Winchester primer too small or primer pocket to big

[hard h2o]

I sat down to prep and prime some .300 WSM cases. I have reloaded for other rounds but these are the first in the .300 WSM for me.

They are Federal once fired cases.

I use almost exclusively Federal primers. Due to the shortages I bought what I could find on the shelf and that is the Winchester large rifle magnum primers.

I got the cases sized, pockets cleaned, trimmed, deburred and chamfered.

I cleaned the primer pockets with a hand held Lee primer pocket cleaner.

I went to seat the primer using the Lee Auto-Prime XR and it seemed like there was no resistance. I took the case out of the shellholder and the primer fell out of the pocket. I tried a few more with the same result. I tried a different package of primers but they were undersized as well.

I just primed a bunch of .30-06 cases using the last of my Federal large rifle primers using the same lee tool and they had good feel and primed just fine. I also cleaned those primer pockets using the same Lee hand held tool.

I measured the primers and they seemed to be around Ø.210" while the pocket on the .300 WSM seems to be Ø.219".

It would seem to me that the primer pocket is oversized.

Are the primers undersized or are the primer pockets oversized?

I have never had to use undue pressure to seat a primer. I assume I am not supposed to press them in hard enough to deform the cup to hold them in.

Anyone ever run into this situation?

Is there any way to "shrink" the primer pocket?

Should I just order new brass? I have read that maybe Federal brass is prone to having oversized pockets. Is this true?

[hard h2o]

I have read that even if you can somehow shrink the pocket or otherwise get the primer to stay you might be prone to gas leakage around the primer and that can lead to erosion on the bolt face.

So I think I will most probably go with new brass but I am very curious if others have experienced this.

It is very frustrating. i was all ready to load them up. Last step before dropping powder and seating bullets.

[Hoot]

I have read that even if you can somehow shrink the pocket or otherwise get the primer to stay you might be prone to gas leakage around the primer and that can lead to erosion on the bolt face.

So I think I will most probably go with new brass but I am very curious if others have experienced this.

It is very frustrating. i was all ready to load them up. Last step before dropping powder and seating bullets.

I have around half a bag of new Winchester 300 WSM brass that I was experimenting with trying to make 300 WSSM cases out of. Didn't work out no matter what I tried. You are welcome to them for $5.15 to cover a USPS Small Flat Rate box. If you are willing to drive to Golden Valley on a work day, you can pick them up for free.

Hoot

[engnerdan]

I would say your brass is toast.

"0.210" (5.33 mm) diameter large rifle primers, and a thinner or softer metal cup large pistol version for use with lower pressure loadings in weapons with light firing pin impact."
Source - https://en.wikipedia.org/wiki/Centerfire_ammunition

Stated as a very general note, Federal rifle brass tends to be very soft. Typically it is reported that people get fewer reloads on Federal rifle brass because it stretches too much or the primer pockets loosen up. The soft brass property may only be with select calibers but I do not know. I know in 223 and 308 Win Federal brass just is softer and does not take the abuse some others will.

[Rip Van Winkle]

If the primers are falling out the brass is junk.

As engnerdan said, Federal brass is soft, the web of their case head is also thinner than others.

I know of a couple guys who have experimented with making swaging tools to resurrect brass with loose primer pockets, but unless you have the ability to make your own tool I would think the cost would be prohibitive.

[Hoot]

...snip...
I know of a couple guys who have experimented with making swaging tools to resurrect brass with loose primer pockets, but unless you have the ability to make your own tool I would think the cost would be prohibitive.

Tools like the Hart Primer Pocket Tightener



which rely upon smacking it with a handheld hammer are a subjective process. It probably can be regulated better with an arbor press, but from what I've read, the pockets get loose all over again, the next time they're fired.

Hoot

[yuppiejr]

Sounds like the primer pockets in your brass are oversize, the measurement on the primers seems right. Are these "once fired" brass that you made yourself from factory new ammo or something you purchased second hand?

The Lee primer pocket cleaner should not alter the size of the pocket unless you chucked it up in a drill and spun it off-axis enough to alter the dimensions of the pocket slightly while cleaning (doubtful).

[hard h2o]

The brass is once fired from factory I bought and fired in the new Savage rifle with the goal of benchmarking against factory and reloading them.

In googling around I saw some of the tools that can maybe tighten them up but I would still be worried about gas leakage.

Thanks for the tips.

I think this brass will go to the recyclers.

[OldmanFCSA]

R&R Brass.

Recycle and REPLACE with new brass.

[Hoot]

I have around half a bag of new Winchester 300 WSM brass that I was experimenting with trying to make 300 WSSM cases out of. Didn't work out no matter what I tried. You are welcome to them for $5.15 to cover a USPS Small Flat Rate box. If you are willing to drive to Golden Valley on a work day, you can pick them up for free.

Hoot

Wound up being more like 3/4 of a bag on its way to a new home.

People before profit

Hoot

[BigDog58]

I have around half a bag of new Winchester 300 WSM brass that I was experimenting with trying to make 300 WSSM cases out of. Didn't work out no matter what I tried. You are welcome to them for $5.15 to cover a USPS Small Flat Rate box. If you are willing to drive to Golden Valley on a work day, you can pick them up for free.

Hoot

Wound up being more like 3/4 of a bag on its way to a new home.

People before profit

Hoot

Good Deeds ALWAYS come back to you Hoot.

[hard h2o]

I have around half a bag of new Winchester 300 WSM brass that I was experimenting with trying to make 300 WSSM cases out of. Didn't work out no matter what I tried. You are welcome to them for $5.15 to cover a USPS Small Flat Rate box. If you are willing to drive to Golden Valley on a work day, you can pick them up for free.

Hoot

Wound up being more like 3/4 of a bag on its way to a new home.

People before profit

Hoot

Thank you very much. I assume the primers will fit in these cases. The primers look like they are in spec. I am back on track.

[hard h2o]

Again, thank you Hoot.

I am up and running.You even had a lone funky little case in there with a strange fold in the neck.

They are beautiful. Now to just see how they shoot.



The one on the right is the bonus lone case with the folded neck:

[Hoot]

Oops, that was from my 300 WSSM wildcat. 300 Win Mag velocity in an AR15 platform, but due to length restrictions of an AR magazine, the heaviest practical bullet was 150gr. Tossed them at 3k fps. Talk about turning heads at the range when that AR15 barked! Doubly so since it had a Holland style muzzle brake to tame the recoil. Generally assured me a vacant shooting position on either side of me after a few shots.

Hoot

[hard h2o]

Was it a .25 WSSM down to .223 therefore the folded neck due to sizing the case down?