Input Please: Starting Charge For Short 9mm COL

[otisrush]

Both when I was buying factory 9mm, as well as now with reloading it, I've always shot FMJs. Due to both cost as well as need (i.e. I didn't need them) I didn't mess with Hollow Points. Now that I can get Hollow Point loads pretty economically by reloading them I thought I'd give 'em a try - just for giggles. So I bought a bag of Winchester 115gr JHPs.

These are going to be shot from a Walther PPQ - which is known for having a short throat. I don't have the number in front of me, but I had to go pretty short to get my 124gr RN FMJs to plunk correctly.

I've constructed a dummy cartridge and 1.108" is plunking correctly with these new JHPs.

My Speer manual has the following loads for a Speer Gold Dot 115 gr:
COL: 1.125"
Min: 4.1gr Titegroup
Max: 4.5gr Titegroup

The Hodgdon website has this data for the 115gr Speer Gold Dot:
COL: 1.125"
Min: 4.5gr Titegroup
Max: 4.8gr Titegroup

(That alone is kind of interesting. I thought I noticed a tendency for the Speer manual to have hotter loads than hodgdon.com. Oh well......)

Given my COL is short relative to the above data, I'm leaning toward starting below the 4.1gr min that is in the Speer manual....maybe starting with 3.9gr or 4.0gr. Does that make sense or am I over-worrying about this?

I'd like to know how others approach situations like this. Given the stories I hear about pressures in 9mm going up fast as COL is reduced I'd like to get opinions.

Thanks.

OR

P.S.: I'm not necessarily looking for input of "Don't use Titegroup." I know of the myriad of inputs and concerns with Titegroup. I've loaded a couple thousand 9mm FMJs with it and have had no issues. I know one can get into trouble with it if not really careful. So unless there is something specific about burn rates being inappropriate for a HP I'd like to stay with Titegroup. I do have some HP-38 as well as HS-6 if someone is really adamant Titegroup is a bad choice for this usage.

 

[OKFC05]

I'm leaning toward starting below the 4.1gr min that is in the Speer manual....maybe starting with 3.9gr or 4.0gr. Does that make sense

Not really. You have to have enough to work the action, and the small decrease in length is not going over pressure with the starting load.
I have done quite a bit of loading and chrono with 115gr and 124gr bullets in 9mm, using titegroup, including loading them somewhat short. You'll hit minor power around 4.3 in most guns, which is the competition load shot by the bushel.

 

[Nevada Ed]

The OAL of a bullet is set by the bullet company or the company doing the testing per their testing equipment.

Many of the 9mm 115gr JHP bullets have a different Ogive shape from each company and some even have several JHP in the same weight with a differ style Ogive..........................
so you can end up with a lot of different "Correct" OAL lengths for a JHP bullet, with the same weight.

The "Plunk test" is a great idea when trying out a new bullet or setup. However, some times a little fine tuning is in order for the final load to feed correctly or improve on accuracy.

Nothing wrong with the Winchester 115gr bullets for practice, just hope you can find a OAL where they function 100%, since each type of JHP may enter the ramp area at a little different angle, due to the bullets tip and the OAL involved.

As a note;
the Speer 115gr GD has a tested OAL of 1.125" and a height of .52"
A manual with Sierra data has a 115gr JHP #8110 with a C.O.A.L. of ........... 1.050"
Winchester data in some of my books cheats and has a OAL for its 115gr JHP at 1.165" and we all know, that's not going to work !!

Good shooting.

 

[Twoboxer]

I thought you'd be OK with either, but decided to run some numbers through Quickload (QL). That software most often provides conservative results, ie, higher pressures and MVs, than I've actually experienced. That said . . .

My version of QL does not list that Winchester bullet. The Hornady 115gr XTP may be an acceptable substitute for this purpose. QL shows its length as 0.545". Compare that to length of your bullet and let me know if your bullet is longer because that would increase pressures. If it is shorter, that would tend to decrease pressure.

Not knowing your barrel length, I used a 4" barrel to minimize MV. Here's what QL said:

1.125 COL, 4.1gr Titegroup, 82% of max pressure, 1070fps
1.108 COL, 4.1gr Titegroup, 88% of max pressure, 1083fps

1.125 COL, 4.5gr Titegroup, 99.6% of max pressure, 1137fps
1.108 COL, 4.5gr Titegroup, 107% of max pressure, 1151fps
1.108 COL, 4.35gr Titegroup, 99.4% of max pressure, 1126fps

If I had no other data, I'd be running 5 rounds at 3.9gr, 4.1gr, 4.3gr and looking at accuracy, recoil, and ejection distance as well as for other pressure signs. During that same session, I'd also fire 5 factory rounds of any kind first to give me a basis for comparison. During the session you may or may not decide to fire the 4.3s.

