Range day 7 mm STW

[Elkman]

I picked up my STW (with the new Lilja barrel) a few weeks ago then went on vacation. Last week I did the barrel break in and then started on load development. It did not go well until today. I started with some 20 year old 8mm RM cases, and 162 gr. Match bullets. I settled on 81 grains of H-1000 as the load with the most potential but a after a few range sessions I was not real happy. Even with Nosler Factory ammunition my groups were not stellar. Best group was .910 and was to long for the magazine. Shortening too magazine length saw no improvement. Yesterday I loaded up some 162 gr Hornady BTSP, which have been a very, consistently accurate bullet in all of my 7 mm's in the past. I loaded out at 3.660, 3.650 and 3.640, the latter which is shorter than the factory ammo I have. Here are the results.


View attachment PIC_0183.JPG

As you can see the results were outstanding. Upon retrospect, I believe that several changes were responsible for the results. First was that I quit cleaning the rifle after shooting, and the second was the cases. Of course I will reshoot the 3.640 and 3.650 and see what happens with once fired cases. The groups were corrected from 118 yards to 100 yards. Anyway I will be holding my breath.

 

[DrMike]

Very gratifying performance, Bill. I'd say you have arrived!

 

[hubcap]

very impressive groups. Amazing how a couple changes can improve groups. I think you figured out the rocket science stuff OK. The interesting thing to me is not cleaning the rifle bore after a session. I rarely shoot more than 15 rounds without cleaning. I think I will give that not cleaning idea a fair trial. Very interesting post Elkman.

 

[Guy Miner]

Very fine results!

Cleaning a rifle barrel is over-rated! :grin:

 

[Hegland]

As you can see the results were outstanding.

I'd say so! Nice shooting! I have a particular rifle which, even after a standard break-in, will shoot groups around any other rifle I own, but only after 20 rounds or so down the barrel... :shock:

 

[FOTIS]

Very mice shooting. What was your velocity?

 

[Elkman]

Thank you all, hopefully winter will go away again, and I can shoot a few more groups and see if it holds. Then I can start with the 175's.

 

[Elkman]

FOTIS
I don't know I am one of those dinosaurs that doesn't own a chrony, its a 26 inch stick so I would think about 3100 plus a bit.

 

[FOTIS]

Quickload says 3050....

 

[JD338]

Bill

Nice shooting. I would say you are there

JD338

 

[Elkman]

FOTIS
Quickload says 3050....

When I had the 231/2 inch barrel, my ballistics chart was established at 3030. This is a 26", my oldest Hodgdon shows 3200 but I know that's not right. I will try 3050 when I go out a ways and see how that matches. Thanks for the QL info. !!! Hodgdons online shows 3084, with 80.7 grains so its matching closely to the QL

 

[STW]

That is impressive. What is the length and rate of twist of the barrel?Also what contour is it.
Will you shoot other bullets in it as well?

 

[SJB358]

Very nice Bill. I know you have to be happy with that STW now. That rifle looks like it is going to be a keeper for sure! Can't wait to see what it does with the 175's for you.

Here is what my QL projects for your load Bill.

Cartridge : 7 mm STW
Bullet : .284, 162, Hornady BTSP 2845
Useable Case Capaci: 90.865 grain H2O = 5.900 cm³
Cartridge O.A.L. L6: 3.650 inch = 92.71 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Hodgdon H1000

