DuPont IMR 3031 in the 25 lb metal can

[Barry54]

I used Green Dot to get ~1000 fps with ok chamber pressure and low muzzle pressure. There were actually quite a few other powders that would "work" in a similar fashion. However, many of the really fast powders (N310 included) needed over 55 ksi chamber pressure to get 1000 fps.

My use of 9 x 23 was entirely to show what an existing small capacity round rated at 55 ksi could do in the way of getting low muzzle pressures and useful performance.

For "testing" only, I am willing to run cartridges way over the SAAMI pressure limit if I know it is safe in a gun. However, I have figured out that I am not perfect and I can loose track of things. As such, I refuse to consider routine use of ammo loaded well above SAAMI in a common cartridge. This is just a hobby, and I do not want to take any chance that a "fun little toy" turns into an event that destroys a gun and/or hurts someone.

If I were to embark on such a rifle, I would most likely go with a 23 mm long "stretched 380" wildcat using 223 brass. It would have the same chamber ID as a 380, and I would need to figure out what kind of throat is needed to for all of the bullets expected to be used. I would "neck turn" the brass on my mini-lathe to get the brass thickness Ok for chambering ammo loaded with 0.357" bullets. This would effectively duplicate the 9 x 23, but with a near infinite supply of low cost (but high effort) brass.

Starting with a standard 380 or 9mm chamber might be a way to go. The "for testing only" ammo can be loaded up to both 38.5 ksi (9 mm +p) and to 55 ksi just to see how these pressure levels work out. If the 38.5 ksi pressure ammo is "good enough", the ability to use 9mm brass is a big deal. If the 55 ksi ammo makes a big enough improvement in performance, it could justify something like buying say 200 rounds of 9 x 23 brass from Starline or making the 23 mm long stretched 380 brass.

Note that I have dabbled in this kind of thing to some extent. At least 90% of my shooting is with handguns at a nearby indoor range. I made a 7.4" stub tube Contender barrel from a pulled 30-30 barrel. The chamber is pretty much 32 ACP but I use brass with the rim dimensions of the 32 S&W. My current batch of brass is made from 9mm cases. You could call it a rimmed 30 ACP. I love shooting this thing at 30' paper targets with a 55 gr tumble lube NLG boolit over 1.7 gr TightGroup. Velocity is around 890 fps. However, I also have fired a few rounds with the Lee 150. I do not remember the exact load but it was probably in the 800 to 900 fps range. It was a lot of "thump" with very little muzzle blast or noise. It looked wild as the exposed portion of bullet was longer than the case. I did something to extend the "nose riding" portion of the boolit down closer to the base so it would chamber.

Attachment 306669

Nice little Contender wildcat! I bet it’s good for hours of fun!!

I don’t have any performance requirements for the 24” barrel stub project. My goal was extremely low muzzle pressure. 4 lbs of N310 will last a long time! I’m not looking to go above accepted pressure.

I don’t want to turn brass for the foreseeable future. I would like to know the muzzle pressure for 1.8, 1.6, 1.4 and 1.2 grains of N310 with the 150 grain Lee mold.

I guess I need to just buy the program. I’m sure I would get hours of enjoyment from it.

Thanks again!

[P Flados]

Careful going too low, I have seen a recommendation to keep velocities above 600 fps to avoid risk of sticking a bullet. I am also unsure how accurate the velocity prediction is for a 24" barrel with just a smidge of powder in a round.

Cartridge          : 9 mm Luger (SAAMI)
Bullet             : .358, 150, LEE 358-150-1R
Cartridge O.A.L. L6: 1.169 inch = 29.69 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-47.6   24     1.10    596     118    4587    121    100.0    4.243
-42.8   26     1.20    628     131    5269    129    100.0    4.009
-38.1   28     1.30    658     144    6001    138    100.0    3.808
-33.3   30     1.40    686     157    6775    146    100.0    3.632
-28.5   32     1.50    714     170    7610    154    100.0    3.476
-23.8   34     1.60    740     182    8506    163    100.0    3.338
-19.0   37     1.70    766     195    9462    171    100.0    3.213
-14.3   39     1.80    790     208   10477    179    100.0    3.100
-09.5   41     1.90    814     221   11551    187    100.0    2.997
-04.8   43     2.00    838     234   12682    195    100.0    2.901

For the above, I used the default AOL. Just to show how details matter, here is the result of seating deeper.

