https://marbleduck.com/articles.html Build guides, tooling and lessons learned on Kalashnikov and roller-delayed HK rifles from Marble Duck. en-us muir@marbleduck.com (Muir Hamilton)Fri, 04 Sep 2026 00:00:00 +0000 https://marbleduck.com/articles/mp5-reweld.html https://marbleduck.com/articles/mp5-reweld.html Fri, 04 Sep 2026 00:00:00 +0000 Builds A close look at reweld work on two customer MP5s built using the original magwell and receiver stubs and a new manufacture receiver. https://marbleduck.com/articles/65g-mag.html https://marbleduck.com/articles/65g-mag.html Mon, 20 Jul 2026 00:00:00 +0000 AK The stamped sheet metal 6.5G AK mags available for purchase kind of suck. Why don't we print our own? https://marbleduck.com/articles/65g.html https://marbleduck.com/articles/65g.html Sat, 04 Jul 2026 00:00:00 +0000 AK Here's what goes into my 6.5 Grendel AKs https://marbleduck.com/articles/mandrel.html https://marbleduck.com/articles/mandrel.html Tue, 30 Jun 2026 00:00:00 +0000 Tooling I used to produce some production straightening mandrels for the HK G3 and MP5. These can be critical to establishing the right dimensions for your folded receiver, but they're extremely rare these days. Here's how you could order your own based on my spec. https://marbleduck.com/articles/hk-drilljig.html https://marbleduck.com/articles/hk-drilljig.html Tue, 14 Apr 2026 00:00:00 +0000 Tooling With a few parts from McMaster and a 3d printer, you can precisely drill every single hole in the G3/CETME receiver with whatever rickety press you have laying around. https://marbleduck.com/articles/kyrgyz.html https://marbleduck.com/articles/kyrgyz.html Tue, 01 Feb 2022 00:00:00 +0000 International A lot of things were happening in February of 2022. Here's how the world then looked to a group of upper-middle class, government-connected firearms enthusiasts in Bishkek.