Help me understand this.... Have the laws of Physics been revoked?

[thegunnut]

I have been cruising the www and facebook seeking info on tactical type shotguns.
Lots of good info... and what seems to be lots of good experience.
Common complaint seems to be some models do not function well with std target loads.
AND THEN I came across this post on the Trigger Wholesale facebook site regarding barrel extensions for sale which would increase functionality with target loads.

A direct copy and paste....

Update: Uzkon Barrel Extension Kits (BR/TR/AS46/SBP):

Uzkon is finishing a batch of Barrel Extension Kits (BEK) for us as we speak. Why are these kits important?
-By adding 4", 6" or 8" BEK to your shotgun, you can push the functionality of the shotgun beyond its design perimeters.
-Add a 4" Barrel Extension for an ideal Turkey Gun.
-Add a 6" Barrel Extension for an ideal Deer Gun.
-Add an 8" Barrel Extension for an ideal Waterfowl/Trap Gun.
-Barrel Extensions are threaded for chokes and come with a 5-Choke Kit.
-These items fit on our BR99, TR100, AS46, Short Barreled Pumps, etc.

Although many people are having success using Uzkon AR-Style shotguns for Trap Loads (unike competitive products), these shotguns are designed as tactical shotguns. By adding a Barrel Extension Kit (BEK) to your shotgun, it can perform reliably under a wider range of conditions and for specific hunting applications.

It is well documented that trap loads can be difficult to cycle through many different types of semi-auto shotguns. Although the BR/TR Series Uzkon shotguns dont have this issue, we want consumers (and Dealers) to better understand the primary reason that this happens;
-Barrels shorter than 26" dont allow for adequate back pressure to build up to reliably cycle the ammunition.
-A 'Bandaid' solution is to use a choke to increase back pressure. Although this can improve performance, it is not ideal.
-By adding an 8" BEK to these guns, you build adequate back pressure for Trap Loads, you still have the ability to leverage chokes and you also improve you accuracy with the added length!

End copy and paste

What is "back pressure" ??? and how does a choke increase "back pressure"????
Have the laws of physics and fluid / gas dynamics been repealed???

Surely there is someone out there who can explain this to me.
PLEASE HELP.

If this is a pile of BS (bird shot) I would like to know before I make a decision on which tactical shotgun to purchase.

 

[Suther]

Improving accuracy is a bunch of bull. Length has little to no bearing on accuracy.

By back pressure, they mean the force used to cycle the action. If you've got a longer barrel, the pressure will remain higher for longer, which should aid in cycling the gun. Although they claim the gun functions fine without it,so i don't see how that's a selling point...

A longer barrel swings better, so i could see it being useful for clays or waterfowl.

 

[thegunnut]

Thx for the response.
my lack of comprehension of the "back pressure" commentary is this.....
On gas operated shotguns, if the target load is of insufficient pressure to cycle the action, the only options are to either increase the gas port size or reduce the mass of the object being moved by the gas.
Barrel length or choke should be irrelevant.
Unless the laws of physics have been revoked. LOL
That is of course assuming friction inherant in the action cycle is considered constant.
I remain somewhat confused.

 

[cartwheel]

All utter nonsense. Nobody can explain it to you because it is purely fiction. Maybe the longer barrel allows the gas pressure to act long enough to cycle the action? It would be a very marginal action if it went from not cycling to cycling by adding 8" to the barrel. The versamax method would be much superior IMHO... but I'm not much of a semi-auto guy.

 

[supernova]

Yes, that is how it works. Longer dwell time for the gas to impose on the piston gives a little more force to overcome the action and cycle properly. Ever try to push a wad through a tight choke tube? Constriction raises pressure a little. Basically if you read the article it says these shotguns were not designed to be reliable with light target loads, they were designed to be reliable with slug and buck loads. Depending where the gas port is, barrel length can really affect how a semi cycles with different loads.

 

[polskiogorki]

Yes, that is how it works. Longer dwell time for the gas to impose on the piston gives a little more force to overcome the action and cycle properly. Ever try to push a wad through a tight choke tube? Constriction raises pressure a little. Basically if you read the article it says these shotguns were not designed to be reliable with light target loads, they were designed to be reliable with slug and buck loads. Depending where the gas port is, barrel length can really affect how a semi cycles with different loads.

^^^ this..... the longer the gas stays in the barrel the harder the action will be pushed back

 

[Claven2]

Basically if you read the article it says these shotguns were not designed to be reliable with light target loads, they were designed to be reliable with slug and buck loads. Depending where the gas port is, barrel length can really affect how a semi cycles with different loads.

Uh... no. They claim OTHER PEOPLE'S PRODUCTS have issues cycling light loads, but their guns are fine. But you should buy this stuff to improve things for a problem they say they don't have.

So which is it? Are they lying, or are the youtube videos showing light loads making the Uzkon offerings into single shots lying?

