QuickLoad Request, 270 Win, 140 BT, IMR 4831

[NYDAN]

Would someone be so kind as to run a Quickload projection with the following criteria:

Cartridge: 270 Win.
Bullet: 140 gr. Nosler BT
Powder: IMR 4831
Barrel Length: 24"
Fired Case Water Capacity: 71.32 gr. (I think this may be less than actual)
OAL: 3.390"

If it helps any I have the following actual data: With 55.5 gr. IMR 4831 four shot average of 2947 fps, ES of 20 fps, Std Dev. of 8 fps. 65 degree F ambient Temperature.

If you need any other info, please let me know.

This load is above Nosler max. load, but I think a similar prior QuickLoad projection with the 140 gr. AB showed it to be safe.

I hope this is a safe load because it shot quite well without obvious pressure signs.

Thank you. Dan

 

[DrMike]

Cartridge : .270 Win. (SAAMI)
Bullet : .277, 140, Nosler BalTip 27140
Useable Case Capaci: 64.689 grain H2O = 4.200 cm³
Cartridge O.A.L. L6: 3.390 inch = 86.11 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4831

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0 81 46.40 2502 1946 33967 9699 96.8 1.511
-18.0 83 47.56 2561 2039 36236 9938 97.6 1.474
-16.0 85 48.72 2620 2133 38646 10162 98.2 1.431
-14.0 87 49.88 2678 2229 41205 10369 98.8 1.388
-12.0 89 51.04 2735 2326 43922 10559 99.3 1.346
-10.0 91 52.20 2792 2424 46807 10729 99.6 1.306
-08.0 93 53.36 2849 2524 49872 10881 99.9 1.268
-06.0 95 54.52 2905 2624 53128 11011 100.0 1.231
-04.0 98 55.68 2961 2725 56588 11123 100.0 1.196 ! Near Maximum !
-02.0 100 56.84 3016 2827 60267 11228 100.0 1.162 ! Near Maximum !
+00.0 102 58.00 3070 2930 64181 11330 100.0 1.129 ! Near Maximum !
+02.0 104 59.16 3124 3033 68347 11429 100.0 1.098 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 60.32 3177 3138 72785 11524 100.0 1.067 !DANGEROUS LOAD-DO NOT USE!
+06.0 108 61.48 3230 3243 77517 11616 100.0 1.038 !DANGEROUS LOAD-DO NOT USE!
+08.0 110 62.64 3282 3349 82567 11705 100.0 1.010 !DANGEROUS LOAD-DO NOT USE!
+10.0 112 63.80 3335 3457 87961 11790 100.0 0.983 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 102 58.00 3170 3124 76189 10937 100.0 1.050 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 58.00 2917 2645 52212 11699 98.8 1.235

Your case capacity seems excessive to me. You might want to recheck that.

 

[NYDAN]

Thank you, Dr. Mike. I agree the water capacity seems excessive and I will double check it. When I had the rifle and cartridges at the gunsmith's to cast the chamber he seemed concerned and spent a lot of time measuring a fired case. He commented that the outside diameter of the case was larger than normal. He said it looked larger in one dimension than the other, as if the chamber was asymmetrical or oblong. We were both surprised then to see that the throat/leade was relatively "tight".

I loaded and shot four cartridges using 55.5 grains of IMR 4831 and achieved an average velocity of 2947 fps. The data you provided is predicting 2961 fps with 55.68 grains. So, actuals are tracking pretty close to the program data.

Thank you again.

 

[Ridgerunner665]

The case capacity of my wife's current 270 (Win M70 FW) and a previous M700.....Winchester brass.

Rem 700 = 70.7 grains
Win 70 = 70.5 grains

 

[hubcap]

Nosler book no. 1 shows 55 max for a 150 PT and 57 max for a 130 PT. It made sense to me 56 would be a logical max for a 140 PT. I worked right up to 56 with 140 PT,s, AB,s and BT,s. No issues at all. For me IMR-4831 has been a fantastic powder for the .270.

 

[NYDAN]

If I understand the OBT theory correctly, it appears that if I drop back a half a grain or a full grain (to achieve about 2911 fps) I will be right on the OBT 5th node of 1.228 ms. Is that correct?

