TIGHTEN PRIMER POCKETS, here's how.

[tbrice23]

Nothing catastrophic will happen if the metals are very dissimilar .

Worst case scenario is the tacks break. Nothing a grinder wont fix. If you have 70** series wire for your wire feed and the parent metal isnt too high chrome you'll be fine. Just clean the weld contact areas well before tacking with a wire wheel or scotch brite pad or grinding wheel..

High Chrome (9%) and most of the 316 SS pipe in my world requires pre and post heating but I live (work)in a critical environment. I tend to forget that the rest of the world is more forgiving than a refinery or Nuclear scenario.

 

[tbrice23]

It gets to be tedious enlarging case necks so they'll clear a larger bolt diameter to swage the primer pocket (PP), and then reducing the case necks. I also annealed the 25 RUM case necks twice. Once prior to enlarging, and once again after reducing the case neck back down to .257 caliber.

I learned a lot about the toughness of the 4 brands of cartridge cases while working on these 4 different brands of brass.

Surprisingly, the RWS 404 Jeffery brass had the softest brass. RWS has a reputation of having tough primer pockets, and I now know that's because their case heads are thicker than the other brands, rather than harder/tougher. RWS casings always weigh more than other brands, and they always have the lesser case capacity due to having more/thicker brass in the case head area during/after manufacture.

The Lapua brand 30-06 cases and the Hornady brand 375 Ruger cases seemed about the same toughness/hardness. I mean they took about the same number/force of hammer strikes to swage down the primer pockets.

The R-P 7mm RUM cases seemed to have the hardest case heads, with primer pockets requiring more hammer blows to tighten up. Now these two cases did start with primer pockets that were more expanded than any of the other cases I worked on. But still, these two R-P case heads were stubbornly resistant to getting the primer pockets swaged down. I think these primer pockets measured about 0.212" in diameter prior to swaging. The rest of the primer pockets on the other casings measured ~0.210" to 0.211" in diameter, prior to swaging them down. (Note: these diameter measurements are estimates measured with a Mitutoyo dial caliper using the inside jaws on the caliper.) There's probably something I don't know about the properties of cartridge case brass that explains the R-P case heads being more resistant to tightening of the primer pockets than the other brands of casings.

RWS seems to take the safest approach. They leave more brass in the case head area that is less brittle/hard/resistant to deformation, both in tension and compression (expansion and contraction).

This info about various brass hardness is very interesting .
Now I'm wondering if my Norma 6AI brass was so hard to manipulate because of the brand or only because of the caliber neck.??
I only have one cartridge in Norma so I cant test on a larger cartridge. I wonder if you have any Norma to try?

 

[Pdvdh]

No, I don't have any Norma headstamped brass. Not even any field pickups that I can think of. I have some Weatherby cases that are supposedly manufactured by Norma. These are cases I don't use any longer but remain in the reloading room.

However many guys say the Norma headstamped brass is tougher than Weatherby headstamped brass. The .378 Weatherby brass I necked down to .338-378 Weatherby did seem rather soft/weak (and darn expensive) 25 years ago. Lost the primer pockets pretty quickly, even with what appeared to be rather mild loads. I've also seen factory fired Weatherby cases where the primer pockets expanded on the initial factory firing of the cartridges, and with plunger marks on the case heads. So it appeared to me that Weatherby wasn't concerned with the reload-ability of their fired casings. One reason I sold my 338-378 rifle and moved on to 338 Imperial Magnum, and then 338 Edge, and finally (today), 338 Lapua Improved.

The RWS 404 Jeffery casings have pretty strong primer pockets, but the brass was soft enough that the end of my bolt was getting trapped in the interior of the case head after two hammer blows. I closed the bench vise jaws around the end of the protruding bolt and then twisted the cases to get them separated from one another.

It took quite a number of hammer blows to get the R-P 7mm RUM primer pockets to tighten up. Which surprised me because R-P RUM cases have an average reputation for primer pocket toughness, yet the case heads were resistant to deformation when I hammered on them.

 

[Pdvdh]

Now I'm wondering if my Norma 6AI brass was so hard to manipulate because of the brand or only because of the caliber neck.??

The 1/4" grade 8 bolt I initially attempted to use, without modification, could never have worked for me. I have that bolt and my calipers in my hands now. The diameter of the bolt is 0.245" on both the solid and threaded section of the bolt. However, the end of that bolt cones down to 0.178" diameter. Which means I was hitting the back side of 0.211" diameter primer pockets with a grade 8 bolt that only measured 0.178" diameter. Duh! At least I learned that lesson after damaging only the initial Lapua 30-06 casing.

