most accurate loads for A-bolts in .300wsm and .270 WIN

[shekarchi]

Anyone have some pet loads for Browning A-bolt in .300wsm [BOSS] and .270 WIN?
I have Win Sup 780. Win 760, IMR4831 and IMR4064.

thanks!

 

[Bio-Chem]

what bullet weights are you using in each? each individual rifle will be different, even two browning a-bolts with consecutive serial numbers could end up having different pet loads so it'll take some playing to figure out what your rifle likes.

the 4064 might be a little fast for your chosen calibers, but the others could all find uses depending on bullet weights? generally you will find the heavier bullets will do better with slower powders.

 

[shekarchi]

what bullet weights are you using in each? each individual rifle will be different, even two browning a-bolts with consecutive serial numbers could end up having different pet loads so it'll take some playing to figure out what your rifle likes.

the 4064 might be a little fast for your chosen calibers, but the others could all find uses depending on bullet weights? generally you will find the heavier bullets will do better with slower powders.

I will be loading 150-165/168 grain bullets for the .300 [since from what I have read lighter bullets dont do well out of this cartridge] and 120-140 grain for .270.
would IMR4831 be a better choice?

 

[ArchAngelCD]

IMR4831 and H4831 will produce the highest velocities in the .270 Win with bullets of 130gr or lighter. With heavier bullets slower powders like Win Supreme 780 will edge out the faster powders but not by much. Both produce accurate ammo so you don't lose using either but I would stick with 4831 with the lighter bullets for sure.

Sorry I have no experience with the 300 WSM so I can't comment first hand. That said looking at the load data it seems the 300 WSM is best served by powders slightly faster than used in the 270 Win. The Win W760 you have (or H414 which is identical) seems to be a good choice in that 300 with 150gr bullets. Again, with heavier bullets it seems W780 is a better choice. (but I'm only guessing for the discussion because I never loaded for this cartridge)

 

[Bio-Chem]

lots of people have used 4831 in the .270 Win with great results. I've never reloaded the 300WSM but i've loaded the .325WSM and have had a lot of success with RL17. Seems the 4350 speed of powders are more often used in the WSM cases. of the powders you selected I'd probably start with 4831.

 

[Captcurt]

My go to powder is IMR4350 for both rounds but 4831 works well. My personal favorite load in the 270 is 56 gr. of 4350, CCI 200 and a 130 gr Speer HotCor. The 300 WSM likes 66 gr of 4350,CCI 250 and a 165 gr Nosler Accubond. These are for my guns. You still need to start low and work up.

 

[shekarchi]

Thank you capt for sharing

 

[bergmen]

My best accuracy with my A-Bolt II Medallion in .300 WSM is 68.0 grains of W760 under a 168 grain Winchester Ballistic Silver Tip. Easy to cover 3 holes with a quarter at 100 yards, most consistently accurate rifle I own.

I will probably be switching to an Interbond with this caliber so I'm not sure how those will work out but I am going to start with the same weight of W760.

Dan