Marks on case base on extraction from Ruger 1

[WhelanLad]

fellas, ive noticed on my Ruger 1, when i extract cases theres a decent mark on the base around the cartridge stamped numbers and stuff. i wil upload a photo fairly shortly-----

ive been neck sizing the Brass- seated the 215gr PPSN well out as per 'the g-o' , only a mild-ish charge of Varget..... primers dont glatten but will let photos describe....

i have one idea, but will drop that in once you guys see.

cheers
WL

 

[WhelanLad]

some photos.......................

 

[tiriaq]

Look at the face of the breech block. Is there a burr?

 

[tigrr]

The firing pin is still sticking out when the breech bolt goes down. Clean pin channel.
The mark is on the primer too.

 

[tiriaq]

Is the rounded tip of the firing pin that wide?

 

[Chilly807]

The firing pin is still sticking out when the breech bolt goes down. Clean pin channel.
The mark is on the primer too.

Good eye! Is there a rebound spring on the firing pin? If so, it may be broken.

 

[bigedp51]

Any chance the cases need to have the shoulder bumped back and what we are seeing are scrape marks.

Meaning the case might not have any head clearance and if it was a bolt action you would have a stiff bolt on opening.

I use a .303 British case forming and trim die to bump the shoulders back. This die does not touch the case body or neck and only contacts the case shoulder.

The case fits this die like its in a case gauge and the fired case drops in and when tilted it fall out and again it only contacts the case shoulder.

 

[WhelanLad]

Any chance the cases need to have the shoulder bumped back and what we are seeing are scrape marks.

Meaning the case might not have any head clearance and if it was a bolt action you would have a stiff bolt on opening.

I use a .303 British case forming and trim die to bump the shoulders back. This die does not touch the case body or neck and only contacts the case shoulder.

The case fits this die like its in a case gauge and the fired case drops in and when tilted it fall out and again it only contacts the case shoulder.

This is what Im feelin? if my Case length was too long, just the Brass, would it begin to show this same symptoms?

 

[WhelanLad]

Look at the face of the breech block. Is there a burr?

triaq, not so much a burr, but its nice an sharp edge, the breech is scraping the brass an at times the primers on some cases, i feel like its a Case length issue? or where it headspaces from issue.?

 

[bigedp51]

WhelanLad

I had a Ruger No.3 carbine in 45-70 and full length resized the cases and never saw any marks on the base of the case. And I have no idea what it feels like to close the No.1 action on a bottle neck case with a snug fitting neck sized case.

Below is a .303 British fired case in my Wilson case gauge that was fired in a No.4 Enfield rifle. And the amount the case is sticking above the top of the gauge is how much longer the military chamber was than SAAMI commercial standards.

Below is a brand new Remington case in the same Wilson gauge, and you can see how short the shoulder location was on a new case.

We need the input from the people here who have a Ruger No.1 in .303 British and if they full length resize with minimum shoulder bump.

Meaning does the Ruger chamber have a smaller SAAMI chamber and if full length resizing will have a effect on case life with minimum shoulder bump.

On a military Enfield at maximum military head space of .074 and a rim thickness of .058 you would have .016 head clearance.

And a case with minimum shoulder bump would only have .001 to .002 head clearance or "air space" between the rear of the case and the bolt face.

 

[WhelanLad]

Thank you for tht info.

What would happen if my Cases were a tiny bit long??? same thing thats happening now too?

 

[Boolitcaster]

I don't know if it is a factor, but PPU cases have a very thick rim. I had to get another shell holder for reloading as the rims were too fat to slide into the Lee shell holder.

 

[bigedp51]

Thank you for tht info.

What would happen if my Cases were a tiny bit long??? same thing thats happening now too?

When the case is .001 to .003 shorter than the chamber it springs back slightly after firing and allows the action to open without resistance.

Any neck sized case will eventually need to have the shoulder bumped back to chamber freely at some point.

The marks on the base of your cases "may" just be scrape marks from the action on tight fitting cases.

And again this is where the reloaders here who have a Ruger No.1 need to chime in with their experience in this matter.

I don't know if it is a factor, but PPU cases have a very thick rim. I had to get another shell holder for reloading as the rims were too fat to slide into the Lee shell holder.

