Primer seating depth

[swadiver]

I now have a tool that offers adjustable depth primer seating. the new Frankford Arsenal tool is pretty slick for $60.

I use Sinclair's fixed depth primer pocket uniformer on all my Lapua brass (.308, 6BR, .223) so all brass is cut to the same depth. I use CCI BR2s, #450s, and BR4s.

my questions are, how far deep do I seat them? what form of testing will confirm the "correct" amount? will it show up in ES and SD data on the LabRadar? Does it really matter as long as they go bang every time?

inquiring minds want to know

 

[swadiver]

In a few minutes the usual shill will be here to tell you that you need to spend your easily earned money on more toys and that $100+ primer tool that handles one primer at the time is a work of art and a must have tool for a precision reloader.

I have been using a tray priming tool with fixed depth seating for years and I see no reason to upgrade, although if I thought that I could squeeze one extra point by using one, I would do it in a second.

Then again, if you have money burning a hole in your pocket by all means buy one. The guys selling them are trying hard to make an honest living.

Kindest regards,

Joe

uh huh. i already have the tool.

thanks

 

[Rsadams]

The primer needs to be flush with the case head. Not sticking out, not recessed. It's that simple.

Hmm I guess I have been doing it wrong... You don't want it recessed a bit??? I load alot of auto which you do want it down a bit.. Not trying to be sarcastic I am really asking... I just use a hand primer btw..

 

[Grimstod]

Seat by feel. Not measured depth. Setting them below flush is just a given for safety.
The anviles feet must be bottomed out. If they are not then your SDs go up. Been proven over and over again in benchrest.

 

[Webster]

I now have a tool that offers adjustable depth primer seating. the new Frankford Arsenal tool is pretty slick for $60.

I use Sinclair's fixed depth primer pocket uniformer on all my Lapua brass (.308, 6BR, .223) so all brass is cut to the same depth. I use CCI BR2s, #450s, and BR4s.

my questions are, how far deep do I seat them? what form of testing will confirm the "correct" amount? will it show up in ES and SD data on the LabRadar? Does it really matter as long as they go bang every time?

inquiring minds want to know

You will never see the difference in ES & SD. Too many variables besides the primer. All the manufacturers say to seat the primer so the anvils touch the bottom of the pocket. Seat to 0.002" is a made up number. I believe this number just ensures that the case head touches the bolt face and nothing more. I had misfires last year from pressing too hard and damaging the wafer of primer compound. Every primer will not have the same feel seating since the pocket o.d. and depth is swaged in place, not machined and each primer cup may vary a few 10 thou in o.d. I measured the priming tool push pin protrusion and realized it was too much. There is clearance in the shell holder that needs to be taken up before the primer gets pushed. Ended up reducing the pin height until the primer was below the case head and a little more push until it had a good feel without pushing hard. I uniformed the pockets. Never had a misfire after this adjustment. Even if the tool is properly adjusted about 1 out of 10-20 will feel to tight and the priming tool handle is away from the seat position. I push a little harder on these since the anvils cannot be bottomed based on the priming tool handle position.

 

[gotcha]

I now have a tool that offers adjustable depth primer seating. the new Frankford Arsenal tool is pretty slick for $60.

I use Sinclair's fixed depth primer pocket uniformer on all my Lapua brass (.308, 6BR, .223) so all brass is cut to the same depth. I use CCI BR2s, #450s, and BR4s.

my questions are, how far deep do I seat them? what form of testing will confirm the "correct" amount? will it show up in ES and SD data on the LabRadar? Does it really matter as long as they go bang every time?

inquiring minds want to know

Each of the primers you intend to use will have different cup heights (google rifle primer chart). Measure height of several including anvil, and adjust seating depth accordingly. ............. You can adjust so the anvil legs just touch bottom of pocket or, if you prefer, a slight crush fit. A slight crush fit should make your lock time more consistent but I don't know if this can be proven. I doubt you'll see a significant improvement in SD or ES unless you switch primer brands........ If you're doing it properly you'll see the outline of the primer anvil "feet" in the smoke at the bottom of the pocket when depriming

 

[savagedasher]

At all my primers useing a forster press
It has a dead stop seat of .002 below flush .
You will find primer need to be seated the same to get lowEs Larry

 

[BoydAllen]

The primer needs to be flush with the case head. Not sticking out, not recessed. It's that simple.

Respectfully I disagree completely. What I have heard from shooters that hold records and Benchrest Hall of fame members is that primers should be bottomed in their pockets. They vary in thickness, so seating them to a specific depth does not seem to make sense even if the pockets are of uniform depth. Virtually all of them seat primers by feel. (If this does not sound right to you, consider that it is almost a certainty that all of them shoot better than you do.) Recently a prominent benchrest shooter did a test and found that as long as they were bottomed that the results were good. The best way to do this is by feel. IMO the market for pocket uniformers was created to sell a tool, and is not based on any research that I have seen. I do not know a single competitive shooter that seats his primers flush. If this does not convince you, do your own testing (carefully and methodically) and believe the results. For those of you who do not believe any of the above, I called Federal and they recommend that rifle primers be seated between .005 and .008 below flush. Generally I have found that manufactures' instructions are intended for their average customer.

 

[M-61]

I use a bench mounted RCBS primer seater. When they bottom they are seated. Easy to feel. I have never measured to see how much below flush they are as I don't care. They are surely not sticking UP. Bottomed is bottomed period. Worked lots of years for me using this method and years (decades) ago I used a CH seater which I wore out.
Chuck

 

[Texan]

I use a lot of cheap primers (Wolf, Tula, S&B, etc.) and believe I would be asking for misfires if I seated them flush with the case head.

