300wm, 220gr matchkings, RL25, and no where to start.....

[AMGtuned]

Looking for a little insight here gents. Newer to hand rolling, had great luck with my .308. On to the win mag these days, was using IMR4350 and Nosler 150 Ballistic tips to get myself into the win mag. Also, because most of the supplies came with a purchase of random reloading gear. In my quest for greatness, I decided id like to be shooting heavier, more accurate bullets, from this rifle I've spent what should've probably been my wifes money on. Most of the load data I have read or gathered does not list the combination of a Sierra 220gr hpbt over RL25. I have, however, read many of good things about both of these components when used in conjunction with a .300 win mag. Ramble over. Any insight? Starting loads? My 150gr load was 70.9gr of imr 4350, shoots clover leafs out to 450(haven't tried farther) all day. Thank you

 

[AMGtuned]

Bump.... thought I'd get something here. I think I'm going to try 70-71 and work up from there. Anyone disagree?

 

[Evintos]

Not specifically the Sierra 220gr hpbt, but some data for a 220gr ELD-X + RL-25:
C.O.L. - 3.340"
70.5gr - 2700fps
74.9gr (MAX)- 2800fps

Source - Hornady Handbook of Cartridge Reloading (Tenth Edition)
Hope this helps.

 

[AMGtuned]

Thank you. Spoke with Alliant this morning, his reccomendations were as follows:

220hpbt Sierra Matchking
64.7gr RL25 start 2500fps
70.7gr RL25 max 2700fps

He also suggested that when I'm out of 25, I should go to RL23, which he said is temp stable, and for a 220gr smk the data would be as follows;

220gr hpbt smk
71.5gr RL23 max 2785fps
Reduce by 10% for starting load

I assume no responsibility for anyone using this info, it's just what I was told this morning. Mods, sorry, probably wrong thread now and should be moved to .300wm load data section. I will post results when fired

 

[AMGtuned]

Update for anyone interested:

I fired groups today starting at the suggested 64.7gr, and worked up to the suggested max of 70.7 in .3 increments. Components used were RL25, Hornady twice fired cases (through my rifle, never cleaned, only sized), Winchester Large Rifle primer, Sierra 220gr hpbt. Results were groups ranging from .192" up to 1.25". I have no chrono yet. I know I biffed 2 groups (2 in one hole w/a pull flyer....wife mustve texted) so I will try those again, however, 67.7gr fired a .192" group followed by 65.9gr at .317". Hope this helps anyone. Thanks all

 

[squib-load]

R26 is the cats ass in mag shells and 6.5-284... I was getting 3100 with 140's and no pressure signs at all in my 6.5norma .. other guys are going even higher.... good temp stability but 26 is for velocity and the R23 that came out about the same time is VERY temp stable... slightly less velocity though