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Old June 7, 2019, 12:36 PM   #9
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 16,720
Norma's manual explains the cartridge brass business in incestuous. People make brass for each other all the time. Norma has made brass for Remington in the past, for example. There have been other more recent examples of Remington relying a lot on contract-made brass.

The issue I've seen with this is that European makers tend to make primer pocket diameters at the minimum end of the tolerance range while domestic brass usually goes for the middle of the range. What I've measured is all about 0.3 thousandths tighter in large primer pockets (I don't know the number for small primer pockets) and that made primers significantly harder to seat and required a snug-fitting primer guide that forced the sides of the primer cup to be held perfectly perpendicular to the case head to avoid crushing the primer. My guess is the European makers are trying to get more reloading life out of high power rifle cases before the primer pocket expanded. Normas QC process includes periodically sampling cases from each run and testing to be sure they tolerate being loaded and fired 10 times without failure.

So, then comes the question, why would it be happening in Starline brass, which is made here? I don't know. I can only suggest doing some measuring. SAAMI puts a small primer pocket (page 26/35 (Doc page num/Acrobat page num) of the 2015 CF Pistol and Revolver standard, says the pocket should be between 0.1730" and 0.1745" in diameter. I would expect domestic ones to be about 0.1737-0.1738". Indeed, I have some new Starline 38 Special brass I got about a month ago. I'll go check:

(Pause; imagine elevator music.)

OK. I'm back. The Starline all blocked the 0.1740-0.0002" pin and all accepted the 0.1730-0.0002" pin and allowed it to wiggle just enough that, based on experience, there was almost a thousandth clearance. So I got out a half-ball small hole gauge and fiddled the splaying knob until it was running in and out of a pocket with an inconsistent hint of rubbing. This is another thing you have to develop a feel for, but the accuracy is pretty good when you do. In this case, the trusty Mitutoyo showed it just kissed the anvils at 0.1738", so I would expect the intermittent rubbing to cease at 0.1737". It appears my expectation was on the nose.

(Sound of me patting myself on the back.)

These Starline primer pockets are not small and should not offer any special resistance to primer seating as long as your primer cups don't have burrs on their edges.

So, what's going on? I would (I see 44 AMP posted this while I was editing) unbolt the RL550B's shell plate and clean it. Also, clean the press body under it and the detent ball and its well. Vacuum any powder flakes out. Make sure the press is properly lubed. Put the plate back and check that the detent is positively locating it and that the plate is neither too tight for location nor so loose it can fail to hold the case perpendicular to primer. Check that nothing in the primer carrier or guide sleeve is loose and apply a little motor mica or other dry lube to those parts.

One other thing to try is placing the brass in a baggy and tossing it with some motor mica dust. This puts a little of that dry lube on everything, which won't hurt it the ammo and may get your primers to seat more smoothly.
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