If I cut the threads off the 1/4" bolt shank then the diameter of the bolt would be a full 0.245". That might work, but that still only leaves ~0.017" to spare on all sides of the primer pocket, if the bolt is centrally positioned over the primer pocket.

The 5/16" diameter bolt I ground down to clear the case necks originally had a shank diameter of 0.307". After grinding and reducing the shank diameter to clear the necks of my .280 RCBS Improved casings, the diameter of the end of the bolt that impacts the back side of the primer pockets measures 0.264". So I gained ~0.019", and that bolt now overlaps the primer pockets by 0.026" on all sides if centrally positioned over the primer pocket. And that bolt works just fine, without damaging the primer pockets.

I may grind another 5/16" bolt down and proceed more carefully, as a 0.280" diameter bolt should clear the necks on my fired 280 cases. If I had a lathe and the precision-enabling tools of a machine shop, I'd turn them down more precisely to maintain maximum shank diameter.

 

[Pdvdh]

Nothing catastrophic will happen if the metals are very dissimilar .

If you have 70** series wire for your wire feed and the parent metal isn't too high chrome you'll be fine. Just clean the weld contact areas well before tacking with a wire wheel or scotch brite pad or grinding wheel..

Thanks for the help and advice!
Paul

 

[tbrice23]

Yup, good idea Brice. I wonder if a torch and brazing rod would hold up. Yes, no, maybe?
One good thing about your ball bearing method vs my push-through die is you can use yours for any caliber but mine is limited to the parent case I made it for. I wish I would have read your thread sooner. I just threw away some 6.5x284 brass for loose primer pockets.

Good thread. I like the initial subject and all the subsequent tips that come out of it.

The brazing should crack in short order but I definitely wouldn't let that stop me from trying ( I'm pretty stubborn) in a pinch.
Hell, try it on top of an oak block. Thats what I've been using.

I bet you wish you'd have held on to the 6.5 brass a couple of days longer.

 

[osprey176]

I'm gonna try this with an old small ball peen hammer head clamped in a vise. It's the right size, hardened,and I won't have to chase a ball bearing all over the shop. Why not?

 

[tbrice23]

Go for it.
If you have to chase that bastard around you're hitting it too hard
Let us know how it goes.

 

[LRSickle]

I wonder if a guy could make a "die" that fits in a press and a ball bearing holder that fits in the shell holder groove. Maybe some round stock that's bored out bigger than your case with a bolt/stem sticking down like a blunt decapping stem. Something like an oversized FL die. Hmmmmm

 

[Wedgy]

Tired of loose pockets? I WAS but not no more! | Shooters' Forum

 

[DocB]

Tired of loose pockets? I WAS but not no more! | Shooters' Forum

Awesome!

DocB

 

[LRSickle]

I like that idea!

 

[Wedgy]

If someone has the ability to make those I would be happy to buy one

 

[Pdvdh]

Shortly after tbrice23 created this Thread, I internet researched this subject and found and e-mailed a man in Canada that made something like this tool, on a custom order basis. He didn't stock them. He was making them one at a time out of his machine shop, and the cost was in line with one-at-a-time manufacture, compared to mass production.

It looked like a nice tool to swage down primer pockets (PP), but I decided it was simply too expensive, relative to the cost of purchasing new brass and discarding the old. Before you spend the additional money, you might try the tbrice23 method. It's not overlying expensive, complicated, or difficult, once you get the right size bolt shaft and ball bearing. And an extra blow or two with the hammer won't damage the case heads if you have a carbide PP uniformer (I used a K&M tool) and use it in a battery powered drill to remove the excess brass in the leading edge of the primer pockets. It takes several, typically 3-4, hammer blows on the bolt shaft, to tighten up the PPs. So it's not like one individual hammer blow it going to ruin anything. Just keep your dial calipers handy and measure as the primer pocket is reduced in diameter from 0.210"+ down to approximately 0.208".

tbrice23's method, and the associated cost of the required items, is more in line with what I was willing to spend to salvage some over-pressured casings. You can buy 10 ball bearings for maybe $6, so even if half of them fly through a window and rocket off into the woods, you're still in business. (Slight exaggeration on the flying ball bearings).