Hi All

I've just started developing a load for my Rem700 .223 and am pretty new to this game. I've settled on 25.5gr or Benchmark behind a 52gr Amax. Using an empty case with a slot cut in the neck, I've worked out that these projectiles measure 1.904" to the ogive when seated by the lands (using the Stoney Point comparitor). I set up my Forster seating die to seat 5 rounds at each of 1.908", 1.900", 1.892" and 1.884" ie. 0.004" in, 0.004" out, 0.012" out and 0.020" out.
The problem is that I've discovered my primers (Rem 7 1/2) when seated as far in as they go project about 0.005" from pocket (R-P cases). When I measure loaded rounds, they are all about 0.005" longer (to ogive) that when I measure un-primed dummy rounds seated to same depth.
Any idea if this matters?
Will I be effectively seating longer than I intended? I imagine that when I close the bolt, the primer will be resting against the bolt but the case head will be sitting 0.005" off it and the bullet will be sitting 0.005" further out than I intended.
I've tried to set the sizing die up for minimal head space, so perhaps the primer will be seated by the bolt. But I haven't been able to seat them flush using a lee hand primer.
Any thoughts?!

Cheers
Alex

Your primers should be .002 to .005 below flush (recessed). Either your primer pockets are very dirty, your not seating your primers hard enough, or your primer pockets are to shallow.

You might try a different brand / lot of brass, a different brand of primer, cleaning your primer pockets, or pick up a primer pocket uniformer (make sure it's set for small rifle, not small pistol, small pistol primers are shorter). The uniformer will cut all your primer pockets to the same depth.

Thanks for that - it didn't seem quite right. I just couldn't get any more leverage on the Lee priming tool and also wondered how much you have to lean on it to make the primer go off!
Given that these load development rounds are already loaded, I guess I'll just shoot them as planned and repeat the exercise after I've found a primer pocket uniformer. Any suggestions about brands?
By the way, I "cleaned" the pockets with a small screwdriver and I can't imagine that the Rem brass has pockets that are too shallow, so my guess is that either I'm not leaning on the priming tool hard enough or the screwdriver isn't doing the job. Uniformer should sort it out - thanks for the suggestion.

You can go ahead and fire those rounds, but you may also experience a lot of misfires if the firing pin pushes the primer in before it has time to ignite.

That's the only problem I can see.

Good Luck

HL

It takes a impact to set off a primer, crushing won't do it.
I use the RCBS uniformer, but your going to have to use what you can find (due to your location & possable import-export issues).

Do you have a priming arm on/for your press? You could use it to finish seating those primers that are already assembled.

The uniformers made by R. W. Hart & Son and Sinclair are hard to beat.

Thanks very much for your ideas and recommendations folks! I did wonder about the priming arm on the press but was a bit nervous about putting a loaded round in. You don't think it's possible to set it off by crushing it?

Thankfully we can still import some shooting equipment without a permit and I've ordered optics and reloading gear from the US before (The Opticzone and Lock, Stock and Barrel were both great). I might order the Sinclair tool from their website.

This post made me wonder if the primer pockets are shallow, and given the powder capacity, could a load be had using small pistol primers?

I've heard of using light primers to get better uniformity. What would be the down side of this?

( I realize the primers are already in a loaded round but if the pockets are shallow?) Nate

Just for kicks if you have a unprimed case from the lot you loaded try measuring the pocket depth with your caliper. Take the "tail" of the slide with the jaw opened a bit and press it in the pocket until it bottoms and see what it says. I don`t have a book handy with primer & pocket specs at the moment, but I`m sure someone has the lenght of a primer handy to tell you if the pockets are at or near spec.

Edited to add: I just measured 2 of my 223 case pockets and they went 0.120" deep. I don`t know if this is max or not but primers seat properly in them.

Interesting! I measured 10 primer pockets varying from 0.116" to 0.123" deep. I measured a few primers and they measured 0.120" to 0.124". My understanding is that seating the primer against the bottom of the pocket is meant to slide the anvil into the cup ever so slightly.
BTW, these are once fired Rem cases from their premium grade ammo. The pockets look pretty clean but I'm happy to accept that my screwdriver isn't cleaning them well, especially into the "corner".

Quick update… I’ve ordered a Sinclair uniformer and driver adapter which should solve this problem.

I’m still interested to hear if anyone thinks that having the primers seated proud of the case head (and by varying amounts) will confound the effects of bullet seating depth.

My guess is that it will, leaving the bullets sitting at varying distances from (or into) the lands, relative to what I intended. Unless the head space is zero in which case I guess (again) the bolt will crush the primer into the pocket and the bullet will be sitting at the intended distance from the lands?

I think I'll leave the primers where they are on the loaded rounds. If the pockets are too shallow (or dirty) and I use more force to seat them flush, I might crush the priming compound and cause erratic ignition (according to a manual I read).

Takla--you'll like the Sinclair uniformer. I've used one for years, and I drive it with my battery powered drill. You can use a battery powered screwdriver also. All my brass gets the same treatment--primer pocket uniformed, flash hole deburred, full-length resized, deburred and chamfered. After first firing and resizing, they all get trimmed to uniform length and deburred/chamfered again. Then the accuracy workup begins. Some folks will disagree with the need to do all this, but it has worked for me and it gives me more confidence in my loads. However, I don't weigh the cases---

Cheers dustoffer. I have also trimmed all my once fired,sized brass (Lee trimming tool) just to get them all to the same length. Do you find you need trim them after subsequent firings and sizings? I mean to have consistent length from case to case, rather than just when they get too long.