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Just full length resized some once fired S&B .303 cases that I have been given. As Is my want I always primer pocket ream with a K&M primer pocket reamer/uniformer any cases that come my way, to establish uniform pockets.
I found that my uniformer would not fit into any of the primer pockets. A quick bit of measuring with Digital vernier, reveals that the primer pockets are .205''. The removed primers are .206''.
Now I was always led to believe that Large Primers are .210'' (checked measuring Federal, Remington and CCI). The diameter of my reamer is .208'' which gives a .002'' interference fit.
I have tried seating primers just to see how much effort is required and it is a no go using my RCBS hand prime, same using my Lee hand prime. I can just seat them using a press top Lee Auto prime but the primers are distorted so that is not an option.
Looks like I shall have to put the cases in a lathe so that I can mount my reamer in a chuck in a tailstock. ( I usually put the reamer into a battery drill and hold onto the case wearing kevlar gloves but with these cases I can not hold onto them as the drill tries to spin them out of my hand.
So do S&B use under sized primers and pockets? Has anyone else had this problem?
If any one has some S&B Large primers could they measure the dia please so they I can compare with my Federals and Remmy's.

Steve E wrote:So do S&B use under sized primers and pockets? Has anyone else had this problem?

Recently I was loading some S&B .308 brass that came my way, with the intention of making some plinking rounds (1st time for everything). I found that the (Fed) primers were proud, despite being fully seated. Didn't see or feel anything to suggest that pocket diameter was too small, but I didn't try getting a reamer in there.

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S&B .223 brass also has VERY tight primer pockets, I needed to ream them out a touch to take my CCI primers!

Mike

Hi Steve

NRA has about 20k S&B LR primers last time I looked. Want to buy 100 to play with?

Iain

I use a Lyman universal case trimmer to cut all my primer pockets. I use these attachments. I whizz all my cases through it I use it to trim cases and inside and outside champher the case necks.

Easy peezy. Job done.

I've just had a similar experience with some once fired S&B .308 brass. There was no way The CCI 200 primers I'm using would fit, so a quick chat with Mark at 1967Spud had me sorted with a K&M reamer over the Christmas period, with guidance to expect a fair amount of swarf. Quite amazing how much I had to cut out and took a while to get the right technique. Having tried the handle, then a small bettery powered drill. Ended up fitting the reamer to a mains power drill and hand holding the cases with a heavy duty leather gardening type glove. End result is perfectly seated primers.

Left me in no doubt that S&B must using a slightly smaller diameter primer in their manufacturing process. Just to make sure i wasn't missing something, I did compare to some unfired Winchester brass which only required the smallest of reaming to uniform the primer pocket and even without would accept the CCI 200 primer using the primer seater in my RCBS turret press

There are minute differences in the size of primers manufactured by various different manufacturers. I had a problem with tight primer pockets on some .308win Norma cases some years ago. They just would not take the primers I was trying to fit (CCI I think). In the end the solution was simple, change to another brand of primer but that was after I had tried various other solutions to no avail.