Vespid_Wasp Posted October 1, 2011 Share Posted October 1, 2011 I just received a piston from Powerfactor. Looks top notch. Here is my question, as I understand it, the SLP pistons (light and heavy) are identical except with regard to how many shims are in them. The lighter piston has more shims, for more spring tension. The spring retainer that comes with the Powerfactor steel piston is actually a bit shorter than the factory retainer, which will certainly make it easier to thread it it. Will threading it in further than flush result in a piston which will cycle lighter loads? I broke the spring in my light piston a few months ago. (I only noticed it while cleaning, the shotgun continued to function.) I removed the spring from my heavy piston, and used it to rebuild my light piston. So now I have the Powerfactor steel piston body, and the parts for my heavy piston, and replacement springs from Finland. I really don't need a heavy piston, and would prefer to have two light pistons. Can I simply thread the spring retainer into the piston body farther? Do I need to obtain another shim from FN? (not even sure that is possible) Anyone else ever run into this? Link to comment Share on other sites More sharing options...
Vespid_Wasp Posted October 1, 2011 Author Share Posted October 1, 2011 I pit the heavy piston internals into my new piston body yesterday, with the spring retainer threaded in flush. Tested it with some Federal bulk (just a couple of rounds) and I was getting failures to eject/extract. Not really surprising, since I have essentially put in what is currently a heavy piston, and I was shooting light loads. Daylight was fading, and I didn't have a chance to run anything hotter through it. Regardless, the goal is to have two light pistons so that I always have a backup. Advice? Tips? Link to comment Share on other sites More sharing options...
Vespid_Wasp Posted October 2, 2011 Author Share Posted October 2, 2011 Anyone? Link to comment Share on other sites More sharing options...
Vespid_Wasp Posted October 22, 2011 Author Share Posted October 22, 2011 One more try, hoping someone knows. Link to comment Share on other sites More sharing options...
Vespid_Wasp Posted December 5, 2011 Author Share Posted December 5, 2011 Well if anyone was curious I took advantage of the nice weather yesterday to get in a practice session. Letting the rifle cool down and I decided to get my shotgun sorted out. With regard to a power factor piston using the rest of your SLP piston assembly.... The farther you thread in the internal nut that compresses the spring, the 'lighter' your piston gets. I started with the spacers and the rest of the components from my SLP heavy piston, and a new spring from Jyrki in Finland. With the nut threaded flush with the bottom of the piston, the shotgun didn't cycle. Threaded it in a few turns, and it cycled 90% and the rest if left the shell sitting on the lifter but the bolt didn't travel back far enough to pick it up. A couple more turns in and now it is running 100% again. The problem arose when I broke the spring in my light piston. Shotgun kept functioning but I discovered it when I was cleaning. So to get through the season I rebuilt my light piston using the spring from my heavy piston. (Spring are identical, piston function is determined by spring tension, thus the heavy piston has fewer shims.) Finally, to have a main piston and a backup, I ordered the steel piston from Power Factor and 4 new springs from the guy in Finland who makes them. Link to comment Share on other sites More sharing options...
gerritm Posted December 6, 2011 Share Posted December 6, 2011 Thanks for the info. I just broke the spring in my heavy piston during the FB3G. Using the light one for now. I am sending it back to Winchester. They said they thought it would be replaced under warranty. Once I get the new piston or rebuilt one I was thinking of going with the Power Factor SS piston and reinstalling the parts in it. What is the advantage to the steel piston. Will it help prevent spring breakage? How did you unscrew the nut? Is the a spanner type tool or did you make one? Any other hints about taking it apart? gerritm Link to comment Share on other sites More sharing options...
dmshozer1 Posted December 6, 2011 Share Posted December 6, 2011 Well if anyone was curious I took advantage of the nice weather yesterday to get in a practice session. Letting the rifle cool down and I decided to get my shotgun sorted out. With regard to a power factor piston using the rest of your SLP piston assembly.... The farther you thread in the internal nut that compresses the spring, the 'lighter' your piston gets. I started with the spacers and the rest of the components from my SLP heavy piston, and a new spring from Jyrki in Finland. With the nut threaded flush with the bottom of the piston, the shotgun didn't cycle. Threaded it in a few turns, and it cycled 90% and the rest if left the shell sitting on the lifter but the bolt didn't travel back far enough to pick it up. A couple more turns in and now it is running 100% again. The problem arose when I broke the spring in my light piston. Shotgun kept functioning but I discovered it when I was cleaning. So to get through the season I rebuilt my light piston using the spring from my heavy piston. (Spring are identical, piston function is determined by spring tension, thus the heavy piston has fewer shims.) Finally, to have a main piston and a backup, I ordered the steel piston from Power Factor and 4 new springs from the guy in Finland who makes them. Very good information. Thanks Link to comment Share on other sites More sharing options...
