Tight Primer Pockets

[RC20]

Is there a tool that cuts radially and not the depth uniforming?

My PPU brass in 7.5 Swiss is tight, over time it loosens up to tolerable but the first pass is a bugger.

I did find this the Primer Seating tool of tools (as is the price!)

https://www.primalrights.com/reloading-equipment

[pwc]

Lyman has a hand held primer pocket swaged (ridge) remover for large and small primers, got mine when they were $5. You might try the conservative approach first before spending kids college tuition.l

[lordmorgul]

Or Lyman hand tool primer pocket prep tool set with chamfer, it usually pretty good once you can get them started.

You can buy that separately but I bought a kit with a variety.
https://www.amazon.com/Lyman-Univers...gateway&sr=8-6

https://www.midwayusa.com/product/10...et-reamer-tool


Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / NAGR / NRA-ILA contributor, USCCA member

[hounddawg]

RCBS bench primer works great at about 1/4 the cost of the one you linked. If you want to get precise get the Holland version of the RCBS or the upgrade

https://www.hollandguns.com/

[std7mag]

For the primer pocket your pretty much stuck with either a swager, or a reamer type tool.
I use the Lyman pocket uniformer.
Other people will use something else.
Look at what's out there, make your decision.
Best of luck.

[NWPilgrim]

All that is needed is to radius the opening edge of the primer pocket. This can be done by swaging or by cutting 45 degree. For large volume I use the Dillon Super Swage. For smaller volume I use the pocket reamer on the Lyman case prep center since it also does case mouth prep. Just lightly hold the pocket to the reamer for a couple of seconds does not take much to knock off the sharp edge of the crimped pocket.

[Unclenick]

Originally Posted by NWPilgrim

All that is needed is to radius the opening edge of the primer pocket...

You are thinking of crimped military brass. What the OP has is Prvi Partizan brass. The metric countries have a primer pocket minimum diameter spec that is 0.0003" smaller than ours is after doing metric conversion. They are often a bit tight for that reason. I've seen the same thing in IMI brass. Swaging or reaming are the only ways to set them right, as noted in an earlier post. I will add to the previous information that the L.E. Wilson case trimmer has a primer pocket profiling reamer that produces a very smooth and nice result.

[Metal god]

Sorry I don’t remember, do you have a primer pocket swager for that size primer pocket ? Id try that first . I’m going to assume you’ve tried chamfer the top edge . So I agree with others that swaging is likey what you’re stuck with .

[RC20]

You are thinking of crimped military brass. What the OP has is Prvi Partizan brass. The metric countries have a primer pocket minimum diameter spec that is 0.0003" smaller than ours is after doing metric conversion. They are often a bit tight for that reason. I've seen the same thing in IMI brass. Swaging or reaming are the only ways to set them right, as noted in an earlier post. I will add to the previous information that the L.E. Wilson case trimmer has a primer pocket profiling reamer that produces a very smooth and nice result.

Bingo, I just got in 100 7.5 cases and the same thing I posted last time I believe.

New frustration, hands are a bit arthritis and not fun dealing with these until they are well broken in.

The LE Wilson seems to be a crimp remover, I gather it does some side of pocket grinding/trim as well?

The link was just for fun as its a wild looking machine at a wild cost that I would not begin to buy (got to get that Labradar !)

I have the RCBS tool for pocket bottom but it has not side component. I may have a swager buried some place and not sure how that would work.

[Unclenick]

Yes, the Wilson not only radiuses the pocket for easy start, but it also cleans the sides of tight pockets. In the photo you can see the cutting edges go all the way to the tip.

This tool is not, however, a good idea with arthritic hands, as I've noticed my non-arthritic hands will start to cramp if I try to do too many cases at once with it. I rely on the Dillon Super Swage 600 for volume. The only problem with swaging is the extra brass has to go somewhere, so you wind up with a slightly raises area around the primer pocket perimeter that flattens against the bolt face during firing. That can sometimes make the pocket a little tight again and make it require a second swaging. I don't know if the raised surface has any negative effect on group size, but I doubt it, as it is centered. It would very slightly shorten the excess headspace left by the chambered cartridge, but it's not very high and I've never noticed it interfering with anything.

