Over pressure at 2 grains below max?

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45C

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Winchester XPR 19 inch barrel
I loaded up some 6.5 PRC
Hornady 143 ELDX
57 .3 g H1000
2930 FPS
Max load listed is 59 g H1000

Had to tap the bolt on the bench to open .
Very slight scrape from ejection.
Primer not flattened out.

But I’m getting scuff marks on the case?
They feel rough to the touch
Same spot on multiple cases.
 

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I don't load this caliber, but I did take a look at Hodgdon's online data.
It states a start load at 51.1gr of H1000 and a max of 58.1C gr. for a velocity of 2917 fps.
Looks like you're at their stated max as far as velocity goes.
I have always viewed evidence of a heavy bolt lift ----- it's time to dial it back.
Sticky extraction is telling you something. (don't go there). As far as the marks, could be
a rough chamber, but I'm not seeing clearly the marks you're talking about.
 
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Velocity is a much better gauge of things. Those marks are not indicative of overpressure but they do indicate a defect in your chamber. If you had to use significant force to operate your rifle then yes, you are probably overpressure. Keep in mind the "max" was determined through a very specific firearm. One that is not the same as yours at the least.
 
So it looks like maybe one of the Talley ring screws are touching the case.
Maybe the case is expanding and then the screw is causing the hard extraction?
 
snooker said:
I don't load this caliber, but I did take a look at Hodgdon's online data.
It states a start load at 51.1gr of H1000 and a max of 58.1C gr. for a velocity of 2917 fps.
Looks like you're at their stated max as far as velocity goes.
I have always viewed evidence of a heavy bolt lift ----- it's time to dial it back.
Sticky extraction is telling you something. (don't go there). As far as the marks, could be
a rough chamber, but I'm not seeing clearly the marks you're talking about.
Click to expand...
Small round spot at base of case, I think it might be from the ring screw
 
you could look at 5 different manuals with same charge and max could be different in ea one with the same charge in 10 different rifle could or could not show signs of pressure i have gone 3-4 grains over max with no pressure signs
manuals are only guide lines
i would be more concerned about that ring on your brass looks like someone drilled into your chamber
 
Maximum load can be different for every rifle. Do not accept a posted maximum load as maximum for your rifle.

Has anyone worked on this rifle? That mark on the case appears to be from a hole in the chamber that was poorly plugged. I would explore that concept a bit further. I can not visualize the factory doing that. It will require removing the barrel and exaimination. Does that location line up with a mounting screw hole? Can you see that on the barrel threads when the barrel is removed?
 
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The mount holes are drilled completely through and the front hole lines up with the round mark on the case.
Only work I’ve had done was barrel shortened and open sights installed.

I remember firing these loads last year and not getting pressure signs until max load.
And the round scuff wasn’t there.

Weird stuff.
 
45C said:
The mount holes are drilled completely through and the front hole lines up with the round mark on the case.
Only work I’ve had done was barrel shortened and open sights installed.

I remember firing these loads last year and not getting pressure signs until max load.
And the round scuff wasn’t there.

Weird stuff.
Click to expand...
To put it mildly, that's suboptimal on a dangerous level. Was the hole like that from day one from factory or is it a reciever mounted rear sight you had installed? Either way, I wouldn't be shooting it in its current state
 
Rear sight is no where near receiver ,
Only change was I removed the picatinny rail and installed Tally rings.

So, maybe the rail screws were flush with the inside of the receiver and the talley rings are shorter, thereby allowing the case to expand into that small hole,just enough to cause extraction problems.

Im recalling loading to max (59 grains) and getting stiff bolt open and extraction swipe.
That’s why I backed off to 57 g.

Now I’m getting no bolt open unless I hit it on the bench, that small circle scuff, but no extraction scrape or no flattened primers
 
45C said:
Rear sight is no where near receiver ,
Only change was I removed the picatinny rail and installed Tally rings.

So, maybe the rail screws were flush with the inside of the receiver and the talley rings are shorter, thereby allowing the case to expand into that small hole,just enough to cause extraction problems.

Im recalling loading to max (59 grains) and getting stiff bolt open and extraction swipe.
That’s why I backed off to 57 g.

Now I’m getting no bolt open unless I hit it on the bench, that small circle scuff, but no extraction scrape or no flattened primers
Click to expand...
Shouldn't matter if you swapped rail to rings. A mounting hole should never break through the chamber wall. Ever! Depending on the barrel profile & hole location, you may be able to have the shoulder set back to save the barrel. If not, it needs a new barrel. There's no other way around it. I'd be reaching out to Winchester to see what they have to say. I'm doubtful though they'll be willing to help you with it, now that you've had work done to the gun.
 
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45C said:
Rear sight is no where near receiver ,
Only change was I removed the picatinny rail and installed Tally rings.

So, maybe the rail screws were flush with the inside of the receiver and the talley rings are shorter, thereby allowing the case to expand into that small hole,just enough to cause extraction problems.

Im recalling loading to max (59 grains) and getting stiff bolt open and extraction swipe.
That’s why I backed off to 57 g.

Now I’m getting no bolt open unless I hit it on the bench, that small circle scuff, but no extraction scrape or no flattened primers
Click to expand...
Primers are not a good indication of pressure, however hard bolt left is.
That and the fact that you have what looks like a screw hole going right into your chamber is a big red flag.
If that was factory mounting holes I 'd be sending it back to Winchester .
That barrel is wrecked .
Cat
 
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