Lee n. field,
When reread, I found I had read your report of Lee's response too quickly, and took it to mean they were claiming flush primers were OK when they actually meant the Lyman shell holder should be OK. Sorry about that.
Note that while seating below flush is the common measure, primer pockets have a tolerance of about ±0.001" in depth, plus the primers themselves have a tolerance in height that includes the anvil feet. If you want to double-check your results, you can measure the depth of your primer pockets and the height of your primers, subtract the latter from the former and add 0.002" for small primers and 0.003" for large primers (Federal's recommendation) to get the total number of thousandths below flush that is ideal for that particular case and primer. In other words, the primer anvil feet touch down on the bottom of the primer pocket, then you compress it by 0.002" or 0.003", depending on primer size. That exact figure is useful to know for precision rifle shooting with depth uniformed primer pockets that may need to be a thousandth or two deeper than commercial standards. But it doesn't hurt even the handgun loader to at least work out the average for their brass and primer lots, and to see their average result meets that computed average, ±0.001". Manufacturers don't do any more than that, and it works for them.
Tula primer cups are similar to CCI cups during the 1980's, before CCI revamped their process to remove cup burrs. They can seat with significant extra resistance, making them more likely to be left high, even when seating force seemed more than adequate. My Dillon Square Deal, which is my permanent .45 ACP press, couldn't seat 1980's CCI primers and can't seat Tula primers reliably. But both Slamfire and I have noted in the past that their rifle primers frequently produce the lowest velocity extreme spreads we can get, beating even Federal match primers in many instances in .308 and .30-06 and .223. So they are worth experimenting with if you can seat them correctly.
When reread, I found I had read your report of Lee's response too quickly, and took it to mean they were claiming flush primers were OK when they actually meant the Lyman shell holder should be OK. Sorry about that.
Note that while seating below flush is the common measure, primer pockets have a tolerance of about ±0.001" in depth, plus the primers themselves have a tolerance in height that includes the anvil feet. If you want to double-check your results, you can measure the depth of your primer pockets and the height of your primers, subtract the latter from the former and add 0.002" for small primers and 0.003" for large primers (Federal's recommendation) to get the total number of thousandths below flush that is ideal for that particular case and primer. In other words, the primer anvil feet touch down on the bottom of the primer pocket, then you compress it by 0.002" or 0.003", depending on primer size. That exact figure is useful to know for precision rifle shooting with depth uniformed primer pockets that may need to be a thousandth or two deeper than commercial standards. But it doesn't hurt even the handgun loader to at least work out the average for their brass and primer lots, and to see their average result meets that computed average, ±0.001". Manufacturers don't do any more than that, and it works for them.
Tula primer cups are similar to CCI cups during the 1980's, before CCI revamped their process to remove cup burrs. They can seat with significant extra resistance, making them more likely to be left high, even when seating force seemed more than adequate. My Dillon Square Deal, which is my permanent .45 ACP press, couldn't seat 1980's CCI primers and can't seat Tula primers reliably. But both Slamfire and I have noted in the past that their rifle primers frequently produce the lowest velocity extreme spreads we can get, beating even Federal match primers in many instances in .308 and .30-06 and .223. So they are worth experimenting with if you can seat them correctly.
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