Your Assessment ??

[Pistol Ranch]

Pictured are my first reloads for a 7mm Rem Mag (Ruger Old Model 77).
Cartridge cases are once fired Hornaday, CCI Standard large rifle primers,Powder Hodgdon H-414, 60 grains, Sierra 130 grain spbt.
Cases were full length resized and trimmed to .010 under max length, tumbled,
primer pockets cleaned and bullets seated to 3.185 o.a.l.
I had 4 FTF out of 9 shots.
All primers show good indentation, primers were installed with a RCBS primer tool and primers seemed to seat VERY EASILY..I handled each primer carefully with clean (and dry) fingers.
Rifle purchased used from a good friend and I had no problem with ignition using factory ammo.
Primers stored in my gun safe in new, unopened boxes.
What are your thoughts on the FTF??

P.R.

 

[rcmodel]

I can't tell a hole lot from the fuzzy picture, but?

It looks to me like a tremendous big bevel around the primer pockets from reaming with a chamfering tool or something??

Some of them also appear to set well below flush with the case heads?

The other thing is, maybe excess headspace was created from your FL sizing die adjustment, and the firing pin can't reach them with full force.
I'd adjust the FL sizing die out enough to headspace off the case shoulder instead of the belt.

Or your Ruger bolt is suffering from a firing pin channel full of dried grease & dirt which slows it down enough to not reliably fire the relatively hard CCI primers??

rc

 

[loadedround]

At first glance it appears that your primer are seated too deeply. Why this happened, I do not know with seeing your case prep/loading procedure.

 

[snuffy]

As RC said, check your bolt interior for heavy grease. Also check you firing pin protrusion. IOW how far does the FP stick out from the bolt face?

Hard to see, but it does look like the primer pocket is chamfered heavily. No need for that, they certainly weren't crimped primers.

 

[gamestalker]

Why the short OAL? Especially with the older M77's that have a fairly deep throat.
I load 7mm rem. mag. on a regular basis and haven't loaded anything that seats that short. Try seatig them a bit longer to reduce jump / hramonic distortion, and bring your pressures down some too. I would go 3.285" at min. and work up from there until your off the lands .010" or enough to allow for olgive inconsistencies with the Sierra's. Also, I would bump up to a mag. primer with that powder. Stand 10' from a white paper target and look for small speckled holes when you fire the round. if it's got them, then you need to step up the primer to the magnum maybe?

 

[Pistol Ranch]

I got O.A.L. length from Hodgdon reloading data... When I checked primer depth, the misfires all check ABOVE the rim. Dunno how that happened, all primers were seated with exactly the same process.
There is no chamfer on the primer pockets..my blasted camera does not focus correctly at short distances. What I was trying to show is that the misfires all had pretty good primer indentations. Obviously, the cartridges that fired show tooling marks from the bolt face on the primers.
An experienced benchrester suggested that I might have resized to aggressively as one of you has suggested. I thought that belted cartridges headspaced on the belt, not the case shoulder.

P.R.

 

[918v]

They are supposed to headspace on the rim but it is better to do it off the shoulder. Cases last longer that way.

Check the bolt. Disassemble the firing pin assembly and clean out and dry the innards. It could be dragging on years of solidified sludge.

 

[Seedtick]

When I checked primer depth, the misfires all check ABOVE the rim.

They need to be sitting on the bottom of the pocket with the anvil set in place to pop.

Did you try any of the duds a second time to see if they would work?

Seedtick

 

[ArchAngelCD]

I agree, the high primers have to be the prime suspect. Some of the energy produced by the firing pin is being use to seat the primer instead of firing the round.

ALSO:

I handled each primer carefully with clean (and dry) fingers.

Although I doubt this is your problem I see no reason why you are touching the primers at all. You really shouldn't handle primers.