why is this space in front of the gas ring?
as far as i can tell it does absolutely nothing,
but obviously it exists for a reason.
it definitely isn't to lighten anything as the bolt carrier and buffer are meant to be heavy.
why is this space in front of the gas ring? as far as i can tell it does absolutely nothing,
it scraps the carbon off of the receiver, hence the self cleaning of the ar15
it's inside the carrier. that doesn't make any sense.
the only thing "self-cleaning" is the gas tube. you still have to clean the rest of the gun.
Lmfao. Idiot.
There is probably still some higher pressure gas that went around the rings and will escape through the vent holes.
I wouldn't know for sure but it keeps the gas rings the larges largest part of the diameter and I would hypothesis has a role in clearing extra gas.
It's where the gas expands. The bolt of an AR system acts as a piston, hence gas rings
no, it isn't. i labeled where the gas expands, which is behind the gas ring.
that's why the gas ring is where it is.
My guess is still that it helps evacuate the gas that leaked around the gas rings. When the bolt is closed, I believe that space is open to the outside via the vent holes in the carrier.
This does make some sense as any carbon being scraped by the rings will have a place to go.
I want you to look at that picture and think real hard about this. Why would you look to expand gas in a space that is rigidly fixed front and back?
more of the carbon would be behind the ring and therefore when scraped would also collect behind it,
because that is where the gas is expanding in the carrier.
and again that's not what was described as self-cleaning anyways.
the concern was you could not clean the gas tube with any sort of field tool.
the hot gasses clean out fouling from the previous shot,
so therefore it is "self-cleaning" IF you use a specific type of gunpowder.
this is why there was so much trouble in vietnam with it,
but that's another discussion that i don't care enough to have.
You misunderstand. The rings are there as a gas seal. The rings are scraping the inside of the carrier. Having a cavity on both sides is going to help clear debris from the rings. I'm not the "self cleaning" anon. I'm just pointing out that there is a relatable possibility to the cavities purpose.
My theory is that it's for gas evacuation after the bolt closes but I have no proof of that. Just pure cold logic.
i know what he said. do you understand what i said? that gap wouldn't help with scraping even if that was the reason.
>more of the carbon would be behind the ring and therefore when scraped would also collect behind it
But some of the carbon is going to remain, and the bolt is going to move forwards and backwards every time it unlocks. Make sense to have places for excess carbon to collect in both the front and back of the seal.
>why is this space in front of the gas ring?
Gas rings don't seal as well without low pressure behind them. In fact, even if the gas rings weren't there at all you can make the piston "seal" better by providing volume for the gases leaking past the piston to expand into. Look at an AK piston for example. It doesn't even have rings...but it has grooves.
...and if that area were tightly fitted inside the bolt sleeve it would be more likely for it to get stuck together with fouling.
That's the right-hand side of the pic, genius.
many 74 series and those iterated on it like saiga have no grooves.
And they don't seal as well. Did you have a point to make?
who says they don't?
>who says they don't?
People who understand how the grooves work. Ringless pistons are well known to engineers, though maybe they're some secret sauce to the morons here.
ok so you don't actually have any information about aks that don't have grooves.
besides, car piston's don't have these substantial voids behind their rings like the AR bolt does.
they have grooves but the grooves are filled by rings, so it really isn't like an AK piston either.
*car pistons
dunno why i put the apostrophe there
ICE pistons form an oil barrier. That's what the oil control ring is for
so then what piston has those big concentric channels behind the ring like an AR bolt?
None. They don't need it, and what's more is that the skirts are needed to prevent the piston head from rocking in the bore. The oil barrier helps form the gas seal, ar's don't have that reliable of an oil barrier
so where are you getting this information that lower pressure gas actually keeps higher pressure gas out? because that seems completely contrary to physics.
the whole reason the gas can propel a bullet is because the ambient air in the barrel is lower pressure and doesn't impede it.
same for the ambient air in the gas tube.
