Loading Hornady 115 GN 9mm FMJ Round Nose Bullets

[Ernest T]

I have a general question about cartridge overall length and seating depth for 115 GN 9mm FMJ cartridges.

I've found commercial ammunition all over the place with regard to COAL.
Winchester - 1.164
Remington - 1.107
Aguila - 1.112
Federal - 1.149
Blazer - 1.154

All my 9mm guns feed all these cartridges well.

I'm reloading using the Winchester cases with 115 GN Hornady 9mm FMJ bullets, CCI small pistol primers, and a starting charge of 4.7 GN of CFE pistol powder. The Hornady manual says the COAL for this bullet is 1.100 which is much shorter than the Winchester cartridges and a little shorter than all the other brands. I mocked up a few cartridges using the Hornady data and they fit in my cartridge gauge and the barrel of one gun. I also loaded up a magazine and cycled the slide and the cartridges loaded and ejected without any issues.

My three questions, which are really related:

1. COAL by itself doesn't really tell you much about a cartridge does it?

2. Am I correct in thinking that all the reloading data in the Hornady book pertaining to the 115 GN FMJ bullets use 1.100 COAL so over-pressure isn't an issue even with the short length?

3. Given the same velocity, Is the pressure in a 9mm 115 GN FMJ that is 1.160" long similar to pressure of the same bullet that is 1.099 long even though the bullet is obviously seated deeper in the shorter cartridge or is that an over-generalization?

As an aside, I'm really interested in taking the bullet out of the Winchester cartridge to see how it compares to the Hornady 115 GN bullet. I don't see how it can be any longer given its made of lead and copper just like the Hornady.

Left to right Winchester is the longest and my reload the shortest.

The longest and shortest.

 

[fkimble@charter.net]

The critical measurements are OAL, must fit in the mag. The ogive of the bullet, nose taper if you will, the length of full bullet diameter determines if it will fit in your chamber. Now functioning, getting from mag to fully chambered in battery can be affected by OAL, but usually 9's feed a FMJ without much fuss, just don't load to either extreme.

Look at your pic of the rounds lined up, it;s easy to see there are different bullet nose profiles.

Frank

 

[Ernest T]

The critical measurements are OAL, must fit in the mag. The ogive of the bullet, nose taper if you will, the length of full bullet diameter determines if it will fit in your chamber. Now functioning, getting from mag to fully chambered in battery can be affected by OAL, but usually 9's feed a FMJ without much fuss, just don't load to either extreme.

Look at your pic of the rounds lined up, it;s easy to see there are different bullet nose profiles.

Frank

I only reload one rifle cartridge at the moment, .223 Remington, and I use the case head to ogive measurement to set the overall length in the bullet seating die. Then I just check to make sure they fit in the cartridge gauge and are short enough to fit in my magazine. I didn't think that was too important in a pistol cartridge -- as long as the bullet fit in the chamber. My Hornady comparator didn't come with a insert large enough for 45 ACP for sure. I don't know if I have one to fit 9mm either.

 

[RickKr]

...snip...
3. Given the same velocity, Is the pressure in a 9mm 115 GN FMJ that is 1.160" long similar to pressure of the same bullet that is 1.099 long even though the bullet is obviously seated deeper in the shorter cartridge or is that an over-generalization?
...snip...

I don't know that, given all the components/gun are the same, that you can have the same velocity with different COALs, simply because the pressures are different. I ran your two examples through Gordon's Reloading Tool (for which I have a 115 gr. FMJ load using Unique). All that I changed was COAL. Pressures and velocities differed:

COAL Pressure Velocity
1.160 16027 1007
1.099 19726 1057

Rick

 

[robert8904]

9mm bullets in a given weight and style vary quite a bit in length depending on manufacturer. OAL is less important than the amount of space under a seated bullet.

Say you use Hornady load data for a 115 round nose from a different manufacturer that is .040" longer. Seated to Hornady's 1.100", now there is less room for the powder. 9mm is a small case and can build pressure very quickly if you don't pay attention to the case volume under a seated bullet. In a maximum 9mm load, seating .040" deeper than spec can easily cause a case failure "Kaboom". Having insufficient bullet tension can allow the bullet to drive deeper into the case on feeding, the source of many pistol kabooms.