I'm sure I probably seat my primers too deep (crushing deep...until my RCBS hand priming tool closes completely, about 0.008" below flush) , but I hardly ever have a failure to fire and my numbers are good.

I had an ES of 8 today with S&B primed 308, which had them crushed in.

ETA: I did uniform the flash holes in this brass.

 

[Shynloco]

In addition to what Boyd and Chuck (M61) wrote, I have a K&M Adjustable Primer Seater that I've tested on several calibers I reload for. I have yet to see any discernable difference in accuracy down range in seating primers at different height. Now I have never seated any primers "flush" with the face of a casing (due to safety concerns), but I can't imagine doing that given the advice I've received from either reading books on Accuracy Shooting or in speaking to many shooters, some who compete seriously for the best score possible.

Alex

 

[6BRinNZ]

The primer needs to be flush with the case head. Not sticking out, not recessed. It's that simple.

Flush - you sure?
My experience has been that some primers liked to be seated a bit deeper than that for consistent ignition.
here is how it played out for me - Palma brass and seated primer with my handy dandy adjustable tool. Adjust tool so that primer is ~.002 below flush. All going well then one day no bang but a solid dent in the primer hmmm.
Change nothing and load more ammo 20 odd rounds later no bang and a big dent...hmmm
Seat primer in .004" deeper - more rounds later no bang and a big dent....hmmm
Seat primer .004" deeper - thousands of rounds later on different lots of brass (same primer lot tho) always a bang.
Yip could be a coincidence - but then I still see others at the range get no bang and they are trying all sorts of stuff but seating the primer deeper.
I'm reasonably confident these days - if you have no bang but a good primer strike its not seated deep enough
oh yeah - I bought an adjustable one kos my fixed sinclair one kept breaking. 3 Deep in those and the fancy pants one wasn't so bad. I never had a no bang with my fixed primer tool but I would always sueeze it in until the handle had no where else to go and those primers - well they were seated deeeep.

 

[carlsbad]

I use the holland primer seater that comes with a dial indicator to check seating depth. IIRC, they recommend .003 or .004 below flush. At least this is what I use. Consistency is the key.

--Jerry

 

[swadiver]

thanks all

 

[Zero333]

I seat till I feel the primer touch the bottom, then I keep going a lil farther. It ends up being in the neighbourhood of 0.004"- 0.006" below flush, depending on primers of course.

 

[NorCalMikie]

To the bottom of the pocket! And if you REALLY clean the pockets, the primers will probably be below flush. It'a a feel thing.
Now if you're loading for "Gas Guns", they damn sure better be seated below flush or you're just asking for trouble.

 

[fyrewall]

I use a cheap Lee press mounted priming tool that probably seats the primers so their tiny anvils are very slightly compressed. The Lee tool provided adequate "feel" and will not allow primers to be squashed and appears to have a "dead stop" resulting in primers being seated .002 below the base - all my loaded ammo primers are at that depth. No fail to fire

I think that Lee tool costs less than $20 so I have 2 of them, one large & one small. The Lee tool uses standard type shell holders. I am still looking for the small primer guide that fell off my bench about a week ago sweeping the floor with a strong magnet on a daily basis; hopefully Lee will provide a new guide and not charge me very much. I have never had a problem with fail to fire and see no need for further analysis of my priming procedures. At one time I loaded over 1,000 rounds for a Mini 14 and observed no protruding primers that could cause an out-off-battery firing/explosion catastrophe. I use lots of CCI #41 primers (brass color) that appear to have a tiny bit less anvil protrusion than the silvery CCI 450's (Ni plate). Both provide equal results from .20P and .204R bolt guns.

 

[T-shooter]

I use a cheap Lee Ram Prime ($11) to seat primers on the press. It is slow, one at a time, but easy to adjust for seating depth and easy to feel the seating pressure needed. Also A K&M primer pocket uniformer and an RCBS flash hole uniformer. Primers should bottom out, and slightly recessed by about .005". It's unsafe to have one that is above the surface. This is inexpensive and works well for me. No need to change so far.

 

[fyrewall]

I quit looking for the lost small primer guide and called Lee precision and the nice lady offered to send me a free replacement. To ensure a more pleasant future relation with Lee, I offered to buy a set of 3 Lee aluminum hex die lock nuts with O rings, I like these. The total charge was $9 and change. Possibly, the cat played with it causing it to be moved far away.

I am unable to see how seating depth may be adjusted with this tool assembly as the top end of the punch holder, holding the punch in a fixed position, contacts the bottom of the shell holder - another fixed situation. No doubt, modifications to allow seating depth to be increased may be made by grinding tool parts or raising the punch inside the punch holder (non-threaded) but this could results in squashed primers. Raising or lowering the shell holder adaptor, several turns of coarse threads, has no effect on primer seating depth as the punch up stroke is limited by contact with the bottom of the shell holder. Possibly, use of other than Lee shell holders would affect primer seating depth so I always use Lee shell holders in my primer seating. Use of Lee shell holders with the Lee Ram Prime produces a seating depth of .002 below the brass. Using a thinner shell holder would increase seating depth by allowing the primer punch to push the primer further into the case primer pocket.

Things work out so well that I have not measured primer height and primer pocket depth. Make the primer pockets deeper and the Lee tool may not "bottom them out".

I have lots of Lee shell holders, and Mr. Lee has cleverly, well designed tools.

 

[T-shooter]

The Lee Ram Prime doesn't come close to bottoming out, at least mine doesn't. The platform that the primer sits on will go well up into the #2 Lee shell holder (shown here without the cup). To get room to adjust it, I used the Lee locking nut but turned it upside down and removing the o-ring from the recess on the bottom. It adjust like any other die by screwing it in or out.