Comments on: Will Carbon Build-Up Inside Cases Raise Load Pressure?

By: MSh.

MSh. — Mon, 10 Aug 2020 14:40:38 +0000

Was annealing every used in this study?

By: Mike Conroy

Mike Conroy — Tue, 04 Jun 2019 12:39:11 +0000

At least for me, carbon inside the case neck allows for a more easier and uniform seating of the bullet. I have had cases that were cleaned with SS media and upon seating the bullet….the inside case neck galled the copper jackets.

Editor: Yes, we have discussed this in a couple articles. Ultrasonic cleaning can also leave the neck interiors in need of lubrication. Some guys dip the neck in a dry lube. Others may run a lubed nylon brush inside the necks.

By: js

js — Tue, 28 May 2019 21:19:44 +0000

Let’s think this through. The chief reason carbon residue inside a case would increase pressure would be that there is sufficient carbon to reduce the internal volume of the case. Here’s a relatively easy check. Weigh each case with the presumably evil carbon inside it. Run the case through some process that removes the carbon – either ultrasonic or with stainless pins. Weigh the cases again. The difference is the mass of the carbon inside the case. We can then use the ideal gas law to compute the pressure differentials attributable to reduced internal volume. My best guess – without going through the exercise – is that the calculations will show that the effect on velocity and pressure owing to carbon buildup will be approximately zero.

An important side issue is this – how many loadings are most of us going to get from our brass -with or without cleaning? Most of my brass is going to be pretty well cooked before there’s any chance of carbon buildup being an issue.