Morn'in!
Reading the first post in this topic, my thoughts went to head space. Therefore, I would agree with Graybeard's comments about taking care NOT to set the shoulder back when sizing.
I owned a .35 Rem. barrell and never, I repeat NEVER, had a missfire in that barrel.
I also had case life so good you'd probably accuse me of streaching the truth if I told you the number of times fired.
But, I have made it a practice for years to not over size my brass. All bottle neck cases INCLUDING belted cases must head space on the shoulder with minimum clearence if anything like good brass life is to be expected.
With the small shoulder of the .35, this is doubly important both to case life and relyable ignition.
I followed the directions for setting up sizing dies as a young reloader and my brass life was the pits in a 7mm mag.
It didn't take me long to discover the directions needed to be taken with a grain of salt as "full length" resizing in many cases - depending on chamber and die dementions - quickly ended up as excessive resizing.
The above may sound "off the subject", but the miss fires still sound like a case length/head space problem to me, rather then a barrel or caliber problem.
Just IMHO.
Keep em coming!