Pressure signs...now what

[Bigeclipse]

Usually I back off 1 gr and start accuracy testing and seating depth adjustments from there. That would put it at 60.5 gr. That happens to be the most accurate load tested by Nosler for IMR4350 and the 200 gr Accubond. So maybe you are close to a sweet spot.

+1. This is what I'd do.

I backed off 1 grain. Loaded up 6 (3 at one depth and the other 3 at another). Went to the range and shot my first shot...shell ejected with no trouble but upon case inspection...WOW is all I have to say. The primer blew a hole on its side and I have a faint ejector mark so needless to say I did not shoot the others. I will post up pics today.

 

[Bigeclipse]

+1. This is what I'd do.

Usually I back off 1 gr and start accuracy testing and seating depth adjustments from there. That would put it at 60.5 gr. That happens to be the most accurate load tested by Nosler for IMR4350 and the 200 gr Accubond. So maybe you are close to a sweet spot.

Here are pictures

 

[Bigeclipse]

Top view. Notice the black crud around the primer. Also notice the faint ejector mark on the left side. I cannot tell if this mark occured simple because of the black stuff the primer threw out since there is some black build-up there as well. Notice on the 12 oclock position of the primer you can see what looks loike a hole which it is! The hole does not go through the case but on that side of the primer there is a hole threw the primer which you can see burned that small hole in the case. I am obviously going to throw this case out but I am confused. When I was testing for pressure this load gave no pressure signs. Not I have a blown primer...do you all think this is pressure or simply a bad primer? The load was H4350 60.5 grains with 200 grain accubond seated .050 off the lands.

 

[Barrelnut]

The only time I have ever seem blown primers like that was due to a marred bolt face. It was sort a dimpled crater like spot on the bolt face that looked almost like the crater on a spent primer. Is it possible there was crud on the bolt face when the round was chambered?

Please post a pic of the bolt face if possible.

60.5 gr should be ok. Looks like a mid range load for 200 gr from the Hodgdon site.

Also, what is the green on the primer? Are you using a primer sealant?

 

[Barrelnut]

Another question. What primer are you using. Looks like Winchester? Is it a mag primer?

 

[Kennibear]

Change case brands. My experience with RP is some batches are soft. Try WW or Nosler and check them for water capacity compared to the RP cases. Sometimes (in 30-06 in my case) the RP cases had significantly less capacity. I had to back down 3 grains of 4350 (60 down to 57) to reach acceptable pressure.

When you deprime the case was the primer loosely held? The primer face appears to be high but very acceptable pressure. The primer appearance is my goto pressure indicator so that leads me to suspect the case. Check the primer after carefully removing it (re: slowly) with a caliper. It should read no more than 0.212" across the mushrooming at the top. If it is okay you have case issues.

KB

 

[Bigeclipse]

The only time I have ever seem blown primers like that was due to a marred bolt face. It was sort a dimpled crater like spot on the bolt face that looked almost like the crater on a spent primer. Is it possible there was crud on the bolt face when the round was chambered?

Please post a pic of the bolt face if possible.

60.5 gr should be ok. Looks like a mid range load for 200 gr from the Hodgdon site.

Also, what is the green on the primer? Are you using a primer sealant?

I will check my bolt face when I get home and take pictures. No idea what the green is...was not there before and I do not use primer sealant, so maybe came from the primer?

Another question. What primer are you using. Looks like Winchester? Is it a mag primer?

yes they are winchester mag primers. They are the most plentiful primers I can get around my neck of the woods.

Change case brands. My experience with RP is some batches are soft. Try WW or Nosler and check them for water capacity compared to the RP cases. Sometimes (in 30-06 in my case) the RP cases had significantly less capacity. I had to back down 3 grains of 4350 (60 down to 57) to reach acceptable pressure.

When you deprime the case was the primer loosely held? The primer face appears to be high but very acceptable pressure. The primer appearance is my goto pressure indicator so that leads me to suspect the case. Check the primer after carefully removing it (re: slowly) with a caliper. It should read no more than 0.212" across the mushrooming at the top. If it is okay you have case issues.