I'm not that anon, I was just pointing out that an ICE pistons is a bad example for reasons mentioned above. They aren't really comparable
that's what i'm saying. this feature isn't really relevant to containing pressure which is why nothing uses it for that purpose,
because that isn't the feature's purpose to begin with.
Any gas operated guns bolt acts as a piston, it's incredible how people just parakeet talking points they read.
Is it not just weight reduction?
Sorry, I mean more about tuning the weight, rather than just reducing it
Like the other guy said, only place on the bolt to tune weight. Looks specifically like it does because it's done during the same turning process as the bolt tail.
yeah and that doesn't make any sense because the weight difference is so insignificant and the bolt is rotating, not moving rearward during unlocking so it makes even less sense.
plus piston ARs don't have it, even though their carrier and buffer mass are otherwise identical to a standard AR (excluding bufferless designs).
The bolt is moving forawrd at the start of the unlocking cycle.
The piston bolts don't have it because they cut out the mass of the tail instead.
more realistically it is held forward. the carrier moves rearward.
no expansion chamber = no tail.
Before the carrier starts moving the lighter bolt will move forward a small amount.
The tail is still mass. Without the tail there is no need to cut a groove to lighten.
they don't need to lighten it to accomplish that in the first place.
the gas will hold it forward regardless.
because it weighs significantly less than the carrier,
it will always be held forward prior to the rearward carrier movement.
you contradict yourself when you say they cut off the tail to maintain the same mass.
piston bolts are not acted on by the gas to begin with, so that detail is irrelevant.
plus the carriers of piston ARs are actually heavier because they lack the expansion chamber, so the overall weight difference with vs without the bolt groove is totally negligible.
>piston ARs don't have it
Well now I'm 100% convinced I
was right.
how is this the case if the gas rings prevent gas from escaping?
if there's excess gas, the gun will simply run more violently.
it isn't capable of acting as a self-regulating gas system.
although i'm sure you could alter it to behave in such a way which would be very interesting.
i know there are tunable bolt carriers.
Who told you the gas rings prevent gas from escaping?
the whole point is that they seal the expansion chamber so that the gas doesn't just spray out the front of the bolt
i'm saying there is no excess gas. that doesn't really make any sense. whatever is needed to run the action efficiently is not in excess unless it is overgassed.
you would not design a gun to simply spit gas for no reason. there can't be magical extra gas that has no effect on the action.
what you are saying is that the cut in the bolt exists to collect gas simply for the sake of collecting gas.
but the gas rings exist to keep it behind that area so how is a bunch of high pressure gas getting in there?
Gas rings ain't perfect anon. They keep enough gas contained.
the bolt moves dude. think about how the bolt moves inside the bcg.
It goes past the gas rings as we said. The BCG couldn't move how it needs to in the environments and dirtyness it needs to if it formed a perfect seal. You are dumb, to imagine that seal is perfect. And even everything has already been explained in this thread. The weapon needs an operating range. It's a weapon of war.
When I say excess gas I am not meaning the gun is over gassed. Also the amount of excess gas changes over the life the weapon, as the gas rings wear, and the gas port wears. The system has more gas inside it.
Yeah, I meant left over pressures after the gun cycles. I would imagine that cavity, which is aligned with the vents when the bolt is closed, allows any residual trapped gasses to clear out quicker. It might be significant on full auto. I don't know.
It allows excess gas to vent into it lowering excess pressure. Same idea as a bore evacuator.
probably gives a place for oil and crud to collect so the bolt doesn’t bound up if it happens. the design was probably chosen because it is easy to perform on a lathe, is easy to clean, doesn’t create stress points, and doesn’t ruin the strength of the part
thats to allow for, and to route, excess gasses to escape through the vent holes in the bcg.
bad diagram, in reality the gas rings move behind the gas key. just imagine the bolt moving further back.
>bad diagram, in reality the gas rings move behind the gas key.
Not him, but you are wrong and stupid. Stop posting about things that you don't know about and are easily looked up.
https://www.youtube.com/watch?app=desktop&v=Uv6a1hs9U5o
>moron fight
Stupid channel by dude with bad takes.
what's wrong with SOTAR?