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0 88 72.90 2768 2756 42900 12420 98.7 1.504
-09.0 89 73.71 2799 2818 44374 12529 99.0 1.481
-08.0 90 74.52 2830 2881 45906 12631 99.3 1.457
-07.0 91 75.33 2861 2944 47490 12725 99.5 1.434
-06.0 92 76.14 2892 3008 49132 12812 99.7 1.412
-05.0 93 76.95 2922 3071 50835 12892 99.8 1.390
-04.0 94 77.76 2953 3136 52600 12963 99.9 1.368
-03.0 95 78.57 2983 3200 54431 13027 100.0 1.347
-02.0 96 79.38 3013 3265 56331 13083 100.0 1.326
-01.0 97 80.19 3043 3330 58300 13133 100.0 1.306 ! Near Maximum !
+00.0 98 81.00 3073 3396 60346 13181 100.0 1.286 ! Near Maximum !
+01.0 99 81.81 3102 3462 62462 13229 100.0 1.266 ! Near Maximum !
+02.0 100 82.62 3132 3527 64646 13276 100.0 1.247 ! Near Maximum !
+03.0 101 83.43 3161 3594 66905 13321 100.0 1.228 !DANGEROUS LOAD-DO NOT USE!
+04.0 102 84.24 3190 3660 69245 13366 100.0 1.209 !DANGEROUS LOAD-DO NOT USE!
+05.0 103 85.05 3219 3727 71670 13409 100.0 1.191 !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 98 81.00 3194 3668 73089 12697 100.0 1.188 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 98 81.00 2890 3004 48442 13409 97.6 1.415

And here is a projection with H1000 and 175 PT's.

Cartridge : 7 mm STW
Bullet : .284, 175, Nosler PART SP 35645
Useable Case Capaci: 88.039 grain H2O = 5.716 cm³
Cartridge O.A.L. L6: 3.650 inch = 92.71 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Hodgdon H1000

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0 89 71.55 2731 2899 45709 12327 99.6 1.504
-09.0 90 72.35 2761 2962 47301 12415 99.7 1.481
-08.0 91 73.14 2791 3026 48950 12496 99.9 1.457
-07.0 92 73.94 2820 3091 50665 12569 99.9 1.434
-06.0 93 74.73 2850 3155 52440 12634 100.0 1.412
-05.0 94 75.53 2879 3220 54282 12691 100.0 1.390
-04.0 95 76.32 2908 3286 56194 12745 100.0 1.368
-03.0 96 77.12 2937 3351 58175 12798 100.0 1.347 ! Near Maximum !
-02.0 97 77.91 2965 3417 60225 12850 100.0 1.326 ! Near Maximum !
-01.0 98 78.71 2994 3483 62340 12901 100.0 1.306 ! Near Maximum !
+00.0 99 79.50 3022 3549 64527 12951 100.0 1.286 ! Near Maximum !
+01.0 100 80.30 3051 3616 66792 13000 100.0 1.267 !DANGEROUS LOAD-DO NOT USE!
+02.0 101 81.09 3079 3683 69139 13048 100.0 1.247 !DANGEROUS LOAD-DO NOT USE!
+03.0 102 81.89 3107 3750 71571 13095 100.0 1.228 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 82.68 3135 3818 74091 13140 100.0 1.210 !DANGEROUS LOAD-DO NOT USE!
+05.0 104 83.48 3162 3886 76705 13185 100.0 1.192 !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 99 79.50 3130 3806 77907 12495 100.0 1.192 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 79.50 2858 3174 51717 13383 98.8 1.413

Here is what RL25 looks like.

Cartridge : 7 mm STW
Bullet : .284, 175, Nosler PART SP 35645
Useable Case Capaci: 88.039 grain H2O = 5.716 cm³
Cartridge O.A.L. L6: 3.650 inch = 92.71 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Alliant Reloder-25

