Ok...... tension tube barrel idea!

Guys,

I had a thought....
Some folks say a tension tube barrel is a faux pas due to the steel barrel expanding/contracting at a different rate than the aluminum tension tube. So, why not spec out a bellville washer setup (that is engineered) to a certain compressive value. Co-efficient of steel expansion in 11.5 +- 1.5 * (10 to the -6) per degree per inch between 10-30 degrees celcius. If you can load a bellville washer to "take up" this expansion, it should accomodate for the growth of the barrel inside the tube.
Hope im onto something.

Best regards,

Stu

There are several company's making carbon fiber sleeved barrels that seem to compensate for heat transfer and growth. Just an idea.

Larry
Tinkerer

Build it and let us know how it works...and cost...and how it compares to a standard tensioned barrel set-up. If you have the knowledge and equipment, or money and resources, it should be a fun project at the least.

Well, i bought the aluminum tube tonight for $6. I have some other alum scrap kicking around here that i can make the base "head" that rests on the corrected barrel nut flange, and muzzle brake out of. Problem is, i dont have an engineer buddy that can work the bellevile waher strength i need. I know the 1" id tube with 1/8" wall has a tensile strength of approx 1100 psi with a safety factor of 10X (yup, thats longitudinal, assuming no lateral force and pefrectly square ends). So im thinking of turning a base, with a thrust bearing to sit on top of the barrel nut, then tube, then muzzle brake with double lock nut to seat tension tube and muzzle brake at the same time. Tubing is fully extruded 6160, and wall thickness is consistant within .003" as far as i can measure with the bore guage and mic. This might get real interesting guys....
BTW, im shooting a factory Stevens 200 in 300 win mag. I might get 1.5 moa if i do my job.... just looking for something to cheaply sort this sow out myself. Im no superstar shooter, just a toolmaker lol

Stu

It seems you'll need to take the actual expansion of the base/bearing/barrel/tube/brake/nuts into consideration as they won't be subjected to the same/consistant heat and are of different materials. A lot of precise measurement and a controlled environment would help to plot POA/POI changes and consistancy.

Not what you are talking about, but a couple temp measuring ideas if you get it going

http://img.photobucket.com/albums/v6...0899638239.jpg
laser for out side temp

http://img.photobucket.com/albums/v6...striker001.jpg
Grill meat thermometer to take inside temp

http://img.photobucket.com/albums/v6...striker002.jpg
air pump to move air inside the tube, vented at muzzle.

After I got is set up, I never followed through to see what it would do. :( 6BR

Seems like you might have the inside track here lol
What were you looking for with the laser thermo and the bbq thermo?
Are you using one as a pyrometer inside the chamber? Would you not lose a lot of pressure/temp.... unless it is in there with a compressed fitting?

Stu

Wow. Getting very technical here...any chance of a diagram to better show us your idea (no I don't want to steal it ;))
I think i understand, but a photo or diagram would be great.

Here is another idea that i read about and saw first hand at the Pittsburgh NRA convention last year: It is not exactly like what you are trying to do. They control the expansion by the heatsink material they inject in between the barrel and the outer tube.
It's called the StraightJacket® Barrel System and it is by a group called Telydyne Tech.
(I was seriously thinking of trying this on one of my rifles. When I last looked their price was 399, now it has almost doubled. Probably out of my wallet's (and also SWMBO's) comfort zone at that price. >:( )

ok thome what is a SWMBO

drybean

She Who Must Be Obeyed!!

::)

Sorry, was not trying to hijack the thread.

It just lays inside the chamber after each round to monitor the rise between rounds. Not very technical. Seeing if the air pumped between the barrel and sleeve has any useful temp control value.

Wait Im confused u r gonna use compression on barrel rather than tension ?

I think the OP is planning on using the compression on the tube, thus creating tension on the barrel. The issue here is getting a constant tension applied to the barrel via a constant compression on the tube with the washer setup he's going to work with.

Three 44s

Quote:

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Originally Posted by macds

Guys,

I had a thought....
Some folks say a tension tube barrel is a faux pas due to the steel barrel expanding/contracting at a different rate than the aluminum tension tube.

Stu

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Ya ever think "some folks" never tried it that way?
I have a tensioned barrel on an AR-15 chambered in .17 Rem. It will shoot .5 moa, fast as I can empty a 20 rd mag. It is tensioned with 2 aluminum tubes.

I sure have thought that!
To be honest with you, theres likely a million ways to skin this cat.
It was just a thought on my behalf as well, fwiw. Simply looking for opinions as to what is maybe the most correct way to do it, all things considered. If we all did things the same way, without trying different things, we'd still have wooden spoked wheels on our wagons lol.
Guess i could try it that way too?

Regards

Stu

Quote:

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Originally Posted by Blue Avenger

It just lays inside the chamber after each round to monitor the rise between rounds. Not very technical. Seeing if the air pumped between the barrel and sleeve has any useful temp control value.

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And.......???

I saw something shinny and got distracted ;)

Macds,I say try your idea. I have a friend who made a tension sleeve for a 50 bmg.It worked wonders and it shot pretty decent considering it was a new wartime made m2 barrel.If you can come up with a cheap way to do it,keep us up dated.