Your chamber may be different . . . the 3.9s may not cycle . . . the 4.3s may eject much further than factory and show pressure signs . . . or they may not.

But the loads are appropriate for test IMO, and should be safe. Ql (and I) are no guarantee of course . . . all I can tell you is that's what I would do. Based on those results you will have learned what to do next.

 

[Rule3]

Don't forget )especially with tight chambers) that if you have over flared or do not taper crimp correctly the round is not going to "plunk" test correctly. The case mouth if not tapered is what will hang up and prevent it from dropping in, not the bullet.

Some bullet profiles like round fat lead bullets will of course effect how they chamber.


My CZ has to have some bullets seated very short, less than min OAL, but I do not use super fast powders in the 9mm so it's not that much of a concern I still began at the start load and worked up.

As mentioned you should be OK
I experimented with some 10 mm rounds and 180 gr fn bullets, I barely flared them the bullet just fit in the case and would not chamber in a Block until I taper crimped it, Then it fell right in.

 

[gwpercle]

You are looking at data for Speer bullets but going to use Winchester, The profiles are not the same. Thus the discrepancy. Bottom line is the bullet must be seated to fit your chamber.
Seat your bullet so it passes the " plunk" test. Make up a few dummies, no powder or primer, load them into the clip and manually cycle the slide to see if they feed and eject . If they do, go to the next step, charging with powder and seating bullets. Don't start out with a maximum load, start in the middle of min. and max. If they feed, fire and eject at the range, you can start adjusting loads for your needs. Starting at or below minimum in a semi-auto load usually results in improper functioning and then you don't know if it's the seating depth or powder charge.
This is how we did it in the dark ages and it works. Keep your dummies to set your dies with next time, they come in handy. I have them for every bullet I use. Saves on all that pesky measuring .
Gary

 

[otisrush]

I thought you'd be OK with either, but decided to run some numbers through Quickload (QL). That software most often provides conservative results, ie, higher pressures and MVs, than I've actually experienced. That said . . .

My version of QL does not list that Winchester bullet. The Hornady 115gr XTP may be an acceptable substitute for this purpose. QL shows its length as 0.545". Compare that to length of your bullet and let me know if your bullet is longer because that would increase pressures. If it is shorter, that would tend to decrease pressure.

Not knowing your barrel length, I used a 4" barrel to minimize MV. Here's what QL said:

1.125 COL, 4.1gr Titegroup, 82% of max pressure, 1070fps
1.108 COL, 4.1gr Titegroup, 88% of max pressure, 1083fps

1.125 COL, 4.5gr Titegroup, 99.6% of max pressure, 1137fps
1.108 COL, 4.5gr Titegroup, 107% of max pressure, 1151fps
1.108 COL, 4.35gr Titegroup, 99.4% of max pressure, 1126fps

If I had no other data, I'd be running 5 rounds at 3.9gr, 4.1gr, 4.3gr and looking at accuracy, recoil, and ejection distance as well as for other pressure signs. During that same session, I'd also fire 5 factory rounds of any kind first to give me a basis for comparison. During the session you may or may not decide to fire the 4.3s.

Your chamber may be different . . . the 3.9s may not cycle . . . the 4.3s may eject much further than factory and show pressure signs . . . or they may not.

But the loads are appropriate for test IMO, and should be safe. Ql (and I) are no guarantee of course . . . all I can tell you is that's what I would do. Based on those results you will have learned what to do next.

Thanks for this and all the other responses as well.

The Winchester bullet is .541" - so I've got a little more margin of safety.

I definitely learned through the school of hard knocks about making sure it fit my chamber, etc. when I was doing the 124gr FMJs.

Good reminder on the flaring and not having it be too much.

Thanks all!

OR

 

[venomballistics]

I'd change up powders in favor of CFE pistol.
That'll gain you both safety margin and performance over TG.

 

[Gamecock]

Pie are squared. H.

The volume of a cylinder is

volume = Pi * radius2 * height

So the impact on volume by a change in the depth of bullet seating is linear (height).

A reduction from 1.125" to 1.108" is .017 inches out of 1.125 (only 1.5%). BUT, you need to apply that to the 'cylinder' containing the load, which is considerably less than the overall length of the cartridge. I went through this exercise with 45 ACP a few months ago. Top of the case base web to the bottom of the seated bullet and the inside diameter of the case, plugged into the formula. I don't remember the number I came up with, but it seemed like a fairly modest change, so I proceeded. So, do some measuring and use the formula. Then do it all again to be sure you measured right and did the math right.

I have loaded 38 Super and 45 ACP well under recommended COAL for the same reason as OP without incident.

 

[Twoboxer]

. . .The Winchester bullet is .541" - so I've got a little more margin of safety. . . .

