internet bum
I have an older Sinclair uniformer that allows you to adjust the depth of the cutter so maybe that could help if you can find one. Hope it wouldn't end up making the brass too thin in that area. One end for LP the other for SP.Originally Posted by grahame
Registered User
Yes It is. One of my friends uses military brass that I prep for him. When there is an issue with crimped primer pockets I put the chamfer tool in my 3 jaw and have at it. You just kiss the pocket and your done.Maybe he could post a pic of the case head. That would confirm things. It kind of sounds like that could be the case, but not definitive IMO. One would think that the extra lip around the primer pocket would be obvious and worthy of mention. It doesn't seem that Priv is currently producing brass that is intended to have the primer crimped afterwards. If he has some it is likely discontinued product.
How hard would it be to close the bolt on a round with the lip protruding?
https://www.prvipartizan.com/rcases.php
Note the 4 footnote where 8 x 57 is C.I.P. which I expect is Crimped In Primers.
A cursory Google search doesn't bring up anything where someone is having a similar problem. Most is from folks talking about fired crimped primer brass.
This little doodad is great for removing the crimp from military brass.
Mort
Registered User
I think I know what my problem is...i just measured 10 primers #34CCI . they vary in depth from .1241" to .1270" Also I found a chart in Accurateshooter.com that shows primer depths of : CCI .118" , Fed .117" Rem .119" and Win .121". my prvi ocket measures .130" so seating the primer fully in should not be an issue.....Except for the radius in the bottom of my prvi brass..... Has anyone measured Lake City 7.62x51 pocket depth? Grahame
Registered User
what I'm going to try is to chuck my RCBS pocket reamer into my mini lathe and then Dremel the face a little...hopefully this will dig into the radius at the base of the pocket. i.e to remove some of the tool chamfer.....it will taper more of the mouth of course...grahame
internet bum
My Sinclair cutter is carbide, but man it's slower than Mike Tyson at a spelling bee when it comes to removing brass from the primer pocket. I use it more for a cleaner than I do for a uniformer.
Last edited by antelopedundee; 03-24-2023 at 02:46 PM.
Registered User
you are looking at the wrong tool to fix the percived problem.
you need a primer pocket UNIFORMER...non adjustable...sinclair
you can radius the mouth of the pocket with a bunch of tools the most practical are crimp removal tools the ad a nice radius to the top of the pocket.
Registered User
The Op may have 2 issues with his military brass.
First, the primer pocket might be too much conical, second, the primer pocket bottom radius might be important, both making thet he can't seat properly.
One must remember that a primer pocket is put in shape by the hammering of a punch while the exterior of the case is in a fixed and adjusted volume defined by an exterior matrix and a drawing punch at dead center in the inside. The punch guide fully close the volume the the punch hit the raw case. Brass is pushed away from the punch and finish the case head by filling the volume allowed by the tools.
To remove that punch (forming the primer pocket and finishing the case head in a fixed volume) (therefore with a very high material pressure), the punch HAS TO be conical and with a round edge to limit wear and help material to flow. The more angle, the lower the effort on the punch, the easier to eject the punch, the higher cycling rate of manufacturing.
Keep in mind military ammo manufacturers use priming machines that push an enormous lot on the primer cup to force it into the primer pocket. The more "cup swagging" into the (conical) primer cup, the more sealing against immersion without varnish. Please notice that as long as the mixture is not stressed in between anvil and cup it won't bang.
(if the drawn raw case is to thick at the head, the primer pocket will not be deep enough, so primer WILL 150% bang at the priming machine)
As far as I know of, primer pocket uniformers are "only" 1 cut mill bit. They are not designed to cut on side to change the cone into a cylinder. Even using a drill press can be a PITA to correct this issue with the various uniformers I own.
Hope this help.
Registered User
"As far as I know of, primer pocket uniformers are "only" 1 cut mill bit. They are not designed to cut on side to change the cone into a cylinder. Even using a drill press can be a PITA to correct this issue with the various uniformers I own."
being a straight end mill config they will cut the sides if smaller than the tool
Registered User
Mines do not.
In case of too much conical shape of the primer pocket, which SHALL be corrected because of very hard priming or impossible priming with my tooling, all my uniformers do get stuck inside the pocket one depth or another, whatever the rpm, lube and feed speed.
No pressure screw ever handled the torque (ie old sinclair hexagon bar, 2 carbide bits, pressure screws). I had to go with bigger, shouldered carbide bits direct in chuck. Still a PITA on the brass handling side.
Furthermore, as these cutting tools are "free fingers/hand use" , I mean they have no guidance to keep milling end on axis with the primer pocket, one would, after many use, should the bits also cut on side, enlarge the normal primer pocket on a regular basis.
Once again, with my tools, that did not occur even on training cases that have seen hundreds of shots ... and cleaning.
Just gave a look with a magnifier, there is no sharpening on the side, no cutting edge, no clearance angle. Mines can't cut on side. And they get stuck.
I am very interested in the brands /models you own that are ALSO cutting on the side. Here, just having a mill bit ground to specific diameter is already $$$$$$$$$.
Registered User
I solved my problem...it was the small radius at the bottom of the primer hole that was causing the bulged or not seated enough primer....But first , I measured my #34 CCI primers at an average over ten primers at 0.126"....I found on Accurateshooter.com an table giving primer thicknesses of : CCI .118" , Fed .118" and .117" , Rem at .119" and lastly Win at .121" i.e all a bit thiner than my #34...I think this tells me that (if) the Rad at the primer hole is a bit generous , then seating the .126" primer is going to be a challenge. So , I put my RCBS primer pocket reamer in my mini lathe and using my Dremel i removed the chamfer off the nose of the tool....i.e it now has 90 degree edges to the cutting bits...i tried it out on some new prvi and it works...primers now seat fully. Grahame
Registered User
I have done some measuring and fixing of my problem...I measured my primer pocket depth to exactly .130" I then measured 10 of my CCI #34 primers for seating depth , they varied in thickness from .1259 to 1.270"...since i cannot get my primer to seat fully i think to radius at the bottom of the pocket is the issue...So , I put my RCBC primer pocket trimmer in my laithe and spun it up and using my dremel / cutting disc i removed the nose chamfer off the trimmer i.e now a 90 deg nose....retrimmed the prvi and now I can prime perfectly.
Registered User
I forget to say that I found a table under Accuratshooter.com that gave some dimensions of other makes of primers :: CC! .118" , Fed .118 and .117" Rem .119" and win .121". grahame
internet bum
So all's swell that ends swell, but in the future I'd be thinking another brand of brass.
Posting Permissions
Reply With Quote