300 WSM Compressed Loads

[bob_dobalina]

thanks great info

 

[bob_dobalina]

I tried loads of 60,61,62,62.5 grains of H4350 with 180 ABs all seated to 2.9" and none of them were too promising. The best group was 62 grains (maybe a 1.5" group). I can post pictures if anyone's interested. I have 63 grains loaded, but with the 62.5 grain load the bolt lift had much more resistance than a fresh shell. I need to get a chronograph. So far I have tried IMR7828 as well and that didn't do too well with 180 accubonds. Nothing compares to my 10 year old RL19 and Hornady 150 interbonds that I loaded to break in the barrel. These were seated to 2.86" and were toucing at 100 yards! Maybe I should try that seating depth with the H4350. My thoughts were I would try the RL17 next, and then maybe 165/168 grain bullets.

 

[steve4102]

I tried loads of 60,61,62,62.5 grains of H4350 with 180 ABs all seated to 2.9" and none of them were too promising. The best group was 62 grains (maybe a 1.5" group). I can post pictures if anyone's interested. I have 63 grains loaded, but with the 62.5 grain load the bolt lift had much more resistance than a fresh shell. I need to get a chronograph. So far I have tried IMR7828 as well and that didn't do too well with 180 accubonds. Nothing compares to my 10 year old RL19 and Hornady 150 interbonds that I loaded to break in the barrel. These were seated to 2.86" and were toucing at 100 yards! Maybe I should try that seating depth with the H4350. My thoughts were I would try the RL17 next, and then maybe 165/168 grain bullets.

I'm a Big Fan of Ramshot Hunter in my 300WSMs. If you can find it you might want to give it a try.

Browning BAR
300WSM
65.5gr Ramshot Hunter
18gr Nosler Partition
Fed 215M
Win Brass
100 yards
3 rounds.

 

[steve4102]

To verify the load I when back to the gravel pit a few days later.

First round went high and right. Next two back on target. I'm guessing the first round flier was me, but even if it wasn't, good enough.

 

[bob_dobalina]

Nice - looks interesting!

 

[bob_dobalina]

Not to beat a dead horse, but given DrMike's data, do you ever stop your max load based upon the 10% lot difference, or do you just work back up each new can of powder? I am planning on working up to 63gr of RL17 at this point, and if a 10% increase for 64.5 grains is ~ 76K PSI, 63gr would certainly be above max PSI. Do you find that powders really vary that much or are they generally more consistent? I have not worried too much about it using reloading manual loads. On a side note, 180 Accubonds started to shoot for me at 62 grains (.75" group strung out) so I plan on shooting 62.5 and 63 next. On DrMike's advice, I used my "coolest" primer - standard WLR, however it might be pretty in line with the magnum CCI 250 since that is a cooler mag primer.

Cartridge          : .300 WSM (CIP)
Bullet             : .308, 180, Nosler AccuBond 54825
Useable Case Capaci: 70.084 grain H2O = 4.550 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-17

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    64.50   3118    3886   75927  10114    100.0    1.065  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     95    64.50   2870    3293   50306  10954     99.5    1.253

 

[DrMike]

Yes, powders can change from lot-to-lot. Ten percent simply gives a safety factor. I have witnessed some pretty dramatic differences in powders. Remember, newly manufactured lots can be slower burning just as frequently as they can be faster burning. So, you may discover that you require more charge rather than less charge. You should have no problem using the CCI250. Certainly, you can use primers with higher brisance; it is important to work up, however, because you will likely witness higher chamber pressures.