Bullets vaporizing in mid-air

[Mikecr]

Not that there is anything wrong with moly,,
But I have to atleast suggest Tungsten(WS2) for a bullet coating. You can pick up a tub at RoseMill, and coat dry/clean bullets in a pill bottle & tumbler.

It cleans right out of the bore, so it's a bit less committed than going moly. And as far as I can tell, WS2 offers all the same benefits.
It's just an easier solution.

 

[BryanLitz]

I haven't carefully read every post in this thread so I apologize if I'm repeating someone here.

I remember someone telling me once that PacNor likes to make their bore/groove dimensions a little on the tight side, which doesn't hurt anything for non-overbore cartridges but can generate too much heat in larger chamberings.
Unless you specified otherwise, you might have a tight barrel. If this is so, it can certainly play an important role in your heat and bullet failure. Other 6mm-284's may get away with hotter loads if the barrels aren't as tight.

Just something to consider,
-Bryan

 

[sandytye]

Mike,
I found some WS2 but it comes in different micron sizes. 0.4 to 1.0 Micron. what stuff do you recommend. Thanks for the heads up.

Bryan,
That is an interesting fact. Will I be able to measure that with my dial calipers or would that take more precise tools?

Thanks for the help guys.
Tye

 

[Mikecr]

I use this;
-Moly & Tungsten Disulfide Powders - Tungsten Disulfide Powder

1/2lb has lasted 10+ years, and I plan to reorder in 100yrs.

 

[BryanLitz]

Tye,
I doubt you can measure it with your calipers.
If you have your invoice for the PacNor barrel, it might say the bore/groove dimensions on it.
If not, I would recommend calling PacNor and asking them what 'standard' diameter they make their 6mm barrels.
Unfortunately, a tight bore isn't a problem that can be fixed short of replacement. Hopefully the coatings your discussing will be enough to counter the adverse effects (whatever they are) and allow your bullets survive this barrel.
-Bryan

 

[sandytye]

Bryan,
I talked to pac-nor and it looks like mine is .236". as I am somewhat new to this game I do not know if this would be deemed "tight". what is the usual diameter for a 6mm?

Tye

 

[BryanLitz]

To be honest, I don't have a good idea of what size is considered a tight bore either.

According to this article:
6mm Bore Diameter and Bullet Selection « AccurateShooter.com Bulletin
It gives the impression that bore sizes range from .236" to .237", so .236" would be minimal.

Kriegers site lists .236" or .237" options
Calibers & Prices

According to the above, it would seem that PacNors .236" may not be radically tight, but certainly on the tight side. The difference between .236" and .237" may not seem like much, but I'm willing to bet it makes a big difference regarding the heat generated from friction as the bullet scrapes down the tube.

It might be a good idea to specify a .237" bore if you build another 6mm-284. Maybe you can ask someone who's not having bullet failures if they know their bore size.

-Bryan