Buffer: Circle vs. Square

[Merry Ploughboy]

If you think this board is immune from "flame wars", you weren't here about ten years ago. I won't mention board names, but one of the participants has not been active for quite some time and the other one does not appear in the member roster.

 

As far as the buffer goes, Gen. John T. Thompson did design and patent "an improved buffer adapted to cushion shocks and absorb surplus energy...with an embodiment particularly adapted for use as a recoil buffer with firearms of the automatic and semi-automatic types". See, U.S. Patent No. 1,351,141, patented Aug. 31, 1920.

 

MHO, YMMV, etc.

[Motorcar]

If you think this board is immune from "flame wars", you weren't here about ten years ago.

 

I was here, maybe my memories faded from old age. I still don't like it.

[lightguy]

I vote for a motion to ban scrambles from the forum board. Taking cheap shots at experts and dragging on long jibberish posts that have absolutely value is annoying

 

 

No vote here.

 

Personally I don't mind conversations that"kick the hornet's nest" every now and then and in the first post he was just presenting an observation.

That observation led to this interesting discussion about how a simple thing like a Thompson recoil system really isn't that simple after all.

 

Here is JP Enterprises tweeking an AR15/M16 buffer/recoil system decades after the M16 design was set in stone;

[Adg105200]

 

I vote for a motion to ban scrambles from the forum board. Taking cheap shots at experts and dragging on long jibberish posts that have absolutely value is annoying

 

No vote here.

 

Personally I don't mind conversations that"kick the hornet's nest" every now and then and in the first post he was just presenting an observation.

That observation led to this interesting discussion about how a simple thing like a Thompson recoil system really isn't that simple after all.

 

Here is JP Enterprises tweeking an AR15/M16 buffer/recoil system decades after the M16 design was set in stone;

Yes, it's fine and dandy to have the usual banter on a given subject, and to have your own opinion on it. BUT, we shouldn't be pointedly calling people fool's or other names, or saying things about people's work, credentials, etc. It's ok to get fired up, but still possible to keep it civil at the same time. People shouldn't get so mad about others opinions or suggestions, when that's what this board is here for.

 

I mean this topic is a perfectly valid to discuss, just don't bash people who give their input after you ask for it.

 

My 2 cents.

 

Andrew

[buzz]

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. Your arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

Edited January 23, 2018 by buzz

[RChapman]

I want to try to develop the idea , since there isnt much space to work with at the back, the only solution without having change alot, seems to develop a new elongated buffer pilot who catch

 

directly the actuator flat area on the inside, hows that sound? i know its not alot of energy left, but my plan would not to be to try save the receiver who dont need to be saved, but to eliminate the kick.

 

Edited January 23, 2018 by RChapman

[Paladin601]

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

[Bridgeport28A1]

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

A Superball, now that is a childhood toy that I had not thought about in a long time. Thanks for the childhood flashback.

[buzz]

I want to try to develop the idea , since there isnt much space to work with at the back, the only solution without having change alot, seems to develop a new elongated buffer pilot who catch

 

directly the actuator flat area on the inside, hows that sound? i know its not alot of energy left, but my plan would not to be to try save the receiver who dont need to be saved, but to eliminate the kick.

 

test a.jpg

 

 

Not sure what you mean.

 

There's no way to eliminate the "kick" of the firearm.

 

picture if the gun was floating in outer space and nobody was touching it.

 

when the round goes off, the bullet and the gunpowder go left and the gun itself goes right.

 

the mass of the bullet and the mass of the powder times their velocity will equal the mass of the gun times velocity of the gun

 

M bullet x V bullet + M powder x V powder = M gun x V gun

 

the bullet will go about 850 fps, the powder will go about 4700 fps and the gun will only go about 20 fps because of the heavier weight of the gun.

 

since a moving object has kinetic energy, the kinetic energy of the gun is called "the free recoil energy" and this number is used to compare how hard guns kick.

 

no matter how many springs the gun has inside, the final rearward velocity of the gun and free recoil energy will be the same.

[buzz]

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

 

sure, why not?

 

The thing is, if you want to reduce the load on the receiver a lot, you need to increase the distance that the bolt is slowed down.

 

If you brake to a stop in your car in 1000 feet, the braking force required is twice as high as if you come to a stop in 2000 feet.

 

If you really want to make a change in the force on the receiver, you need to make the buffer much thicker.