Cartridge          : 9 mm Luger (SAAMI)
Bullet             : .358, 150, LEE 358-150-1R
Cartridge O.A.L. L6: 1.000 inch = 25.40 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms\
-47.6   46     1.10    630     132    8019    104    100.0    3.786
-42.8   50     1.20    663     147    9494    111    100.0    3.572
-38.1   55     1.30    695     161   11163    117    100.0    3.387
-33.3   59     1.40    725     175   12990    124    100.0    3.226
-28.5   63     1.50    754     189   14995    130    100.0    3.081
-23.8   67     1.60    782     204   17186    137    100.0    2.953
-19.0   71     1.70    809     218   19572    143    100.0    2.839
-14.3   75     1.80    836     233   22158    149    100.0    2.735
-09.5   80     1.90    861     247   24953    155    100.0    2.642

[Barry54]

Careful going too low, I have seen a recommendation to keep velocities above 600 fps to avoid risk of sticking a bullet. I am also unsure how accurate the velocity prediction is for a 24" barrel with just a smidge of powder in a round.

Cartridge          : 9 mm Luger (SAAMI)
Bullet             : .358, 150, LEE 358-150-1R
Cartridge O.A.L. L6: 1.169 inch = 29.69 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-47.6   24     1.10    596     118    4587    121    100.0    4.243
-42.8   26     1.20    628     131    5269    129    100.0    4.009
-38.1   28     1.30    658     144    6001    138    100.0    3.808
-33.3   30     1.40    686     157    6775    146    100.0    3.632
-28.5   32     1.50    714     170    7610    154    100.0    3.476
-23.8   34     1.60    740     182    8506    163    100.0    3.338
-19.0   37     1.70    766     195    9462    171    100.0    3.213
-14.3   39     1.80    790     208   10477    179    100.0    3.100
-09.5   41     1.90    814     221   11551    187    100.0    2.997
-04.8   43     2.00    838     234   12682    195    100.0    2.901
+00.0   45     2.10    860     247   13870    203    100.0    2.811
+04.8   47     2.20    883     259   15116    212    100.0    2.729
+09.5   49     2.30    904     272   16418    220    100.0    2.652
+14.3   52     2.40    926     285   17777    228    100.0    2.582
+19.0   54     2.50    946     298   19194    235    100.0    2.516
+23.8   56     2.60    967     311   20669    243    100.0    2.454

I’m sure the odds of a bullet not exiting increase when going from a 16” to 24”

I’m going from memory but I think it was 1.2 grains where the velocity got noticeably erratic in the 16” carbine. Might happen sooner in a 24”

I’m really looking forward to the project now! Thanks for taking the time to get the information I requested!

[Barry54]

I’m not sure if the erratic velocity was due to the blowback carbine? I’m on the search for something to cast a lead buffer spacer in. I measured some 1” pipe nipples and they are fifty thousandths over. I need something 0.050” smaller than 1” for my lead spacer test.

[P Flados]

And if I drop down to a 380 case, it predicts around 74 psi at 600 fps. The difference is the reduced free space in the round. If you were to try for you a lowest achievable muzzle pressure round for 600 fps with a 150 in a 9mm case, you would want to seat as deep as you can without causing problems.

Cartridge          : .380 Auto (9mm Kurz)
Bullet             : .358, 150, LEE 358-150-1R
Cartridge O.A.L. L6: 0.920 inch = 23.37 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-66.6   47     0.50    385      49    4149     50     91.2    6.115
-60.0   56     0.60    445      66    5588     60     96.9    5.267
-53.3   66     0.70    500      83    7408     67     99.6    4.651
-46.6   75     0.80    548     100    9675     71    100.0    4.190
-40.0   85     0.90    592     117   12471     74    100.0    3.837
-33.3   94     1.00    632     133   15897     78    100.0    3.553

[P Flados]

I tried a Blazer 9mm case and found that I could seat right at 0.40" deep without a bulge.

This allows seating a Lee 200 up to 0.5" deep if you leave off the gas check.

