A chronograph is nice to determine what your velocity is. There is no real good way of telling when you approach recommended top pressures. If you look for signs and find them, you are probably over pressure by the time you note them. Primers are a poor way to tell about pressures for a variety of reasons. You can measure case head diameter before and after firing, but again if there is case head expansion you are over the limit, probably way over. Same with sticky cases. By the time you note a sticky case, you are way over the limit. In extreme cases you will have pierced primers or primers falling out of the pocket. Pierced primes do not necessarily mean over pressure, it can be from other causes, but generally too much pressure. The best way to determine over pressure situations is to have a chronograph to measure your velocity as you increase the powder charge. Once you reach the top velocity in a reliable loading manual (or two or three) then you are probably at the upper pressure threshold, no matter what powder charge you are using. It is not real scientific, but probably the best you can do. Some use a chronograph to determine extreme spread, thinking that it will tell them the most accurate load. The theory is the lower the extreme spread, the more accurate. I shoot what is the most accurate on paper and pay no attention to velocity or extreme spread. If the velocity I am getting with my most accurate load is way too low ( I do not worry about 100 fps), I then work up another load, switching powders or bullets. I personally do not own a chronograph. I have a friend that has one that I borrow when I am developing a load. His is a Chrony Beta. They make an Alpha and a Gamma model too. I am not sure when I get one for myself if I would get that one or another brand/model. It is very touchy about lighting conditions, but I think they are all that way to a certain extent. You can purchase chronographs on sale for under $90 or you can pay $250+ for one. It depends on the brand you get and how many bells and whistles you want. How important are they? If you stay with in recommended limits from reliable loading data and use the same components, work up from the lower limit and stop before you exceed their recommendations, you will probably be safe. Chronographs are relatively cheap now, but there was a time when the cost so much no one could afford them, except the rich. When I was early in my relaoding, I had no one to mentor me, there was no internet and I made plenty of mistakes. Even though I had reloading manuals, I would start at the top loads and seat the bullets into the lands causing over pressures. I gas cut the breech face of my T/C through blown primers. I learned through such experiences and now I do not push the limits so hard. I developed a dandy load for my BDL 700 VS 222, it was 24.9 grains of BLC2, WW cases, Hornady 50 SXSP seated .020" off the lands, and Rem 7 1/2 primers. It was not near top pressure, but it shot lights out. I could put 5 into .3 every time if I did not do something dumb. I learned from that too. Good luck to you. and keep us posted on your progress
