I've done reading, and I know some general premises, but I'd like to learn more about how some of them work. For instance, I've read about bolt action operation, and I know K98ks have two large lugs (forget if rotary or locking) What are lugs? What do they look like and what do they do?

 

Also, I'd like to learn more about the mechanics of automatic firearms as well, we all hear that AKs are reliable due to their piston-based system, but how does it work and what makes so much more efficient?

 

I've seen some gifs and images online, but I'm still curious to learn more about how this stuff works, so I can repair my own stuff better, or design stuff, or whatever. I feel like it would be useful to know, but I'm not sure how to learn.

You can learn a lot from forums like this, friends, NRA Safety classes cover the basics.

There are a number of books about home Gunsmithing that will teach the mechanics and terminology.

When you remove the bolt of your Mauser, there are two block like things that extend from the sides, up near the front. These are the lugs.

AK's have loose tolerances (free play between parts) which also adds to the dependability. The mechanism can handle dirt between moving parts without the dirt creating enough friction to stop the parts from moving.

Tales of the Gun, series from the history channel, has a number of episodes that are devoted to a particular gun or designer, these give a lot of info on guns.

There are many many many resources available. If you can learn the basics, then you will be able to understand the specifics of the different guns when you encounter them.

in addition to loose tolerances on the AK platform, the piston system keeps a lot of the gasses out of the mechanical portions of the firearm. not all of it, but far more than say an AR-15 where the gases themselves are blown directly into the bolt carrier group to push it back. this results in a lot of carbon build up if you don't clean it well. i have heard you can shoot an AK with out lube or cleaning for thousands and thousands of rounds without a malfunction. try that on an AR

 

i would check out youtube. if you have some mechanical apptitude you can just watch some detailed take down videos of any gun you want and usually by looking at the parts and their locations you will be able to see how they work together. theres also some cool articals stickied in the AR forum on this site about twist rates, which will also link you to an article about the length of the DI gas system on ARs. different length tubes for different lenth barrels. i'm not really an AR guy but i thought it was very cool and informative.

Hmm... I've assembled an AR lower, and understand how that works, the part that typically gives me a hard time on automatics is how the BCG of a gun interacts with the trigger groupings. I know the AK uses some sort of rotating mechanism?

 

 

I love tales of the gun, I watch, and pretty much have watched, any sort of gun-related programming available on Cable.

 

What books would you guys recommend?

i'm not 100% sure but i don't think there is any difference between a semi auto and full auto BCG on an AK. the full auto portion comes from one or two extra components in the fire control group. one is a sear, which can provide select fire by itself. all it does is hold the hammer in place until the BCG is all the way forward then it releases, and since the disconnector is held up by the selector switch in full auto mode the hammer flies free. i forget what the other part is called but it basically slows down the rate of fire by holding up the hammer for a fraction of a second after the sear releases. this second part is not necissary for a full auto AK.. i think the first milled russian ones did not have it, nor do the chinese type 56. rate of fire is 800 or 850 per minute without it, 600 to 650 with.

 

the AK does utilize a rotating bolt design, but this is just the "lock up" mechinism, similar to moving a bolt action forward and then down.

 

if i am wrong on any of this, please, someone correct me. i'm still new to all this myself, this is just how i understand it.

I should have specified, by automatic I simply mean any repeating firearm that uses recoil or gas pressure. Might be an out-dated term since people typically associate them with full-auto. I guess I just get that term from poppop.

 

But yeah, I mainly meant semi-auto, since that's where the most practical stuff I could use this knowledge for.

the cool thing about AKs is you can work the action and even shoot the gun with that top dust cover removed.

is a video showing how the carrier interacts with the fire control group. the bolt itself doesn't actually touch the hammer, its just the carrier that pushes the hammer back and the disconnector holds the hammer in place. when you release the trigger the disconnector lets go of the hammer and the hook (or hooks) on the upper part of the trigger itself catch it, making ready for the next shot.

Heres a good visual aid to play with on how a AR works http://www.bushmaster.com/anatomy_bushmaster.asp

I guess acuevo pretty much said it, but full and semi are the same on these common closed-bolt gas-operated weapons, essentially the only difference is a semi trigger group has an additional piece that will catch the hammer after the bolt carrier recocks it. That extra piece forces you to release the trigger so it can fall a short distance and be caught by the sear.

 

EDIT: I see the OP asked about locking lugs in general...most, if not all, centerfire guns that are breech loaded have a locking system, and many rifles use a rotary lockup, whether its operated by your hand (bolt action) or a cam in the operating group (semi).

 

The lockup is necessary because high pressure centerfire rounds cannot be contained by just the recoil spring so the locking lugs in the bolt carrier get held by the lugs in the barrel. When the gas system pushes back on the operating group the first step is to unlock the bolt (with a slight turn) and then things start moving. The bullet pressure when fired only pushes straight back so it can't get the bolt to turn, which is why the action stays safely locked until the pressure drops.

 

Hope that didn't muddy the waters.