Is there any problem with going from copper to moly-coated bullets in a .223 AR15? Some one told me you should stick with one or the other exclusively, and not go back and forth. Is this BS? Sorry if this has been covered, but the search function doesn't come up with anything.

Moly was susposed ot be the second comming as far as bullet performance was concerned. It was initally very popular, but now almost no one is using moly for a number of reasons. The biggest problem is once you get moly in your barrel, it's very hard to remove. It's not the moly itself, but the moisture it attracts that causes problems. Another issue is target shooters work up a load and then stick to it. Moly coated bullets have an efect on velocity, and can change the way a load shoots. If you're a casual shooter who reloads, I wouldn't spend any extra money on moly bullets. If you do use them, make sure you clean your barrel to prevent moisture problems.

Black Hills makes the SMK-77g Moly-Coated ammo for the USMC marksmanship team....that I do know.  I wonder why they still use Moly-Coated ammo?

Major

i reloaded some v- max bullets that were moly coted and the actualy shot the same if not better than non-coated.   i see know problem with cleaning either. seeing how powder residue does not stick to the moly. and besides, you are supposed to lube the barrel with moly before you shoot moly-lubed bullets, so, theretically , you dont ned to clean all the moly out of your barrel when cleaning.   Moly lube being hydroscopic, i dont know, but i have know problems with it. i have also heard that moly helps heep your barrel life go a lot longer, so why not use it.  

Like Sgt._Gold sez:

the moly is "hydro-scopic." Read: "attracts moisture."

clean real good after firing.

Moly entered the shooting arena in the lat 1990's with all sorts of hoop-la.

The vast majority of shooters that started with moly are no longer shooting with moly. Google is your friend......

I have seen some studies that just about say that moly will ruin your barrel... attracts water, causes corrosion, etc.  This has never been my experience.

Moly works great in some situations, and has much less effect in others.

Works Great:
- in smooth clean barrels
- reduces copper fouling
- with moly-coated bullets in pre-molied barrels

Much less effect:
- in barrels with a rougher internal finish
- when the shooter tries to coat the bore by shooting moly-coated bullets
- when coated over a copper-fouled bore

Many people who have tried moly have done so in such a way that almost guarantees problems.

A rough bore that fouls heavily will not be fixed by using moly. You'd have to fix the bore (lap it) before fouling problems will abate.

Expecting the bore to be evenly and quickly coated with moly by shooting coated bullets is wishful thinking, in my opinion. Reportedly, it takes 25-30 rounds before enough moly is in the bore to be effective. During this time the same bullets are causing copper fouling as they travel down the bore after the moly wears off. During this time the friction qualities of the bore are changing, making consistent shooting very difficult.

Moly coating over copper fouling is not a good thing. Copper fouling alone is bad enough... Moly over the top does not help.

Here's my moly routine:
I carefully clean the bore until there are no signs of copper fouling. If I'm cleaning a bore that I have used moly in already, this job is much easier for me.
When the bore is clean and dry, I take a dry patch and put dry moly powder on it. I run this patch through the bore several times to burnish the moly into the bore.
After the bore has moly burnished into it for its full length, I run one dry, bare patch down the bore to get any loose moly out.
The rifle is ready to shoot. The 1st shot from a cold, clean barrel is at the same point of impact as further shots.

Cleaning:
Use a high quality, one-piece cleaning rod. Use the segmented, screw together rods for emergency use ONLY, or (better yet!) toss them.
Use a rod guide if at all possible.
If it is a custom barrel, then it has probably been hand lapped and has a very smooth interior finish. These barrels foul very little, especially with moly. I don't use copper brushes in them; nylon is plenty.
I generally avoid cleaning solutions with high ammonia contents. Butch's Bore Shine, Shooters Choice, and TM Solution work well.
USP Bore Paste or Iosso paste work well when I occasionally want to clean down to bare metal, remove the moly and start over.
In very high-quality, custom barrels I have great results with Kroil, USP Bore paste, nylon brushes, and patches only. I only use the USP Bore paste after a couple hundred rounds. Regular cleaning is with Kroil, the brush, and patches.


Using moly in an AR-15 may not help much. Chrome-lined bores are intended to foul less and hold up better under heavy use, so you'll see less benefit from moly.  

Switching back & forth between moly and non-moly bullets will not ruin anything, though it is not optimal. I do this occasionally... though I am extra careful to clean well after shooting non-moly bullets.

can you send me the web site for kroll???i cannt find it

HBruns  - Dead On, Excellent info on using moly coated ammo.

Quoted: can you send me the web site for kroll???i cannt find it

Kroil, made by Kano Labs
Kroil for sale at Sinclair International (scroll down)