TIGHTEN PRIMER POCKETS, here's how.

[Wyo7200]

Thanks for the info. I'll try to do some tests on my cases in the next few days.

 

[bob4]

Great idea. Just started loading for 300WM. Pricey brass. Thanks Brice.

 

[jsthntn247]

I'll try my 'tools' on some .223 this weekend and post if someone hasn't done so by then.

Thinking about it, I would expect better results with the smaller primer pockets because the rim of the PP will make contact at a more vertical angle. Being so, I would think LESS force would yield the same result. We'll see.

Pete

Interested to hear how this worked out. Nothing like neck turning and fire forming brass to get them perfect and only get 3 firings out of them before the pockets open up. I run 90 vlds's in my 223 and it's hard on the pockets, would love to get 10 firings out of Lapua but I'm lucky to get 4.

 

[Dr. Vette]

I have just tried this on a couple of pieces of Weatherby brass for our 300 Wby. I tried tapping, pounding, and using a 2 pound hammer (i.e. using increasing amounts of force) No change at all in primer pocket diameter, and they still fall out. I then used my vice as a press instead of as a support, and do it in that manner. Again, no change at all.

It did seem to shorten/collapse the primer pocket as I did then use my primer pocket chamfering tool and did remove brass. Obviously these pieces will not be reused except as test pieces for annealing.

Interesting thing is that this brass was used only 3x before the primer pockets opened up, and none of it was over pressure. I'm not sure if I will try another method to fix the primer pocket or if I'll just buy some new brass.

 

[jsthntn247]

Check out the Henry Remple primer picket tool.

 

[Pdvdh]

Check out the Henry Remple primer picket tool.

Henry Rempel primer pocket tool

 

[SidecarFlip]

Very impressive. Very creative.

I wonder if the RCBS primer pocket swagging die set can be "modified"

Say just use it with a ball bearing in the shell holder. I may turn a ball bearing holder.

Jeff...

I didn't read the entire thread...all the posts so someone may have already mentioned it, but why could you not use either an RCBS or Dillon bench mount PP swager and exchange the standard anvil for a radiused one? You could make one from oil hardening drill rod and harden it in your shop with a gas axe and quenching oil....

That way you could set the penetration depth od the ball end and consistently size the pockets....

 

[Rich Coyle]

Great info.

 

[Pdvdh]

Have you experimented with any different size hardened ball bearings, or have you only done this with the 3/4" diameter size? Could you envision any benefit to going with a larger or smaller diameter ball bearing?

I own and have used the RW Hart tool that was designed and sold to do the same thing. The face of the punch that was used to compress the brass surrounding the primer pocket was too soft to endure long use. It worked well for several casings, but then it deformed more so than the brass case head. This was a tough one to figure. It shouldn't have required too much effort or expense to fabricate the punch out of steel that would be strong enough to deform/compress the brass, rather than vice versa.

I've not used your technique yet, but I view it as the better method. lightbulb I'll probably brainstorm a differing means to secure the ball bearing than using my bench vise. Perhaps a beefy piece of steel with a 5/8" diameter hole which supports the lower half of the ball bearing. Then set both on an anvil or a concrete floor and hammer away.

Finally got around to tightening up some primer pockets with this method today. Works much better than the RW Hart Tool.

I used a 5/8" ball bearing. Purchases a 10-pack months ago. I drilled a shallow indentation using a 1/2" drill bit into the surface of a 1/2" thick piece of plate steel that's only about 3"x3" square. This indentation served as a pocket to hold the ball bearing somewhat captive. Then I placed the 1/2" thick 3"x3" plate steel on top of the anvil type surface on my bench vice. That's where I hammered the primer pockets tight.

Use the biggest bolt that will fit through the case mouth. I ended up grinding down oversized grade 8 bolts on a bench grinder until they just cleared my case mouths. I tightened up primer pockets on 30/375 S.I. brass (parent cases 375 Ruger brass), on 280 RCBS Improved brass (parent cases 30-06 Lapua brass), on 338 Edge brass (parent cases RWS 404 Jeffery brass), and on some 25 RUM brass (parent cases 7mm RUM R-P brass).

Here's a tip. The bolt head that contacts the base of the interior of the cases has to be larger than the primer pocket hole. Otherwise you'll simply pop out the thin base in the bottom of the primer pocket where the flash hole is located. I used a factory bolt small enough to fit inside one of my 280 RCBS Improved cases and that's what happened. That's when I ground down a 5/16" Grade 8 bolt to barely clear the .284 case mouth. Then the end of the bolt was large enough to catch the meaty part of the case head and all was good.