Dr. Mike, would you be able to run the exact same projection except use a OAL of 3.380"? I am curious as to how much affect that will have on the barrel time. That would be a better OAL if it works. Thank you.

 

[DrMike]

Cartridge : .270 Win. (SAAMI)
Bullet : .277, 140, Nosler BalTip 27140
Useable Case Capaci: 64.527 grain H2O = 4.190 cm³
Cartridge O.A.L. L6: 3.380 inch = 85.85 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4831

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0 81 46.24 2497 1938 33790 9661 96.7 1.514
-18.0 83 47.40 2556 2031 36045 9901 97.5 1.477
-16.0 85 48.55 2614 2125 38441 10125 98.2 1.434
-14.0 87 49.71 2672 2220 40984 10333 98.8 1.391
-12.0 89 50.86 2730 2317 43684 10523 99.2 1.349
-10.0 91 52.02 2787 2415 46552 10695 99.6 1.309
-08.0 93 53.18 2844 2514 49597 10847 99.8 1.271
-06.0 95 54.33 2900 2614 52832 10980 100.0 1.234
-04.0 97 55.49 2955 2715 56271 11092 100.0 1.199 ! Near Maximum !
-02.0 99 56.64 3010 2817 59926 11196 100.0 1.165 ! Near Maximum !
+00.0 101 57.80 3064 2919 63814 11298 100.0 1.132 ! Near Maximum !
+02.0 103 58.96 3118 3022 67953 11397 100.0 1.100 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 60.11 3171 3126 72362 11492 100.0 1.070 !DANGEROUS LOAD-DO NOT USE!
+06.0 108 61.27 3224 3232 77062 11584 100.0 1.041 !DANGEROUS LOAD-DO NOT USE!
+08.0 110 62.42 3277 3338 82077 11672 100.0 1.013 !DANGEROUS LOAD-DO NOT USE!
+10.0 112 63.58 3329 3445 87434 11757 100.0 0.985 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 101 57.80 3165 3114 75775 10905 100.0 1.053 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 57.80 2911 2634 51899 11659 98.8 1.239

 

[NYDAN]

Thank you Dr. Mike. That seating depth change didn't seem to change the time very much.

 

[SJB358]

Dan, good luck with the loading. That 270 seems like it turns in great looking groups.

That 140 BT is poison on deer. A fellow here took a couple antelope with the 140 BT at 3000 from his 270 Winchester. Said it turned them inside out.

 

[NYDAN]

Dan, good luck with the loading. That 270 seems like it turns in great looking groups.

That 140 BT is poison on deer. A fellow here took a couple antelope with the 140 BT at 3000 from his 270 Winchester. Said it turned them inside out.

Yes, Scotty, I have high hopes for the 140 BT. Just when I thought I had the 150 BT load all developed I ran into pressure signs. I had been concerned since the velocities with the 150 BT were running higher than the book values. Then I had a hard bolt lift.

My chamber seems to be a little large. After a couple of resizings, the cases developed a little ring (donut) around the transition from the shoulder to the neck. I could feel it when I seated the 150 BT's. I am not sure but, I think that might have contributed to higher pressures. The heel of the 140 BT's with the OAL I am using don't reach the bottom of the neck so I don't need to worry the donut. Plus they group very well with velocities under 2950 fps. I am stuck at a 4 shot group sizes of 5/8". I believe, 4 shot 1/2" groups are just waiting to be shot with that rifle. I am hoping that a slight adjustment will get me into the fifth OBT node for the 24" barrel.

Rol_P is getting tired of hearing me say, "Oh crap, another 5/8" group". :grin:

 

[DrMike]

Rol_P is getting tired of hearing me say, "Oh crap, another 5/8" group". :grin:

Serious problem, that.

 

[Rol_P]

It is fun to watch Dan, stuck on success.... He is very analytical. I am continuing the trial and error barrel break-in/load searching using some old loads that I had developed for my Remington. Dan even accused me of throwing a shot Sunday afternoon to spoil a nice 5 shot group.... I had not :-(

 

[NYDAN]

Dan even accused me of throwing a shot Sunday afternoon to spoil a nice 5 shot group.... I had not :-(

Note to others: Shooting is a lot more fun when you have someone to kibitz with.

