Reloading the 9mm Luger - Bullet seating depth & pressure concerns

[Kokopelli]

How concerned should I be about bullet seating depth and how it affects safe pressures when reloading the 9X19? I have reloaded bottle neck rifle calibers and rimmed pistol cases for a long time. However, I'm just starting to reload the 9X19. My manuals publish cautionary notes about bullet seating depths and how pressures can spike above SAAMI recommended levels.

My plan is to reload cast lead 124 grain round nose projectiles to starting levels listed from the Lyman 49th Edition reloading handbook. This is for economical plinking ammunition. I seated a Lee 356-124-2R in a dummy case to 1.169". I loaded in my magazines, dropped into into the chambers of my guns and it was a maximum length but fit easily.

Next, I decided to seat the dummy round a little deeper so that the front lube groove would be just below the rim of the case. I adjusted my seating die using a loaded round of factory RN ball that measures 1.064" and ended up pushing that thing in, about .010" deeper into the case. Drat. Is that round ruined? Then I remembered about seating depth and pressure warnings and... here we are.

How cautions should I be with 9X19 loads? Are any of my supplies super sensitive to seating depth? Here are the supplies that I have to work with:

Powders: Bullseye, WW 231, AA#5, Unique

Primers: CCI 500, CCI 550, Winchester WSP

Bullets: Lee 356-124-2R lead, cast & lubed

Brass: Winchester, Federal, Remington, Blazer (All are once fired cases)

[Divernhunter]

Min load levels will not make as much a difference as max loads. Bullseye will be more touchy than Win231/Unique and I have not used AA#5.
I would try both loads but tend to want the longer load or something between.
You can always pull the bullets on loads you do not want.

[p1choco]

Depending on the manufacturer some barrels can handle +p+. That being said, I wouldn't want to experiment and risk compromising my safety. That being said, unless you trim the all the cases so that they all have uniform length, you will get varied seating depths in relation to the crimp groove from case to case.

[Christopher761]

Yes, you should be cautious.

Your reloading manuals should recommend over-all-length (OAL). And it is a recommendation that fits the powder.

I would be more careful if you are shooting older 9mm like a walther p38 or luger. The older they are, the more likely they will be affected by over-pressures.

Start your loads with the starting load pressures. And measure the speed with a chrono. Also, inspect the brass after firing to look for over pressure signs. Also, how does the gun feel when you shoot it?

The most concern is a double charge, or a zero charge.

If your bullets are longer than the published recommendation, then they will be under pressured, and that should be fine.

Do not set your seating die based upon a factory round. The factory round is a different material (FMJ or copper plated) and it uses different powder. Set the length by hand, and measure the completed round with a set of calipers.

You should buy a bullet puller.

Shooting a factory round that has been pushed into the case an extra .010 is a wild card. Would I shoot if from a 60 year old p38? No. Would I shoot it from a hi-point carbine? yes. Those things can handle +P+. But that is me. It is a risk, and if you shoot it, the risk is all yours.

[rm1911]

[Ktm45]

What firearm and what measurement did you get when you measured MAX OAL in the gun you are loading for?

[Divernhunter]

No need to trim 9mm brass.
Again with starting loads or a bit more you will be ok.
I would load to the longer OAL when possible so long as they work in your firearm.

[Kokopelli]

Thank you all. Sounds like I'll be okay sticking to those starting level loads. I can use this experience when I start reloading 45 ACP down the road.

[Ktm45]

Kokopelli.
Here is a plethora of great info. It would be great reading for you.

https://czfirearms.us/index.php?PHPSESSID=0218076a4d8229f807334ee12e21b6d0&board=33.0