Casman Posted December 6, 2011 Share Posted December 6, 2011 Well if anyone was curious I took advantage of the nice weather yesterday to get in a practice session. Letting the rifle cool down and I decided to get my shotgun sorted out. With regard to a power factor piston using the rest of your SLP piston assembly.... The farther you thread in the internal nut that compresses the spring, the 'lighter' your piston gets. I started with the spacers and the rest of the components from my SLP heavy piston, and a new spring from Jyrki in Finland. With the nut threaded flush with the bottom of the piston, the shotgun didn't cycle. Threaded it in a few turns, and it cycled 90% and the rest if left the shell sitting on the lifter but the bolt didn't travel back far enough to pick it up. A couple more turns in and now it is running 100% again. The problem arose when I broke the spring in my light piston. Shotgun kept functioning but I discovered it when I was cleaning. So to get through the season I rebuilt my light piston using the spring from my heavy piston. (Spring are identical, piston function is determined by spring tension, thus the heavy piston has fewer shims.) Finally, to have a main piston and a backup, I ordered the steel piston from Power Factor and 4 new springs from the guy in Finland who makes them. Extremely good info! Thanks for sharing your findings. One question that came up in my mind was; how far inset are you finally taking the spring retainer? The reason I ask, is it seems that the contact face of the polymer pushrod could be essentially chiseled away by the offset face of the metal piston if the inset is too great. Not having performed the tests myself this is just a question. I would love to hear about what you find out in that area. Thanks again! James Link to comment Share on other sites More sharing options...
MarkCO Posted December 6, 2011 Share Posted December 6, 2011 Yes, please keep us informed. Link to comment Share on other sites More sharing options...
boomfab Posted December 6, 2011 Share Posted December 6, 2011 Got a link to the site in Finland that sells the piston springs? Link to comment Share on other sites More sharing options...
nheiny13 Posted December 6, 2011 Share Posted December 6, 2011 You guys can always have the piston sealed by Surecycle. That replaces the spring so there will no longer be any breakage issues. That's what I did on mine and it runs great. Link to comment Share on other sites More sharing options...
MarkCO Posted December 6, 2011 Share Posted December 6, 2011 You guys can always have the piston sealed by Surecycle. That replaces the spring so there will no longer be any breakage issues. That's what I did on mine and it runs great. What exactly does that do? Cost? Can you run slugs to light loads with equality? Link to comment Share on other sites More sharing options...
nheiny13 Posted December 7, 2011 Share Posted December 7, 2011 They replace the spring with a metal spacer. I don't know exactly how or why it does what it does. I don't shoot heavy slugs or loads through my gun so I don't know about that but it does run light slugs just fine. Link to comment Share on other sites More sharing options...
gerritm Posted December 7, 2011 Share Posted December 7, 2011 What is the approximate cost and will it help with the breakage? Does he do it to a stock piston? gerritm Link to comment Share on other sites More sharing options...
technetium-99m Posted December 7, 2011 Share Posted December 7, 2011 (edited) It was around 40 when I did it plus shipping. The spring can't break after that because there isn't one. Its replaced by a metal spacer. I sent them my heavy piston and had it sealed. Edited December 7, 2011 by technetium-99m Link to comment Share on other sites More sharing options...
Vespid_Wasp Posted December 12, 2011 Author Share Posted December 12, 2011 Got a link to the site in Finland that sells the piston springs? http://gas-piston-springs.com/ Link to comment Share on other sites More sharing options...
boomfab Posted December 12, 2011 Share Posted December 12, 2011 I can tell a noticeable recoil difference between the Browning Gold sporting clays 1 1/8oz piston and the factory Winchester sx2 "1 1/4 oz and less" piston. The sealed piston design must not bleed off any gas? It must kick pretty hard. Link to comment Share on other sites More sharing options...
SmurfJet Posted December 31, 2015 Share Posted December 31, 2015 I've looked everywhere I can think of and still haven't been able to find a good description of how the gas system on the SLP operates, namely the gas regulating function of the piston's internals. Is it anything more complicated than the piston's spring rate determining how much gas energy actually cycles the action? Link to comment Share on other sites More sharing options...
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