45 Auto OAL??

Nathan · May 11, 2015, 10:24 AM

I am loading Powerbond 230 PHP's. I know mag length is 1.275". I have loaded other FMJ or PHP's to 1.230". My Speer Gold Dot factory ammo is 1.205". Other FMJ factory was 1.260.

These Powerbonds had to be loaded to 1.190" to pass the "plunk" test. Anybody else load this short to pass the plunk test?

noylj · May 11, 2015, 02:55 PM

No, if that is what it takes, then that is what it takes. Simply start at lowest start load you can find (or, maybe, a little lower) and work the load up.
Did you cover a round with magic marker and determine that the COL was actually too long?

skizzums · May 12, 2015, 08:36 PM

different bullet shapes will have drastically different coal. FMJ will geneally be the longest and HP will be everything in between to much shorter depending on who makes them. BUT, may I ask why they would fail the "plunk" test when loaded to normal length?

**Unclenick** · May 13, 2015, 03:32 PM

With its flat meplat, it looks like that bullet is somewhere between a round nose and a truncated cone. It will seat short with that shape. The only bullets with noses long enough for 1.275" are the elliptical round nose profiles. The hemispherical round noses and flat meplat noses are too short in shape for that, meaning the distance from the tip down to the bullet shoulder where the meplat starts is too short to allow full cartridge overall length. Instead, that shoulder runs into the lands and stops the case mouth from getting all the way to its chamber shoulder.

If you want to know if this can affect pressure, then look for a difference in seating depth from that of the longer round nose shapes.

For example, the military's round nose projectile is 0.680" long. Typically you find their cartridges are about 1.265" long, giving them a little wiggle room for cartridge-to-cartridge seating variation. The seating depth is:

Case Length + Bullet Length - COL = Seating Depth

so we have:

0.898' + 0.680' - 1.265" = 0.313"

So if you seat your bullet that same amount using the same powder charge you are likely to be fine. You said you had to go to 1.190". So, rearranging the above, if your bullets are:

Seating Depth + COL - Case Length = Bullet Length

0.313 + 1.190" -0.898" = 0.605"

So if your bullet is 0.605" long or less, you are at or have less than the same seating depth as military ball ammo and should be fine up to their load level or to commercial ball load levels (about 350 ft-lbs using Bullseye or Unique or something in that burn rate range).

Nathan · May 14, 2015, 03:52 AM

Thanks for the math. I may have time to measure som tonight and see.

May 11, 2015, 10:24 AM	#1
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	45 Auto OAL?? I am loading Powerbond 230 PHP's. I know mag length is 1.275". I have loaded other FMJ or PHP's to 1.230". My Speer Gold Dot factory ammo is 1.205". Other FMJ factory was 1.260. These Powerbonds had to be loaded to 1.190" to pass the "plunk" test. Anybody else load this short to pass the plunk test?

May 12, 2015, 08:36 PM	#3
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	different bullet shapes will have drastically different coal. FMJ will geneally be the longest and HP will be everything in between to much shorter depending on who makes them. BUT, may I ask why they would fail the "plunk" test when loaded to normal length? __________________ My head is bloody, but unbowed

May 13, 2015, 03:32 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	With its flat meplat, it looks like that bullet is somewhere between a round nose and a truncated cone. It will seat short with that shape. The only bullets with noses long enough for 1.275" are the elliptical round nose profiles. The hemispherical round noses and flat meplat noses are too short in shape for that, meaning the distance from the tip down to the bullet shoulder where the meplat starts is too short to allow full cartridge overall length. Instead, that shoulder runs into the lands and stops the case mouth from getting all the way to its chamber shoulder. If you want to know if this can affect pressure, then look for a difference in seating depth from that of the longer round nose shapes. For example, the military's round nose projectile is 0.680" long. Typically you find their cartridges are about 1.265" long, giving them a little wiggle room for cartridge-to-cartridge seating variation. The seating depth is: Case Length + Bullet Length - COL = Seating Depth so we have: 0.898' + 0.680' - 1.265" = 0.313" So if you seat your bullet that same amount using the same powder charge you are likely to be fine. You said you had to go to 1.190". So, rearranging the above, if your bullets are: Seating Depth + COL - Case Length = Bullet Length 0.313 + 1.190" -0.898" = 0.605" So if your bullet is 0.605" long or less, you are at or have less than the same seating depth as military ball ammo and should be fine up to their load level or to commercial ball load levels (about 350 ft-lbs using Bullseye or Unique or something in that burn rate range). __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

May 11, 2015, 02:55 PM	#2
noylj Senior Member Join Date: October 21, 2007 Location: Between CA and NM Posts: 858	No, if that is what it takes, then that is what it takes. Simply start at lowest start load you can find (or, maybe, a little lower) and work the load up. Did you cover a round with magic marker and determine that the COL was actually too long?

May 14, 2015, 03:52 AM	#5
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,331	Thanks for the math. I may have time to measure som tonight and see.