https://www.shootingsoftware.com/pressure.htm
That is the brand I have. The hardware and the software is designed for ammunition.
Otherwise if I had to come up with something on my own more or less, I'd start with what is called a "Crimp Force Monitor". They are made for the presses used to put on the terminals for electrical connection in the wire industry. They are really more accurate than what I gave the link for, have good software, available on the used market, etc. But them I'm very familiar with them and would be staying with the devil I know.
As for the chemicals, it depends on the desired outcome. Longevity of the powder, how easy to make, desired use, cost, etc.
Ammonium nitrate ones are the cheapest and about simplest. There are some in the A&O book available are the arradvak website that is linked in these thread. Be sure to use one that is 7-10% potassium nitrate. Also I'd recommend adding 1-5% potassium dichromate-nasty stuff and DON'T get any on your body. Nasty but the best getting the desired mass burn rate. By the way, AN based ones have always been the holy grail of smokeless powder and is still being worked one.
There are several others that can be made besides those that are nitrocellulose based. Guanine based ones fairly simple, the chemicals needed are available in a store and what I'm currently looking into again.
But for normal nitrocellulose based powder, the simplest is to see if you can get actual lacquer as that is nitrocellulose. I normally add by weight 10% potassium nitrate or sometimes AN at a greater per cent. But the lacquer you buy would likely have urea in it to stabilize it, which over time creates voids in the grains and increases the burn rate. Therefore one doesn't want to wait to long before using it. IMO for DIY, a flake powder is best because it's the easiest to change burn rate by increasing the thickness or the size using the same equipment.
For nitrocellulose powder starting with just the base chemicals, one would need to really sit down and decide if it is needed. For example a shotgun/pistol powder is much easier to do than a full powered rifle powder. Also for a start read Urbanski's volume 2 book on making the base and what Mendeleev wrote on doing it, otherwise it can get very expensive to make.
Keep me up to date and let me know what you are thinking of doing.
By the way, I've mainly worked with AN based ones and of the 100-200,000 rounds I've loaded and shot only about 2000 have been done with DIY powders. Kind of like gasoline. I can't make other fuel to run an engine, but a lot simpler to buy gasoline or diesel for may needs currently.