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grottulf

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Everything posted by grottulf

  1. Yes, I'm having issues with intermittent 2-3 round bursts with my FM9. I just assumed it was trigger related, and since I'm planning on swapping out the stock trigger, I didn't look into it more thoroughly... Is there a way to tell if it's because of a week firing pin spring, or if it's trigger related?
  2. I have the same issue with some of my glock mags in my FM9. Did you sand the mags or the magwell?
  3. Crystal clear! Thanks for the clarifications, guys! It's strange that FM made the ledge so small. It's only about 1mm (0.04") on my bolt. The angled part could be much smaller and still clear the radius of the charging handle. And I suspect the tolerances between the upper and the bolt are a bit loose, because the charging handle slips of the ledge and pulls on the angled section instead, when the guns not loaded. I hope that has been fixed in their revised bolt, that they have promised to send me. I just have to wait until Brownells starts to export gun parts again, before they can ship it to me.
  4. How come some bolts have this ramp in the front part of the gas key dummy (not sure if that's the correct term for it, but dummy felt right...) My Foxtrot Mike bolt has a ramp like that, and when I pull the charging handle it pushes the bolt down slightly because of it. So if I pull the charging handle while there is no mag inserted, the bolt will drag slightly because of it. But when there's a mag with bullets inserted, it will push up on the bolt and counteract this. So it really isn't a big deal, it's just slightly annoying. I'm just curious why they would design it like that? It's not just FM. CMMG and even JP has bolts with this design. Some seems to have a design without the ramp, like the one in the pic from Angstad arms, and Taccom. That seems like a better design to me. But for some reason they then place it further back on the bolt... Is there a shorter charging handle you can use for these? Or should you just accept that there is some slack in the charging handle before the bolt starts moving...? Am I missing something?
  5. That's not a bad idea I've fixed it now though. I made a new shim from 0.001 stainless steel stock. First I test torqued it with oil and I got it to around 100 ft lbs. I deemed that to be enough as long as I add permanent threadlocker. When I applied a threadlocker, I applied it not only to the threads, but to both sides of the shim as well, for lubrication. (I noticed that shims this thin breaks easily otherwise, at least if they're home made ) But then I couldn't rotate it enough to get it to align... I hadn't considered that the threadlocker takes up some space as well. So I ended up removing the shim (and cleaned the threads thoroughly) And re-tightened it without the shim, and just thread locker, on both threads and the mating surface. It was enough to get just under 100 ft lbs. I think (hope) that will work fine. I'll never remove a comp without a barrel vise again anyway...
  6. I've gotten my hands on a sheet of stainless .001" stock now, so I'll cut out a new shim. I'll just have to find the time for it...
  7. Sorry, I totally forgot about this thread. I had a lot of stovepipes issues with it at first. But after I adjusted the ejector with a home made shim, it has worked perfectly. There was some other minor issues as well. I've emailed the factory with feedback and they have been very responsive, so I'm pretty confident they will have fixed all potential issues before they start to sell them in the US. All in all, I really love the shotgun. I mostly shot 28g shots due to the minimum power factor in IPSC, but it works fine with 24g as well. Not sure what that is in oz, you do the math. The recoil is really soft. I think it has a lot to do with the rotating bolt design. It's the first AR I've had that I don't feel the need to change anything about. I really like the pistol grip and the stock. And I love the handguard. The comp works great, and you can change chokes without loosening the comp. You don't have to loosen the comp when you remove the handguard to service the gas system either. I also love the low weight and the balance of it. But in all fairness, I haven't shot a Derya MK-12(RIA VR80) or Typhoon F-12, so I can't say how it is compared to them.
  8. In IPSC you can choose to have open action at unloaded starts.
  9. Great! Thanks for sharing!
  10. I have barrel nut shims but those are larger. I got my hands on some .001" brass foil, and made my own shim yesterday. But when I tried mounting it again today I only reached 80 ft-lbs when it reached the correct timing... When I disassembled it again I saw that the shim had cracked. I think brass is too soft, so it probably compressed under the load. I'll try to find some stainless steel foil instead...
  11. We ended up threading it M14x1 instead, and redrilled and tapped the comp to match. 1/2" just felt crazy...
  12. I have some questions for you gunsmiths out there. I tried to loosen my comp the other day, and managed to get the barrel extension loose. It didn't take much force at all, so I guess it wasn't torqued to specs from the factory... So I've learned the hard way to always use a barrel vise when removing a comp Now I'm trying to get it back on the barrel with the correct timing and torque. Turning it until it lined up, obviously didn't take enough torque... So I turned it until I got a satisfactory torque reading, and measured how many degrees past the pin it had turned. It was 14 degrees off, and with a little calculations I found that I need a .001" shim to get it right. I tried to Google it but couldn't find any shims for this? Does anyone sell these kind of shims, or do I need to cut it out myself from a sheet? If so would it be better to get a 0.001" steel shim, or should I use a slightly thicker brass shim, and allow for some deformation? And regarding the torque, my Midwest upper receiver rod was beginning to feel sketchy when it got over 135 ft-lbs. But I'm thinking that if I use permanent thread locker, it should be enough with 135... Or will it be too hot for thread locker? What do you think?