The rims on the Prvi Partizan .303 cases are thicker than American made cases by .003 to .004. And this is to your favor because it tightens up the headspace and decreases the head clearance.

Below a Remington .303 British case on the left with a .058 rim thickness and on the right a Prvi Parizan .303 British case with a rim thickness of .062.

 

[Chilly807]

If the rim recess in the chamber isn't deep enough to fully accept the rim it'll protrude further than it should, also if the head to shoulder distance is too long and the case bottoms too soon on the shoulder the same thing will happen.
I used to have an old .303, but didn't reload in those days.
If you re-chamber the fired cases, do the marked ones have more resistance when the action is closed and opened? If so, find out why they're different and the problem will reveal itself.
I'm no expert when it comes to the .303, so if I'm wrong in those thoughts please point out the difference so I can learn from it.

 

[bigedp51]

If the primers are flush with the base of the case it means the chamber pressure was great enough to make the case stretch to meet the bolt face.

When neck sized only the case will eventually become "longer" than the chamber headspace. And when the action is closed it compresses the case length at the shoulder and the action becomes harder to close. Meaning the bolt or breech block is firmly rubbing on the base of the case. This is why when full length resizing they recommend .001 to .002 shoulder bump and give a very slight clearance at the rear of the case.

You can find the amount of head clearance if you take a new unfired case and measure its length.

Next take a fired spent primer and start it into the primer pocket with just your fingers. You may need to push it in further depending on the clearance with the breech block.

Now chamber this test case and allow the bolt or breech block to seat the primer and the remove the case.

Now measure the case again from the case mouth to the base of the primer.

Then subtract the first case measurement from the second and the difference is your head clearance. Or the "air space" between the rear of the case and the bolt or breech block.

And if you add your rim thickness to the above measurement you will have your actual chamber headspace length.

Below I'm measuring a "fired" .223/5.56 case from my AR15 rifle in my Hornady cartridge case headspace gauge. I then set the die up to bump the shoulder back .003 and allow the cartridge to have head clearance when chambered.

Having the Hornady gauge allows you to measure your fired cases and set your die for minimum shoulder bump.

 

[Potash shooter]

I had the same problem, found it was caused by a sharp edge in breech face at the upper edge of firing pin hole.
The breech "sweeps" down across the case head, as the action is opened, and leaves that mark on the cartridge case head as material is scraped away.

My issue was caused when primer pierced and subsequently hot gases eroded breech bolt face

Need to disassemble the action and polish away the sharp edge

 

[bigedp51]

I'm thinking the edges of the firing pin hole in breech block is rough around the circumference of the firing pin hole and leaving scrape marks.

If you look at the marks on the cases the marks are straight sided and extend from the primer and across the base of the case.

This indicates the cases need to have the shoulders bumped back and the firing pin hole needs to be stoned to remove any sharp edges.

Below on the left the mark starts on the primer then skips across a low area then starts again on the letter N. The case on the right the mark starts on the primer and then continues on the entire flat surface of the base.

 

[WhelanLad]

Lots of Reading to do, will check it all out an get back when i can!
tnank you kindly for diagrams an indepth info!

 

[WhelanLad]

i watched this.... i think ill be needing this info..

ill need to purchase a FLS die n do a minor bump perhaps too!

https://youtu.be/dgTJfITvDJI

 

[Chilly807]

I think you have two problems. One is a burr on the breech face that becomes a problem with tight fitting cases, the second is somewhat over-length cases. In the second of your original pics, the last case on the right actually shows three scuffs on the case head. That tells me it's been loaded and fired at least three times.
Your firing pin doesn't strike dead centre in the primer. From what I see the fresh scuff marks on the case are directly in line with the scuff on the primer, and also in line with the part of the FP indent closest to the edge of the primer.
I'm willing to bet your FP "offset" from centre is at the 12 o'clock position. As the action opens the burr drags over the expanded primer and case head, leaving the scuff.

Try loading a round, then ejecting it without firing. Mark it first so you can tell where the 12 o'clock position is. There should be no new marks on it after ejecting unless the case is too long, but I doubt you'll see a scuff on the primer unless your primers are seated above the case head surface.
The firing pin and rebound spring itself is probably fine, the scuff mark looks too wide to be caused by the tip of the pin as I first thought it might be.