blowback or recoil operation

gotstolefrom

In describing auto firearms, could someone explain the distinction between "blowback operated" and "recoil operated" ?

Thanks

Jim Rau

In the 'blowback' the bbl is not locked to the slide. This is common in small cal like the 22 RF and etc. The pressure is used to cycle the action. In the higher pressure cals the bbl and slide lock together and when the slide travels back slightly they unlock. This is nessesseary to keep the case in the chamber alittle longer due to the higher pressures. The Browning Short Recoil action, like the 1911, is the most common but there are others that are used as well.

Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska

v35

There's also short (1911, Luger) and long recoil operation ( Browning SG and artillery) as well as variations in blowback operation like delayed blowback ( Remington 51).

bobski

and to go a little further, look at it this way....for every action there is an opposite and equal reaction. when the bullet in a 22 goes forward, the case goes backward and is ejected from the gun...as it blows back the slide too. (hi standard/ruger mk2/winchester 50) so its action reaction, bullet vs. case. on a recoil action as the bullet or shot leaves the 'muzzle' the whole gun 'recoils' from the blast. so its action reaction, shot vs gun. to capture some of this valuable energy, certain operations of the gun tap into its reseviour. for instance, the bbl is mounted in grooves and has a spring installed. as the bbl slides back and recoils after the shot leaves the gun, it pushes the bolt back and operates the action for reloading and ejecting. (ak-ak or pom-pom guns, browning A5/remington 11-48) thus the two 2 types are explained. blowback and recoil has been around a long time and are prefered in european designs and have been adapted by american designers too. gas....is an american design. trapped gas pushing piston moves bolt. action reaction, bullet or shot midway down bbl venting pressurized gas thru port vs. piston. hope it helps.

former air operations officer SEAL Delivery Vehicle Team 2. former navy skeet team, navy rifle/pistol team member. co-owner skeetmaster tubes inc.. owner/operator professional shooting instruction.

rhmc24

As stated above, .22 rimfires semi autos are of the blowback type. Blowback also in the smaller centerfires such as .25, .32 and .380 autos plus a few 9mms. In the higher powers blowback is less practical, requiring a heavy bolt, slide or very strong recoil spring to handle the higher forces involved.

bobski

look at an old winchester 351 or 410 cal rifle. there were exceptions since many recoil operated guns of the times were patented and could not be copied. thus...numerous winchester large cal guns had to sidestep brownings pat.!

bobski

looking back at the posts i noticed someone said the 1911 is a short recoil action. may i challange that? the bbl is afixed to the frame thru the means of the mag catch lever which goes thru the bbl lug on the underneath of the bbl, making the bbl part of the frame. when you cycle a 1911, the bbl stays fixed. its loose...but fixed. proof is the bbl pops out the front of the gun when you pull the slide back. if it was a recoil action ,the bbl would move with the slide. the slide moves, not the bbl. thus the action reaction is bullet vs casing. as the bullet goes forward the casing flies back and it begins the cycling procedure. therefore...its a blowback. cycling begins once the bullet is fired. this is why experts will agree that having a 'matched gun' is so important; its also what you are suppose to be paying for when you buy a high dollar race gun, (since the bbl is actually moving before the bullet leaves the muzzle.) if the bbl band and bbl are not matched tightly, the bullet can actually go off course because the bbl is moving off center during the bullets travel down the bore. and too, this is why a slide needs to be lapped into the frame rails to ensure it has no side movement during cycling so the bbl band keeps the bbl straight until the bullet leaves. so...the 1911 is a blowback folks.

former air operations officer SEAL Delivery Vehicle Team 2. former navy skeet team, navy rifle/pistol team member. co-owner skeetmaster tubes inc.. owner/operator professional shooting instruction.

Jim Rau

The 1911 is the classic browning short recoil action. The Bbl moves with the slide for a 'short' distance to unlock the action. Am example of the long recoil action in a sporting arm is the Auto-5 shot gun and in a machine gun is the M-2 50 BMG.

Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska

bobski

yes...but, the interesting argument is...where does the action/reaction take place? at the muzzle or the chamber where the brass and bullet seperate? if it was a recoil operation, the bullet would have to be past the muzzle for there to be a blast to push the spring loaded bbl, bolt, and gun back. (in this case, bolt and slide are one.) i/e: a civil war cannon doesnt jump until the ball has left becasue the wheels are chaked. since there are no springs to absorb the blast if it wasnt tied down or chained down it would 'blow backwards and run the loading team down. howitzers are recoil operated. granted, i wont argue john brownings pat., but the 1911 bbl ...(which moves only the length of the bbl pin) and slide, travel away from the bullet while its still in it. the hot gases are 'blowing backwards,' thus its my claim that its a blow-back. follow me? again, i wont argue brownings pat. but my argument for sake of debate is if its recoiling (def: recoil: to spring back,)'everything' must recoil from the bullet. the instant the short recoil ceases, it becomes blowback the rest of the way in order to finish the cycle. follow me? [;)]

Jim Rau

Well not realy. The rearward motion does not start until the bullet and hot gas exit the bore to start the 'recoil'. The recoil imparts the energy to operate the action. The lock-up remains until after the bullet and gas leave the muzzel to contain the pressure. The momentem (energy) in the slide continues the movement, not the gas pressure. The movement of the bbl is stoped by the link after it unlockes in the 'short' recoil action, but in the 'long' recoil action the bbl continues rearward with the bolt/slide. But the bottom line is the ineritia of the slide is what operates the weapon, not the gas pressure as opposed to a true blow back action.[;)]

Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska

bobski

as long as the rearward motion begins after the bullet leaves, then its a recoil operation. im sure you saw mu point. i was always taught that the bullet is still in the bore when cycling begins, thus the importance of holding it steady. im talking just the length of the bbl tip and the bbl band distance. but thats all it takes. follow me? its really spliting hairs, but oh so interesting none the less. agree? hard to believe the simplicity of the design from such a man 100 years ago. i hope our 1st poster is following along~!

v35

I have a full size xray photograph of a 1911 with a bullet inside the barrel within a 1/4" of the muzzle. If the slide has moved at all, it hasn't moved more than 1/16".

Jim Rau

If it were to move even a fraction before the bullet exits the bbl you have a very inaccurate weapon!! The science of internal ballistics is very interesting.[^]
And yes iit is very profound that JB could have such a lasting influnce on weapons design even today.[^]

Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska