block are all .1360" and the port in the barrel is .073. The gas block was painted. In the pic of the inside of the gas block it is shiny around the port. On the barrel pic you can tell where some of the gas left a mark. This was one of the ways that I could tell the block was aligned with the port correctly. The build up on the barrel is paint. I only fired 10 rounds from half opened to full opened on the gas adjuster. You can tell that gas was escaping in places it shouldn't have due to it haveing to go somewhere when the rifle was fired and not fully stroking relieving pressure thru the piston bleed hole,,, Quote Link to comment Share on other sites More sharing options...
survivalshop Posted May 8, 2012 Report Share Posted May 8, 2012 The gas port thru the gasblock is bigger than the hole in the barrel; originally due to helping if I missed the alignment up slightly. Could I have gone too big? The ports in gas block are all .1360" and the port in the barrel is .073. The gas block was painted. In the pic of the inside of the gas block it is shiny around the port. On the barrel pic you can tell where some of the gas left a mark. This was one of the ways that I could tell the block was aligned with the port correctly. The build up on the barrel is paint. I only fired 10 rounds from half opened to full opened on the gas adjuster. You can tell that gas was escaping in places it shouldn't have due to it haveing to go somewhere when the rifle was fired and not fully stroking relieving pressure thru the piston bleed hole,,,Of course you will need to close the adj. down more . Could also be return spring tension.You do want to have a usable range for adj. , including for a suppressor ?I would also make sure the gas block is aligned properly . It will seal its self will round count . Quote Link to comment Share on other sites More sharing options...
antifederalist22 Posted June 17, 2012 Report Share Posted June 17, 2012 Any more news on this topic? Curious. Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted June 17, 2012 Report Share Posted June 17, 2012 A little gas leakage evidence is ok. Both my Mini14s and both M1As had a tiny bit around the gas block.Jon Quote Link to comment Share on other sites More sharing options...
unforgiven Posted June 17, 2012 Report Share Posted June 17, 2012 Welcome from Indiana brother antifed. Quote Link to comment Share on other sites More sharing options...
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