N320 and RMR 124 grain Hardcore Match Flat Nose Plated Question

[cwall64]

Finally got some N320 and looking at the Vihta Vuori #14 PDF seems as though they recommend a longer COL (1.142") than I have been using for BE-86 (1.12") or Hornady #9 (1.05"). I realize that SAAMI is 1.169" max, but with the 0.4 grain min to max spread (3.9 - 4.3 grains) should I actually start a little lower that 3.9 for the workup, since the bullet is different than the one I am using? I'll be using these in a H&K USP 9 or a VP9.

[JRM83]

Overall length should be determined by your barrel. Pull the barrel, load a dummy round long, and drop it in the chamber. If it rotates freely, then the length is okay. If not, load a little shorter and try again. When you determine the max length you can load at I like to subtract .01 or .015 for reliability and that's my length for that bullet/firearm. You should be fine starting at 3.9gr and working to 4.3. N320 with a 124 at 3.9 isn't particularly hot and the HK chambers are pretty forgiving.

[cwall64]

Thanks, after rereading my question I rambled a little!!! Funny thing is I looked back at the Hornady #9 and they only list N350 as a tested VV powder for 9mm 124 grain bullet. They used the shorter COL (1.050" for the FMJ-FP) and less charge than VV #14 on N350 - that was my main concern - if I went down in COL I did not want to be too hot with minimum charge...

[Garmil]

At 1.145 with 3.95 grains of n320 I'm at 1050fps with the 124rn. If you're going much shorter I'd start at 3.8 and work up.

Edited August 7, 2015 by Garmil

[cwall64]

At 1.145 with 4 graibs of n320 I'm at 1050fps with the 124rn. If you're going much shorter I'd start at 3.8 and work up.

I am going to test the suggested 1.142", and if it works in the chambers I am good with that length. I just had not seen that length in anything but the VV manual, and was curious.

[2kcrewcab]

Different bullet profile, but my load data for 124gr. RN plated bullets from The Bullet Works is 4.0 gr N320 @ 1.127" OAL, giving me 1070 FPS out of a Springfield XDm 5.25".