 

[SJB358]

Dan even accused me of throwing a shot Sunday afternoon to spoil a nice 5 shot group.... I had not :-(

Note to others: Shooting is a lot more fun when you have someone to kibitz with.

Heck yeah it is!

 

[NYDAN]

Your case capacity seems excessive to me. You might want to recheck that.

Dr. Mike and Ridgerunner665,

I double checked the case capacity of the four cartridges that I fired for this target. With a small convex meniscus (rounded up) water capacity of the four fired cartridges measured 72.0 grains. I believe that when I measured them first time I tried to have the level of the water level with the neck of the case. That resulted in a case capacity of 71.3 grains.

In spite of this excessive case capacity the head space is very good. Should I be concerned?

Dan

 

[DrMike]

I don't know that I'd be concerned. I would watch for evidence of case separation at the web. Look for a bright ring or even use a bent paper clip to see if there is incipient separation detected on the inside of the case. If not, you should be good to go.

Here's some updated data with your new measurements. There's not a lot of difference.

Cartridge : .270 Win. (SAAMI)
Bullet : .277, 140, Nosler BalTip 27140
Useable Case Capaci: 65.369 grain H2O = 4.244 cm³
Cartridge O.A.L. L6: 3.390 inch = 86.11 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4831

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0 80 46.40 2491 1929 33443 9697 96.6 1.522
-18.0 82 47.56 2550 2021 35658 9939 97.4 1.485
-16.0 84 48.72 2608 2114 38010 10166 98.1 1.444
-14.0 86 49.88 2666 2209 40506 10376 98.7 1.400
-12.0 88 51.04 2723 2305 43154 10570 99.2 1.359
-10.0 90 52.20 2780 2402 45963 10745 99.6 1.319
-08.0 92 53.36 2836 2500 48945 10900 99.8 1.280
-06.0 94 54.52 2892 2600 52109 11036 100.0 1.243
-04.0 96 55.68 2947 2700 55470 11152 100.0 1.208 ! Near Maximum !
-02.0 99 56.84 3002 2801 59039 11259 100.0 1.174 ! Near Maximum !
+00.0 101 58.00 3056 2903 62832 11363 100.0 1.141 ! Near Maximum !
+02.0 103 59.16 3109 3005 66866 11464 100.0 1.109 !DANGEROUS LOAD-DO NOT USE!
+04.0 105 60.32 3162 3109 71158 11561 100.0 1.079 !DANGEROUS LOAD-DO NOT USE!
+06.0 107 61.48 3215 3213 75728 11656 100.0 1.049 !DANGEROUS LOAD-DO NOT USE!
+08.0 109 62.64 3267 3318 80599 11746 100.0 1.021 !DANGEROUS LOAD-DO NOT USE!
+10.0 111 63.80 3319 3424 85795 11834 100.0 0.994 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 101 58.00 3157 3098 74556 10970 100.0 1.061 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 58.00 2902 2618 51145 11713 98.7 1.249

 

[NYDAN]

Oh my! My load with a charge of 55.5 grains averaged 2947 fps with a std Dev. of only 8. This prediction shows 2947 fps with a charge of 55.68 grains. My scale is probably accurate to +-0.1 grain at best. Who knows how accurate my chronograph is. So, this projection is essentially dead on!

Thank you for running these projections for me Dr. Mike. You are such a big help.

 

[DrMike]

Glad to help, Dan. Your load workup is a joy to watch.

 

[FOTIS]

No q/l at work but I maxed out at 57 gr with my lot

 

[pre6422hornet]

Dan,

I have never shot 140's and 4831, but I have shot a TON of 4064 with the 140's.

49 gr's had an average of 2986 FPS with a standard deviation of 23 FPS. Very good groups and no pressure signs.

50 gr's had an average of 3001 FPS with a standard deviation of 14 FPS. Very good groups and no pressure signs.

51 gr's had an average of 3058 FPS with a standard deviation of 25 FPS. Very good groups and no pressure signs.

52 grs had an average of 3150 FPS with a standard deviation of 21 FPS. Very good groups, no pressure signs but this is over quickloads thresh hold and since I love my face and eyesight I backed her down to 50. But 52 was a sweet load.

I never deviated from 3.350.

And yes it turns antelope inside out.....

My rifle was a pre 64 270 and I can't remember case capacity. I have it, it is out in the shop...