Question on seating shorter than book recomends.

[Red_Dog_Leader]

Have a Walther P99c that needs very short COL.

Trying to load Ibejihead 128RN, plunk tests is 1.075ish.

My Sierra manual for a 130RN FMJ COL is 1.150
My Lyman 47 for a 130g alloy is 1.016....

Now I know if I use the sierra load data to back down start charge for shorter COL (and also the Ibeji being a coated bullet), but was wondering how much.

Start at the min load, min load -5%, -1/2 grain less than min load?

How do you all approach this?

Thanks, T

 

[Conservidave]

http://www.thehighroad.org/showthread.php?t=755119

Take a look at this post where i had a similar issue........

Hope i linked it correctly.

 

[au_prospector]

Are you saying you have a 9mm Walther P99c with a chamber that is only 1.07 inches? That is a head scratcher for me. I have factory Federal American Eagle 124 grain RN FMJ ammo that is 1.155 OAL. Are you saying that would not chamber?

 

[Red_Dog_Leader]

Are you saying you have a 9mm Walther P99c with a chamber that is only 1.07 inches

Using dummy round I seat till round drops into barrel and drops out freely when barrel is turned over, also check end of round with barrel hood.

With this bullet, 1.075 or so allows the round to drop free from chamber....this seems to be the case (shorter COL's) with a lot of bullets from different manufacturers when loading for this pistol

 

[Red_Dog_Leader]

Thanks, Conservidave...

Seat where you have to seat.
Start at the Starting load.
And work up until you get proper functioning and ejection distance.

When I start back up I'll try this.

 

[Sunray]

"...min load -5%..." Do not do that. It's not necessary and can be unsafe.
Something isn't right with how you're plunking. Walther wouldn't make a barrel that is that much under SAAMI spec.

 

[Edarnold]

Were it my gun, I'd be finding a reputable pistol smith to correct the leade, which is apparently way too short. Being stuck with he current chamber means you have a 9x19 with the case capacity of a .380.

 

[rooster59]

There's nothing wrong with your pistol. The bullet profile of your Ibejihead 128RN is fatter on the part of the bullet sticking out of the case. If it's fatter, there is more weight in the part sticking out of the case, and less inside the case. But then you have to seat it a bit deeper to clear the rifling in the barrel.

Do any factory loads from Fed Win Rem Speer Horn not chamber? No, they all fit fine.

Look at the 9mm bullets here-

http://leeprecision.com/bullet-casting/hand-gun-bullet-molds/bullet-mold-6-cavity/

I'll bet your profile looks like bullet 356-125-2R. That bullet is going to stick in the rifling at a point farther forward than bullet 356-124-TC, or a bullet with the usual profile of a factory FMJ.

 

[Rule3]

I have the same issue with CZ 75 Custom and MBC 125 softball lead bullet. The shape of the lead bullet is fatter and will not "plunk: unless seated much deeper. Other brands of lead with a sharper angle seat just fine as do FMJ.

Somewhere around 1.080 or less for my gun.

There is nothing wrong with you gun. Does a factory FMJ round plunk in and out??

So as above seat where you need to and start at the min charge.

 

[Red_Dog_Leader]

"...min load -5%..." Do not do that. It's not necessary and can be unsafe.
Something isn't right with how you're plunking. Walther wouldn't make a barrel that is that much under SAAMI spec.

Using an auto pistol barrel find a MAX O.A.L with your bullet
http://www.thehighroad.org/showthread.php?t=506678

Set your OAL for the longest recommended - then try The Plunk Test -

remove the barrel from your gun, and drop the loaded round into the

chamber.

The cartridge should fall all the way in, without any pushing, and spin

freely in the chamber, and drop freely from the chamber if you turn the

barrel upside down.
Been doing it this way above for all my pistols.
Just loaded up Berrys115RN @ 1.125...drops in and out freely
Just checked HOR Critical Defense 115FTX's, 1.092, drops in and out free

Am I missing something?

 

[Red_Dog_Leader]

I have the same issue with CZ 75 Custom and MBC 125 softball lead bullet. The shape of the lead bullet is fatter and will not "plunk: unless seated much deeper. Other brands of lead with a sharper angle seat just fine as do FMJ.

Somewhere around 1.080 or less for my gun.

There is nothing wrong with you gun. Does a factory FMJ round plunk in and out??

So as above seat where you need to and start at the min charge.

Yes, some Win white box, just checked those too...

so, back to the question, this will work OK;
Seat where you have to seat.
Start at the Starting load.
And work up until you get proper functioning and ejection distance.

 

[Red_Dog_Leader]

There's nothing wrong with your pistol. The bullet profile of your Ibejihead 128RN is fatter on the part of the bullet sticking out of the case. If it's fatter, there is more weight in the part sticking out of the case, and less inside the case. But then you have to seat it a bit deeper to clear the rifling in the barrel.

Do any factory loads from Fed Win Rem Speer Horn not chamber? No, they all fit fine.

Look at the 9mm bullets here-

http://leeprecision.com/bullet-casting/hand-gun-bullet-molds/bullet-mold-6-cavity/

I'll bet your profile looks like bullet 356-125-2R. That bullet is going to stick in the rifling at a point farther forward than bullet 356-124-TC, or a bullet with the usual profile of a factory FMJ.

Yes

 

[kcofohio]

The way I read the SAAMI specs for the chamber, that if a bullet's bearing surface exceeds .797" from the head stamp, you could potentially have a misload problem with a barrel being within specs.

