Why Cast Trunnions SUCK! 

"You're lying, and God's watching"

My blankity blank -47 has shoots stuff

Props for that marker shopping

Glad I bought all my Com Bloc rifles back in the day...

Americans: My $500 cast turnnion AK is awesome Soviets: _Laughs in mass production _

Stay away from the century American made rifles

Yes and no. The density doesn’t change from billet to forge. The density of the metal is the density of the metal, regardless of your harding process. Forging is elongating the grain structure that is on the surface of the metal. The forging process induces compressive forces on the surface which then hardens it. It forces a strain on the metal surface that moves based on the Young’s modulus, which dictates the stiffness of any metal; E= tensile stress/linear Strain. Billet is tough but not hard and that’s a function of the billets carbon content. A billet piece can be forged; density doesn’t change and carbon content doesn’t change. Tough meaning how much energy it absorbs. So a cast part will break because it’s brittle, a billet part will absorb energy and you’ll see “indentions” from impact and a forged piece is hard on the surface because the grain structure has gone under compressive forces. Now, you can machine a piece of bar stock in the direction of the grain structure and then you forge the same piece in the direction of of how the grains grew during the heating process. This will use the grain structure to your advantage. The same idea as wooden baseball bats. Grains only change when the metal is being heated. It’s a phase of the metal. But yes, the forging process hardens the surface of the metal, making a very hard part. In the end, your company and the AKs you all make rock, please continue to use the forged parts. Btw 4150 billet steel has a brinell hardness of 197 on the surface and after cold forging(cold hammer forging) it goes up to around 340

Hey hey, im a redheaded stepchild and im a good boy

Great video. I made a video a while back about why I sold my RAS47. I took Jim Fuller out to breakfast to pick his brain and he told me a bunch of things about cast trunions....so I sold my RAS47. Well that set off a firestorm of haters who love their RAS47 and called me all kinds of names. I guess taking advice from an AK expert isn't something many agree with??? LOL Great video bro.

"You're lying, and god's watching" roflmao! Great info, more like this please

content like this is great for the stale environment and helpful for people like me getting into AKs

I really wish I’d known about this channel before I bought an IO.

“Your gonna have a bad time” sounded like Paul harrell

I didn't know mac from it's always sunny made Ak's

AK-50 with forged parts that is going to be expensive but worth it.

"The forums" U mean the mongolian basket weaving forum?

The term for that Sponge Bob effect in the castings is porosity, we deal with it all the time in the welding field.

Castings can be quite strong. Example, almost all production engine blocks are cast. The real problem is investing in things that reduce gas entrapment (Such as vacuum casting) and mold types that let the part cool very slow to provide the best interlocked grain structure such as sand molds. And by the time you do that for small parts such as AK trunions you might as well have invested in forging.

Thank god I bought my WASR back when they were $400. It just wont die. There are certain parts I'm fine with them casting, but nothing that's important to the rifles major operations and stress.

Really enjoyed this video. Just picked up a Mak 90 and SLR 104 yesterday and those are my first AKs so I'm looking forward to learning more about them!

your channel has taught me so much about AKs, and I made sure my first AK purchase wasn't a garbage one. keep up the good work

As a machinist in training, I’m falling in love with firearms for a third separate time. The precision and tolerances of these arguably intricate machines is fucking amazing.

This video was awesome. Explained everything very well. My friends think I'm stupid for paying more for a quality AK. I try explaining to them the differences in metals used in new production ak's compared to surplus style ak's but they just look at me like I'm stupid and making things up. This video will help get my point across. On the bright side everyone I know that had held or shot my ak's has had a smile in their face. Ak's have a sole. Everyone I know that's held and shouldered one knows what I'm talking about.

In b4 "RAS47 is fine" comments.

This is why ak shooters union and Tim from mac got 5k round count before the rifle was stretching apart (go-no/field) gauge just fell in and the bolt closed all the way

VSKA now has Billeted Trunnions. For those like me that were worried after making an impulse purchase you can rest assured that its a decent AK.

1:14 In terms of grain structure, we have no grain structure

I like Whiteboard writing stuff...Thanks for helping Raising the Noob AK Guys including me. You and Rob Ski are the Best of Guides to AK .Good Luck :)

Older video, but I feel the need to comment. For background, I'm both a 5 axis CNC aerospace machinist and a metallurgist, specializing in ferrous metals. This is a bit misleading. The "grain" of steel does not flow like wood grain, as is pictured here, it is a crystalline structure. If you take a billet and machine it, the structure will be the same as the original billet, unless you thermally cycle the machined part, which is called normalizing, it reduces stresses induced by machining and reduces grain size, which is objectively the most important part, large grains = structural weakness. It also helps to "align" the structure, to stick with your analogy. This is where forging gets its strength, because it is heated and formed, it helps reduce grain size, leading to stronger parts. BUT, if forged parts are not normalized after forging, they will not be as strong as they potentially could be. Cast parts have absolutely HUGE grain size, a product of the insane temperatures needed for casting, unless they are properly thermally cycled, which is not easy with cast steel, and is also expensive, which is why they dont do it. So your advice stands. Avoid cast parts, because they will not put the money into properly heat treating them. If a billet trunnion is properly heat treated after machining, it will be just as strong as a forged one, and objectively better then a poorly heat treated forged trunnion. Just wanted to clarify on some things. Great video as always.

