300 WSM primers ?

[chiefkerdog]

Has anyone used magnum primers with H4831sc in 300 WSM ? My go to load was 65.5 H4831sc with CCI BR2 behind a 210 JLK. But accuracy has gone away. Stiller/Viper RBRP with 30" 1.45 Diam. Broughton 5c 10 twst bbl in a barrel block Heavy Gun. Tried 7828SSC with 215M primer and had too much vertical. Anyone have suggestions.

 

[mr45man]

215 M,s work for me with 208 Hornady and 210 Berger's.
Using 7828 ssc gives excellent vertical out to 1,000.
1/10 Douglas 29" SS
John H.

 

[chiefkerdog]

215 M,s work for me with 208 Hornady and 210 Berger's.
Using 7828 ssc gives excellent vertical out to 1,000.
1/10 Douglas 29" SS
John H.

I was using 65.5 grns 7828ssc , jumped to 67.0 and had hard bolt lift. How much of it are you setting on fire ?

 

[4xforfun]

Has anyone used magnum primers with H4831sc in 300 WSM ? My go to load was 65.5 H4831sc with CCI BR2 behind a 210 JLK. But accuracy has gone away. Stiller/Viper RBRP with 30" 1.45 Diam. Broughton 5c 10 twst bbl in a barrel block Heavy Gun. Tried 7828SSC with 215M primer and had too much vertical. Anyone have suggestions.

"Accuracy has gone away"

My question is.....What changed?

How many rounds down the tube? Have you tried changing the seating depth to keep pace with the throat erosion?
Do you have a fowling/carbon problem starting up?"
Have you checked your crown?
Have you switched lots of powder? Bullets? Brass?

In my experiance, accuracy doesn't just "go away" unless something physical has happened to the gun, you are shooting in temps that are way different than what it was when you developed your load, or you have changed something with you components.

 

[chiefkerdog]

Well I shot up all my 210 JLK's that where doing so well for me and yes I have just discovered I have some throat erosion. But started the thread to see if Magnum primers could close up some of my vertical. The rifle has shot 10 rds almost always in the 5.5 to 6" range when I do my part. My sister even out did me one match using my rifle in a different relay. So maybe it's just me, nah just a bad time out first match this year. So with no time to try Magnum primers before a match with the H4831sc guess I will go back with CCI BR2's and hope for better conditions.
Would welcome anyone's pet load with me starting low and working up to it.

 

[Steve Blair]

I'm using 7828 SSC with 230 Hybrids and Russian LR primers. Long seating about 3.260" for .016" jump. Good vertical, no ignition problems.

 

[4xforfun]

Well I shot up all my 210 JLK's that where doing so well for me and yes I have just discovered I have some throat erosion. But started the thread to see if Magnum primers could close up some of my vertical. The rifle has shot 10 rds almost always in the 5.5 to 6" range when I do my part. My sister even out did me one match using my rifle in a different relay. So maybe it's just me, nah just a bad time out first match this year. So with no time to try Magnum primers before a match with the H4831sc guess I will go back with CCI BR2's and hope for better conditions.
Would welcome anyone's pet load with me starting low and working up to it.

I don't think I would try and re-invent the wheel. Shoot a couple groups with the bullet seated longer. 1 five shot group for each 10 thou increase in length. Do not change ANYTHING else and see what happens. Shoot these groups at long range. This is where you will see any change.

If you find a sweet spot, but still isn't quite there yet, try a powder weight switch of one or two thenths in both directions and see if you can find that perfect tune.

I am still not sure of your bullet situation....are you still using the JLK in a new lot number, or have you switched bullets?

keep us informed,

Tod

 

[ar10ar15man]

not the same but close..
i shoot a 300 wm..not a wsm....
i use std h4831 and tula lrm primers....with 208's..2950fps...0.32/0.31 at 200yds
just testing berger 210s and bib 187's
30.3 broughton 1/11 twist

 

[Fordnutter]

Hmmm I'll watching this thread with interest. I'm building a 300WSM & not sure what primers I should be running. Large rifle, Magnum.......? I've got some CCIBR2's on hand so might give those ago but is there any concensus?

 

[Steve Blair]

I usually consider Russian LR and CCI BR2 interchangeable. Tula LR are working fine for me. [br]
The following chrono data is for 68.6, 68.7 and 68.8 grains 7828 SSC. All grouped under .30" at 100 yards. These are acceptable numbers that indicate uniform ignition. A given rifle might perform best with either primer.[br]

Max Min Avg ES SD
2950.20 2939.70 2945.10 10.50 4.21
2948.70 2935.40 2941.00 13.30 5.76
2954.50 2941.10 2948.36 13.40 4.98

 

[chiefkerdog]

Well will let you all know what happens after match tomorrow. I gave her a good cleaning , throat was nasty as was the est of the barrel. Me and JB shined it up. Changing my primers to 215M's and using Berger 210 VLD's. They are pretty close to the profile of the JLK bullets. I am feeling good about the match just wishing for the wind not to blow. Yeah right !

 

[chiefkerdog]

Well headed in the right direction. I went with 65.5 H4831SC and 215M's and won my relay for score. Conditions were lousy but managed to keep all ten shots within 5" of vertical. Just to say how bad the wind was none of us HG relay winners got all 10 shots on in the shoot off. Now that I have a baseline back going to add or subtract tenths of grain of powder and check my results. Thank-you all for your feedback on this manner.

Kerwin