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0 86 69.12 2748 2934 46670 11956 100.0 1.511
-09.0 87 69.89 2774 2990 48204 12027 100.0 1.489
-08.0 88 70.66 2800 3047 49784 12097 100.0 1.467
-07.0 88 71.42 2826 3103 51411 12167 100.0 1.446
-06.0 89 72.19 2852 3160 53085 12236 100.0 1.425
-05.0 90 72.96 2877 3217 54809 12304 100.0 1.404
-04.0 91 73.73 2903 3274 56584 12371 100.0 1.384
-03.0 92 74.50 2928 3332 58411 12438 100.0 1.365 ! Near Maximum !
-02.0 93 75.26 2953 3390 60292 12503 100.0 1.345 ! Near Maximum !
-01.0 94 76.03 2979 3447 62229 12568 100.0 1.326 ! Near Maximum !
+00.0 95 76.80 3004 3505 64224 12632 100.0 1.308 ! Near Maximum !
+01.0 96 77.57 3028 3564 66279 12695 100.0 1.290 !DANGEROUS LOAD-DO NOT USE!
+02.0 97 78.34 3053 3622 68395 12757 100.0 1.272 !DANGEROUS LOAD-DO NOT USE!
+03.0 98 79.10 3078 3681 70575 12819 100.0 1.255 !DANGEROUS LOAD-DO NOT USE!
+04.0 99 79.87 3102 3740 72821 12879 100.0 1.237 !DANGEROUS LOAD-DO NOT USE!
+05.0 100 80.64 3127 3800 75135 12939 100.0 1.221 !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 95 76.80 3092 3715 76953 12282 100.0 1.215 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 95 76.80 2870 3201 51308 13140 100.0 1.435


And some RL33

Cartridge : 7 mm STW
Bullet : .284, 175, Nosler PART SP 35645
Useable Case Capaci: 88.039 grain H2O = 5.716 cm³
Cartridge O.A.L. L6: 3.650 inch = 92.71 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Alliant Reloder 33

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0 88 78.30 2749 2937 44359 13952 96.9 1.562
-09.0 89 79.17 2783 3010 46011 14105 97.3 1.535
-08.0 90 80.04 2817 3084 47724 14250 97.8 1.509
-07.0 91 80.91 2851 3159 49502 14387 98.2 1.483
-06.0 92 81.78 2885 3235 51346 14516 98.5 1.458
-05.0 93 82.65 2919 3312 53260 14636 98.9 1.433
-04.0 94 83.52 2953 3389 55246 14748 99.1 1.409
-03.0 95 84.39 2987 3467 57307 14851 99.4 1.385 ! Near Maximum !
-02.0 96 85.26 3020 3545 59448 14945 99.6 1.361 ! Near Maximum !
-01.0 97 86.13 3054 3624 61670 15029 99.7 1.338 ! Near Maximum !
+00.0 98 87.00 3087 3704 63979 15103 99.9 1.316 ! Near Maximum !
+01.0 99 87.87 3121 3784 66378 15168 100.0 1.294 !DANGEROUS LOAD-DO NOT USE!
+02.0 100 88.74 3154 3865 68871 15223 100.0 1.272 !DANGEROUS LOAD-DO NOT USE!
+03.0 100 89.61 3187 3947 71464 15268 100.0 1.251 !DANGEROUS LOAD-DO NOT USE!
+04.0 101 90.48 3220 4028 74159 15311 100.0 1.230 !DANGEROUS LOAD-DO NOT USE!
+05.0 102 91.35 3252 4111 76964 15352 100.0 1.210 !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 98 87.00 3237 4073 79006 14497 100.0 1.202 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 98 87.00 2867 3195 49462 14980 95.2 1.470

If you have any others you wanna look at, let me know Bill.

 

[JD338]

Bill,

Again, great shooting. Your rifle is a tack driver.
The velocity just seems low. Have you considered Magnum or Retumbo?
I worked up loads for a 7mm RUM with the 160 gr AB and was able to get MV's just over 3300 fps.
I am thinking you should be around 3200 fps and Retumbo may be the powder to get there.