Thanks for your honesty. I understand more. Just started out with an Ak,

Really dig the style of video. We want more!!!! Can you do one about the different quality of ak parts from Romania, hungry, Bulgaria, China or Russian. Maybe rank them as to which you like best. I saw ur video about not all ak mil-spec parts are the same and that got me thinking.

Im sold on the intro. Love, love, LOVE your channel. Funny, badass, and VERY informative without droning on and on or using high science verbage.

Dude this was highly informative. Do it again.

PSAK-47 GF3 has a forged trunion, bolt and carrier with all new manufacturing for 599.00

As a fellow engineer (in the automotive sector though) the whiteboard of knowledge videos are the most enjoyable for me. Nice work.

Thanks for the exact clarification, I had an idea of the differences, however noone had explained it in detail.

Shhh! let them come to the forums.....

Cool , Never realized exactly how that all worked , Great job explaining it, and i Hope to own one of your AK-50's when they come out !! Keep up All your Vid's there informative.

By far the best explanation. Ty Brandon!

I like that at the end you showed us everything we need to know in a few seconds. A true slav!

Seems strange that these days you have to explain all this. I learned in shop class and on the drag strip when factory cast rods went through my oil pan and I upgraded to GN Billet rods.

This was actually extremely interesting to me. I'm just now getting into AK-47's, and learning the design, construction, and pitfalls of various models. I am coming from a small billet AR manufacturer, and have been very confused as to why American AK-47 rifles have been such garbage, and why no American company has stepped up to make quality billet 8620 steel trunnions and bolts, and perhaps BCG's/pistons, to address the failings of the budget guns. Seems like there is a market for it, and justification for the investment. And as you stated, with a properly outfitted machine shop, production of quality billet parts, offer costs that rival cast, with strength comparable, though slightly less, than forged. Billet receivers with MCX stock mounts on the rear, billet bolt carriers, billet trunnions perhaps with a new AR style barrel mounting system, and a Weatherby Mark V interrupted lug pattern billet bolt while we're at it. effectively creating an AAK-19 (American AK) like the STI 2011 did to the 1911 design. But I digress.....

Please keep the knowledge coming. I appreciate it. Thanks again

Thanks for these great videos. Really helping me understand the AK platform on a whole new level and with a new level of appreciation for the platform.

Zee professor is in now. Class is in session 😂 Thanks for the knowledge Brandon 👍

people be like " my RAS47 has 200 rounds thought it and its fine"

Very educational video, thanks man. My only AK as of now is the Arsenal SAM7SF and from what I know it’s well made (better be for the $1200 I paid). Anyhow, I’m not an AK expert so it’s nice to learn. Keep pumping out vids man!

Love the knowledge flow. Good looking out! I’m ready for more!

Can you please make a video on nitrited barrels vs chromed lined??

I’m extremely impressed with PSA’s GF3! It has a forged trunnion, forged bolt, and forged carrier all for a very affordable cost. I got a GF3 a few days ago and I’m in love with it 🥰

this video single handedly got me into Brandon for years to come

i love the white board of knowledge. i always learn so much. keep em comming mate!

It's good to know that Gen3 PSA,the current Riley Defense are both using forged trunnions,bolts and bolt carriers.Both passed the AK Operators union 5000 rd test with flying colors.I'd still opt for a new Wasr because of the CHF barrel.

8:00 for "Too long, didn't read version."

such a more humble & informative Brandon.

Great educational video on something ,all gun enthusiasts should know , safety as well ,good lighthearted presentation , keep them coming

I enjoy my ras47, but I'm only ~800 rounds into it. I'll purchase a headspace gauge next payday. Can I replace the cast parts without having to form a new receiver? If so; would a Romy G parts kit potentially be a good component source? I assumed that "made in USA" would mean sexy akm without 922r restrictions. Instead of passing a potential disaster to another end user, I'd like to correct this machine's deficiencies if it makes more sense than taking it out of service. Thank you for your time and for any leads on reliable information.

Stay true to the big Q..... classic mechanical engineering will always be best.

