Xtreme RN VS Xtreme HP col

[slayer61]

Fellas,
I've been loading Xtreme round nose for a little while and thought I'd give their HPs a shot (sorry bad pun) I found their 9mm 124 gr HPs to be shorter than the RN version. No worries, shorten COL accordingly to get the projectile seated the same distance as the RN version. Leaves my COL about 1.10 iirc. Feeling pretty good about bullet seating depth being the same in both applications.

Set up for 40S&W and I find that the HP projectiles are LONGER than the RN version. I didn't want to stuff the projectile that much further into the case without changing powder charge, so I went back to minimum load and made the COL same as the RN...

Am I on the right track? or is there another approach I should be taking?

[Metal Fiend]

Tagged, I'm in the same boat but with .45acp

[David-K]

FWIW, I always maintain the same COAL for the particular caliber, regardless of bullet profile or weight. If needed, I'll adjust charge weight one way or the other. In a couple of instances, I left the charge weight the same, despite the difference in projectile length and experienced no ill effects, no drop in performance and no exessive pressure signs.

[9mmepiphany]

I took a different approach...doesn't mean it's right

My goal is to maintain the same volume, for powder, in the case.

What I do is compare the different bullet lengths and reduce/increase my OAL by the difference

[rsrocket1]

I've worked the other way from David-K and similar to 9mmepiphay. If the different COL's are proven not to cause feeding problems, I like to keep the seating depth the same. That way your MV and pressures will remain fairly consistent. The 9mm case has such little volume that a bulky powder like Unique will fill the case to compression and the SD has a big effect on pressures.

Things like ultra short throats and choke-a-matic guns like some 1911's will dictate whether COL is flexible or rigid.

[David-K]

I've worked the other way from David-K and similar to 9mmepiphay. If the different COL's are proven not to cause feeding problems, I like to keep the seating depth the same. That way your MV and pressures will remain fairly consistent. The 9mm case has such little volume that a bulky powder like Unique will fill the case to compression and the SD has a big effect on pressures.

Things like ultra short throats and choke-a-matic guns like some 1911's will dictate whether COL is flexible or rigid.

Probably the best advice so far. I'm very familiar with the powder, primers, brass, projectiles, etc., that I'm using for the caliber in question. As a result, I'm very comfortable loading things the way I do. Mind you, I'm well within the established/published load range when maintaining the consistent COAL that I choose to. However, by the OP's own admission, he's just starting out and I think following rsrocket1's advice would be a good idea.

[Burbur]

I've worked the other way from David-K and similar to 9mmepiphay. If the different COL's are proven not to cause feeding problems, I like to keep the seating depth the same. That way your MV and pressures will remain fairly consistent. The 9mm case has such little volume that a bulky powder like Unique will fill the case to compression and the SD has a big effect on pressures.

Things like ultra short throats and choke-a-matic guns like some 1911's will dictate whether COL is flexible or rigid.

+1

When feeding issues are not present, seating depth is a great indicator when venturing into uncharted territory.

[stilly]

What is SD again? I keep thinking:
Standard Deviation
Standard Definition

But they do not seem to make sense here.


OH, SEATING DEPTH! NM...

**** this internet and its damn 50 thousand acros...

[sofbak]

^^^^^ Thank you. I was having the same block with "SD"..