 

The neoprene buffer that we use now only probably compresses by 1/100th of an inch. You want something that is thicker and squishier.

 

The problem is that squishy elastic materials dampen out a lot of energy, turn it to heat.

 

I would not make a real thick neoprene buffer, you'll just jam the bolt to a stop sooner and use the recoil spring less. The recoil spring is your friend.

[Adg105200]

I think what RChapman is getting at is using a 21 style pilot and essentially sort of making it into an extra spring loaded buffer for when the bolt reaches the end of the recoil cycle.

 

Andrew

[buzz]

The big mystery is what this means:

 

"And please Buzz, . I see your unproductive posts across many of the boards, "oh that's not gonna happen, too bad etc". It's a reoccurring theme. Pessimism isn't going anywhere. Go radius the sharp cut on your K frame and shoot it forever. You are more of a detriment to this community than ANYthing else."

 

This is the only forum where I use the username "Buzz", so if there is some guy named Buzz being a pain in the ass on some other forum, I can't claim credit.

 

I did a google search on "posts by Buzz" and I found a whole giant bussload of Buzzes.

 

Like this fancy pants guy:

 

http://thebuzzblog.hercules-design.com/blog/author/admin/

 

I found this guy on a pinball website, seems like a nice sort of person, gives blood:

 

https://pinside.com/pinball/forum/topic/saving-pinball-through-blood-donation

 

So I'm not really seeing all the negative and pessimistic posts by the guys calling themselves "Buzz". Seems actually like an upbeat sort of crowd.

 

Buzzes unite!

[Paladin601]

 

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

 

 

If you really want to make a change in the force on the receiver, you need to make the buffer much thicker.

 

The neoprene buffer that we use now only probably compresses by 1/100th of an inch. You want something that is thicker and squishier.

 

The problem is that squishy elastic materials dampen out a lot of energy, turn it to heat.

 

I would not make a real thick neoprene buffer, you'll just jam the bolt to a stop sooner and use the recoil spring less. The recoil spring is your friend.

 

Why not denser ?

[Paladin601]

 

 

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

 

 

If you really want to make a change in the force on the receiver, you need to make the buffer much thicker.

 

The neoprene buffer that we use now only probably compresses by 1/100th of an inch. You want something that is thicker and squishier.

 

The problem is that squishy elastic materials dampen out a lot of energy, turn it to heat.

 

I would not make a real thick neoprene buffer, you'll just jam the bolt to a stop sooner and use the recoil spring less. The recoil spring is your friend.

 

Why not denser ? something like this. (I am not going to even try to explain this, I will just screw it up)

 

 

https://en.wikipedia.org/wiki/Super_Ball

[Paladin601]

 

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

A Superball, now that is a childhood toy that I had not thought about in a long time. Thanks for the childhood flashback.

yeah, those things broke a lot of windows.

[RChapman]

you cant modify the buffe too much, the buffer component dimensions are precisely calculated

 

if you move the buffer forward more than 1mm from whre it is, the bolt wont catch the last sear. on the other hand, you have only

 

1.5mm of space at the back (1.5 is the max measurement, in which the blish lock pushes against the oiler pads, anything above 1.5mm of travel back will destroy your oiler pads... i dont think a total of 2.5mm its enough to

 

gently stop the run... an elongated spring loaded buffer pilot gently catching the actuator flat area, will makes the job!

 

or yes, that superball would do even better!!

Edited January 23, 2018 by RChapman

[buzz]

 

 

 

I welcome any opinions on any topic, as long as people don't start screeching at me like an angry fishwife.

 

If someone points out a mistake on my part, I figure they did me a big favor. I'm not too proud to take correction when it's offered.

 

This is actually a real good topic, who knows, maybe someone will come up with a miracle buffer.

 

The problem with this topic is there is no data and there are a lot of unknowns.

 

The way the bolt jerks around in there makes it hard to even come up with a comparative or qualitative statement.

 

The only thing i can come up with to say at this point is that the bolt has about 20 ft-lbs of energy and that's not a lot, it's practically nothing.

 

The gunpowder has about 1000 ft lbs of chemical energy, about 400 gets used to propel the bullet, the bolt picks up around 20, the rest is lost to the air as heat.

 

That's not very much energy, it's hardly anything. You arm can deliver about 17 ft lbs of energy with a 1 lb hammer.

maybe a Buffer made of "Flubber" or super ball material?

 

 

If you really want to make a change in the force on the receiver, you need to make the buffer much thicker.