The Maximum Effort Deadpool shirt...perfect! Great informational vid

Your Last Minute Or So At The Whiteboard Is The Man I TRUST & Tune in For

7:23 I just bought a PSA AK-P with a hammer forged front trunnion for $719. I'm impressed with it.

Awesome video dude. I love this type of content. However I've got a quick question. What about Century's milled AK rifle? Would this theoretically hold up better than their stamped AKM clone since it has a milled receiver?

You had my laughing in my car while I drove to work this morning. Funny but very informative. Subbed

Love all the info brother!!! Can’t wait to get an AKG for my newly started AK collection

As an individual who is a visual learner, I'm a fan of the white board.

Sooo when do we get vibranium forged parts.

Excellent explanation Brandon! PSA is now forging the important parts in their GF3 Rifles. Hammer Forged Front Trunnion , Hammer Forged Bolt, Hammer Forged Carrier. They run $599 MOEKOV or less (Blem) for GF3 rifle versions.

Awesome video, love this in depth type of info

Subbed. Paul Popov told me to

I bought a wasr10 & detailed cleaned it. The next day I noticed rust on the front barrel . I emailed century customer service & wanted to know if I should send it in. Or in the long run ,cericoat it In my local area & just go that route. Do they correctly fix issues or just add more bs? & just hope it doesn’t get noticed? Thanks for the schooling of the platform. 👍🏼 paid $750 on 3/19

Concise explanation. Enjoyed it.

Thanks for explaining why high-end forged knives seem to hold an edge a bit better then their hardness would indicate!

What about Wasr10 ??

You are generally right, that forged is best, but it's not true to say that cast components are garbage. First off your claim that cast parts do not have a grain structure is absolutely false, cast parts absolutely have a grain they're just more complicated. They usually grow from the cooler regions of the cast part towards the warmer regions. You can actually very very strong parts if you control this. Cast parts have regions where temperature variations as well as shrinkage can change grain structures, which must be controlled with various techniques. Second off, it's not like all cast parts are bad. Even the soviets switched to cast components in the 70s, izzy front sights, rear trunnions gas blocks, trigger components and a few other non pressure bearing parts where cast. Early chinese AKMs (Reverse engineered) used cast front trunnions as well, until they purchased soviet tooling. There are good cast trunnions on the market right now, like WBP from poland, they've been making cast trunnions for years and it's not been an issue, rob ski put it to the 5000 test and found no issues in the cast trunnion region. Third off. There are cast guns currently on the market that have no (strength) issues, ruger mini 14, Springfield m1a, etc. These guns have no issues as far as strength goes, and consider the AK lockup is derived from the m1 garand, so this is as close to an apples to apples comparison you can get. And finally before anyone calls me a shill for whatever, i exclusively build from eastern European parts kits, currently Romanian RPK. The problem specifically with american casting is the cost part, controlling casting grains is actually pretty expensive, the cost diffrence between high strength casting and just forging it is pretty negligible, the cost saving comes from less spindle time and tooling required because casting can make more complex parts. Importantly, no one has ever made a good cast bolt or carrier, which probably means something. However, for specifically trunnions casting is a valid technique to produce, IF DONE RIGHT. Ofc, american manufactures are trying to hit a price point so they can't do it right, which makes the public more weary of a technique which is perfectly valid but applied poorly, and so you end up with people turning their nose up at a whole manufacturing process. It's like if american manufacturers skipped heat treating to save money and people turned their nose up at all billet parts. It's equally silly.

Informative, Humble, passionate and funny.....good job done

I absolutely enjoyed and learned from this. Thanks!

Love those educational vids !!!!!!!

Like your teaching style. Love you morals. Your printing is just fine.

Thanks for the info , very helpful .

Thanks for explaining that. I'm still new to the AKM realm as I bought my AKM about 2 years ago. When o first started looking around for one I considered an American made AK but I'm American and why not support an American company. I had a friend who works at my local gun store warn me about low cost AKs. I continued to shop around and found a Romanian SAR1 wire side folder used but for less money than the American made AKs were selling for.

I already made the mistake of getting a C39v2 as my first AK, but oh well, live and learn, definitely interested in picking up one of your AKG's in the future.

An honest salesman. My hat's off to you, sir.

Oh, man! Mentioning Paul by name. My AK guru!

The more I watch from you the more I like it.

Nice video, good basic breakdown on the differences

so many love comments. nice. anyway, billet or forged, i plan on buying one. however what i think would be a thing to do if ya get big enough, is like go for like forged if ya can as like a higher tier option ya know? idk. either way have fun man. cant wait to see what ya turn out.