  13. Update: I got lazy and bought one of these instead https://www.3gsports.de/3g-pcc-compensator-3px.html
  14. Thanks, that would be really great!
  15. 5/8 would be a little too big on my pencil barrel. I'm considering drilling and re-tapping the comp to M14x1 or something like that... And do the same to my barrel.
  16. Thanks for the advice, but I'm not sure I understood exactly how you did it. Do you happen to have a have pic of the pin and weld?
  17. Ok. Most 9mm comps I've seen has been 1/2-28. But nevermind the pitch, it's the choice of diameter I think is strange... The thickness if the barrel will be under 0.06" with a 1/2" comp! The comp itself will strengthen the barrel, but there will be a substantial stress riser between the barrel and the comp.
  18. How come 1/2x28 is the "standard" thread for 9mm comps? With so little material left, I feel like it'll snap right of, if I drop the gun... And if I'll pin and weld on a comp, how close to the bore do I dare to drill?
  19. It is possible to get a permit for a shorter barrel in Sweden, if I compete in a sport that allows shorter barrels. In IPSC you're allowed to compete with a shorter barrel, but for some reason they don't give approvals for shorter barrels. (You must always have an approval from a sanctioned shooting association, when seeking permit for a gun. If it's not for hunting then it's easier, but then you are much more restricted in what you can get.) So I'd like to keep it at 16" for legal reasons. How you measure the length isn't really defined in the law here though. I interpret it like you guys, and think that pinning and welding a threaded comp would be ok. As I said in the first post, I was comptemplating buying a Brekke comp. But I'm leaning towards building one myself, with help from a friend. Instead of threading it, I'm thinking of making a shrink fit between the barrel and comp, and press it on. I'd also like to make it in aluminum to keep the weight down. But I don't think that would work with aluminum, since that expands more than steel when the temperature rises. Maybe I'll just bite the (9mm) bullet, and get a Brekke comp after all...
  20. That's one of the reasons I'm considering alu. But keeping the weight down is more important to me since I'll probably make it 6" long. Do you mean that an alu-comp has a life span of 1500-2000 rounds in a 223? How about in a 9mm?
  21. Thanks for the advice! I rarely clean the comp on my 223, so it'll probably take a while before I wear out a comp from cleaning, even if it's in alu...
  22. Ah, I hadn't thought about that. Good to know! Sucks though, since I only shoot FMJs, and was thinking about making a an aluminum comp...
  23. What difference does the bullet do?
  24. I've realized that drilling out the rifling is not a realistic option, due to the surface hardening of a barrel... At least not as deep as I wanted to go. I spoke with a friend who is truly awesome with both a mill and a lathe. He works professionally with them and does custom work on a daily basis. (I have both mill and lathe myself, but I really suck at using them ) As we discussed it, we came to the conclusion that it would be better to cut the barrel at 10", and shrink fit a tube over the barrel. I've also abandoned the idea of porting where there is rifling, due to the risk of getting burrs. But I could make the extension with a smaller inner diameter at the beginning, to get better effect from the comp holes, and with a larger ID at the muzzle to avoid unnecessary weight and minimize the risk of contact with the bullet. But now when I examine the pictures of the Taccom super feed 10/16 barrel, I realize that's probably exactly how you made that...? So I realize I'm trying to reinvent the wheel here. It sucks that I can't get a hold of those barrels on this side of the pond ☹
  25. Thanks a lot for the input! I really value it. My original plan was actually to build a AR9 with taccom components (I emailed you about it last summer), but since I couldn't get my hands on that here in Sweden, I went with a FM instead. Too bad about the US export restrictions Do you mean that the sweetspot is centering the ports at 10", or placing the ports after 10"? (like with a 10" barrel) And do you have any advice on what diameter I need to use when drilling out the rifling? I was thinking about drilling with a 10mm drill first (maybe 4-5" deep). But is there a risk that the bullet touches the barrel because of the recoil? Should I drill the last section (maybe 3" deep) with a larger diameter (12mm?)...? The reason for not going 12mm all the way, is I'm thinking about drilling a few holes after the rifling as well (more like a comp than a porting) And I think those holes would be more effective with more goods thickness...? And do you have any input on the diameter for the port holes? I'm thinking about drilling (or actually milling to avoid burrs) 5mm holes... Is there a risk that I end up with a barrel that overcompensates and actually dips on recoil, if I drill to many ports and comp holes...? I should mention that I'm no fan of handloading, so I want it to work well and keep a PF of at least 125 with standard pistol ammo. Preferably 115gr, but heavier bullets is ok as long as it's easy obtainable standard ammo. I know I'm probably over analyzing everything...
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