Pressure question - 24hourcampfire

I normally load pretty conservatively but have worked up a load I consider about max based on velocity and pressure signs. It is:

270 Win
W-W Brass
WLR Primer
61.0 grains RL26
Barnes 129 LRX @ 3.265
Rifle is a SC Production M70, 22” Fwt barrel which yields about 3100 fps.

Due to the lack of published RL26 data, is there software available which will estimate the pressure of this load?

Quickload will do it and quite accurately if you input numbers are accurate.

How does the velocity compare to the same bullet using other powders?

P

Originally Posted by Pharmseller

How does the velocity compare to the same bullet using other powders?

P

60 grains of H4831SC nets about 80 fps less

The 129gr LRX is not included in the latest version of QL so I got as close as I could.

Keep in mind RL-26 acts like magic pixie dust in the .270 Winchester, or at least that's what all the published data and QL seems to indicate. I haven't had the opportunity to test it myself.

Code

Cartridge          : .270 Win. (SAAMI)
Bullet             : .277, 130, Barnes 'TTSX'BT 30276
Useable Case Capaci: 59.268 grain H2O = 3.848 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Alliant Reloder-26 *C

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.794% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-07.9   99    58.00   2920    2461   46358  13371     98.0    1.176
-07.1  100    58.50   2950    2513   47816  13469     98.4    1.160
-06.3  100    59.00   2981    2564   49326  13561     98.7    1.143
-05.6  101    59.50   3011    2617   50894  13646     98.9    1.126
-04.8  102    60.00   3041    2670   52518  13725     99.2    1.109
-04.0  103    60.50   3071    2723   54204  13797     99.4    1.093
-03.2  104    61.00   3102    2777   55953  13862     99.6    1.077  ! Near Maximum !
-02.4  105    61.50   3132    2831   57771  13919     99.7    1.062  ! Near Maximum !
-01.6  106    62.00   3162    2886   59657  13970     99.8    1.046  ! Near Maximum !
-00.8  106    62.50   3192    2941   61620  14012     99.9    1.031  ! Near Maximum !
+00.0  107    63.00   3222    2997   63659  14048    100.0    1.016  ! Near Maximum !
+00.8  108    63.50   3252    3053   65779  14075    100.0    1.001  !DANGEROUS LOAD-DO NOT USE!
+01.6  109    64.00   3282    3109   67985  14097    100.0    0.986  !DANGEROUS LOAD-DO NOT USE!
+02.4  110    64.50   3311    3165   70281  14119    100.0    0.971  !DANGEROUS LOAD-DO NOT USE!
+03.2  111    65.00   3341    3222   72671  14139    100.0    0.957  !DANGEROUS LOAD-DO NOT USE!
+04.0  112    65.50   3371    3280   75162  14158    100.0    0.943  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    107    63.00   3280    3105   68634  13817    100.0    0.985  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 3% relative to nominal value:
-Ba    107    63.00   3156    2876   59031  14202     99.5    1.048  ! Near Maximum !

Alliant doesn't list the 130 but comparing to 150's you are not maxing out. https://www.alliantpowder.com/reloa...;type=1&powderid=40&cartridge=63 I went up to 62.5 with130 Hornaday's for near 3,200 fps and no signs of excess pressure. I thought that was fast enough so stopped there.

Originally Posted by antelope_sniper

The 129gr LRX is not included in the latest version of QL so I got as close as I could.

Keep in mind RL-26 acts like magic pixie dust in the .270 Winchester, or at least that's what all the published data and QL seems to indicate. I haven't had the opportunity to test it myself.

Code

Cartridge          : .270 Win. (SAAMI)
Bullet             : .277, 130, Barnes 'TTSX'BT 30276
Useable Case Capaci: 59.268 grain H2O = 3.848 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Alliant Reloder-26 *C

