How hot is to hot for .257 weatherby Mag

[tyson22250]

Started playing around with my 257 Accumark. I am using 110gr Accubonds and IMR 7828. Started at 68grs and worked up to 71grs. 71 grs was the best group with just being under and inch. I am using 71 grs of powder, Fed 215 match primers, norma brass and OAL is 3.250. The velocity ran at 3610, 3611, 3605 and 3611 FPS. I see that is about 100 fps faster then what most people get. No extraction marks on brass, easy to open bolt. Do you think i should go down to 70grs and play with seating depth, or try slower burning powder?

 

[FOTIS]

Honestly, anything over 3400 is great and your brass and gun will last longer . You should not be getting over factory velocities.

 

[JD338]

I agree with Fotis, Wby loads are on the warm side and I wouldn't try to push them faster. You will get longer case life.

JD338

 

[kraky]

Another guy that agrees with the others. Every gun is different but my gun seems to max out with pressure signs pretty close to quickload predictions. Quickload doesn't seem to think the 110 should be run much over the 3525'ish range with most powders. I can't help but think that if you ran that 3600 range over 4-5 reloadings you wouldn't see the primer pockets growing noticably.

 

[Antelope_Sniper]

Cartridge : .257 Weath. Mag
Bullet : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 7828

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.714% 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

-07.1 95 65.00 3339 2724 54886 13941 99.0 1.238 ! Near Maximum !
-06.4 95 65.50 3365 2765 56252 14016 99.2 1.224 ! Near Maximum !
-05.7 96 66.00 3390 2808 57648 14087 99.4 1.210 ! Near Maximum !
-05.0 97 66.50 3416 2850 59075 14155 99.5 1.197 ! Near Maximum !
-04.3 98 67.00 3441 2892 60537 14219 99.6 1.183 ! Near Maximum !
-03.6 98 67.50 3466 2935 62034 14278 99.7 1.170 ! Near Maximum !
-02.9 99 68.00 3492 2978 63568 14334 99.8 1.157 !DANGEROUS LOAD-DO NOT USE!
-02.1 100 68.50 3517 3021 65141 14385 99.9 1.144 !DANGEROUS LOAD-DO NOT USE!
-01.4 101 69.00 3542 3064 66752 14432 99.9 1.132 !DANGEROUS LOAD-DO NOT USE!
-00.7 101 69.50 3567 3107 68403 14475 100.0 1.120 !DANGEROUS LOAD-DO NOT USE!
+00.0 102 70.00 3592 3151 70095 14513 100.0 1.107 !DANGEROUS LOAD-DO NOT USE!
+00.7 103 70.50 3616 3195 71830 14548 100.0 1.095 !DANGEROUS LOAD-DO NOT USE!
+01.4 103 71.00 3641 3238 73608 14581 100.0 1.083 !DANGEROUS LOAD-DO NOT USE!
+02.1 104 71.50 3666 3282 75432 14614 100.0 1.071 !DANGEROUS LOAD-DO NOT USE!
+02.9 105 72.00 3690 3326 77302 14646 100.0 1.060 !DANGEROUS LOAD-DO NOT USE!
+03.6 106 72.50 3715 3370 79219 14677 100.0 1.048 !DANGEROUS LOAD-DO NOT USE!


According to quickload, you are up around 73k PSI. That's a little on the warm side in my opinion.

 

[efw]

Can't answer how hot is too hot, but generally speaking if I'm more than 50 fps or so above book max and what reliable, experienced, and safe handloaders are getting in their rifles all things being equal I'll back off.

Of course if you're not getting signs of excess pressure you might be ok... what I like to do in instances such as these is take 3 cases and fire them first each time I go to the range... see how many times they can be loaded w/ this combo before primer pockets expand. If you can get over 8 or 10 you're likely fine.

 

[nitis]

Those are impressive velocities

Remeber that most get the best accuracy with case length most are in the 3.15-3.17 range longer is not always better especially when there is freebore