I am in the process of getting a 6.5-300 win mag made. My question is where does a person start with loading data. Goin to start with 130 accubonds and 140 berger hunters. I have lots of imr 7828ssc, 4350, and retumbo. Anybody shoot one and have some wisdom they could send a rookie to the cartridge.

You know it's overbore with those light bullets.

You need to measure the water capacity and compare it to others. 6.5 remmag is 68 gr, 300 Winmag is 98 gr, so the slowest stuff you can use. Retumbo, H869, 50BMG etc..

IMO get a 1 in 7.5 twist as Woodleigh makes a very nice 160 gr spitzer.

http://www.woodleighbullets.co...tional/264q-333q/162

I have a 22-06 and 244 H&H so "overbore" is not a foreign word.

Ok, my barrel is a 8 twist , 4 grove shilen. That all I know right now

may I suggest a few changes ?

1. get a 3 groove barrel from Lilja and have it nitrided. It will almost double the cost but it will last at least 4 times as long, be faster, require almost no cleaning and not weaken the bullet as much.

2. get at least 26" if it's a carry about hunting rifle, otherwise at least 30, preferably 36"

My latest build 338 RUM, 36" 3 groove nitrided Lilja barrel. closing in on 3000 fps with 300 gr Bergers (Retumbo) and 1/2 MOA to 600 (as far as it's been on paper.) Rings a 12" gong @1000 every time if the "nut behind the bolt" gets the wind and mirage right.