Sierra vs Alliant 85 grain game king with RE-15

[Boatschool02]

All,
Loading up some .243 for my dad's Ruger M77. Intended usage is groundhogs within 300 yards.
His preferred load used WW 760 in a metal can that cost $7.35... its been a couple years.
Replicating his load at 2.640 COAL, seated just forward of the NSJ, I was able to shoot two 3-shot groups that covered with a dime at 100 yards with both 41.1 and 41.5 grains.

His Remington brass was pretty beat up, so based on the case volume data available on this forum, I bought 50 pieces of Lapua to try.
With same load data, the best I could muster was 0.81" at 100 yards.

I have several pounds of RE-15 on hand and was going to give it a try, but ran into the following:
Sierra load data lists a max of 38.7 for RE-15 with the 85 grain game king.
Alliant lists a 41 grain max for the 85 grain Speer bullet.

Doesn't this seem like a stark difference? (Wider than the entire useable range listed for WW760 from Sierra, BTW)
Any experience with this bullet weight and powder in .243?

Thanks in advance,

 

[AckleymanII]

I think that you need to go find some win 760, or H414. You substituted Lapua for Rem, things went down hill. Now you are wanting to make another change from 760 to R#15.

Sounds like you are going to be chasing your tail for a while. Things were working perfect, all you have to do is duplicate what he was loading.

760 is a lot slower than R#15. If you wanted to improve on the 760 loads, then try R#19 with a win primer, you will get great speed and accuracy with close to a max load of R19~44+g. R 15 is fast powder for a 85g bullet, if you want to get any speed at all.

If you want to improve on him slinging Chucks, then go to the 80g Sierra BT Blitz, use 760 for that bullet also or R#19, you will get 3500+ with accuracy with 19!

 

[hunter243sgk]

Also try imr 4064. I get great results with it and the 85g sgk.

 

[Boatschool02]

Thanks for the input.
Local gun store has 760, 414, and 4064.
Will start testing with some fresh 760 and report back.

 

[MildBill]

you might just need to dial in the charge of 760 in the new brass and fresh powder.

 

[stacy]

H-414 IS ALL U NEED WITH THOSE BULLETS THATS MY FAVORITE COMBO IN 6 243 THAT COMES THOURGH MY SHOP EACH YEAR TOO ZERO SCOPES FOR HUNTING SEASON AND LOAD 50RDS FOR EACH !!!!!!!!!!!!