standard for.223 primer seating depth in AR-type rifles?

[jaredr]

can't find a published specification, am seeing between 5 and 8 thousands (.005 - .008) on factory ammo from Black Hills, Remington, Federal. Would like to know what others have adopted as a minimum seating depth? Attempted to find what the "mil specification" is for green tip but my search-fu is weak, if anyone has a link would appreciate it if you would pass on. thanks, jared

edited to clarify: am referring to seating depth below case head, so primer would be (using figured above) between .005 and .008 below the surface of the cartridge head.

Edited January 14, 2011 by jaredr

[WDB]

I don't know the "book" answer but, most of the ones I've measured are 0.005 for M855 right out of the box.

[Kyle O]

I've never measured primer depth....

I case gauge my match ammo, when in the gauge I "feel" the primer/case rim, and if it "feels" good, it passes.

[THM7]

I am with kyle....knock on wood I have not had a primer issue yet with my rifle reloads. I use the feel method.

[jaredr]

maybe it's just the OCD in me i've used .005 as a minimum for as long as I can remember but couldn't recall where I got that number from. Not sure that .005 is meaningfully better than .004 (or some other number), but it was a nice round number and none of the new-manufactured commercial ammunition i used for comparison was under .005.

Plus, when you run a straightedge over a cartridge with the primer .005 below flush, you get a nice clear shadow that tells you you're good:lol:

[AlamoShooter]

I thought, that I was obsessive. I can see on a 1050 how you could set the depth close. how would you set the depth on any thing Else?

I just make sure I have the pressure and the primers are lower than flush. How are you measuring 0.005 for depth?

most of my printer paper is 0.004

Edited January 14, 2011 by AlamoShooter

[jaredr]

I can see on a 1050 how you could set the depth close. how would you set the depth on any thing Else?

don't believe you can set the depth on a 650. I'm loading .223 (and pretty much everything else) on 1050's which allows you to vary primer seating depth by raising (or lowering) the primer system tappet.

How are you measuring 0.005 for depth?

depth micrometer

I had to recently switch from WW to remington primers and for the first time I can recall, I actually saw high primers when I checked the first test run from the press. Usually, you mike the first dozen or so cartridges, make sure that everything measures out, charges weight out, etc. but you never expect to to see any variances that require attention. I ran the first five rounds after breaking open a case of remington 7&1/2's, ran a straightedge across the cartridge head and let out a stream of curses. I then spent an hour measuring individual primers with a dial caliper (no measurable difference from the remaining winchester primers i had for reference measurements), pulling bullets and decapping high-primed brass to measure primer pockets, etc. couldn't figure out why primer seating depth needed to be increased but it sure did. Prompted me to ask what depth others considered "good" (but pretty obvious that a round which teeter-totters on a primer protruding from the base is <not> good:angry2:). I'll call it an x-files experience and move on, but frustrating as it was, reminds you that you're not wasting time on first article inspection...

[AlamoShooter]

Well I never saw a Depth micrometer before = Thanks

[DyNo!]

I haven't had problems with primers that were even completely flush.

Aside from primers sticking out of cases, I don't think you should be concerned (assuming they're hard primers).

[George]

I am not sure a specific specification matters here. Primers need to be seated until they "hit" the bottom of the primer pocket and then just a tad more so there is some very small amount of crush, but not much. Primers can vary a tiny bit in height from brand to brand so IMHO seating feel is most important to achieve this. Additionally, brass pocket depth can be a variable in mixed lot brass. I don't see any single specification being something you should strive for unless you use one lot of brass and primers exclusively AND take the time to measure it all out including accounting for the correct amount of crush.

[Kyle O]

Seriously, it might matter with precision rifle competition when thousandths of an inch matter, but for what we do, or even hunting, or varmiting, it's not gonna make a difference that would be even noticed.

Flush or less is good enough, I promise!

Edited January 16, 2011 by Kyle O

[Dan Sierpina]

Did you uniform the primer pockets first? If you didn't, there is no way that trying to have uniform seating will work. Doing all the extra steps is fine if you're going to use the same 30 cases for benchrest. For brass that gets slammed while being chambered, and often left on the ground, don't bother!

[Merlin Orr]

Put a little flat spot on the top of the primer and you are good to go.

[Mike Morcillo]

After reloading, I drop each loaded round in a cartridge guage to see if it will chamber. While the cartridge is in the guage, I look and then drag me finger over the primer checking for high primer. Done.

[jaredr]

thanks guys - just to clarify, concern about primer depth wasn't with respect to accuracy but rather safety. While I want my ammunition to be as accurate/consistent as possible, I'm not trying to produce benchrest-precision rounds using mixed headstamp brass and volume-thrown charges. Rather, concern was what (if any) is a "standard" for primer depth below flus to prevent slamfires. I'd adopted .005 simply because it was what I measured from M193. What I'm hearing from others re: optimal depth ranges from flush with cartridge head to deep enough to catch with your fingernail. Fair enough. I'll stick with looking for something below flush, but maybe only because it satisfies my deep seated paranoia about floating firing pins...

Also - found an interesting bit of info re: where my high primers came from. As I mentioned, what prompted this question re: optimal primer depth was a recent spate of high primers I encountered when switching over from WW small rifle to Remington 7&1/2's. I recalled reading in my RF100 manual that a different stabilizer plate was required when using remington primers. I called dillon and spoke with Lee, who explained that they'd found Remington primers to have a taller cup than winchesters, hence loading remington's required swapping in a different part (stabilizer plate 17295) to provide more clearance. I don't see myslef buying any more remington primers now that WW are available again, but good to know that if I do have to swap back and forth, no question that I'll have to adjust primer seating depth.

[Mike Morcillo]

Dillon recommends the use of Winchester primers, at least that's what they told me. I run CCI in the .223 without problem.

[holist]

If the paranoia is that bad the last primer besides Federal Match I would use would be WW. Quite a few years ago WW was the primer of choice for XTC High Power shooting. WW then went and switched from a chrome plated cup to a all brass cup. They quickly fell out of favor due to slam fires and pierced primers happening on a regular basis. Primer of choice now is pretty much the Rem 7.5, you can hot rod them and they hold up. As long as they are at least flush I dont worry about it.

Ray