"Open Bolt"?

[No1_sonuk]

What does "open bolt" mean WRT GBBRs, and why are people raving about it on guns which are closed bolt in real steel?

[demoncase]

Re: "Open Bolt"??

The 'open bolt' airsoft guns appear more like the real deal, as they look more realistic as they cycle....For those in seach of the last word in realism. (And For those who spend their games gazing not at the target but into the chamber of their gun as they shoot )

In real steel terms, closed bolt self-loading weapons are inherently more accurate than open bolt ones....Because for when it really matters, accuracy is all.

[guard-sniper87]

Re: "Open Bolt"??

Bingo, open bolt just allows you to see the actual chamber and bolt fly backwards :P

its just a fancy term airsofters use mate, basically ignore it all, if it shots loud and hard its nice

[BigAl]

Re: "Open Bolt"??

In airsoft terms the open bolt refers to the WE GBBR. When theybfirst came out they had a brass pipe in the breech as part of the design. The WA GBBR's didn't have these and wher therefore more realistic. WE Subsquently modified their mech to do away with the brass tube, this is refered to as the Open Bolt system.

With reference to firearms the term open bolt refers to how the weapon cycles. an open bolt gun would generally be something like a sub machine gun. When cocked the bolt stays in the rear position until the trigger is squeezed, then it flies forward strips a round from the mag chambers and fires it. It then ejects the empty and stays locked back unless the trigger is still held in which case it wil continue to cycle until the trigger is released or the mag empty.

A closed bolt weapon is more complex. When cocked the bolt will move forward and load the round into the chamber but will not discharge until the trigger is squeezed. This is a lot more accurate than open bolt and better for slower accurate fire, open bolt is best for less accurate but rapid fire.

[tisane]

Cant get any better description than that ^^^^

[hoggy21]

Re: "Open Bolt"??

Examples in the real world:

GPMG is open bolt. The bolt and firing pin sit at the back of the weapon until pulling the trigger, which send the bolt, block and firing pin forward, forcing a round into the chamber. The firing pin then strikes the percussion cap, firing the round and recocking the bolt and leaving it at the rear.

SA80a2 is closed bolt. The bolt carry assembly (containing the firing pin) is pulled back and released, leaving it sat at the front. When the trigger is pulled, the hammer in the trigger mechanism housing (TMH) strikes the back of the firing pin, and the pin then strikes the percussion cap. Gas discharged from the round propels the round down the chamber, with a small portion of the gas being pushed into the gas block. Said gas then enters gas plug, forcing the gas cylinder back, forcing the gas recoil rod back, and ultimately forcing the bolt carry assembly (still containing firing pin) backwards. Part of the bolt has two parts of metal on them, one which grabs the fired round, and the other which helps project it from the weapon. Once the bolt carrier reaches the back of the rifle, the recoil rod assembly forces the bolt back forwards, whilst teeth on the bolt push a new round from the magazine into the chamber.

In airsoft terms, the brass tube in a closed bolt system means when a magazine is fitted, the feed tube on the top of the magazine will sit inside the brass tube. In an open bolt weapon, the whole system in the gun will move backwards and forwards.
I know its a long winded explanation for something which has already been explained, but i thought knowning about the real world versions might make it a little bit easier to understand for anybody else reading this in the future!

[BigAl]

Re: "Open Bolt"??

^one minor thing mate, it's a primer not a percussion cap.

[hoggy21]

Re: "Open Bolt"??

Primer / percussion cap is the same thing.

Wikipedia:
CartridgesSee also: Cartridge (firearms)
A major innovation in small arms and light artillery came in the second half of the 19th century when ammunition, previously delivered as separate bullets and powder, was combined in a single metallic (usually brass) cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. The main technical advantage of the brass cartridge case was the effective and reliable sealing of high pressure gasses at the breech, as the gas pressure forces the cartridge case to expand outward, pressing it firmly against the inside of the gun barrel chamber. This prevents the leakage of hot gas which could injure the shooter. The brass cartridge also opened the way for modern repeating arms, by uniting the bullet, gunpowder and primer into one assembly.

Before this, a "cartridge" was simply a premeasured quantity of gunpowder together with a ball in a small cloth bag (or rolled paper cylinder), which also acted as wadding for the charge and ball. This early form of cartridge had to be rammed into the muzzleloader's barrel, and either a small charge of gunpowder in the touch hole or an external percussion cap mounted on the touch hole ignited the gunpowder in the cartridge. Cartridges with built-in percussion caps (called "primers") continue to this day to be the standard in firearms. In cartridge-firing firearms, a hammer (or a firing pin struck by the hammer) strikes the cartridge primer, which then ignites the gunpowder within. The primer charge is at the base of the cartridge, either within the rim (a "rimfire" cartridge) or in a small percussion cap embedded in the center of the base (a "centerfire" cartridge). As a rule, centerfire cartridges are more powerful than rimfire cartridges, operating at considerably higher pressures than rimfire cartridges. Centerfire cartridges are also safer, as a dropped rimfire cartridge has the potential to discharge if its rim strikes the ground with sufficient force to ignite the primer. This is practically impossible with most centerfire cartridges.

I'll have a look tomorrow in Pam 5 and check to see what the book says. Dont like wikipedia because its normally people who think they know what theyre talking about, but normally dont.

Edit: The bold isnt to state a point, its to highlight the bit needed for ease of reading.

[hoggy21]

Re: "Open Bolt"??

I lie. Percussion cap is on ther bottom of the round, the primer is inside and ignited the gunpowder. Missed the edit by about 20 seconds because of a phone call.

[No1_sonuk]

Re: "Open Bolt"??

Primer / percussion cap is the same thing.

Seconded.
A percussion cap is a primer, but a primer doesn't have to be a percussion cap.

[seansamurai1]

Re: "Open Bolt"??

Cordite, not gun powder :D

Open bolt in real world applications also minimises over heating issues, a major issue on the M4/M16 when on full auto, there is a modded M4 that uses an open bolt system, its so effective that after 30 rounds of full automatic fire, you can actually touch the bolt without burning yourself, try that on a standard M4.
Im wondering if open bolt on a GBB works a similar way, just minimising cooldown instead as it allows air to circulate when being fired and when primed but not shooting.

[No1_sonuk]

Re: "Open Bolt"??

Cordite, not gun powder :D

Not necessarily.
The first metal cartridges had black powder in them. Cordite isn't a powder, either. It's extruded like pins.
So actually "gun powder" IS a more accurate description of the currently in-use smokeless powders.

[seansamurai1]

Re: "Open Bolt"??

Its called ground up cordite, its used instead of gunpowder as its more stable, all but smokeless, is less prone to failing when damp and safer to manufacture, also cordite has a much more stable yet vigourous burn making it more suited to fireing projectiles at high speeds. It also stinks and people who have girlfriends/boyfriends at home always know when you have been shooting that day, it makes yer parp smell like cordite . thats no joke either.

[hoggy21]

Re: "Open Bolt"??

it makes yer parp smell like cordite . thats no joke either.

Seconded. I know that feeling and that smell. LWP and Cordite. Its what real men smell of!

Having split a round or two in the past, it is granules. Well, British rounds are anyway lol. The granules look like small flat discs, and may be cordite or gunpowder, i dont know, and dont really care The end of the day, i know when i pull the trigger, 'nearly' all the time the round goes off.

[Caveira]

Re: "Open Bolt"??

Guys, back on topic please. I know this just sort of went off on a tangent, but I'd rather not have to clean the last 8 posts unless I have to.

Cheers

Robin