Taking a fired case from the Rem 700 light varmint rifle and a Nosler 55 grain Ballistic Tip I determined the seating depth that just lets the bullet touch the rifling lands. I followed the method I documented in detail in Overall Cartridge Length.
It is a very simple and effective way to determine the seating depth of any projectile where it just engages the rifling lands. You can clearly see that for my 223 Rem reloading below. The scratches where the lands have engaged the projectile stand out clearly. More importantly, you can see that on extraction the projectile has been pulled out of the case neck slightly by the grip of the lands – that is the narrow clean band where the projectile meets the case neck.
By very carefully pushing the projectile back into the case, to make that clean ring just disappear, you have JTL – the overall cartridge length where the bullet seating depth will just touch the lands. I had previously done this and determined 2.310”, but on a more careful procedure and inspection today I could see that the correct JTL was in fact 2.305”.
Having determined that as my starting point I then did a batch of re-loading to test accuracy for varying distances of bullet seating off the lands; that is 0, -10, -20 and -30 thou off the JTL.
I find it useful to actually keep a written log of what I have loaded, then later enter that data into computer records. As you can see, I slightly overshot my goal for the 2.285” and actually ended up with 2.283”. There was no point in mucking about to get exactly 2.285”, because there is nothing special about that exact dimension. The key is test seating depth is approximately 10 thou increments.
After a couple hours of effort at the reloading bench I treated myself to some very strong brewed coffee, sipped out of a small cup, and accompanied by some Turkish Delight. I learned to appreciate Turkish style coffee and sweet pastries at the hospitality of my old Macedonian and Croatian friends. My interpretation of that is very strong, unsweetened, brewed coffee with some sweet nibblies.
The misty, wet weather continues. I foraged about in the wood pile and dragged out a few of the drier blocks, then split a barrow load of firewood. One of my imminent projects is to build a wood shed to keep a good store of dry firewood.
I managed to mow about half of the 2 acres in bits and pieces over the last week. The remaining area is badly in need of a trim – but that ain’t gonna happen today!