[RC20]

I saw some references to chucking it in a drill.

I don't have lots to do at any given time, 100 usually.

I had to look on Wilsons sight, the perspective was twisting my brain.

I see now its just eh very tip that the working part.

Looks like it will work - I can finale with the approach and see what does best, thank you.

[Unclenick]

There is a power screwdriver adapter for their cutters and reamers. You still need the trimmer and case holder to line them all up nicely. They are a bit more aggressive at cutting the brass than the Lyman hand-held ones I acquired long ago, so having their case holder hang onto the case against the cutting force and let you feed the cutter gradually is helpful.

[Metal god]

With out ever having this issue to date . I’d likely swage the pockets then put a light chamfer on the pocket edge , and that’s only because I have the tools to do that .

[NWPilgrim]

Originally Posted by Unclenick

You are thinking of crimped military brass. What the OP has is Prvi Partizan brass. The metric countries have a primer pocket minimum diameter spec that is 0.0003" smaller than ours is after doing metric conversion. They are often a bit tight for that reason. I've seen the same thing in IMI brass. Swaging or reaming are the only ways to set them right, as noted in an earlier post. I will add to the previous information that the L.E. Wilson case trimmer has a primer pocket profiling reamer that produces a very smooth and nice result.

Yeah, I just treat Euro brass like military and swage or ream the pocket opening. Once the primer gets started it seats fine. It’s just getting it past the tight opening that it hangs up a bit.

[kilotanker22]

I had a similar problem recently with some hornady brass.
I couldn't find brass for my 7mm locally so I bought a few boxes of Hornady factory ammo to shoot and use the brass. Deprimed fine, but I had to use my chamfer tool to be able to insert new primers. Even so, they are still really tight after 2 firings.

[T. O'Heir]

0.0003" is 3/10000". Won't make a lick of difference.
Neither will spending $600 on a primer seating tool make the ammo any better.
Best to use a primer pocket swager. $41.99 at Cabela's for the RCBS tool.

[RC20]

TOHAIR: Once again you are plain wrong.

Doing a bit of chamfer may help getting started, but the 7.5 PPU is clearly sub sized from US standard. Its still going to be tight.

I have PPU in 06 and 308 and it does not have the same issue.

If you would actually read the post the $600 Primer tool was humor and admiring a lovely tool.

[Metal god]

Am I wrong in thinking they must use a smaller primer to start with .

I was thinking , is there a foreign primer like tula available in the US that is spec-ed a little smaller you can use ?

[hounddawg]

every good mechanic knows if it won't fit you need to get a bigger hammer

[Unclenick]

As long as it's not a bigger firing pin requirement, all is good.

[RC20]

I was thinking , is there a foreign primer like tula available in the US that is spec-ed a little smaller you can use ?

I doubt it. As us cartridge type PPU is right size, I expect the same ting from Primers. Right size of US, European size kept over there or they would be slightly loose in anything but the fairly rare mostly Eu8ropn cartridge (7.5 is very local)

[hounddawg]

ok a serious recommendation

Do you have access to set of pin gages ? .173 minimum specs for small rifle pockets and .2085 is minimum spec for a large rifle pockets. Seven dollars each at MSC

the .2085 https://www.mscdirect.com/browse/tn/...ge&hdrsrh=true

and the .1730 https://www.mscdirect.com/browse/tn/...ge&hdrsrh=true

[RC20]

When you have found definitely that its an issue, then no, no plan to get gauges.

Sure I could afford it, but as I have reloaded on and off for 50 years more or less (? ergh)

Sometimes that is the answer and its a well founded suggestion but in this case, no.

PPU in 308 and 30-06 does not exhibit this problem, the one aspect that might help sans getting the Wilson reamer might be the bevel. Not so much as a full solution but a help to get it started and might be enough.

Will play with it and let you all know.

The Wilson is a solution clearly, but its a bit on the trendy side and I have to figure out the hassle vs the cost ($50 or so could be spent on ?) - there is alwyas the saving account for that Labradar to fill.

