Flattening a priming horn

[Bluegrass]

I took my first shot at making a flat priming horn last night and it didn’t work out. I heated my vegetable oil to 330 degrees and dunked it for a few seconds at a time until it was soft, but some deep blisters popped up and ruined the horn. Did I heat it too quickly/overheat it or does something else cause this?

 

[Robby]

Sometimes there are delaminations in the layers of horn that don't show up on the outside. Maybe from taking a good whack sometime during its lifetime. Sometimes there is enough horn below the blister where you can rasp right through it and reshape the horn to where no one is the wiser.
Robby

 

[Cattywompuss]

Organic material is unpredictable. Sounds like you just need another horn to try again.