Magnum primer suggestions for 300 win

[338 dude]

After reading your list of your processes I think you're doing pretty good considering

 

[79m1a-texas]

I tested several mag primers compare to my go to CCI BR2. The BR2 was the smallest group at 200 yards hands down.

 

[Coldfinger]

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.

I use Federal 215 match religiously!

 

[TRG65]

Like NW Hunter and 79m1a-texas, I use the CCI BR2 for all my large rifle primer loads. I don't hunt in super cold, ie 20F is low, so ignition isn't a problem like if I was in the -X temps. I've compared the CCI BRs to FGM mag primers, and the CCI hands down gave smaller groups and lower SD/ES. It does take more powder to get to the same velocity, but that's the trade off. I used them in 7RM and 7WSM loads years ago, and now load them in 338WM loads.

 

[baldhunter]

I compared WLRM Primers and Federal 215 Match a while back.I was getting 8fps faster velocity with the Winchesters and group size didn't change between the two.

 

[Old Shoat]

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.

Same here for moving to Federal. I had been using CCI. Tightened up groups and as an added bonus, my chron numbers went from 15-20 fps spread down to 5-10 fps spread.

 

[338 dude]

Same here for moving to Federal. I had been using CCI. Tightened up groups and as an added bonus, my chron numbers went from 15-20 fps spread down to 5-10 fps spread.

I have roundS loaded up now for a 338 Lapua magnum I normally use cci 250s but have federal gold medal match 215's and will do a comparison also I will post results when done

 

[hpmag308]

I think it's more of a powder issue than a primer. Go to a magnum powder and you will probably see the difference

 

[JimFromTN]

x2 on the CCI 250's. I have had issues with the winchester primers leaking. I think I read somewhere there was a recall on some of them.

 

[Lenny Foffa]

I have always used Fed 215 Mag Primers , with IMR 4350, with both 130 grn. and 150 grn. bullets ,in my 270 Weatherby Mag Loads. Also used Fed 215 Mag Primers , with H 4831, in my 300 Weatherby Mag . Good Hunting loads back in 1971 -1980 . Cases Separated by 1 Grn weight; Bullets separated by 1/10th grn weight. ( 129.9 ; 130.0 ; 130.1) No Complaints. Worked well.

 

[Bdog35]

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.

Use federal premium match primers in the large magnum and it will help.

 

[Coldfinger]

I compared WLRM Primers and Federal 215 Match a while back.I was getting 8fps faster velocity with the Winchesters and group size didn't change between the two.

Ok, I usually only chrono 1-2 of my best handloads when developing a load. I'm after accuracy as long as I get acceptable speeds. I've never payed attention to speed deviations just groups. Not necessary for the ranges I shoot at in NY.

 

[Wedgy]

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

You are chasing your tail with that chrono, get a maneto speed or labradar.
Then start looking at case prep, weights, volume, etc. and yes primers can make a difference.

 

[Mike Matteson]

What type of rifle? Barrel length? Now I have M-98 action with a 26" barrel 1-10 twist No. 5. I develop a load that was running at 3300 fps with a nosler 165 b.t.b.t. under 1/2" at 100 yds with a Norna 308 Mag. That was using fed-210 primers, and h4350 powder. Cases necks cut and brass weight, flash holes cleaned up. Annealed. At the time Win.Brass was lightest case weight. Now a late friend that I don't have his reloading data on his ruger-1 300 Win Mag got 3400 fps same grouping. They are max hot loads. You won't find it in any reloading book. The powder is plus of 70gr. You will need to develop your loads for your rifle. You can general increase your powder in a 70+ case at .5 grains at a time. Pay close attention to your primer as you increase your powder charge for high pressures signs. Back in the late 90's and early 2000 I was going up at .1 grains at a time and 5 round sets. I learned and found out about stepping up powder weight. Just load one round with one powder increase per case until you hit the max. If you change anything in how the bullet is moved toward the lands, be careful. Chamber pressure can go up quickly.
Presently working on 338 win mag in a Browning A bolt for my son. Using W760 powder with a Fed-210 primer with a 1-10 twist barrel. Now I have achieved the same powder charge I use in my Ruger Mark-1 in 24" barrel. His is 26" barrel. We haven't check the velocity yet and grouping. Just looking for pressure signs. The Ruger is shooting 200 gr. Nosler @ 3220 fps.
SSS
Mike