Good video man. Learn a lot. Thanks

Great metallurgy class Thanks Brandon 🤘🏼

New to the AK world to be honest. I’ve shot all my life, and have shot AR platforms (deepest apologies, Mr Brandon) for decades' since my first trip to the rifle range in boot camp a thousand years ago. On top of doing repairs for people I knew, I have built probably a couple dozen AR-15s in the past 7-8 years for friends or people that friends have sent to me. Im a disabled Paramedic, so doing the repairs & builds gave me something do and something to sort of lose myself in the details of, along with that dreaded pursuit of perfection you begin to feel as you see your own skills and potential improve. What you said about lower end companies taking advantage of people really got to me. Whether it’s just dumb luck or rather the fear of letting someone down (or possibly injuring or killing someone)... I have not & will not give someone a firearm that I’ve worked on if I would be even the tiniest bit uncomfortable letting my son run a thousand rounds through it. It’s a responsibility and really a genuine fear of handing something potentially dangerous over to someone knowing that I might have exponentially raised that danger. I’d much rather have a catastrophic failure happen to me rather than give someone else even a possibility of one. I’ll never be a huge business or manufacturer. For most jobs I did them at cost + exactly one beer after taking them out to shoot it for the first time. Being a ‘business’ was never really even a thought, and maybe because of that I shouldn’t be so judgmental towards a company wanting to save a bucks here or there. But I can’t really stomach the idea that this happens. If not for the joy and satisfaction of knowing the level of detail achieved & the feeling of accomplishment in seeing someone enjoy it... I don’t know if I’d still be here today. It’s a purpose that wasn’t really there for me for awhile prior to that. Just the thought that there are people out there who allow substandard & potentially dangerous crap to go into someone’s hands, only because the buyer couldn’t afford to or didn’t know how to find or get a decent rifle - well, that eats at me pretty hard. Money is important. We’ve all learned that it’s an unavoidable truth. But how much is saving a few bucks really worth knowing that you’ve sold a rifle to someone that is going to have it most likely fail them? Or at the very least, having it & shooting it end up NOT be enjoyable to them? The nicest thing I can think is that they’ve maybe turned a weekend shooter into a guy or girl with a $600 rust & dust accumulater. Because they couldn’t afford a more dependable rifle, had the misfortune of coming across a shady dealer, and now can’t even part their rifle out for a few bucks because it’s built with crap parts. Sorry to be so wordy. It’s only that your message here really got to me. We are a bit of a beleaguered community that is back under attack from those who want to take away a pleasure of ours that they’d rather portray as something horrible. You’d think we’d try to take a little better care of each other than that. At any rate. I’ve always had a sort of nervous curiosity of the AK world. The whole Sov-Bloc “bag guy guns” mystique laughably kept me at arms length. But I’ve REALLY enjoyed your content & the amount of information you’ve provided me I could never thank you enough for. I’ve always really enjoyed the level of detail that firearms & ballistics can involve, and I can often see in your face that you have a similar level of enjoyment. You seem to get it in a manner that strikes me as pretty similar. So thank you... not only for all you’re doing, but just as much for how you’re doing it. Now for my bedtime scotch, and a little light reading from Hatcher’s Notebook. 😂 Be well, God bless, and take care. (Again, sorry for the mentions of ARs)

Thanks for the info and more videos like this would be great.

Awesome. Thanks for this! I learned a lot.

I use to shoot a lot and I am an AR guy. I guess I am three times a month type of shooter now and just got into the AK market and I just picked up a Sam7 pistol from arsenal. I haven’t shot it yet and plan for some work to it to be done but it does feel nice.!! And I am looking forward getting one of your AK’s in the near future.!!! And thank you for the lesson , I read buyers reviews and listen to RU-vid a lot and got lost on what type to own or trust and I rather pay more for a better product because I plan on passing it down the family line.

My Zastava m70 zpap has all forged trunions and barrel. So far 1000 rounds and it runs perfect. If ammo ever comes down I’ll run a lot more. Love it. Just subscribed

I had no idea they actually forged those trunions. Good info, Herrera.

Please do more videos like this, but can you do a similar video but on the topic of building your own gun, in such as laws and tools from basic, to moderate to hella high expenses.

Great explanation. Thank you.

Glad my AK is made with surplus parts. Important parts shouldn't be cast. Trunnions, bolt and carriers should always at least be milled. Now front sight blocks might be OK to cast to save a few bucks on a budget build but certainly not parts that will send you to the hospital if they fail. Thanks for putting out this public service message!

This video got me to subscribe. I'm honestly afraid to buy any AK made in the US without looking through a ton of reviews. I nearly bought a Pioneer Arms AK awhile ago, put it on layaway, took it off layaway after seeing that it couldn't get past 500 rounds before the shit trunnion caused very dangerous head spacing problems.

You've come a long way padawan.

This popped up on my feed. I enjoyed watching it again, I'm such a nerd.