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.794% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-07.9   99    58.00   2920    2461   46358  13371     98.0    1.176
-07.1  100    58.50   2950    2513   47816  13469     98.4    1.160
-06.3  100    59.00   2981    2564   49326  13561     98.7    1.143
-05.6  101    59.50   3011    2617   50894  13646     98.9    1.126
-04.8  102    60.00   3041    2670   52518  13725     99.2    1.109
-04.0  103    60.50   3071    2723   54204  13797     99.4    1.093
-03.2  104    61.00   3102    2777   55953  13862     99.6    1.077  ! Near Maximum !
-02.4  105    61.50   3132    2831   57771  13919     99.7    1.062  ! Near Maximum !
-01.6  106    62.00   3162    2886   59657  13970     99.8    1.046  ! Near Maximum !
-00.8  106    62.50   3192    2941   61620  14012     99.9    1.031  ! Near Maximum !
+00.0  107    63.00   3222    2997   63659  14048    100.0    1.016  ! Near Maximum !
+00.8  108    63.50   3252    3053   65779  14075    100.0    1.001  !DANGEROUS LOAD-DO NOT USE!
+01.6  109    64.00   3282    3109   67985  14097    100.0    0.986  !DANGEROUS LOAD-DO NOT USE!
+02.4  110    64.50   3311    3165   70281  14119    100.0    0.971  !DANGEROUS LOAD-DO NOT USE!
+03.2  111    65.00   3341    3222   72671  14139    100.0    0.957  !DANGEROUS LOAD-DO NOT USE!
+04.0  112    65.50   3371    3280   75162  14158    100.0    0.943  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    107    63.00   3280    3105   68634  13817    100.0    0.985  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 3% relative to nominal value:
-Ba    107    63.00   3156    2876   59031  14202     99.5    1.048  ! Near Maximum !

Much Thanks. The text wraps kind of funny, if I’m reading it right 61.0 grains is producing 55953 psi?

Interesting data. FWIW when I worked up a load for the 145ELDX, the velocities were not at all linear so I'm assuming the pressures were not linear either? I had a velocity "plateau" that went from about 59 to 61 grains where the average velocity only changed 75fps or so. I settled on 60.0 of RL26 for 3136fps.

I have been using 59.0 grains with 150 Nosler Partitions and 150 Speer hot cores. Cases have been through enough reloadings that I feel comfortable with that one.

All published data I have found shows these loads as acceptable with the exception of Speer data, which is ultra conservative compared to others, 270 and RL26 specific.

Originally Posted by TomM1

Originally Posted by antelope_sniper

The 129gr LRX is not included in the latest version of QL so I got as close as I could.

Keep in mind RL-26 acts like magic pixie dust in the .270 Winchester, or at least that's what all the published data and QL seems to indicate. I haven't had the opportunity to test it myself.

Code

Cartridge          : .270 Win. (SAAMI)
Bullet             : .277, 130, Barnes 'TTSX'BT 30276
Useable Case Capaci: 59.268 grain H2O = 3.848 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Alliant Reloder-26 *C

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.794% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-07.9   99    58.00   2920    2461   46358  13371     98.0    1.176
-07.1  100    58.50   2950    2513   47816  13469     98.4    1.160
-06.3  100    59.00   2981    2564   49326  13561     98.7    1.143
-05.6  101    59.50   3011    2617   50894  13646     98.9    1.126
-04.8  102    60.00   3041    2670   52518  13725     99.2    1.109
-04.0  103    60.50   3071    2723   54204  13797     99.4    1.093
-03.2  104    61.00   3102    2777   55953  13862     99.6    1.077  ! Near Maximum !
-02.4  105    61.50   3132    2831   57771  13919     99.7    1.062  ! Near Maximum !
-01.6  106    62.00   3162    2886   59657  13970     99.8    1.046  ! Near Maximum !
-00.8  106    62.50   3192    2941   61620  14012     99.9    1.031  ! Near Maximum !
+00.0  107    63.00   3222    2997   63659  14048    100.0    1.016  ! Near Maximum !
+00.8  108    63.50   3252    3053   65779  14075    100.0    1.001  !DANGEROUS LOAD-DO NOT USE!
+01.6  109    64.00   3282    3109   67985  14097    100.0    0.986  !DANGEROUS LOAD-DO NOT USE!
+02.4  110    64.50   3311    3165   70281  14119    100.0    0.971  !DANGEROUS LOAD-DO NOT USE!
+03.2  111    65.00   3341    3222   72671  14139    100.0    0.957  !DANGEROUS LOAD-DO NOT USE!
+04.0  112    65.50   3371    3280   75162  14158    100.0    0.943  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    107    63.00   3280    3105   68634  13817    100.0    0.985  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 3% relative to nominal value:
-Ba    107    63.00   3156    2876   59031  14202     99.5    1.048  ! Near Maximum !

Much Thanks. The text wraps kind of funny, if I’m reading it right 61.0 grains is producing 55953 psi?

Yes. That's the QL estimate.

Thanks again.