Originally Posted by xJPxHatchet
here is what i have to go by for 165g FMJ FN using unique
lyman - 165g TMJ OAL 1.120 5.4-6.0 TMJ is total metal jacket - plated.
lee - 165g XTP OAL 1.120 6.3c-7.2c (no data for jacketed for unique powder) XTP is a specific bullet and it's jacketed. And you MUST use the recipe for the powder you're going to use! You cannot substitute another poweder.
Alliant Powder Website as mentioned above.
As you can see this is were i get confused. I guess i am having issues deciphering the hand-loading lingo.
I could go to Walmart and get a Speer and Hornady manual if i have to.
powder burns at different rates and that affects the pressure - too much pressure and things explode....i've talked in person to 2 folks that reload...one of which blew up his gun (thinks it was a double charge...not really sure)
You have the amount of space in the case with the bullet seated - shorter OAL means less space - same powder in a smaller space = higher pressure. A too long case (for you gun with the bullet you're using) will put the bullet against the rifling and you get higher pressures again. Can't win for losin', I know!
I've seen recipes for what I"m doing show 3.8 to 4.4...and in another book same bullet and powder 4.2 to 5.1... some of that variance is based on their test barrel, perhaps the brass they used, primer, etc. This is why you need to start at the lower end of a recipe and work up watching for pressure signs.
I've done a lot of searching and research to find what I feel confident in using - you can google for your bullet, your powder and sometimes for 'xd 40 load for idpa' or similar and just begin to make a spreadsheet of everything you find. After 4 or 5 hours of this (no lie) you'll have a pretty good cross section of info and knowledge to worth with.
I need a 1.06 OAL for my berry's FN bullets...there is ONE book out there that lists it (a book I don't have but found quoted by differnt folks in different forums). I also ran across folks having the issue as me with XD9 and the berry's FN and there were a few posts from folks that talked to a guy at berry's that got a recipe. Once I had info on that bullet and length and found 3 different powder loads (some with chrony info) I felt pretty confident to give it a go.
I also learned that for every inch of barrel you add about 80 FPS to the speed, and my comp gun has a lightened slide- combined these mean lower power loads should work the action fine so beginning on the low end is I think safer for me - YMMV of course.
Reloading means you'll spend more time on the hobby and have a lot more knowledge - and appreciation - for what happens and why when you pull the trigger!