9mm OAL

[glennv]

I've been reloading Powerbond 124 grain round nose with 5.5 grains of Power Pistol, OAL of 1.135 and a light crimp on the Lee factory crimp die. I've had no issues at all until I switch to the same bullet but in a hollow point. The ten I loaded up all failed to drop into and out of the barrel chamber. I understand that the HP should have a shorter OAL so I worked from Speer's Max OAL down to 1.105, where they will now chamber fine. Is this way to short for 9mm?

Thanks

 

[Dudedog]

I load a lot of ammo 9mm ammo 1.10 OAL. Different bullets and pistols may require a different OAL than is listed in a manual or on a web site.
You need to do the plunk test to see what OAL will work in your firearm with the bullet you are loading.

http://www.thehighroad.org/showthread.php?t=506678

Be aware as you shorten OAL (bullet deeper) pressure goes up (less space in the case),
so a safe "MAX" load at 1.12 might be over "MAX" at 1.08 for example.
So if you need to shorten the OAL back off your powder charge and work back up.
In one of my pistols with the same powder charge going from 1.10 to 1.08 raised the avg velocity about 35 fps.
This is not to say you would get the same results in your loads by going .02 shorter it's just an example to show that it will increase pressure.

 

[7mmb]

The biggest thing to watch out for when seating bullets for auto pistol cartridges is how far the bullet seats inside the case. The HP bullet is shorter than the RN bullet and if they are seated to the same OAL the RN will be seated deeper inside the case. With the HP seated to the same OAL as the RN it isn't seated as deeply and part of the shank of the HP bullet is outside of the case. When chambered the shank hits the lands of the rifling. That's why it fails the drop test.

To seat the HP bullet to the same depth as the RN measure the length of each bullet. Subtract the length of the RN bullet from your 1.135" OAL. This is the length from the case head to the bottom of the seated RN bullet. Add this number to the length of the HP bullet and you will get the OAL of the HP round seated to the same depth as your RN rounds. Done this way both bullets will have the same powder capacity beneath them. If the HP rounds pass the plunk test at this OAL (and if the shanks of both bullets are the same length they definitely will pass) you are good to go and you can use the same data with both bullets.

 

[Sunray]

1.135" is too short for a 124 jacketed according to Hodgdon. And Lyman. Both say 1.169" is max OAL. Been loading cast 121's to that for eons. Not an HP though.
Don't think you have a length issue. Any bulging on the case?

 

[CZ9shooter]

Shorten OAL and work up. No big deal. The OAL in load manuals is just a suggestion. Use what works.

 

[tightgroup tiger]

I understand that the HP should have a shorter OAL

That would not necessarily be correct. XTPs have a higher straight shoulder so they do have to be loaded deeper than say another brand of hollow point with a lower break in the shoulder.
The gun in question plays a huge part also, I have one 9mm that is short chambered that I have to load 1.10 for and another that I can reach out to 1.140 to before hitting the riflings with the same bullet.
Welcome to reloading!

 

[Toprudder]

I load a lot of ammo 9mm ammo 1.10 OAL. Different bullets and pistols may require a different OAL than is listed in a manual or on a web site.
You need to do the plunk test to see what OAL will work in your firearm with the bullet you are loading.

http://www.thehighroad.org/showthread.php?t=506678

Be aware as you shorten OAL (bullet deeper) pressure goes up (less space in the case),
so a safe "MAX" load at 1.12 might be over "MAX" at 1.08 for example.
So if you need to shorten the OAL back off your powder charge and work back up.
In one of my pistols with the same powder charge going from 1.10 to 1.08 raised the avg velocity about 35 fps.
This is not to say you would get the same results in your loads by going .02 shorter it's just an example to show that it will increase pressure.

^^^ This ^^^

There are some FP 9mm that I have to seat way less than 1.100" in order to plunk in my gun.

I created a list of common name brand bullets and their lengths (not seating depth, but bullet length) so that I could know the seating position of the base of the bullet when referencing published load for those bullets. It has come in handy a few times when I was working up loads for different bullets.

 

[LiveLife]

9mm ... round nose ... OAL of 1.135 ... switch to ... hollow point ... all failed

1.105 ... now chamber fine. Is this way to short for 9mm?

No.

Most FP, RNFP and HP bullets will seat deeper than RN bullets of same weight due to shorter nose and longer body. While most RN bullets are designed to be loaded up to 1.169" (with exceptions), FP/RNFP/HP bullets need to be loaded shorter around 1.100" or the shoulders will hit the start of rifling.

Some RN bullets (like MBC, Dardas, etc. without stepped nose) have shorter/rounder nose with longer body and need to be loaded shorter than 1.080"-1.100" to work in barrels with quicker start of rifling.

To avoid compressing the powder charge (which significantly increases chamber pressure), when I am loading with bullets that get seated deeper, I will first determine the max/working OAL then calculate the bullet seating depth by subtracting the bullet length from the working OAL. I will then fill the case with powder to bullet seating depth and weigh the powder charge to determine max case fill for that powder/bullet seating depth to reference with load data.