Had the day off today and decided to load some ammo,I decided to load to the lands of my rifle using 165 spitzer boat tails for .308...I started by cutting slits in the case using a dremel tool and seating the bullet slightly so it will chamber I my rifle,I closed the bolt and extracted the round very carefully...coal from tip of bullet to base was 2.905 I done this a few times to be absolutely sure it was correct,I did notice on the bullet rifling marks which I believe to be the OGIVE ring,so I measured from tip of bullet to the OGIVE ring with my callipers and it measures 0.685....do I need to subtract that OGIVE measurement from the original measurement of 2.905 tip of bullet to base to give me the coal to the OGIVE....if so would I also need to subtract a further 0.010 to be off the lands.....sorry for all the confusion as I'm only learning (at least trying to ).....your replies are appreciated.... Cheers
Im not sure how all that works, I do the same thing with a split case only I use a hacksaw with a fine tooth blade, then seat them and put one in the chamber, I then just seat it a bit more and try for length in the magazine, if this works out ok, that's my seating depth. Usually works for me, but then I don't load for target shooting, well inanimate ones that is.
I don't shoot for targets either,I want these loads for hunting purposes only so they must feed in the magazine which all of them are right now,I have measured and chambered all of them to make sure and the coal is set to 2.885....I hope they will be alright,I will find out this weekend.....fingers and toes crossed that all goes well..I have used the ADI loads which state minimum to be 42gr and max 46C for 165 gr projectile and I'll be going in .5 increments to 45.5....see how I go.....cheers
Your on the right track, if you subtract the 0.6XX from your base to tip this will then give you the base to ogive length. Unless the bullets are really bad I doubt the difference in base to ogive compared to base to tip will vary much. I think the main thing is not to confuse them.
You can subtract 0.010 from the oal's and this will be 0.010 off the lands. Then check if it fits the magazine fine etc
Both of the bushing FLS dies come with comparators that attach to verniers to measure shoulder set back (bump) Dies take normal redding and wilson bushings which is good and the lock rings are very positive at locking. Best of all the price of them was right, even with the falling dollar. Much better than a custom set of reddings as they are available in a few obscure calibers that arent easily available.
Finding the point where projectile first touches the lands.
On a fired case neck size only a small amount of the neck, 2mm area. Seat a bullet which it to long. Close bolt on it, will push bullet down neck and be a hard jam into the lands. Now back the seater die down to this OAL as a starting point. Take fine steel wool and polish off the lands marks on the projectile. With the seater slowly reduce the OAL (seat bullet deeper), only a small amount each time. After each seating deep change, chamber in rifle and check for land marks. Polish off land marks between each test. Keep seating deeper until on one of the test tries, the land marks disappear. You should be able to get it that accurate that by just increasing the seating depth you can get the land marks back. This will give you a measurement of when the bullet very first makes contact with the lands. Your choice how many thou in or out from that point. Also don't confuse land marks with marks from the chamber caused by chambering and removing the round. All that make sense?
Ackley improved's method can be made easier by colouring in the projectile with texture in place of polishing with steel wool. If this all seems a bit tedious try buying a modified case and oal tool along with some comparitors from lgs. Not always possible for some obscure cartridges but easily done so for 308. you can also make your own modified case for tool by driling and tapping your own brass, can not remember the diameter but it is a36 tpi tap which you will probably need to buy from an engineering supplies shop
