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Posted: 12/11/2025 10:04:43 PM EDT
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I have an older Mega Maten billet upper with a slip fit handguard held on with 12 torx head screws. I'm hoping someone in the hive has an idea of what size screw (thread pitch) is correct. I snapped the head off of one and need to replace it. Want to get a few more to keep on hand as replacements. This is the upper im working with: Attached File |
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The MKM had five pages of documentation. On page five it states, "using a T-15 Torx wrench, install Torx screws into your MKM." I can not document the actual screw size. Nor can I measure the screws. Wild ass guess, placed on the internet, this is certainly not information that I would act on... use at your own discretion and risk. These ARE incorrect and too long, but easily enough corrected. MSC# 15299654 Mfr# 16-1030 M3.5 thread??? Seriously, this thing was well documented. I would expect Zev to have the exact information if not the actual screws. EDITED TO ADD: even more important... Have you ever driven steel bolts into an aluminum BMW block? It is possible for the bolt to strip the entirety of the threads out of the drilled hole. I encourage you to also determine the proper torque setting. NO, it is NOT found on page 5. This is an additional piece of external motivation to call ZEV. Do not over tighten. |
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I tried to call Zev but they were most unhelpful and were not able to tell me the screw size or recommended torque value. They wanted a serial number, however the upper is not serialized  The threads were clean and it did not feel like the fastener or hole stripped out. At most there was 15 in / lbs of torque applied assuming my torque driver was still in calibration. I have had a similar thing happen on slim 1911 torx grip screws. The torx drive pocket thins out the head to where it will easily snap off. |
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Ok, perhaps the institutional memory might be found at Icon Defense. Try contacting killer-innovations.com. db Edited to add: would not be surprised if Zev was asking for the specifics of the bolt and not the upper. "Oh, so that is what these are for!" |
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Originally Posted By DBrown: Ok, perhaps the institutional memory might be found at Icon Defense. Try contacting killer-innovations.com. db Edited to add: would not be surprised if Zev was asking for the specifics of the bolt and not the upper. "Oh, so that is what these are for!" Originally Posted By ARgonot: You said there's 12 screws holding the handguard on. Why not remove one, take it to your local hardware store and determine exactly what you need? Thanks DB, I'll try killer innovations. Argonot - I guess I could try that but I don't have "real" hardware stores around my neck of the woods. Just HD and Lowes. Doubt they would have what I need. |
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The screw size is #8-32 and is likely 5/16". The problem is that the factory screw is recessed in such a way that I have not been able to find a replacement that fits perfectly. ZEV did tell me that mcmaster-carr made the screws for them so I would reach out and see if they have a UPC for it. |
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Originally Posted By GlockWrench: Argonot - I guess I could try that but I don't have "real" hardware stores around my neck of the woods. Just HD and Lowes. Doubt they would have what I need. No Ace Hardware or a True Value? Technically even Lowes would have enough variety to identify which thread type and diameter of screw you have. You can tell what the length is by measuring a screw you remove from the handguard. Even Lowes has helpful demonstration plates that have threaded holes so you can identify your screw by screwing it into the holes in the plate. You have everything you need to identify a simple screw. |
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Originally Posted By Smurgeon: The screw size is #8-32 and is likely 5/16". The problem is that the factory screw is recessed in such a way that I have not been able to find a replacement that fits perfectly. ZEV did tell me that mcmaster-carr made the screws for them so I would reach out and see if they have a UPC for it. Thanks Smurgeon. At $10 i dont have much to lose with the Mcmaster 8-32 5/16" Screws. Im going to give them a shot. I also submitted a contact request to Killer-innovations so i'll see what they say. |
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Ordered the screws from McMaster - now to find time to work on it... lol. McMaster P/N: 94414A352, 8-32, 5/16" Long, Torx Plus T-20 I'll report back if those screws worked once I give them a try. |
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Finally had a chance to work on it. The McMaster screws fit as far as thread pitch was concerned, but the head was slightly larger than the original screws like Smurgeon had experienced. Replacement screw will work for now, Although I am going to try the Lancer replacement handguard screws and see if their head is more like the original Mega screws. I never did hear from Killer Innovations. See below for the OEM vs McMaster screw on the cleaning patch (McMaster on the bottom on the cleaning patch) (McMaster on the top installed in the upper) Attached File |
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Well, Looks like those new Aero M5 screws may work. I had another chance to work on this yesterday as the Seekins screws came in. They still don't fit 100% but are closer in fit than the McMaster screws. The heads of the Seekins appear to have a similar bevel on the underside as well. Attached File |
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Originally Posted By GlockWrench: Well, Looks like those new Aero M5 screws may work. I had another chance to work on this yesterday as the Seekins screws came in. They still don't fit 100% but are closer in fit than the McMaster screws. The heads of the Seekins appear to have a similar bevel on the underside as well. https://www.ar15.com/media/mediaFiles/505498/2026-01-25_09_48_31-494_jpg_png-3701352.JPG The part number for them is APRH100381C. |
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