On the two 25 RUM casings, I expanded the case mouth up to .284 using a K&M outside neck turning mandrel. Then I was able to use the same bolt that I'd used for the 280 RCBS Improved cases. Then I necked back down to .257 case neck by running the casings into a Redding 25 RUM full length sizer die, the same way I necked down the 7mm RUM brass in the first place. Kind of a pain in the ***.

I don't think this method will work well for smaller calibers cartridges, because the bolt will have to be small enough to clear the interior case neck and when the end of the bolt gets smaller than the primer pocket, or even just a little bigger than the primer pocket hole/diameter, then the bolt will rupture and ruin the thin base of the primer pocket where the flash hole is drilled/punched through.

I tightened up a few of the primer pockets tighter than desired. Then I simply used a K&M primer pocket uniforming tool in a battery powered drill to open the primer pocket back up a wee bit. This is probably an even better approach, because a greater depth of the primer pocket sidewall gets swaged down, and should therefore endure more shots than if a lesser depth of the primer pocket sidewall has been swaged down.

 

[tbrice23]

Phorwath,
The smallest caliber I've tried before last week was .277.

Then I tried to tighten a 6AI in Norma brass, I bought a metric 6mm hardened hex head bolt to do the job. I was only able to reduce the pocket diameter to .209" which is not enough. IMO.

I wasn't sure if it was the diameter of the mandrel or the composition/ primer pocket design of the Norma brass. You stated you had tightened Lapua brass which has the same outer PP ring( case head disign) that Norma has, so I'm with you on the difficulty of tightening smaller caliber case PPs.

Untill last week I had only used this on Winchester brass so I wasn't sure if it was the make of brass or the small caliber that was giving me problems untill you mentioned it.

If I felt like I might expand to 7mm or 270 and maybe try a larger bolt and smaller diameter Ball Bearing to see if I can push more material into the PP.

 

[Pdvdh]

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).

 

[Pdvdh]

For general information:
In order to grind down the bolt diameters in order to use the largest bolt diameter possible, I cut off the bolt heads, mounted the bolt shafts in a cordless drill, and then spun the bolt at high speed against the coarse bench grinder wheel - initially. Then the finer stone as I approached the correct diameter. Then I spun the bolt in some emery cloth to smooth up the exterior surface. I just free-handed the battery operated drill, so don't get the idea that the diameters are perfect. I didn't use a lathe. They may not look professional, but they get the job done.

I prepared on bolt shaft for .284" case necks and one for .308" diameter case necks. I used the bolt I prepared for .308" diameter case necks on the .338 Edge cases and it seemed to be plenty large enough in diameter and plenty stout.

Although I also purchased an even larger diameter bolt for 0.338" case necks, I don't think I'll bother grinding the larger bolt down in diameter for use on .338 caliber cartridges. The bolt I ground and used on .308" case necks seems more than sufficient for larger caliber cartridges.

 

[Wedgy]

I made a little nipple on the end of the bolt or punch to center it in the flash hole.

 

[Pdvdh]

I made a little nipple on the end of the bolt or punch to center it in the flash hole.

That didn't seem to be necessary if the bolt face diameter is sufficiently large to extend out past the perimeter of the primer pocket. The inside of the cartridge case is concave. If the bolt head diameter is large enough, it contacts the case head around the perimeter, rather than in the center. Which is exactly what you'd want to help ensure the base of that the base/bottom of the primer pocket isn't bulged outward - because that will completely ruin the brass. I found that my bolt shaft was getting stuck in the RWS .404 Jeffery cases because of the concave shape and the softer brass in the RWS case heads.

When I cut off the bolt head, I use the cut face in the base of the cases to maximize the diameter of the bolt in contact with the interior of the casings. If I wasn't cutting off the bolt head, I would at least recommend grinding the end of the bolt down to full diameter prior to use. The RWS brass was soft enough that the edge of the bolt head must have been indenting itself into the brass. I had to grip the bolt shaft in the vise and twist the cases off the bolt shaft to remove the bolt after PP tightening was complete. But the base of the primer pockets were not swelled outward at all, based on my testing them with the K&M primer pocket uniforming tool/cutter.