Yes. FYI, QL says that a 1.108 COL using a 0.541 bullet allows 4.4gr to just kiss max pressure (vs 4.35gr before). Likely a fine enough load if you needed a max load and could control COL and powder throws that closely. But, as you say, it gives 4.3gr a nice margin other factors considered.

Again, only firing your reloads of these loads from your firearm will be proof. QL is only a simulation. But even if you go over pressure due to stacking tolerances (shorter OAL, more powder) they should be safe.

 

[fredj338]

Check the other thread started on oal & the 9mm. Oal is important, but as powders get slower or charges closer to starting, it doesn't move the pressure needle much. I load my 124gr ltc @ 1.040", well above what would be a starting load. Every guy is diff, every bullet shape, hence book data is just a rough guide.

 

[rwsmith]

Start with

Start with the longest that will work through the action as long as it's not over max for a 9mm.

 

[m657]

I found some 'remanufactured 9mm' in 124 RNL that were OAL 1.020. Oddly enough they were all fine accuracy with no noticeable pressure issues.

And they worked fine in the PPX short throated devil my son dropped off for 'testing'. Same boolit/ogive/124 RNL @ 1.160 (IIRC--it's in the book) shot fine out of the other pistols but were unreliable feeders of this one.

 

[Rule3]

Pie are squared. H.

The volume of a cylinder is

volume = Pi * radius2 * height

So the impact on volume by a change in the depth of bullet seating is linear (height).

A reduction from 1.125" to 1.108" is .017 inches out of 1.125 (only 1.5%). BUT, you need to apply that to the 'cylinder' containing the load, which is considerably less than the overall length of the cartridge. I went through this exercise with 45 ACP a few months ago. Top of the case base web to the bottom of the seated bullet and the inside diameter of the case, plugged into the formula. I don't remember the number I came up with, but it seemed like a fairly modest change, so I proceeded. So, do some measuring and use the formula. Then do it all again to be sure you measured right and did the math right.

I have loaded 38 Super and 45 ACP well under recommended COAL for the same reason as OP without incident.

Were did you obtain information that an increase in seating depth is linear to increasing pressure? As you get towards max loads(especially with fast powders) the pressure increases much faster

Pressure increase is not linear as to pressure in a firearm cartridge, it also has a lot to do with the burn characteristics of whatever powder is used.

Hence the caution on using fast burn powders vs slower ones in high pressure small cases like the 9mm.

 

[fredj338]

Pie are squared. H.

The volume of a cylinder is

volume = Pi * radius2 * height

So the impact on volume by a change in the depth of bullet seating is linear (height).

A reduction from 1.125" to 1.108" is .017 inches out of 1.125 (only 1.5%). BUT, you need to apply that to the 'cylinder' containing the load, which is considerably less than the overall length of the cartridge. I went through this exercise with 45 ACP a few months ago. Top of the case base web to the bottom of the seated bullet and the inside diameter of the case, plugged into the formula. I don't remember the number I came up with, but it seemed like a fairly modest change, so I proceeded. So, do some measuring and use the formula. Then do it all again to be sure you measured right and did the math right.

I have loaded 38 Super and 45 ACP well under recommended COAL for the same reason as OP without incident.

This shows a complete lack of understanding of powder burn rates. Most, especially faster burn rates, do NOT build pressures in a linear fashion up thru max. Some, like Clays, will spike as it gets near the max. These powders don't take compression well. So any math equation gets tossed right there.
Other powders, slower burn rates, can be compressed to 110% & not show any pressure signs. So it isn't a simple equation. You could chrono & graph the changes to get an idea what is happening, then adjust oal to accommodate, but w/o pressure equip, we are all just guessing, if even educated guessing.

 

[Gamecock]

So the impact on volume by a change in the depth of bullet seating is linear (height).

You argue with this ?!?!

 

[Rule3]

The important thing is pressure.

Yes, the equation for VOLUME is correct and linear, but we are concerned with PRESSURE which does not increase in a linear fashion.

Plus a 9mm case is not a true straight wall case it tapers, so the equation for a cylinder is not valid.

That said, I mis read your post, I thought you had said pressure not just volume, but even in a true straight wall like a 38 special the increase in pressure is not linear. Then take into account all the different burn rates and it is beyond mere mortals to calculate what the increase is or will be

 

[rsrocket1]

Yes you can use Titegroup, but be careful (long)

Background:
I scored an 8# jug of Titegroup recently and have been experimenting a lot with it particularly with 9mm and a bit with 40 S&W. I've also ran a bunch of Quickload calculations to see if I could get in trouble with it and it did give me some concerns. I like to load my pistol rounds to 75% SAAMI max (as calculated by Quickload) so that I have tons of margin. Quickload is good at predicting stuff, but it's not perfect (and clearly states that in their disclaimers). It is usually within a few percent of calculations so giving myself this much margin has worked very well in the past years.

