D.E. Watters Posted October 9, 2018 Report Share Posted October 9, 2018 On 9/24/2018 at 9:26 PM, Meplat said: Now make it in 6.5X55 Swede.. Hahaha! (which no kidding, would be a fantastic idea, as 6.5X55 is absurdly underrated..An AR platform using 6,5 Swede would be amazing,) A Czech company did just that, as well as a 7.5mm Swiss variant. Google the Luvo Arms LA-11. Meplat 1 Quote Link to comment Share on other sites More sharing options...
Meplat Posted October 9, 2018 Report Share Posted October 9, 2018 21 hours ago, D.E. Watters said: A Czech company did just that, as well as a 7.5mm Swiss variant. Google the Luvo Arms LA-11. Okay, now I know what I want for Christmas. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 7, 2018 Author Report Share Posted November 7, 2018 Back to work on this. Fooling around with some color, first: Lord_James 1 Quote Link to comment Share on other sites More sharing options...
Oedipus Wreckx-n-Effect Posted November 7, 2018 Report Share Posted November 7, 2018 Gonna keep the finger grooves? Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 7, 2018 Author Report Share Posted November 7, 2018 2 minutes ago, Oedipus Wreckx-n-Effect said: Gonna keep the finger grooves? That's just a Hogue AR grip I imported bc I am lazy. Quote Link to comment Share on other sites More sharing options...
Belesarius Posted November 7, 2018 Report Share Posted November 7, 2018 Just now, Sturgeon said: That's just a Hogue AR grip I imported bc I am lazy. At least he's honest. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 7, 2018 Author Report Share Posted November 7, 2018 Magazine is now complete: Lord_James 1 Quote Link to comment Share on other sites More sharing options...
Oedipus Wreckx-n-Effect Posted November 8, 2018 Report Share Posted November 8, 2018 5 hours ago, Sturgeon said: That's just a Hogue AR grip I imported bc I am lazy. HACK FRAUD Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 Wrapped up the mechanics of the magazine. There's a ton of reverse-engineering going on with the guts of the magazine (thanks, Magpul!). Two followers are modeled here to illustrate its movement within the magazine. Here you can see a sketch of the cartridge stack overlaid onto the magazine: There are 33 rounds in that stack; the magazine doesn't accommodate the last two and aaaalllllmost clears the third from last. This makes it a 30 round mag with about 3/4ths of the 31st round's worth of extra space. Notice the generous spring chamber even when the follower is fully collapsed. The idea here is to be similar to an AK magazine and use a super long stiff spring for added reliabilitah. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 @Ulric Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 This design does come with a penalty: Weight. We're currently looking at 192 grams empty (with spring). For comparison a Gen 3 30 round PMag is 139 grams, and a 30 round USGI mag is 113 grams. Oof! Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted November 8, 2018 Report Share Posted November 8, 2018 I assume you're handwaving the spring weight, but just so you know, when it comes to coil springs, a long coil spring is weaker. Making a coil spring long is the same thing as putting a bunch of short coil springs in series, which reduces spring constant. If you want a coil spring that's both long and generates a lot of force, then the coil material needs to be thicker, which results in an outrageous and gigantic magazine spring. Which I think you already knew, from looking at AK magazine springs. Just pointing out that there's a further weight penalty for this design choice. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 11 minutes ago, Collimatrix said: I assume you're handwaving the spring weight, but just so you know, when it comes to coil springs, a long coil spring is weaker. Making a coil spring long is the same thing as putting a bunch of short coil springs in series, which reduces spring constant. If you want a coil spring that's both long and generates a lot of force, then the coil material needs to be thicker, which results in an outrageous and gigantic magazine spring. Which I think you already knew, from looking at AK magazine springs. Just pointing out that there's a further weight penalty for this design choice. I measured the weight of one of my AK-74 mag springs and added that to the weight of the complete magazine model. That spring was like twice as heavy as the Gen 3 Pmag spring! Spent some time this evening finishing up the rear trunnion (which is now aluminum instead of steel): Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 Currently sitting at an estimated complete weight of 3.13 kg / 6.90 lbs without magazine or gun food. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 Gave it coolguy gofast colors: Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 8, 2018 Author Report Share Posted November 8, 2018 Working on the gas system today: Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Rifle now has a gas system: Wireframe of the gas system: Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Two sectioned views: Oedipus Wreckx-n-Effect 1 Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Clearer labeled diagram of the gas system: N-L-M 1 Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 I've now done enough work that I can be quite confident in mass estimates. We're sitting at 3.15 kg / 6.94 lb without magazine, ammunition, optics, or accessories. That's with a SOCOM profile barrel. With an A1-profile barrel that drops to 2.96 kg / 6.53 lb. A hypothetical 14.5" lightweight barreled SCAR-L with no sights would weigh about 3.08 kg / 6.79 lb, so that improves my estimation of the rifle somewhat I must admit. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Overtravel is currently just shy of 1.68". Decent. Cut the vent hole for the gas system: Revised gas system: Weight is now a little less than 3.16 kg / 6.96 lbs. Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted November 9, 2018 Report Share Posted November 9, 2018 No BARS? How old school. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Shaved some weight, and sitting at 3.10 kg / 6.83 lbs even with a 5.5:1 mass ratio. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted November 9, 2018 Author Report Share Posted November 9, 2018 Torx! Quote Link to comment Share on other sites More sharing options...
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