300WM and H4350

[86alaskan]

So, I ran some loads through the Tikka today. Started ast 69gr H4350 and went in .5gr inc to 71gr. This was all under a 165gr sierra gameking, hornady virgin brass and Winchester LRM primer. I loaded to mag length, 3.360 i think. So here's the deal, it was 75deg and sunny. ONly the top load was over book but all loads in question flattened the S""T out of the WLRM primers. Are they that soft that even a med load wil smooth them over? I saw no other signs, bolt lift normal, recoil normal, brass looked nomal. Should I try my CCI 250's or Rem 9 1/2M primers? or not worry and run the WLRM? The 69gr load did a prelim 3 shot group at .25in, pretty good.

 

[MagnumManiac]

So, I ran some loads through the Tikka today. Started ast 69gr H4350 and went in .5gr inc to 71gr. This was all under a 165gr sierra gameking, hornady virgin brass and Winchester LRM primer. I loaded to mag length, 3.360 i think. So here's the deal, it was 75deg and sunny. ONly the top load was over book but all loads in question flattened the S""T out of the WLRM primers. Are they that soft that even a med load wil smooth them over? I saw no other signs, bolt lift normal, recoil normal, brass looked nomal. Should I try my CCI 250's or Rem 9 1/2M primers? or not worry and run the WLRM? The 69gr load did a prelim 3 shot group at .25in, pretty good.

Primer appearance means very little in the real world, some are simply softer or harder than others.
Your velocity is a better indicator of what your pressure is running at, if you are 400fps above the manual, your pressure is probably higher.
I have found ejector marks to show up around 70, 000psi, but primers looked normal. I have also seen primers flatten at less than 55, 000psi.
The case itself tells a story, loose primer pockets are a good indicator you are running at or slightly above max pressure, even though there are no other signs of excessive chamber pressure. If continued, the brass doesn't last and the action is stressed over time.

Cheers.
lightbulb

 

[86alaskan]

makes sense, I'm thinking since it's virgin brass i may be getting some headspace gap, along with the primer hardness. These WLRM primers have been pancake flat from the bottom to the top in all loads i've used them in. maybe i'll try the CCI and see if accuracy and primer condition improve.

 

[philipbrousseau]

when you have headspace gap the case is initially pressed against the chamber wall, the primer is pushed to the bolt face then as pressure builds the case head is forced to the bolt face and the primer is flattened and can take on a rivited appearence. with a very low psi load the primer will be protruding from the case head as the case is not forced to the rear of the chamber.

 

[philipbrousseau]

i reread your post and see it is a belted case. i was refering to what i have seen with rimless such as 30-06 type cases so this should be much less with the belted case providing h.s. is very small and controlled on the case head end by the belt. always best to size belted cases to h.s. off shoulder if it has one.

 

[86alaskan]

yep, i always set my belted sizer to do minimum for case life, these were all virgin brass. I've gone through a bunch and will start with once fired next trip out. As bad as it sounds, its a hunting rifle and if these loads beat the brass... oh well. I hope thse aren't over pressure but there are no other signs than the "rivet" looking primers. not to mention i was getting excellent grouping with the 69gr load.

 

[Frank in the Laurels]

Sounds like a stiff load to me but what the heck do I know....if your shooting quarter inch groups why would you need or want to change anything ????????

 

[86alaskan]

right Frank? kinda what i was thinking, if the gun hasn't blown up yet, it won't right. I has been kind of toasty here in alaska, it was 75 at the range this weekend. I figure the temps during hunting season will struggle to hit 50, so i should be just fine. quarters it is....

 

[tbrice23]

right Frank? kinda what i was thinking, if the gun hasn't blown up yet, it won't right. I has been kind of toasty here in alaska, it was 75 at the range this weekend. I figure the temps during hunting season will struggle to hit 50, so i should be just fine. quarters it is....

" the gun hasn't blown apart yet"
I never like to hear that,
metal fatigue is a real thing.

You really should chronograph your load.

 

[86alaskan]

Just kidding. The chrono goes this weekend. I only ran a few of those test loads for rough grouping.

 

[86alaskan]

Update, 69gr H4350 in my rifle produced 2750fps from 21" barrel and suppressor. Flat primers due to very soft winchesters. I loaded some at the same charge with cci 250's and the primers were still very nicely rounded. Anyway, h4350 safe but no where near fast enough. my 16" 3006 pistol shoots 168 amax bulelts fast with 10gr less powder.

 

[MagnumManiac]

Update, 69gr H4350 in my rifle produced 2750fps from 21" barrel and suppressor. Flat primers due to very soft winchesters. I loaded some at the same charge with cci 250's and the primers were still very nicely rounded. Anyway, h4350 safe but no where near fast enough. my 16" 3006 pistol shoots 168 amax bulelts fast with 10gr less powder.

Powder is too fast for the 300WM.
Try 4831's, any brand, or H1000, RE22 or RE25.

BTW, shorter barrels DO NOT require faster powders, it is a myth.

Cheers.
gun)

 

[86alaskan]

Yep, h4831, re22 and imr4350 on the menu next, maybe 7828ssc too