JD338

 

[SJB358]

Cartridge : 7 mm STW
Bullet : .284, 175, Nosler PART SP 35645
Useable Case Capaci: 88.039 grain H2O = 5.716 cm³
Cartridge O.A.L. L6: 3.650 inch = 92.71 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0 92 74.70 2772 2986 45590 12692 100.0 1.521
-09.0 93 75.53 2802 3050 47220 12758 100.0 1.496
-08.0 94 76.36 2831 3114 48912 12822 100.0 1.473
-07.0 95 77.19 2860 3177 50669 12886 100.0 1.449
-06.0 96 78.02 2888 3242 52494 12948 100.0 1.426
-05.0 97 78.85 2917 3306 54389 13010 100.0 1.403
-04.0 98 79.68 2945 3371 56357 13070 100.0 1.381
-03.0 99 80.51 2973 3436 58395 13130 100.0 1.360 ! Near Maximum !
-02.0 100 81.34 3002 3501 60498 13189 100.0 1.338 ! Near Maximum !
-01.0 101 82.17 3030 3566 62671 13246 100.0 1.318 ! Near Maximum !
+00.0 102 83.00 3057 3632 64919 13303 100.0 1.297 ! Near Maximum !
+01.0 103 83.83 3085 3699 67246 13358 100.0 1.277 !DANGEROUS LOAD-DO NOT USE!
+02.0 104 84.66 3113 3765 69655 13412 100.0 1.258 !DANGEROUS LOAD-DO NOT USE!
+03.0 105 85.49 3140 3832 72150 13465 100.0 1.239 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 86.32 3168 3899 74733 13517 100.0 1.220 !DANGEROUS LOAD-DO NOT USE!
+05.0 107 87.15 3195 3967 77410 13568 100.0 1.201 !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 83.00 3162 3886 79782 12872 100.0 1.196 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 83.00 2897 3261 50832 13934 100.0 1.435


Just for reference. Seems like it thrives on the slower burners, so H1000, RL25, RL33 and Retumbo would be top picks.

 

[HTDUCK]

Looking good Bill !
Great shooting !
What action is this rifle on ?
My STW and my ace compadres are both Win Mdl 70s and we are severely restricted in the OAL dept by the magazines in our rifles. Can't even load to 3.600 and have them run through the mag.

Also, I'd look at a slower powder.
I'm loading WC872 in mine and it clocks 3320 with 160 NPs.
The 162 Hornady's were leaving the muzzle at 3400.

 

[FOTIS]

160 Accubonds at anything over 3100 would make me smile.

 

[Elkman]

Thank you "all" for the great support and advice. I really appreciated the QL and Powder choices info. I am not familiar with RL-25 (I do have a pound) and after looking through 9 reloading manuals today I only found two with a suggested load for the 175 grain bullet. The QL data got me going. Of course 1/2 of those manuals were printed prior to the birth of the STW. I loaded some 175's today which I will share after I catch up on the questions.
Howard, its a Remington 700, my best guess is that magazine length is about 3.670 + or a bit. I know that I have to be real careful loading the rifle at 3.660.
STW, its a 26 inch 1-9 inch twist, with what I believe they call the Factory Contour, its a little smaller that a factory barrel, so there is a gap on the barrel channel however I believe that, more is better. For hunting I prefer the 175 gr bullets, I have killed two elk with the160 Barnes TSX (which was the most accurate bullet in the other barrel), but neither hit the ground like I expected so I carried it for a while with the 175 PT. I did some load work today with the175 gr. Sierra GK, used H-1000, with the AOL at 3.640, using 78, 79, 80, grains. No extraction or signs of pressure, other than the primers were starting to get flatter. The 80 gr. load I believe is showing that I have exceeded the max efficiency for that rifle. Here is the target
View attachment PIC_0191.JPG
Here is the rifle
View attachment PIC_0193.JPG
The groups were not as dramatic as the 162 gr. Hornady, but a little tweaking with the AOL may help.

 

[SJB358]

Bill, the 175's will shoot just fine. I think once you start tweaking seating a little, you'll have a load. That rifle looks great buddy. I'm liking that alot!

 

[tecumseh]

Good shooting! That's a good way to start working up a load.