[Unclenick]

The size difference is smaller than the tolerance. The U.S. tolerance has a 1.5 mil span in both primers and pockets. So 0.3 mils one way or the other is not enough to make or break things. It's just harder to seat. Probably the bigger factor is that U.S. makers tend, I think, to aim for around the middle of the tolerance range and the Europeans tend to aim for the low end, figuring that allowing some head expansion then won't take them outside the range so soon. Norma, for example, actually removes cases from their production line periodically and makes sure they will withstand 10 loadings and firings.

To do a cursory test of that theory, I did a little pin gauging myself. My small pin gauge set is the more common minus tolerance type, with gauge diameters at even thousandths with a tolerance range of +0.0000" and -0.0002". I really need a plus set as well for this test to bracket the hole sizes better, but still better would be one of the narrow range sets of higher tolerance gauges in 0.0001" increments. But I'm just not willing to drop a Franklin and a half on that for this one test.

My Mitutoyo digital micrometer says my actual gauge values for my 0.2080" and 0.2090" pins are:

The 0.2080" gauge is actually 0.20790", or -0.00010" below nominal
The 0.2090" gauge is actually 0.20895", or -0.00005" below nominal

At least, they were at my basement's current temperature.

I grabbed an IMI .308 Match case, which I know offers resistance when it is primed. The 0.20790" pin fit in. The 0.20895" pin would not go in. Now here's where the +pin would help and the 10ths would rule, but I had to go it by feel. I've reamed and fit enough holes for press-fits and for small shaft journals that I can pretty well guess the fit of steel in brass by how easily the steel fits in the hole. My sense of feel put the first pin at about 0.0005" slip fit. There was just a little rubbing going in, but with some oil, the pin would still spin in it, albeit with no appreciable additional wiggle room. So my finger feel puts the IMI primer pocket at a diameter of 0.2084", just under U.S. Minimum and not quite Euro-minimum of 0.2082".

Next, I picked out a piece of Federal brass. The smaller pin slipped right in with room to spare and easily a full thousandth of room. The 0.20895" that would not go into the IMI primer pocket did fit, with a good bit of rubbing, very snuggly into the Federal primer pocket. My sense of feel put the slip fit at about 0.0002". Too tight for a free spinning journal, but not a true force fit yet. So I put the diameter of the Federal primer pocket at about 0.20915", just a tenth of a thousandth short of the exact halfway point between minimum and maximum. And the Federal is a case that is much easier to prime.

I realize that my measurement by "feel" method is not very satisfactory, but there is no question in my mind that there is certainly over half a thousandth and less than a whole thousandth of difference between the two primer pockets and that this accounts for why primers are so much harder to seat in the IMI brass. On the other hand, the IMI brass will certainly withstand more high-pressure loads before its primer pockets come loose than the Federal brass will.

I have now got about half a dozen domestic and half a dozen foreign headstamp new, never-loaded cases in .308. I should go through them all, but the pins aren't resolving enough. I need to go to another measuring method; cast Cerrosafe or use a small hole split gauge to try to get a more consistent comparison. When I get time, I probably will. For now, the fact IMI is rather harder to seat a primer into than Federal and that the simple pin comparison confirms it should be so will have to be satisfying enough. I don't have any PPU brass, but maybe someone else who does will try what I did and will confirm it is tight.

[RC20]

GO Unclenick!

When I was younger I did a lot of surveying. One guy actually took air temps (or I did, hung on the tripod the Transit was mounted on) - 200 ft chain (tape measure) was calibrated at 68 and it did have a marginal affect on the length - up, he was nuts, but he sure was a damned good surveyor and I felt it was privilege to have worked for him.

Lo many years latter, I was working on Power Generation (we repaired diesel engines as well) - we had some Volvo diesels to overhaul. I was working the bottom end and the Journeyman was working the top end when suddenly he said stop, I have to fiuge this out.

We had A and B marked pistons and C and D marked liners, turned out A piston went with a C Liner and a B piston went with a D liner.

Yep, their tolerance for mfgs were sloppy. So rather than tighten em up, they matched sets to have them fall with spec for the rings to seat and work right.

You just can't trust those European!