I load lots of different brands and styles of 9mm bullets. If using Hornady data with a different bullet, I compare the length of the bullet to the Hornady bullet in the data. If, for example, the other bullet is .015 longer than the Hornady, I'll load it .015 longer than the Hornady so there is the same space under the bullet.

 

[Ernest T]

9mm bullets in a given weight and style vary quite a bit in length depending on manufacturer. OAL is less important than the amount of space under a seated bullet.

Say you use Hornady load data for a 115 round nose from a different manufacturer that is .040" longer. Seated to Hornady's 1.100", now there is less room for the powder. 9mm is a small case and can build pressure very quickly if you don't pay attention to the case volume under a seated bullet. In a maximum 9mm load, seating .040" deeper than spec can easily cause a case failure "Kaboom". Having insufficient bullet tension can allow the bullet to drive deeper into the case on feeding, the source of many pistol kabooms.

I load lots of different brands and styles of 9mm bullets. If using Hornady data with a different bullet, I compare the length of the bullet to the Hornady bullet in the data. If, for example, the other bullet is .015 longer than the Hornady, I'll load it .015 longer than the Hornady so there is the same space under the bullet.

I see that now. I'm using a load from the Hornady manual for this specific bullet. They used Hornady brass and Winchester primers. I don't have those, but the CCI SPP and Winchester cases should be close. I did some investigating this morning and these are short bullets.

I measured the overall length of the bullet and the portion outside the cartridge and there isn't a whole lot in the case so the short COAL makes sense. It does feed and chamber in at least one of my guns.

I measured a few cases to double check they were in spec. All of them come out to within 1 thousandth of an inch.

I'm going to load 20 cases and see how close to the expected velocity they come.

 

[Ernest T]

I don't know that, given all the components/gun are the same, that you can have the same velocity with different COALs, simply because the pressures are different. I ran your two examples through Gordon's Reloading Tool (for which I have a 115 gr. FMJ load using Unique). All that I changed was COAL. Pressures and velocities differed:

COAL Pressure Velocity
1.160 16027 1007
1.099 19726 1057

Rick

That makes sense to me. I wish the manual gave you the pressure for each load.

 

[Louisiana Shooter]

In my experience, pistol ammunition can be very sensitive to setting depth for velocities and pressures. Seating deeper than recommended OAL will increase pressure. Don't stray too far from OAL generally recommended by the manuals for the bullets you're loading.

 

[Ernest T]

In my experience, pistol ammunition can be very sensitive to setting depth for velocities and pressures. Seating deeper than recommended OAL will increase pressure. Don't stray too far from OAL generally recommended by the manuals for the bullets you're loading.

I won't. The shortness of the recommended COAL threw me off, that's why I looked at commercial ammo and asked the questions. I've reloaded 45 ACP FMJ and the maximum COAL for the cartridge is not much longer, only .025, than the COAL of the Hornady 230 GN FMJ bullet.

 

[Beiruty]

115gr RN plated Xtreme or Berry

1.150" COAL
Any range pick up case
4.2gr Titegroup

With some good factory crimp use LEE crimping die.
Try it you will like it

 

[Beiruty]

If less than the bullet bearing surface is not in the case, the bullet may come out of the case while riding the ramp to the chamber, that is especially true if the reloader did not apply enough crimp

If bullet is seated deep in the case, the bullet may be pushed back into the case while riding the ramp to the chamber, that is especially true if the reloader did not apply enough crimp

 

[Ernest T]

I made ten cartridges each with 4.7, 4.9 and 5.3 gr. of CFE Pistol and seated the bullets at 1.100, per the manual, with a light crimp. I skipped the last two loads as I'm not looking for hot loads, just range ammo. If one of these three loads work well, I'll be done. They all dropped in my barrel just like the commercial cartridges. I'll chronograph them at the range and see how close they come to their rated velocity. It'll probably be middle of next week before I can get out.