You decide

 

[supernova]

Just gotta take your lawyer thinkin cap off and read between the lines . Of course they don't admit their product that came from the same factory as the others doesn't have the same issues. They're just selling a product to fix said issues that don't exist as if you need to fix said issues so that it can perform reliably under a wider range of conditions and for specific hunting applications. They're helping their competitors, not their customers, by selling a fix to their customers on behalf of their competitors. The only people who are lying are wrong, of course

Uh... no. They claim OTHER PEOPLE'S PRODUCTS have issues cycling light loads, but their guns are fine. But you should buy this stuff to improve things for a problem they say they don't have.

So which is it? Are they lying, or are the youtube videos showing light loads making the Uzkon offerings into single shots lying?

You decide

 

[Juster]

Thx for the response.
my lack of comprehension of the "back pressure" commentary is this.....
On gas operated shotguns, if the target load is of insufficient pressure to cycle the action, the only options are to either increase the gas port size or reduce the mass of the object being moved by the gas.
Barrel length or choke should be irrelevant.

Suppressors increase back pressure, on blowback pistols you can get early ejection and flame coming out the ejection port. So muzzle devices can affect barrel pressures.

 

[thegunnut]

So if I order a Hastings 32" Metro barrel extension, I should be able to make the gas operated unit function on significantly lighter loads?
Or.... Worthy of consideration..... Assuming that the wad/ shot charge acts properly as a gasket to harness the gas pressure... Lets call it "front pressure" as it is moving down the barrel toward the front of the gun......
As the wad/shot moves down the barrel, it effectively increases the volume of the closed cylinder (the barrel) which should in theory reduce the pressure of a finite volume of captive gas.
Less,pressure (front or back or perhaps even side) means less functionality. Particularly in the parameter of this discussion which is regarding function of light target loads in tactical shotguns.
I remain somewhat confused.

 

[supernova]

Pull the cork and the pressure is gone. Leave it in just a little longer and you get a slightly longer dwell time before pressure drops to zero. It doesn't matter so much that the pressure has reduced significantly because there is still pressure passed the original dwell time that otherwise would not be there with the shorter barrel. That extra energy exerted on the gas piston can make all the difference when cycling light loads. That's why a 20" AR-15 will reliably cycle a wide range of ammo while a 10.3 is often a bit more sensitive to ammo as far as reliable cycling goes. Of course that assumes both rifles are in good working condition. The longer dwell time afforded by the longer barrel helps fully cycle the action and eject the spent case/hull when lighter loads are fired but standard loads do not beat up on the action because that surplus pressure is from the backside of the pressure curve.

 

[Claven2]

Trust the retailers... trust them...

 

[stubblejumper]

Uh... no. They claim OTHER PEOPLE'S PRODUCTS have issues cycling light loads, but their guns are fine. But you should buy this stuff to improve things for a problem they say they don't have.

So which is it? Are they lying, or are the youtube videos showing light loads making the Uzkon offerings into single shots lying?

You decide

The simple fact is that virtually every quality semi auto shotgun made these days functions just fine with target loads.

 

[Claven2]

The simple fact is that virtually every quality semi auto shotgun made these days functions just fine with target loads.

Umm.... yeah. I agree with your statement.

I don't usually buy quality guns from Turkey for $250 or less a copy and re-sell them in Canada for $1000 though.

The name of a quality semi-auto manufacturer tends to start with a B in my world

 

[thegunnut]

I am semi-sorry that I started this thread.
It had prompted me to do substantial independant research on my original topic.
From this I have learned:
There are a lot of folks who have limited knowledge, and unlimited enthusiasim.
"Often in error, but never in doubt"

This is NOT a slam on any of the posters who sought to help me understand the science of the "back pressure" thing.
I have also learned that the original fb info from Trigger Wholesale on the barrel extension/ backpressure is absolute and total Bird Shot.
Clearly a retailer who presents a "science based" resolution to a perhaps imaginary issue which is absolute "Bird Shot"
Is not worthy of my business.
Hello Derya.. Here I come.
BTW.. Trigger.... Watched the video on th fb page again re tactical shotguns. Are the sights mounted the right way around?
Please advise.

 

[stubblejumper]

Umm.... yeah. I agree with your statement.

I don't usually buy quality guns from Turkey for $250 or less a copy and re-sell them in Canada for $1000 though.

The name of a quality semi-auto manufacturer tends to start with a B in my world

Or a W, my SX-3 shotguns have proven to be very reliable for less than a B gun.

 

[Claybuster]

-Barrels shorter than 26" dont allow for adequate back pressure to build up to reliably cycle the ammunition.
-A 'Bandaid' solution is to use a choke to increase back pressure. Although this can improve performance, it is not ideal.
-By adding an 8" BEK to these guns, you build adequate back pressure for Trap Loads, you still have the ability to leverage chokes and you also improve you accuracy with the added length!

I think the appropriate phrase regarding the above is "complete bullsh!t."