Magnum primer suggestions for 300 win

[Highvoltage]

I've been working up a load in my 300 win using h4350 and 165 accubonds. I've been using Winchester large magnum primers ( nosler load data) And it seems like no matter what I do whether groups are 1/4 moa or 2 moa extreme spreads hover in the 30 ft per sec. I'm using hornady 1x fires brass and full length sizing. What are your thoughts on a different primer to reduce spreads. Any and all advice is welcomed.

 

[Riflehunter1776]

I've had good luck with the Federal gold match mag primers in my 300's

 

[rsmithsr]

fed large rifle, large rifle mag, large rifle mag match, tula large rifle mag . but I have never shot 4350 in a mag, nor lite bullets.

 

[NW Hunter]

I have used CCI BR2 large rifle primers with H1000 for 10 years now with my 300.
ES is at 8

 

[mwkelso]

CCI 250's have done well for me.

 

[Bob Wright]

If you purchase or get a loan from a buddy, Try Fed 215M over a chrony, just use normal cautions on changing components.
I noticed quite an improvement in ES/SD going from Remington 9 1/2 to the Feds. I was using Hodgdon H4831 powder in a 7RM load.

 

[Lefty7mmstw]

215...

 

[Lefty7mmstw]

215...

also, your case fill probably isn't high enough with 4350

 

[jdyoung]

Years back, I shared a reloading space with my Father-in-law. He always believed it was the "shock" of the bullet/load that killed an animal. So he always picked the hottest load in the manual for his caliber and weight of bullet.

I was working up a load from a different manual then he was using. I had a stock of Winchester WLR primers for use with that load. My Father-in-law was using CCI 200 primers. He ran out of primers. So without my knowledge, he borrowed some of my Winchester WLR primers.

Next thing I know, I hear from my wife through her mother that my Father-in-law took his rifle to the gunsmith for some reason. Turns out, he locked up the bolt in his Rem 700, 270 win. I don't remember the load, it was the hottest as was his usual choice. Like above, he substituted my Winchester WLR primers for his CCI 200. The WLR is the hottest non-magnum primer. Using it instead of the CCI 200 caused unsafe higher pressures and locked up his bolt.
Here is a chart I found showing primers in order of the coolest to hottest :
Just be careful with the Magnum primers ! Some think the Fed 215 is hottest, others believe the Winchester WLRM is the hottest. Winchester does have a habit of producing the hottest primers.

 

[348 fan]

Thank you for that chart

 

[bowkill02]

I've had good luck with the Federal gold match mag primers in my 300's

Could also try the 210 large rifle

 

[Wedgy]

What chrono are you using ? (1st suspect)
Annealing ?
What scale ?
Necks turned/measured for thickness/ concentricity, cases sorted,... etc. ?
Even seating depth can affect ES.
30 fps with your load 165 @ 3,150 is ~6" at 1,000 yards

 

[jdyoung]

Thank you for that chart

Just be careful with the Magnum primers ! Some think the Fed 215 is hottest, others believe the Winchester WLRM is the hottest. Winchester does have a habit of producing the hottest primers.

 

[Highvoltage]

What chrono are you using ? (1st suspect)
Annealing ?
What scale ?
Necks turned/measured for thickness/ concentricity, cases sorted,... etc. ?
Even seating depth can affect ES.
30 fps with your load 165 @ 3,150 is ~6" at 1,000 yards

not sorting components, turning neck, or concentricity, hornady powder thrower scale, no annealing, and I can't remember brand of chronograph it's similar to a Caldwell