KB

Honestly, these are once fired brass from stock ammo I have shot. I tried finding a factory load this gun liked to no avail...shot over 70 rounds of different brands. I was simply using those spent cases for reloads trying to save some money. Figured since I was not trying to get crazy performance (all shots are under 400 yards) that case brand would not matter.

 

[Barrelnut]

You can check how loose the primer pockets are. To do this, take a new primer and place it anvil side down on the table. Take a piece of brass that you have sized and cleaned the primer pocket on and try to push the primer pocket down on the primer. If you can easily push the primer in all the way, the primer pocket it too loose and could be root cause. Actually you shouldn't be able to push the primer all the way in with this test.

Different shooters have wildly different experience with different brands of brass. Some have no issues with brand X and others have had terrible results. It just shows that different manufactures (even great ones) can have bad lots from time to time. Just because it fired once great from factory loads might not mean that it's reloadable one more time.

My understanding is that factory loads for 300 WSM are loaded pretty hot to get the performance requirements up. I shoot a 300 WSM and have shot factory loads (Federal) thru it before and was amazed how stout they were.

You can verify the pockets with the test above. It may be that just a few of them have issues.

 

[Barrelnut]

Another thought. The 300 WSM shoots fine with regular primers. Some pet loads for 300 WSM use regular primers and H4350. So backing down to a regular primer might be a good idea too.

I use Federal 215M magnum primers with my 300 WSM. Before that though I used Federal 210M. I went to the magnum primer to get my extreme spread down. That is not a golden rule though. Some shooters have gone from magnum primers to standard primer to lower their ES.

 

[Bigeclipse]

The only time I have ever seem blown primers like that was due to a marred bolt face. It was sort a dimpled crater like spot on the bolt face that looked almost like the crater on a spent primer. Is it possible there was crud on the bolt face when the round was chambered?

Please post a pic of the bolt face if possible.

60.5 gr should be ok. Looks like a mid range load for 200 gr from the Hodgdon site.

Also, what is the green on the primer? Are you using a primer sealant?

Change case brands. My experience with RP is some batches are soft. Try WW or Nosler and check them for water capacity compared to the RP cases. Sometimes (in oto pressure indicator so that leads me to suspect the case. Check the primer after carefully removing it (re: slowly) with a caliper. It should read no more than 0.212" across the mushrooming at the top. If it is okay you have case issues.

KB

Picture of bolt face...it looks scarred from that round at about the 3 o'clock position?!?! Is it now ruined!?!?

 

[Barrelnut]

Might help to clean up that bolt face and ejector with some q-tips and solvent. Lots of copper on there. Also, on the extractor side, at the edge of the firing pin ring, is that just soot from the pierced primer or is there more there? Is there a pot hole or something that collected that soot?

Maybe just clean the head real good and give us another look.

 

[Bigeclipse]

Might help to clean up that bolt face and ejector with some q-tips and solvent. Lots of copper on there. Also, on the extractor side, at the edge of the firing pin ring, is that just soot from the pierced primer or is there more there? Is there a pot hole or something that collected that soot?

Maybe just clean the head real good and give us another look.

It actually looks like a pot hole in the bolt face. I will clean it up and check but if it is...is it ruined?

 

[Barrelnut]

It actually looks like a pot hole in the bolt face. I will clean it up and check but if it is...is it ruined?

IMO the pot hole is what is causing the pierced primers. With heavy loads the primer is flowing into that pot hole and allowing the primer to brass seal to open up. It will probably work fine with lighter loads. I have seen them work that way before.

Otherwise you would have to take it to a smith and have the face smoothed out.

Is that a Winchester bolt?

 

[Bigeclipse]

IMO the pot hole is what is causing the pierced primers. With heavy loads the primer is flowing into that pot hole and allowing the primer to brass seal to open up. It will probably work fine with lighter loads. I have seen them work that way before.

Otherwise you would have to take it to a smith and have the face smoothed out.

Is that a Winchester bolt?

It is a browning bolt and the pothole was not there before my shooting session so definitely from that primer. Here is a cleaner picture.