I'm wondering if there is a reason that I'm getting soot on my case heads in every 3rd or 4th round fired out of my Ruger Bisley .45 Colt.

The cylinders are all bored to .452 as close as measurable.

I posted earlier about case head expansion, so my thoughts are turning toward inceased pressure, but there are conflicting signs:

Using CCI 350 mag pistol primers and H110, I have worked up loads to 23.0gr with a 300gr BTB WFNGC. I noticed some head stamp marking and slight primer flattening, but no powder residue. I stopped there.

Using CCI 300 non-mag pistol primers and H110, I have worked up loads to 23.0gr with the same bullet and brass, and I am noticing powder residue on the case head. But, there is no flattening of primers or other signes of pressure.

In the other thread, some folks were citing that the H110 is almost required to have a mag primer ignition because of the H110 burn rate, but with nearly 100% case capacity used, I'm not quite sure I understand.

Are the primers of different construction causing the CCI 300's to pop out sooner, and the CCI 350's to stay in longer?

Is the pressure spike/time different enough that the brass swelling on the CCI 300 loads slows the brass's rearward retreat just long enough for the primer to pop out far enough to release the powder residue?

If any of the above why does it happen intermittently?

I love reloading:D

Can anyone educate me on reading these conflicting signs?

Many thanks
EMC2

You need to get primer flattening out of your head as anything but a sign of, well, flattened primers. And leaky primer pockets are a sign of leaky primer pockets - not pressure.

RUN YOUR LOADS OVER A CHRONOGRAPH.

Untill you do this you are just guessing, and so are the rest of us.

Period.

If you'll recall, I mentioned that with non-mag primers or low bullet pull, H110 ignites/burns inconsistently.

Well, that's what you're seeing. Sooty cases are generally from LOW pressure loads that do not swell up enough to seal the chamber. Gas flows around the case, cools and condenses into soot.

As the French say, voila. The evidence matches the theory. And a chrono would have revealed a markedly slow velocity on those shots.

EMC2 - you've just been given the best advice available. Look in your reloading manuals and note the types of primers used with types of powders and the charge rates, plus seating depths.

As previously adivsed - be sure you have a firm rolled or tapered crimp to assure best consistent ignition.

A chronograph is a MUST item of equipment when experimenting with handloads and working up to full cases/near max loads.

Thanks guys,

I have one, I just need to travel a bit to get to use it. They closed my outdoor range, and the indoor doesn't allow it's use.

I'll report back when I have some vel data.

Many thanks
EMC2