 

The neoprene buffer that we use now only probably compresses by 1/100th of an inch. You want something that is thicker and squishier.

 

The problem is that squishy elastic materials dampen out a lot of energy, turn it to heat.

 

I would not make a real thick neoprene buffer, you'll just jam the bolt to a stop sooner and use the recoil spring less. The recoil spring is your friend.

 

Why not denser ?

 

 

what you're trying to do is lower the accelleration force on the bolt

 

if you lower the force on the bolt, you lower the force on the receiver.

 

the softer (or weaker) that the spring is, the more it will compress when the bolt hits it

 

the more it compresses, the longer time it takes for the bolt to stop

 

the longer time it takes for the bolt to stop, the lower the force is

 

 

if you were bungee jumping, would you want to use a real stretchy bungee cord that took 30 seconds to slow you to a stop, or a real stiff one that jerked you to a stop in one second?

 

same job, different amount of force used

 

the weaker bungee might take 100 feet to stop you, but the stiff one only takes 2 feet.

 

 

so if you want to stop the bolt with less force, you need a thicker buffer that's made from softer material.

 

The ideal thing would be to use a stiffer recoil spring that stops the bolt 1mm away from the buffer

 

because that way you have the whole length of the bolt retraction to stop the bolt, a nice smooth decelleration

Edited January 24, 2018 by buzz

[dalbert]

I personally don't know who "Scrambles" is. I hid his earlier post because it is inconsistent with the standards of the board. Future posts by "Scrambles" are currently set to have moderator approval prior to posting, for the next 30 days. I don't use the warning, and other moderator tools often, but I feel it is appropriate here, and I've received one text, and multiple e-mails asking me to review these posts, and am therefore applying some of the moderation tools.

 

That being said, if "Scrambles" would like add substantive content, and continue to post in a respectful manner, I will approve his posts.

 

David Albert

dalbert@sturmgewehr.com

[buzz]

This is one of the best technical gun forums on the internet. It has been an invaluable source of information for me.

 

If you can't get along with the people on this site, you have "issues".

[mnshooter]

This is one of the best technical gun forums on the internet. .

 

 

Almost agree; I'd have deleted "one of".

Edited January 24, 2018 by mnshooter

[reconbob]

We are stuck here because we can't make stronger or weaker

springs unless they fit into the hole in the bolt, and also have the

buffer pilot fit inside the spring. All that can be done is to make the

spring stronger by making itfrom thicker wire and you could not make

it much thicker because it would bind on the buffer pilot. You can make

It weaker by making it from thinner wire.

A thinner or weaker spring would be easier for the bolt to compress

and the bolt would slow down less on recoil and strike the receiver

harder.

A thicker or stronger spring would be more difficult for the bolt

to compress and it would be slowed down more and strike the receiver

with less force.

However, unless parts are modified or redesigned there is a small

"sweet spot" where the gun will work. Too heavy a spring and the bolt

will not recoil far enough - it may eject and feed the next round for example,

but not move back far enough to be held by the sear. Too light a spring

and the bolt will not have enough force to strip the cartridge out of the

magazine - the bolt will hang up.

So no formulae and equations here but this is all fresh in my mind

because we spent months working out this for the blank gun. The blank

gun is different than a standard gun in that is has a smaller bore volume

and two surfaces that the powder gases impact.

The gun at first fired extremely fast - faster than an MG-42. It was

found that the way to control the cyclic rate was with the POWDER and

the final production gun uses a standard recoil spring. It took almost

a year and a half of trial and error/educated guess test firing of thousands

Of rounds to come up with the correct load.

 

Bob

[bug]

Great post. Visualizing and understanding "The Sweet Spot" in a TSMG recoil cycle is all I need.

 

Bob D

Edited January 24, 2018 by bug

[Scrambles]

Buzz, you include these math and equations to get people excited

 

, but then leave us with "about 20"

What?

 

 

What you mean we have to have recoil..?

 

No we don't and kick can be avoided.

 

Where is muzzle blast in that equation? Or the blish.

 

Or anything other than a perfect Newtonian system in a vacuum?

[Scrambles]

Common 45 acp loads are not consistent pressure with many older guns being considered during ammunition production.

 

The Thompson was rated at a higher power output, and can accept higher loadings

[Scrambles]

Also. On your bungee rope analogy

The idea is that there is a trampoline at the bottom

Not a pile of rocks/urethane)