Barrel Material

My youngest Son has been a U2 crewchief for 18yrs. My wife has ridden in the Camaro chase plane that they use in U2 landings. There is a SR-21 on static display at Beale AFB out of Sacramento. Both of them are very neat birds.
Butch
 
asa do the math

I love technology and bare feats that you listed but I did the math on the tank at 4000 yards. SWAG figures 12 MOA. Useful for coyote hunting, not winning benchrest matches unless exploding projectiles are used and you are having a bad day at the range.:eek:
BV
 
Brian Voelker said:
....but I did the math on the tank at 4000 yards. SWAG figures 12 MOA. Useful for coyote hunting, not winning benchrest matches unless exploding projectiles are used...
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Brian,

A T-72 tank is 31' long including the overhang of the barrel - 9 MOA. A more realistic 20' (hull and turret only) shrinks this to ~6 MOA. The T-72 is also 11' 9" wide and 7'4" tall (3.4 x 2 MOA). Now try hitting such an object when both you and it are manuevering at 40 MPH. BR rifles or not, it won't be easy.

APFDS rounds are solid - they shatter on impact. Fragments from US ones burn afterwards, because the core is made of depleted uranium.
 
brian roberts said:
have Scandium OR Titanium in the barrels!!! The Scandium is ONLY in the receiver & barrel shroud, there is a stainless barrel "liner" inside the shroud that has the rifling imparted through some nanoprocess. The Titanium is only used to form the cylinder & the extractor. :) Anybody know what the price of Scandium is now??? Last time I heard, the price was $7,000 a pound, & the largest deposits were in Russia.
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I'm not kidding when I write this. Scandium is rare earth dirt.


I have two of the scandium frame S&W's.

As to the use of Stellite 21 and 25 has been in use for machine gun barrel liners for many years. The M-60 has had the liner since the 1960's. The link that I have provide will take you to a PDF file that will discuss the use of the liner in the M-2 .50 caliber machine gun.

http://www.arl.army.mil/arlreports/2007/ARL-CR-595.pdf

Once upon a time in my checkered youth, I used a M-60 barrel to make a barrel for a Mauser 98. It shot vary well. Vary good accuracy for it's day. However I would not want to spend the time today making one work. Back then time was paid for by Uncle Sucker, and strangly the barrel was free.:D

There is a web site (I can't find) that shows Stellite barrel liners being made by a manufacture that are for large bore arty barrels.
 
The problem with coatings is that, well, they're COATINGS........... coatings by definition provide a wear surface over a substrate. Picture paint on a wall, or deck sealer on a cedar deck or the shiny surface of a hardwood floor.. The SURFACE is hardened, friction coefficient is changed and an acceptable surface finish is achieved. The problem is, this surface coating must be maintained, must be periodically renewed for the desired effect to be maintained.

This cannot happen in smallbore rifles.

Once the coating wears through (a matter of 5 to 500rds) you've got bullets transitioning from substrate to coated surface. You've got weird washboard wear patterns developing in the bore. You've got pressure variances that change and evolve over time......materially changing the pressure curve.

"Accuracy," Asa, is obviously relative...... for YOU 5moa is "accuracy" and 1moa is "pinpoint precision"....... This isn't about my blinders, it's about RELEVANCE to a given situation.

Blackbirds are COOL.

The fire control system premiered on the old Abrams was and is COOL....just not relevant to accurate small arms barrels in a target context.

Same Planet, Different Worlds.....


al
 
Stellite liners is a misnomer. They are a sleeve. They are and insert that goes into the and outer housing. The M-134 mini gun uses these sleeves also. After a million rounds you can not find any throat or bore wear measured with erosion gauges. Remember the high rate of fire on the M-134 is around 6,000 rounds per minute. Do the math. Six barrel firing each, firing once per barrel every revolution. The old 20mm cannons had the same sleeve type along with the M-60 machine guns. I have never seen any of these sleeved barrel exhibit any bore wear. On aircraft the six barrel Vulcans fired at the same high rate of fire at 6,000 rounds per minute.
 
Watched a friend of mine machine titanium shotgun barrels for the goverment. They were about 18inches long and went on the robotic carts for investigating and shooting suspicious packages. He made a boat load of them. I thing he said they were 8000.00 each.

Hovis
 
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