Hi, guys. I need some advice on overall length for 9mm.

I'm going to be setting up loads with WSF powder under a 115gr FMJ bullet. The Hodgdon/Winchester load data has min charge of 4.9gr (24,200 psi) and max charge at 5.7 (31,900 psi). No problems there. But they list COL at 1.169. That's right at max COL for the 9mm and doesn't leave any room for variance. (Have you ever seen COL spec'd at max like that?)

I have factory ammo that runs fine in my guns that come in at 1.158. so I know I'm good up to that. I'll run a drop test at 1.169 just to be sure I can go full length.

I'm thinking about cutting back on the COL just a bit to allow for a bit of variance in seating without exceeding max. I know decreasing COL will increase pressure, but how sensitive is it? If I cut my COL back to 1.160, does that 9/1000 send pressures crazy? I'm not interested in hot loads. I'll start at min and probably run in the 4.9 - 5.3 range. Is a .009 decrease pretty safe when I'll be in the low to mid range?

Thanks for any insight on this. I'm new to reloading the 9mm and I keep hearing how sensitive the 9 is.

Rick

1.169 from lee lyman manuals deep seated bullets in a pistol can raise pressures a lot.

The 1.169 is the SAAMI max. I believe the SAAMI min is 1"

QL doesn't list WSF but just looking at my Accurate No 5 load going from 1.169 to 1.16 raises pressure about 1000psi. About .2gr of powder

I think I'm not asking my question clearly...

I know the min and max for the cartridge. The issue is that the load data calls for a COL of 1.169, which is right at max. Any variance from round to round would result in exceeding the max. That's why I'm thinking about backing off the recipe COL, to allow for any variance from round to round. So the question is if I back off the recipe by .009, is the resulting increase in pressure in the crazy/dangerous level or in the "be aware of it, but safe" level?

ETA: ramrod- I posted this before you added your new info. Thanks for the info. 1,000 psi sounds like the "be aware of it, but safe" level. I may back off the .009 and start at 4.7 rather than 4.9. Good info.

Didn't notice it was your first post welcome.

For the .009 change I doubt I would worry about dropping my starting charge.

I doubt .009 will make any detectable difference in pressure of that load. I usually load to whichever is the shorter, magazine length, throat length, or ejection port length. If it is a modern 9mm you probably have lots of wiggle room.
I just looked up some of my loads for my M&P and the oal's vary from 1.050 to 1.170, depending on bullet.
C.G.B.

Thanks, both of you.

I'm shooting all modern guns, M&P's, XDm's, etc. You've both confirmed what I suspected and was hoping for.

From Speer: "loads that produced 28,000 CUP went to 62,000 CUP when bullets were purposely seated .030" deeper!"
Caution is advised.