Help diagnosing Ruger #3 firing pin/breech block problem.

[pertnear]

I apologize for the pictures, but it is hard to get a close-up of a primer with my camera. My rifle is a Ruger #3 that has been rebarreled to a 6.8mm SPC. The firing pin has always been off center, even in its previous chambering. That’s no big deal, as far as I can tell. But the firing pin indentation kicks up a burr no matter what the load. On a minimum book load you can see it & easily feel it with a finger nail. As the load & pressure goes up the burr gets more pronounced & eventually it flows back so much that you can “feel” the burr being rubbed flat as you lower the breech block. The primers look curved on the edges, so still far from “flattening”.

My question is has anyone ever encountered such a problem with a Ruger #1 or #3? Is the firing pin sloppy? Is the breech block hole sloppy? Does the firing pin “float” so could it be a hammer/spring issue? Any ideas would be most welcome.
246126
This primer show the burr with a min book load.
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246127
This load is .5 grain below book max. The primer indent flowed into the firing pin hole & was rubbed flat when the breech block was lowered. (The red is from a marker I used to ID my loads.)

[eck0313]

If the firing pin hole is too large for the firing pin (or conversely the firing pin worn/too small for the hole), primer material can flow like what is shown in your pictures. If it is doing that with minimum loads, with a variety of primers . . . That’s your problem. You can either install a bushing in the breechblock, or examine the firing pin, and perhaps have a slightly oversized firing pin made. That is usually easier than boring the breech for a bushing, and installing.

[country gent]

.5 grn below max with a shorter throat or tighter neck may up pressures some. a worn firing pin or hole may allow flowback. if rebound light spring the actual ding would appear lighter and not the full dimple. Look at the face of the breech block firing pin hole under magnification for a light radius or worn edge to start. This can be caused by use also a few pierced primers blow back can cause this

[pertnear]

I was thinking that the first place to start would be to buy a new firing pin. Numrich shows a firing pin ($8) & a beech block ($47) but they both seem to be on perpetual back order. Is there another source for a firing pin?

TIA for all your comments.

[gnostic]

.5 grn below max with a shorter throat or tighter neck may up pressures some. a worn firing pin or hole may allow flowback. if rebound light spring the actual ding would appear lighter and not the full dimple. Look at the face of the breech block firing pin hole under magnification for a light radius or worn edge to start. This can be caused by use also a few pierced primers blow back can cause this

I've blown primers with lesser loads, because the bullet was seated touching the lands.

[pertnear]

I've blown primers with lesser loads, because the bullet was seated touching the lands.

Yes, I have popped a primer due to zero freebore too. But it's hard to tell from the photo's but the edges of the primers are not flattened & head expansion seems nominal. The bullets are seated .010" away from touching riflings. There are two different types of brass available in this caliber - with large or small primers. I use SR primers with the thickest cups at .025". In the pictures are Rem 7-1/2 BR primers. All LR primers have a cup thickness of .027" & they exhibit the same problem.

[gnostic]

Yes, I have popped a primer due to zero freebore too. But it's hard to tell from the photo's but the edges of the primers are not flattened & head expansion seems nominal. The bullets are seated .010" away from touching riflings. There are two different types of brass available in this caliber - with large or small primers. I use SR primers with the thickest cups at .025". In the pictures are Rem 7-1/2 BR primers. All LR primers have a cup thickness of .027" & they exhibit the same problem.

You're right, if the pressure was too high for whatever reasons, the radius on the primer would be gone. Did case extraction feel normal? The case head doesn't look like the pressure was too high...

[pertnear]

Case extraction was normal. Extractor kicked the cases out with ease. BTW: I was shooting in 100 degree Texas heat too.

[Reverend Recoil]

The firing pin on the Ruger No.1 is tipped up at a slight angle to the center of the barrel. For this reason I think your firing pin marks are normal.