This allowed me to eliminate all of the free space to get a very low muzzle pressure at 600 fps. I expect that the throat would need to be much more than typical for a 9mm.

Cartridge          : 9 mm Luger (SAAMI)
Bullet             : .358, 200, LEE C358-200-RF
Seating depth      : .464 inch                  
Cartridge O.A.L. L6: 1.115 inch = 28.32 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-16.0   90     1.05    572     145   21970     77    100.0    3.864
-08.0   99     1.15    602     161   27454     81    100.0    3.645
+00.0  107     1.25    631     177   33885     86    100.0    3.457

[Barry54]

I tried a Blazer 9mm case and found that I could seat right at 0.40" deep without a bulge.

This allows seating a Lee 200 up to 0.5" deep if you leave off the gas check.

This allowed me to eliminate all of the free space to get a very low muzzle pressure at 600 fps. I expect that the throat would need to be much more than typical for a 9mm.

Cartridge          : 9 mm Luger (SAAMI)
Bullet             : .358, 200, LEE C358-200-RF
Seating depth      : .464 inch                  
Cartridge O.A.L. L6: 1.115 inch = 28.32 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N310

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-16.0   90     1.05    572     145   21970     77    100.0    3.864
-08.0   99     1.15    602     161   27454     81    100.0    3.645
+00.0  107     1.25    631     177   33885     86    100.0    3.457

Now we are talking something special! Chamber pressure is up there with ultra low muzzle pressure!! I was wondering if I was going to need a tight “match” chamber reamer with the 150 grain load to get the case to seal in the chamber?
This combination lets me use a more effective flat point I already have with decent kinetic energy too. Holy smokes, at the pressure rise with 0.1 grain charge increase!

Thank you for sharing the knowledge!!

[P Flados]

One key to very low muzzle pressures is getting the load real close to 100% fill. However, getting 100% fill with a very small charge means that small difference in either charge weight or OAL can make a big change in pressure. However, note that the velocity change that goes with the 0.1 gr charge variation is not nearly as big.

Loading this kind of ammo deserves more than typical care with respect to charge variations and AOL variations.

The above info has lead me to consider a different type of "ladder" loading. Pick a charge and start with say 90% fill, and then increase fill (i.e. decrease AOL) in small increments to work up to increase chamber pressure. Once you get to 100% fill (or even slightly compressed) with no sign of excess pressure, drop the charge 0.1 gr, and keep the final AOL from the previous load as the starting point to work down to 100% fill (or slightly compressed) with the lower charge.

It has occurred to me that your previous experiments with very small chares probably may not have had good fill percentages as you were reducing charges.

[pmer]

I use IMR 3031 in a 35 Whelen as well. The Boolit is an Accurate 36-225AG gas checked and powder coated with 45.0 / 3031. It's got some recoil but it's not too bad. It's more of a shove compared to faster rifle powders.

https://www.accuratemolds.com/bullet...ullet=36-225AG

A big can of 3031 is a good problem to have LOL. I've had great results with it in multiple cartridges. I'd probably reuse a 1 lb container and fill that with the 3031 so I would'nt have to open the main container all the time.

[Eddie Southgate]

Why the rush to get rid of it ? If I had 25 pounds of 3031 I'd be tickled and in no hurry to be rid of it.

[Rickf1985]

I am trying to find it and he is trying to get rid of it!

[Shanghai Jack]

I miss the days of Kegs and Barrels of Gunpowder.

[Shanghai Jack]

I wish I had 25# of 3031! It is my one of my favorite powders. If you want to use it quickly buy a 458 WM

Yeah I think there's a compressed load of 70 some odd grains.

[Barry54]

Why the rush to get rid of it ? If I had 25 pounds of 3031 I'd be tickled and in no hurry to be rid of it.

I am tickled to have it. He retrieved it from an outdoor shed when he gave it to me. It was one of the old metal shed structures from the railroad. I assume it got mighty hot in there during the summer. It’s DuPont and in the metal can so it’s old, along with not being stored indoors.
How long till it goes bad???

[Texas by God]

It works great for New cartridges(6.8 SPC) and Old cartridges ( 30-40 Krag) with cast or jacketed. I also would love to have keg of 3031- IMR- no such thing as H, AA,WW, or V- 3031!
It's unique- no pun intended.

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