Same bullet different c.o.l.

[wvbuckbuster]

Have you ever encountered a situation where using the same bullet with different powders causes the c.o.l to be changed when switching powders? I can't recall this happening myself. Just wondering. Dan.

 

[SJB358]

I have Dan. Different powders make different harmonics, so I have had to change seating depth a few times to bring everything back together.

 

[JD338]

I've delt with this as well. Depends on load density as well as the bullet. The ogive can sometimes vary too.

JD338

 

[lhsako]

My experience is the ogive problem is more common than we would wish.

 

[DrMike]

I've delt with this as well. Depends on load density as well as the bullet. The ogive can sometimes vary too.

JD338

Jim is delivering the straight skinny on this.

 

[RL338]

I have a lot of Weatherbys with their long freebore that a slight difference in COAL doesn’t come into play.
Now if your working with compressed loads with different powders , some will compress more than others leaving you with a possible variants in length.

 

[Lazy Bushman]

by reading the replies I'm struggling with my interpretation of your question. Are you saying that by changing only powder, could there be a variation in cartridge over all length? If so I would say No. That's the way the post reads. But are you asking if by changing powder, do you need to adjust seating depth as a result the cartridge over all length to achieve the same accuracy then my answer would be Yes. Sorry I'm not quite getting the question

 

[wvbuckbuster]

by reading the replies I'm struggling with my interpretation of your question. Are you saying that by changing only powder, could there be a variation in cartridge over all length? If so I would say No. That's the way the post reads. But are you asking if by changing powder, do you need to adjust seating depth as a result the cartridge over all length to achieve the same accuracy then my answer would be Yes. Sorry I'm not quite getting the question

I meant using the same bullet but with different powders does it or would it cause the c.o.l. to be changed in order to achieve the same group size. I know not all bullets and powder make good combinations. Let's say you're using a Nosler 165gr AB with RL15 then try Varget with the same bullet. If the established load using Rl15 and that c.o.l. would or could it have to be changed using Varget? Hope this helps. I've adjusted seating depth with a given powder until acceptable accuracy was achieved as we all have. Just hadn't thought having to change c.o.l. when switching powders. It's possible I have done this, just didn't remember. Will search my loading data. Dan.

 

[TexasLife]

My issue is a little different? I run the same coal, but ctbo is different. Bullet length is close to the same tho. Sierra 24cal 90fmj's.

 

[TackDriver284]

Going from one powder to a different powder may require seating depth adjustments due to barrel harmonics and burn rate / velocity to find the perfect node. Different powders have different densities, different case fill and compress more than others. More compressed powders will have a slightly longer COAL than a less compressed powder if using the same seating die adjustment.