My dilemma is that I use the 9mm barrel in an M&P 40 slide which is a bit heavier than the M&P 9 slide. That makes case ejection weak even with medium speed loads. I need 120g bullets to shoot around 1100 fps to get enough recoil to eject the cases so they don't land on my head or hit me in the forehead. Yes a weaker spring would help, but that can lead to other complications like weak slide return and battering the frame with heavier loads. The other thing is I just got a Beretta 92fs and it's barrel slugged at 0.357" compared to my M&P 9 and Shield 9 barrels which slug at 0.3545" so I want to use 0.358" lead bullets but need to seat them so that none of the 0.358" part of the bullet sits above the rim (otherwise the slide will not close 100% of the time).

Normally I seat to 1.10" COL like the bullet at the bottom of the picture, but for my "one size fits all" load, I would have to seat to 1.050":

Lots of shooters like Titegroup especially competitive shooters who use a lot of it. Typically, they can shoot 14,000 rounds with 8# of Titegroup and only get about 10,500 rounds using other powders. The problem with all powders is that the max pressures rise faster than the seating depth (exponentially) and the faster the powder, the faster the rise. In a larger case like 40 S&W or 45 ACP, the volume is "huge" so there is lots of margin. With slower powders like Unique, Universal, AA5, BE86 and Power Pistol, you are far from the peak pressures so they behave nice and gentle too.

Really fast powders like Red Dot, Clays, Titegroup, N310 have a hard time generating enough muzzle velocity without going over pressure. Here is a plot of Muzzle Velocity and Max Pressure versus seating depth for the bullet I use which is a Lee 356-120-TC. The actual bullet length is 0.560" so these are the COL and seat depth ranges:
COL-->> SD
1.135-->>0.179
1.125-->>0.189
1.115-->>0.199
1.105-->>0.209
1.095-->>0.219
1.085-->>0.229
1.075-->>0.239
1.065-->>0.249
1.055-->>0.259
1.045-->>0.269

Here is the plot:

Since this was at the hairy edge of SAAMI limits, I had to be very careful. At first I stayed below 3.8g, but noticed I was getting lower than expected velocities, sooty cases and weak recoil. That's signs of low pressure but a lot of people say Titegroup is "dirty". When I worked up to 3.9 grains, the soot cleaned up and I got decent case ejections.

I noticed that Quickload uses 13.3g H2O for the volume of 9mm cases and I also know that 9mm cases vary all over the map. Sizing the cases gets you a uniform outer dimension, but the inner dimensions can still vary and case volume has a huge effect on Pmax when you are on the edge of performance. I measured a couple dozen cases for volume using an eyedropper, water and a scale and found the volume anywhere between 13.7 and 14.6g H2O. After adjusting the case volume to 14.0 for a very conservative calculation, the MV's started to look a little better.

I also noticed that the same loads shot faster in the 4.25" M&P 9mm than in the 5" Baretta 92fs. The Baretta not only has a wider barrel than the S&W barrels, but it also has a larger chamber than the S&W barrels too so that would account for a looser bullet fit and larger volume for the gases to expand before being stopped by the barrel chamber and rising further.

My takeaways:

• As you seat the bullet deeper, the pressure goes up faster than the MV so you can't simply make a linear MV to Pmax assumption
• When working up loads near Pmax, case volume is a very big determining factor. That includes chamber and bore area in your particular barrel
• Really fast powders which include Titegroup work very well in moderate pressures in large cases but are very volume sensitive at SAAMI max pressure ranges. 9mm is about the smallest case I would be comfortable loading with it in an autoloading pistol to get even medium velocities
• Slower powders like Unique, Univesal, AA#5, BE-86 and Power Pistol would be better in 9mm and I would use it if I could get it. Right now you have to use what you can get
• Work up loads with Titegroup very slowly and carefully. Don't assume sooty cases mean low pressure. My soot went away right at the point of what might be max loads.
• This may be a spot where Quickload is diverging from reality, but I would rather stay on the safe side (low) than to blow up a gun trying to push the limits
• If you are going to load Titegroup in 9mm, you should seat your bullets as long as possible (pass plunk test and reliably feed in your gun) and work up loads to the point of getting good cycling and lock back of the slide on the last round while staying under the published Max loads.

Whew, hope that helps

 

[Gamecock]

You guys are scaring the children. Initial pressure is a function of the volume of the container. A 5% reduction in the volume of the container is not going to cause spontaneous nuclear fission of all matter.

 

[Rule3]

You guys are scaring the children. Initial pressure is a function of the volume of the container. A 5% reduction in the volume of the container is not going to cause spontaneous nuclear fission of all matter.

Depends on what material is being put into the "container".

A 1/2 (.5) grain of TG increases pressure by 5,000 psi.