Reloading 9mm FMJ w/concave base

[downtown]

I've been reloading 9mm for about 9 years now. I've used XTreme plated and Hornady FMJ, all 115gr. I've recently got some FMJ from my local shooters supply shop and they have a concave base to them, which makes them longer. The Hornady is .550 and the concave round is .570, but it has a .030 recess at the deepest point. Question is that if I load these up and not adjust my seating depth, would the pressure be much different. Pics show the Hornady on left and concave on right .

[RED333]

Back off the charge a bit, get a cronograph and get a comparison between the 2 loads. You do have a chronograph, yes?

[BigK]

I picked up a 250ct box of something similar on a trade once. Once I got a good OAL that worked in all my pistols, I never changed it. The powder charge is the only variable I tinker with. I don't recall ever needing to change it by more than a few tenths of a grain because I use Bullseye and it's really small.

[leroy]

I wouldn't worry... Volume difference is too small I'ma thinkin... If ya are a bit apprehensive, load up 20 n shoot ta get a good representative sample.  Look at the brass to be sure...

Good luck...

leroy...

PS... I regularly shot a genuine overload in a Ruger 41 mag for years, and saw nothin other than an occasional sticky case.  I discovered the problem re reading the loading manual.  Pistols are susceptible to " double charges " of fast powder... That's why I look in EVERY case I load prior bullet seating with Bullseye, 321, even Unique...

[gregintenn]

I don’t think you’ll see any noticeable difference.

[krunchnik]

6 minutes ago, gregintenn said:

I don’t think you’ll see any noticeable difference.

I will second that-

[downtown]

Thanks everyone

[deerslayer]

10 hours ago, krunchnik said:

I will second that-

Third