He has bad takes on stuff.
He has bad takes on bcg coatings.
He has bad takes on castle nuts.
He has bad takes
that's 2 things.
>He has bad takes on BCG coatings
Rank the coatings order as you see it. He thinks NP3 and Chrome are top tier.
>He has bad takes on castle nuts.
He recommends staking steel end plates to steel castle nuts and to make sure the threads line up well if you mix brands. What do you think is superior?
> He has bad takes on stuff
I personally hate his whoring of FCD and SOLGW.
Ranking them in the first place isn't really valid when, like anything else, quality of specific product is what matters. For example, Nickel Boron done by Fail Zero is on a lot of high end stuff and has a hardness of 82 rockwell, harder than hard chrome. The entire argument that chrome is better than NiB is that NiB has to be made properly. Well, no shit. Here are some arguments that Nib is better. It provides a lower coefficient of friction resulting in less wear, particularly when dirty. It bonds most strongly to the metal. Yes, it has to be done right but that's not an argument against it. That would be like saying FN's chrome lined barrels are low tier because some makes do a shitty job with their chrome lining. Personally, I don't even have a dog in the race. Yes I have a Nib BCG but I also have other non-NiB BCG. I can't say I've had issues with any high end bolt carrier group.
Castle nuts, you need to stake them so they don't walk off. You aren't trying to weld them to the sun. If you use a torque wrench to properly tighten them, they aren't going to walk off anyway outside of maybe some abusive use. So, staking isn't rocket science. Do it but the ratchet nuts also work fine so long as you aren't taking them on and off a bunch of times. He holds up some worn to shit ratchet nut as an example of them being bad. Well guess what, you can't take a staked castle nut on and off repeatedly without needing to replace a part either. He's just circle jerking around his jigs and tool investments. I'm not saying they aren't nice. I am saying that he's a snob with bad takes.
Honestly, after those 2 videos, I didn't bother watching much more. The cut away bolt video that got linked in this thread is pretty good.
cont...
and to be clear, my complaint isn't even that he has opinions. It's that random anon will watch his channel and come here parroting him as if he's some kind of authority.
i think a lot of people will have the misconception that you can take off a ratcheted castle nut over and over because it's not staked.
I heard SOTAR and Sage Dynamics say it is a one time use item.
IDGAF, you can probably use it 2 or 3 times or even shim the detent to take it off without damage.
Regardless they're $40 bucks, include a QD attachment and it's not like mil-spec is something you would want to reuse either.
I don't see anything wrong with spending $40 to get a nice looking end plate that includes a QD mount and is easier to install.
>It's literally moronic or just trolling
Get better material, moron. The source of the photo and video (SOTAR) does not change the physical layout of the BCG that you are still WRONG about. The only issue with the diagram is that it doesn't show the bolt tail portion correctly, but that does not matter for the illustration.
>you are still WRONG about
No you are wrong for thinking I'm that anon. When I said moron fight, I was referring to you and him. Him for having such a bad understanding of how the DI system works and you for spamming that youtube channel like it's some kind of gospel. I've seen you post it in other threads. I know it was you. It's a channel full of opinions many of which are not good.
morons detected
>No you are wrong for thinking I'm that anon
OK, I see that now
>I've seen you post it in other threads. I know it was you.
Try some anti-psychotic meds
>It's a channel full of opinions many of which are not good.
OK, moron.
Overflow.
The gas rings aren't perfect at sealing the piston chamber.
So it is an overflow area that collects carbon so it doesn't get up into the cam pin and extractor.
it's literally just an emergency expansion chamber for any blow by from the rings, how effective it is, is the question you should be asking, don't be so autistic
It's basically this thing but a lil wider.
Gives carbon fouling a place to build up where it isn't harming anything and makes the piston more effective.
It's a failsafe so if you got a shitty gun with worn out gas rings it can escape through the ventholes without breaking your bcg