FOLKS,
I have a 20" SS Contender barrel made by BULLBERRY in 22K HORNET. While fireforming cases it shoots SUB MOA. When I load up & shoot those new 22 K shells my accuracy goes to 1.5" !!!
I'm looking for some help here. I use Redding Deluxe 3 die set (- FL- NECK -SEATER.)
12gr LIL-GUN -35gr VAMX.
I also had some misfires.
Thank you for your time.
SOUP

Try some different primers- just in case they are the cause of the missfires. If they are that is the cause of the poor accuracy as well.
Have you checked the "runout" of your fired brass and compared with the resized case, also on the loaded round? Some times a 1/4 turn of the sizing or seating die makes for complete different results.

I read this post in the other forum, but I don't think you mentioned the misfires there.

If you're sizing your cases down too far, you can get misfires in the Contender. You want your cases to protrude from the barrel about .001" less than the barrel-frame gap as measured with feeler gauges (the gap, not the protrusion). Find the thinnest gauge that the barrel will close on without letting you pull it out easily and that's your barrel-frame gap. Size your cases using the FL sizer so they protrude from the chamber .001" less than that gap. Mike Bellm has designed a tool that allows you to measure the case protrusion along with several other things here. Excessive headspace could be your problem, both for accuracy and reliability. Case life will suffer also, and isn't that part of why you wanted a K-Hornet in the first place?

In my reply in the other forum, I also suggested that you up your powder charge. I use 13.5 gr. Lil-Gun with a 40 gr. bullet in my Ruger 77-22H (not K). Good groups and no pressure. I would think with the extra volume of the K-Hornet, maybe you need to fill the case a bit more.

But try backing off the sizing die first.

quote:

I'm looking for some help here. I use Redding Deluxe 3 die set (- FL- NECK -SEATER.)

[smart ass mode off] Are you useing all three??

Generally break-opens don't like NK sizing only.
So you should be using the FL and the Seater. For your purposes the the NK die is just not needed or used.
Compare the length of the factroy rounds and your reloads from rim to bullet ogive start. You may have too much or not enough bullet jump.

You might try small pistol primers if you are not already doing so.
Pete

Your most accurate powder charge for the standard Hornet may not prove to be the most accurate in the K Hornet . With mine I had to increase the powder charge by 0.4 gns for the K case over what was an accurate but warm load in the original .