problem with ogive &oal with 223 bullets

[lal357]

so far i have been lucky with my 308 i measured some of them and they were good. but i'm going to sort all my bullets by ogive instead of weight first . rain has me boogered this weekend so i'm replanning for next weekend to see if /how much improvement i see

[Budweiser360]

I believe the word ogive began as a French architectual term referring to that spot on the wall where the vaulted ceiling started to curve in.

ogive = aah - geeve

If I'm wrong, I'm sure it will be noted.

uj


Actually, it is pronounced "Oh-jive" FWIW

[lal357]

Bullets will have different ogive's from lot# to lot# as well. I have measured Match grade handmade bullets that will have the same ogive measurement from bullet to bullet, and have noticed a big difference in ogive length going from one lot# to another.


you are correct i had some spare time on my hands last night so i separated my 308's 168gr amax heads when i went to the new box they jumped so i spent 1 hr separating them all in cups (now i have found something i hate more than trimming cases) looks like I'm gonna be busy next week since my midway order is sitting at ups waiting for delivery Monday . hoping to go to the range next Saturday (had to cancel today 60% chance of t'storms in the afternoon today with heavy rain)

[theflatlander]

Every rifle is different and every brand of bullet has a different ogive as well. Two brands of bullets might weight the same but have totally different ogive profiles. Do not rely on OAL of a cartridge as a means to put the bullets at the lands either because there are variations within the same brand and bullets as well. I have seated bullets to the same OAL but when I measured to the ogive I had variations.

Once I settle on which type of bullet I am going to use I use it to take measurements of the chamber. For me I use the 69 SMK's in my 223's. I then measure the distance to the lands using this bullet in a case where the bullet is loose but still snug enough to stay in place once ejected. I measure the seatig depth to the ogive on that bullet and use use that measurement as my zero clearance measurement for that rifle. I recently installed a new barrel so I am still trying to determine what shoots well but my last barrel liked .030" off the lands.

Dolomite

you say you use a bullet in a loose but still snug case to measure to the lands. how do you obtain this? just curious I also shoot a .223 and was just wondering fpr I dont have to buy the spendy measuring equip.

[dolomite_supafly]

you say you use a bullet in a loose but still snug case to measure to the lands. how do you obtain this? just curious I also shoot a .223 and was just wondering fpr I dont have to buy the spendy measuring equip.



Decide which bullet you are going to use, brand and weight. Take that bullet and start it into a case that allows the bullet to move. It needs to be snug enough to keep the bullet in place after you extract it but not so tight otherwise the bullet may stick into the rifling. Some people take a case and split the neck and do the same thing. It is whatever you can do repeatedly.

You chamber the case with the bullet in the neck. As you chamber it the rifling pushes on the bullet's ogive forcing the bullet back into the case. You need to do it a few times to get an average to make sure the rifling isn't hanging onto the bullet. Also, if the case is too tight the bullet can be foreced into the rifling giving you an incorrect size.

Also, it depends on the ogive of that bullet. Bullets within the same box can and often do have different ogives. And different bullets, as in brand or weight, will definitely be different.

In order to get the best results you need to measure the distance to the ogive rather than OAL but OAL worked for me before I started measuring ogive. Before getting the stuff to measure the ogive I would seat mine far enough off the lands that a difference in ogive length wouldn't have caused a problem.

You need to do this each time you change the bullet's weight or brand or both. Never assume that bullets that are the same weight have the same exterior dimensions.

Dolomite

[theflatlander]

Decide which bullet you are going to use, brand and weight. Take that bullet and start it into a case that allows the bullet to move. It needs to be snug enough to keep the bullet in place after you extract it but not so tight otherwise the bullet may stick into the rifling. Some people take a case and split the neck and do the same thing. It is whatever you can do repeatedly.

You chamber the case with the bullet in the neck. As you chamber it the rifling pushes on the bullet's ogive forcing the bullet back into the case. You need to do it a few times to get an average to make sure the rifling isn't hanging onto the bullet. Also, if the case is too tight the bullet can be forced into the rifling giving you an incorrect size.

Also, it depends on the ogive of that bullet. Bullets within the same box can and often do have different ogives. And different bullets, as in brand or weight, will definitely be different.

In order to get the best results you need to measure the distance to the ogive rather than OAL but OAL worked for me before I started measuring ogive. Before getting the stuff to measure the ogive I would seat mine far enough off the lands that a difference in ogive length wouldn't have caused a problem.

You need to do this each time you change the bullet's weight or brand or both. Never assume that bullets that are the same weight have the same exterior dimensions.

Dolomite
[/quote]

whats the best way to go about splitting the neck of the case? I dint have any case loose enough to allow the bullet to slide properly wo getting jammed into the rifling

[Budweiser360]

hacksaw, small cutting disc on dremel etc....