 

[LiveLife]

Ibejihead 128RN

Although their website doesn't say what kind of coating they use, I think IbejiHeads bullets look like "Hi-Tek" type coating and Bayou Bullets who uses Hi-Tek coating recommends that we use lead load data - http://ibejiheads.com/product_info.php?cPath=1&products_id=29

Also, IbejiHeads 9mm bullets come sized either .356" or .357" so they will likely produce higher velocities than .355" sized bullets (as in higher chamber pressures).

Picture above shows bejiHeads 128 gr RN. It's got "non-step" nose which means the nose is less pointed than the typical "stepped" nose RN and will result in longer bullet base than 125 gr RN.

plunk tests is 1.075ish.

If you look at the comparison picture above, you will notice Missouri 124 gr RN (non-step) has shorter nose and longer bullet base than Dardas/Z-Cast RN (stepped) bullets. Instead of typical 1.125" OAL/COL I use with stepped RN, with non-step bullets, I need to use shorter 1.080" - 1.100" to prevent bullet's bearing surface (part that rides the rifling) from hitting the start of rifling. So use the OAL/COL that will allow the dummy round (no powder/no primer) to fall into the chamber freely with a "plonk" and spin without rubbing the rifling but also function test the dummy round by feeding it from the magazine and releasing the slide without riding it to ensure reliable feeding/chambering - this is your final "working OAL/COL" you use to conduct your powder work up.

Due to longer bullet base, using shorter OAL/COL also means the bullet base will get seated substantially deeper and raise chamber pressures.

If you look at the comparison picture below, the Missouri non-step RN loaded at 1.080" compared to FMJ at 1.135" shows different OAL/COL due to different shape of the bullet nose but notice the curvature of the bullet (ogive) just above the case mouth that will engage the rifling are about the same.

Now I know if I use the sierra load data to back down start charge for shorter COL (and also the Ibeji being a coated bullet), but was wondering how much.

Start at the min load, min load -5%, -1/2 grain less than min load?

How do you all approach this?

125 GR. LCN W231/HP-38 Diameter .356" OAL/COL 1.125" Start 3.9 gr (1,009 fps) 25,700 CUP - Max 4.4 gr (1,086 fps) 31,200 CUP

Due to deeper bullet seating depth, when I used Hodgdon's lead load data with 124 gr Missouri "non-step" lead RN at 1.080"-1.100" at 4.2-4.4 gr, I got full-length leading in my .355"-.356" groove diameter Lone Wolf barrels (the higher chamber pressures from deeper seated bullet base were over-driving the bullets). When I reduced my powder charges to 3.6-3.8 gr, my leading stopped and I ended up using 3.8-4.0 gr without leading.

So for your 128 gr coated "non-step" bullet (which will have even longer bullet base than 125 gr non-step RN), I would use lead load data and reduce the start/max charges by .2-.3 gr.

 

[Red_Dog_Leader]

Thanks for your input bds,

Planned on using W231 for this load.
Hodgdons suggested for Berrys 130rn using 231 @ 3.9 to 4.3 at 1.150,

So, start @ 3.6 and load a few and work up from there then?

 

[LiveLife]

If your bullet seating depth is significantly deeper, 3.6 gr could be near your max charge.

For my initial load development/powder work up with a new bullet (especially with bullet type that will seat deeper than listed OAL/COL), I prefer to use the most conservative load data.

After I experienced full-length barrel leading, I suspected I was over-driving the bullets so I used more conservative 1999 Winchester lead load data for 124 gr lead RN which listed 3.3 - 4.0 gr as start/max charges - http://www.thehighroad.org/attachment.php?attachmentid=159609&stc=1&d=1329800605

9mm 124 gr. Lead RN W231 Start 3.3 gr (910 fps) 23,800 psi - Max 4.0 gr (1035 fps) 32,900psi

You can calculate the bullet seating depth by subtracting the bullet length from the OAL/COL. If your bullet seating depth is significantly deeper than what Hodgdon's current load data used, you could even try starting out at 3.4 gr.

BTW, are you using .356" or .357" sized bullets?

 

[Red_Dog_Leader]

.356

 

[LiveLife]

Keep us posted with a range report!

 

[rsrocket1]

Here's a sample plot I made one day by running a bunch of Quickload calculations keeping everything the same except seating depth and plotting muzzle velocity and max pressure vs. COL. You can see that velocity goes up as you make the round shorter, but pressures go up faster. You can see that a 0.06" change increases the velocity by 70 fps, but raises the pressure by 8,600 psi. These are just estimations, but the calculated velocities are very close to actual measured velocities I've measured with my chrony.

 

[Rule3]

Yes, some Win white box, just checked those too...

so, back to the question, this will work OK;
Seat where you have to seat.
Start at the Starting load.
And work up until you get proper functioning and ejection distance.

The pictures by bds are worth a thousand bullets

The Win WB is a fmj bullet with a much sharper taper to the bullet so it will chamber as the nose of the bullet is not hanging up.

It's just the shape of your bullet and as Rooster stated it is just hanging up in the rifling. Exactly the issue I have with my CZ. I use HP 38 and Power Pistol. Again start with the Hodgdon start data (which is conservative to begin with. You are not gonna blow anything up by the change in seating depth using the min charge, Less pressure with a lead bullet plus the guns are rated to go into +P range anyway so there is some leeway.

 

[LiveLife]

Wow, thanks rsrocket1 for posting that information!

And keep in mind that bullet setback may occur pushing the bullet base deeper in the case neck when the round's nose gets slammed on the feed ramp by the slide.

So your "post-chambered OAL/COL" could be several thousandths shorter than your "working OAL/COL".

These days, I also check pre/post chambering OAL reduction after I determine my working OAL as part of my reloading QC steps.

 

[Red_Dog_Leader]

Thanks to all for the info.
Going to try 3.4, just a few...