Age old question about col

[hammrp]

Hi Folks. New to forum, in fact new to forums. I have been reloading since 69 but only worked up loads from accuracy loads and working with the powder and primers with some incredible success in some of my firearms.
I just started reading and trying to work with bullet length. I bought the Hornady OAL Gauge and Comparator and tried them in several guns. Some were ok, but I have 2 Remington Ultra Mags that when measured with the Nosler BTs touching the lands, the bullet is only in the casing about .023". Is this extreme? Obviously the bullets cannot be loaded like this and I am a bit "confused". Is this a normal thing on the ultra mags? Thanks for all your help. I am really enjoying reading the wealth of knowledge and experience on this site.

 

[Richracer1]

Yes, the Rem ultra mags have a lot of freebore. You are limited by the size of the magazine. I have all four RUMs and my maximum COL (measured from base to tip - no comparator) is 3.67". Start with what will fit in your magazine and cycle properly to start with. Most of my RUMs COL length is between 3.62" and 3.64" using the measurement process stated above.

In fact, I can't even load my 7mmRUM with 150 E-Tips to even be within .020 of the lands. There won't be enough of the bullet in the case.

 

[Guest]

From what it sounds like you have alot of "freebore" or bullet lead, which
also means a long throat. Have the rechambered to somthing similar to
shorten the throat, unless you load high density charges with load manual
COAL's.

 

[Ol` Joe]

Some companies put leades in their chambers you need the Hubble telescope to find. Whby is one. Their leads are ~0.5" long.
The leads also move foreward as the throat erodes and a older rifle with a large rd count behind it will appear to be unreachable at some point.

I try to start load development with the bullet at the lands. If I find I can`t do this and maintain a caliber of bullet shank in the case mouth, or load the cartridge in my magazine I go to the longest lenght that allows these parameters to be met. Once I find my max load I shorten the COL in 0.005" increaments to tune for best accuracy. Sometimes the ogive ends up 0.1+" from the lands, sometimes it is still right at the lands.
Load your bullet to a COL that allows filling the mag and has at least 0.2+" of shank in the case and go from there.
Be aware the less you have of bullet in the case the better your chanch of it being knocked out of alinement or neck tension being too light to keep the powder burn starting out evenly and the velocities consistant.

 

[hammrp]

Thanks, makes me feel better. I was beginning to think I was doing something wrong. I did it twenty or more times. I will start with the mag length and work from there. Thanks for those numbers, they are similar to what I was seeing.