Weatherby Back Country 6.5 RPM Primer cratering

[Husky user]

I have brought this problem up before,My 65, RPM has always cratered the primers.
I complained to Weatherby and got some answers that I did not believe.
Last hunting season I shot a cow elk on a special permit in the Big Hole.
When I went to mercy her I had a mis fire,just bearly a mark on the primer.
Long story short I sent the rifle back alone with some cases that showed what I considered a problem.
I have not heard back yet,but I just bought two boxes of once fired from Weatherby.
Guess what a lot of those case had primers that were cratered.
I know it not all Backcountry rifles because my hunting partner just bought a Backcountry TI in 300 Weatherby.
His primers look normal.will post picture on one box I just got.
Focus not great cause my arm not long enough.
My question to the Forum,does anyone else have one of these rifles ,and do they have this problem,the 5 from my rifle the box from Weatherby

 

[sp6x6]

Thats usually a intial sign of pressure.My comp hard to zoom,do you have other signs,ejector marks,heavy bolt lift.Is for sure a hot rod.

 

[WildRose]

I have brought this problem up before,My 65, RPM has always cratered the primers.
I complained to Weatherby and got some answers that I did not believe.
Last hunting season I shot a cow elk on a special permit in the Big Hole.
When I went to mercy her I had a mis fire,just bearly a mark on the primer.
Long story short I sent the rifle back alone with some cases that showed what I considered a problem.
I have not heard back yet,but I just bought two boxes of once fired from Weatherby.
Guess what a lot of those case had primers that were cratered.
I know it not all Backcountry rifles because my hunting partner just bought a Backcountry TI in 300 Weatherby.
His primers look normal.will post picture on one box I just got.
Focus not great cause my arm not long enough.
My question to the Forum,does anyone else have one of these rifles ,and do they have this problem,the 5 from my rifle the box from Weatherby

I'm seeing deep punches there but not necessarily anything disturbing.

If you're concerned I'd either pack it up and send it to weatherby with some ammo and fired brass or have a competent gunsmith check it out.

You could just be starting to show some pressure signs but that is unclear absent more information.

Are you loading your own or shooting factory Ammo?

I think it would certainly be appropriate to run some go/nogo gauges through it.

If you're not using factory ammo, I'd shoot a few and compare.

 

[quarterman]

Sometimes its pressure, Sometimes its the fit of the firing pin in the bolt face. Also are you using magnum primers? Magnum primers often have a thicker cup which can prevent cratering until higher pressures are reached ( I read this some where). I use cci 250 primers in my backcountry 6.5 rpm and I can barely feel anything with my fingernail around my firing pin indentations.

 

[Husky user]

I'm seeing deep punches there but not necessarily anything disturbing.

If you're concerned I'd either pack it up and send it to weatherby with some ammo and fired brass or have a competent gunsmith check it out.

You could just be starting to show some pressure signs but that is unclear absent more information.

Are you loading your own or shooting factory Ammo?

I think it would certainly be appropriate to run some go/nogo gauges through it.

If you're not using factory ammo, I'd shoot a few and compare.

I sent it to Weatherby.
It does it to all shells factory and my reloads.
I know some of my reloads are at max.
But I am assuming the once fired brass I bought is all factory>

 

[asd9055]

I sent it to Weatherby.
It does it to all shells factory and my reloads.
I know some of my reloads are at max.
But I am assuming the once fired brass I bought is all factory>

Not a gunsmith, but when simillar thing came up before, people suggested it had to do with the firing pin and the firing pin hole on the bolt (the size of each)
I am sure the gunsmiths will chime in

 

[Husky user]

Thats usually a intial sign of pressure.My comp hard to zoom,do you have other signs,ejector marks,heavy bolt lift.Is for sure a hot rod.

No heavy bolt lift.My hunting loads are 1.5 gr under what Weatherby has on there web site.
I got as far as 64.5 gr RL25 ,64.8 started to show pressure.
Weatherbys web Site says 66 gr RL25 is max

 

[WildRose]

I sent it to Weatherby.
It does it to all shells factory and my reloads.
I know some of my reloads are at max.
But I am assuming the once fired brass I bought is all factory>

Hmm it may be in "spec" but suffering from an "accumulation of tolerances" or it may simply have a slightly over spec firing pin.

It's hard to tell with those photos but I don't see where it looks like the primers are pushing back and flattening. If it did, I'd worry.

If you run a fingernail across the margin between the primer and edge of the primer pocket on your reloads and don't feel a "bump" or "dip" that is a sign the pressure is too high.

Multiple concentric circles radiating out from the primer mark are as well, they look like waves frozen in time.

Many years ago I came close to blowing up a push feed Model 70 hotrodding some 220 Swift and not only was I over loading them I had been using brass fired in another rifle without full length resizing.

It blew the firing pin back so far that it sheared off the retaining pin and the "cap" just fell off.

I figured out I was dong something wrong at that point.

It's amazing we survive so many 'oopses" fooling around with so much pressure with no serious injuries.

 

[OldElkHunter1961]

My first loads working up for the Weatherby 6.5 RPM used GM215M primers igniting RL 25. I had deep strikes and "flow" or pond rings on all primers and one punctured. Initially I disassembled the bolt measure firing pin depth. None of the work-up loads was at maximum charge weight. I switched to GM210M's and viola, no more pond rings in the primers. No other signs of excess pressure ever manifested. Settled at 66 gr RL 25 with the Sierra 140 GK for 3035 SD 14.8 and 65.6 gr RL 25 with the 143 gr ELD-X for 3045 SD 17.