Hi as most of you know who are in the gun community a bunch of AR 70/90 kits came into the country and theirs still no barrels or receivers in production. Since I cant find anything I decided that I'm just going to make my own barrel and I've found the measurements from a guy on reddit who lives in Italy.
As I was getting the measurements a curiosity ran through my head, how do you mathematically figure out the proper diameter of the gas port hole for the gas block in the barrel?
Much help will be appreciated!
This may have already been answered, but why are so many modern assault rifles gas-operated, when blowback-operated designs are (generally speaking) simpler/cheaper to manufacture and require less maintenance? I've been doing some research and can't seem to figure out why for the life of me. Any assistance is greatly appreciated.
Would having the gas piston or impingement system below the barrel instead of on top help in reducing recoil?By pizza654
This is my first post and im no physicist so if this sounds stupid to you please explain to me why its dumb because I always like learning new things about gun design. Anyways ive had this idea in my head for a while now about a rifle concept and it first popped into my head when I was looking at the mechanics of a pkm. Like a lot of belt fed guns the piston is on the bottom of the barrel instead of the top and because the bolt and piston is so low it gives the pkm a good recoil impulse. My thought was how come no ones ever designed a rifle with the gas system below the barrel instead of on top? Imagine a SCAR but the barrel and the piston gas block is reversed.
This is one modern rifle that I'm insanely interested in, especially since there was a TFB article that hinted that there was a .308 Winchester/7.62mm NATO version being worked on that might use the same upper as the 5.56mm NATO version that HK has shown in several different versions since 2017.
This is the latest (known) iteration of the 433, and if you've seen some of the POTD posts at TFB since May of last year, you've probably seen it a time or two. In short, the 433 is HK's answer to the FN SCAR and to try and one up it. IMO, the most interesting thing about the 433 is that it seems capable of taking way more caliber rounds than items such as the FN SCAR or the Bren 2, which needed new uppers in order to go rounds like .308.
Out of curiosity one day, since I've seen numerous (though not often very new) photos of the 433 and I've also seen patent documents (I'll provide a link to patent documents and an article on Spartanat with some photos of the Gen 5 433), I decided to see if my own thoughts on the 433 being caliber convertible beyond .300 Blackout or 7.62x39mm held water. Using a simple image scaling and measuring program, I've determined that the 433 upper, as is, is capable of taking rounds or at least magazines of 71-72mm OAL. Mind you, this isn't exact, and I was conservative with my measurements.
Of course, this does further peak my curiosity on what the 433 is capable of firing and how caliber convertible it may be. On top of of course how it comes apart and various details about it.
Now the documentation. Spartanat is an Austrian site, and hence is in German, and being new here I'm not sure how Google translate works when linked, so I'll just leave the link (which has good, albeit sadly not ultra HQ/high res images, which IMO is a damn shame) to be copypasta'd into Google's translator or your favorite translator. On the plus side, there's a PDF in the article that you can save or convert to a pretty high res JPG or PNG image, and Google does a decent job of translating the PDF, too:
Now here's the patent documents and images. This series mostly pertains to the charging handle system, but it shows a good idea of how the guts of the 433 are laid out: