cold barrel with cast bullets

[pakmc]

i'm shooting 7.62x39 cast bullets in a palmetto upper(yes, it's a 7.62x39 upper) but I've never seen a "colder" barrel. it needs two to three fired rounds to get the barrel hot enough to be accurate. After I get the barrel warmed up the 7.62x39 upper is quite accurate out to 50 yards (I haven't tried any farther, it still a work in progress). I can shoot two Russian 7.62 rounds or two lead (with gas checks) then the barrel shoots to point of aim and it's accurate.(these lead bullets are running about 17-1800FPS . the barrel is not quite that bad with Russian FMJ's just a little off in a cold barrel. any one have any hints about what can be done about this???

[GhostHawk]

Lube? That would be my first thing to play with.

If you want easy try mixing up a small batch of Ben's Liquid Lube, put 2 or 3 LIGHT coats on, load them.

Next you might try a wet patch of Dextron II or III ATF then a couple of dry patch's, before that first shot. Just to remove old lube, residue. Leave it with just a super thin film. Or, do that after you shoot and you are already ready for that first cold shot.

[Mica_Hiebert]

I would guess lube as well... Esp if your switching from jacketed to cast back and forth or cleaning after ever range session. To shoot cast accurately you want a seasoned bore. If you ever deep clean a 22lr barrel it takes about 50-100 rounds to get them shooting decently again.

[runfiverun]

yep lube.
stop using carnuba wax.

in our c.o.r.e. testing we found reducing the first shot by an average of 4% would throw it into the group.

what your doing is repairing the wax inside the barrel, once it's all smoothed out your rifle is shooting well again.

yep the jacketed rounds do it to.
that's still a c.o.re condition, it's powder and whatever fouling your fixing.

[Strtspdlx]

Not to hijack this thread but with what's being said would the op need to clean the barrel when switching lubes and season the barrel for a new lube before accurate results can be found?

[GhostHawk]

If it was me Strtspdix I would.

Or I would run a patch dampened with Dextron II or III and a couple of dry patch's between changes, and then shoot a fouler.

[runfiverun]

cleaning isn't really necessary.
but re-fouling the barrel with the new lube to make things fair would be the way to go.

[Shiloh]

Depends what a "Cold" barrel is. Last week, the '03 hit the 200 yard gong 3 to of 5 at 60+˚ ambient.
Last ime I took it out in the low 30˚'s seemed like it took me a little longer. I should keep some notes.
I use Larsens BAC lube almost exclusively.

Shiloh