DavidQ 170 Posted April 16, 2014 Report Share Posted April 16, 2014 I recently had my bolt carrier replaced on my Saga 12K due to it having a chunk come out by the op rod (Thanks Legion USA!!) and now I have a concern. The new bolt carrier has about 1/8" horizontal play. It is dimpled on both sides with very minimal twist on the piston. The last one failed right on top where the play is. Can I expect this one to fail just as the other one did? Is there anyway to tighten up the rod slightly? Should I just leave it be and if it fails, have it repaired? (it will probably be out of warranty by then). The last one was the original part and only 8 months old with maybe 700 rounds through it. I really just want to prevent another issue before it happens and try to keep cost down from repair, or preventing it from happening. I have not shot it yet with the new one but plan on taking it out later today. Any advice is welcome. Quote Link to post Share on other sites
pedal2alloy 206 Posted April 16, 2014 Report Share Posted April 16, 2014 That looseness is a design feature, believe it or not. If it were tight, it would increase the stress and fail sooner. Use it the way it is, it will most likely be fine 1 Quote Link to post Share on other sites
DavidQ 170 Posted April 16, 2014 Author Report Share Posted April 16, 2014 I understand it should be loose. So 1/8" up and down wobble is ok? Just took it out and it runs good. Gonna smooth out the action a little. Should I have the piston pinned instead of dimpled to ensure it will last? Or does that not matter? Quote Link to post Share on other sites
Mullet Man 2,114 Posted April 17, 2014 Report Share Posted April 17, 2014 Pin it and see what happens. I believe too much play will cause a stress fracture. Dimples are just a cheap alternative for the assembly line. 1 Quote Link to post Share on other sites
DavidQ 170 Posted April 17, 2014 Author Report Share Posted April 17, 2014 The problem that I think I had before was it wobbled too much and the op rod got caught on the piston chamber and that was how the chip happened. I just don't want to have it happen again if it can be prevented. Is there a tutorial on how to pin it? Quote Link to post Share on other sites
Mullet Man 2,114 Posted April 17, 2014 Report Share Posted April 17, 2014 (edited) Very well could have been the cause. Search YouTube for ak piston install. Drill through the dimples, Mic the hole and install a pin a couple thousandths larger. Best bet is to use common AK pin sizes as drills are readily available for them. Something like a 3mm FSB pin would work just fine. Then just pick up the correct drills for it. Even a pinned piston will develop some wobble but I think it's severity is much less over time, then dimples alone. Edited April 17, 2014 by Mullet Man Quote Link to post Share on other sites
DavidQ 170 Posted April 17, 2014 Author Report Share Posted April 17, 2014 I will look into it. Should I drill all the way through and pin from both sides or drill half way and pin from one side? Quote Link to post Share on other sites
Mullet Man 2,114 Posted April 17, 2014 Report Share Posted April 17, 2014 I guess you could do either way. I would go all the way through if it were mine. With a blind pin I would want to weld it because of the movement the area sees. With through pin, I would ptobably just stake or peen the ends which could still allow some wobble that everyone says is part of the design. Quote Link to post Share on other sites
jdtravers 637 Posted April 17, 2014 Report Share Posted April 17, 2014 That much play is OK. Remember, the Carrier/Op Rod are captured inside the Op Rod Tube which will not allow excessive flex. The problem occurs when the OP Rod does not bottom out inside of the carrier, that is when cracking of the carrier will occur, as the energy is transferred to the walls/sides of the carrier instead of bottom face/flat inside the carrier. (if I said that correctly) There is no need to drill/pin the op rod inside the carrier. Jack Quote Link to post Share on other sites
DavidQ 170 Posted April 17, 2014 Author Report Share Posted April 17, 2014 Thanks for the replies. How do I determine if the op rod is bottomed out in the carrier? If I need to adjust the depth of the piston would I run into a problem of it being to short and the piston not contacting it fully to cycle the bolt? Quote Link to post Share on other sites
jdtravers 637 Posted April 17, 2014 Report Share Posted April 17, 2014 You would have to remove the Op Rod from the carrier, measure the distance from the nose of the carrier to the bottom and transfer that measurement to the op rod. The distance is not detrimental to the relationship of the Op Rod/Piston, etc. We are only talking maybe a max of .050 which is a lot for the carrier/op rod, but not for the gas system. Jack Quote Link to post Share on other sites
Mullet Man 2,114 Posted April 17, 2014 Report Share Posted April 17, 2014 ^ there ya go. Hey jack, is it safe to assume that much play could be from the piston not being bottomed out? If someone were to drill it, bottom it out and pin, what's the best option to address the extra space left between the rod and puck Quote Link to post Share on other sites
DavidQ 170 Posted April 17, 2014 Author Report Share Posted April 17, 2014 Well if I gotta remove the op rod, might as well install a Tom Cole heavy duty one in its place. I just want to make sure I don't rin into cycling problems from it. Quote Link to post Share on other sites
jdtravers 637 Posted April 17, 2014 Report Share Posted April 17, 2014 ^ there ya go. Hey jack, is it safe to assume that much play could be from the piston not being bottomed out? If someone were to drill it, bottom it out and pin, what's the best option to address the extra space left between the rod and puck I have oversize/longer pistons manufactured for that purpose. Jack Well if I gotta remove the op rod, might as well install a Tom Cole heavy duty one in its place. I just want to make sure I don't rin into cycling problems from it. Use your original Op Rod if it is not damaged. Jack Quote Link to post Share on other sites
DavidQ 170 Posted April 17, 2014 Author Report Share Posted April 17, 2014 No damage at all. You're the expert. Quote Link to post Share on other sites
pedal2alloy 206 Posted April 22, 2014 Report Share Posted April 22, 2014 This would be too much wobble: 1 Quote Link to post Share on other sites
pedal2alloy 206 Posted January 26, 2015 Report Share Posted January 26, 2015 This would be too much wobble: This is the right amount of wobble: 3 Quote Link to post Share on other sites
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