Leading at the crown of the barrel?

[44Blam]

I've got a load that is the NOE 401-188-WFN boolit on top of 7.9 grain of AA#7. And my COL is 1.125". This is my goto load in my glock 35 with KKM barrel. In that gun, it sends the pill about 1050 fps. The boolits tend to weigh about 187 grain with the flat point. These boolits are PD'd and have a coat of BLL.

I do not get any lead fouling in my glock with the KKM barrel. But in two other guns I've shot it through get a tiny bit of lead on the crown on the edges where the rifling connects to the crown. The other guns are a S&W M&P2 and a 1911 with a 40 S&W barrel. It does not seem to affect accuacy - it is just at the corners of the rifling at the crown of the barrel... It does just almost wipes off with a little chore boy - there is no other leading in the barrel itself.

Anyone know why it would just lead at the crown of the barrel?

[BLAHUT]

Is there a burr at the end of the rifling ??

[MUSTANG]

Leading towards the end of the barrel or at the crown are often indicators of lube failure. Lube is working until the end of the travel through the barrel.

[elk hunter]

Is there a lube star on the end of the barrel? If not you may be running out of lube at that point.

[waksupi]

Use a softer alloy, and better lube.

[MUSTANG]

For those readers of this string that do not know what a "Lube Star" looks like on a barrel - see following:

Attachment 306865