Primer Pocket Reaming

300magman · July 1, 2011, 11:55 AM

Sorry for another newbie question.....but, I was giving 100 pieces of new 45/70 Starline brass the full treatment and when I got to uniforming the primer pockets (using a Holland Primer Pocket Uniformer, chucked up in a drill) I noticed that a few pieces of brass didn't conform to the rest.

Most of the brass needed about 2 seconds of low speed drilling to sink the uniformer full depth, but a few pieces needed several times that amount of drilling. I'm just wondering if that is caused becaus there was too much brass left in the primer pocket during the brass's creation, OR if the primer pocket was simply located too near to the head of the brass and after being drilled this much, might now be too thin to be used safely.

Is this a fairly normal issue to encounter with brass? and should I be worried about the safety of these pieces of brass?

Missionary · July 1, 2011, 12:06 PM

Greetings
Been along time since I bought a supply of Starline 45-70 and I do not remember any great primer pocket differences. You would be better off measuring with a dial caliper differences. You may just not be rotating the drill press handle with the same amount of force..
Mike in Peru

Shootest · July 1, 2011, 12:27 PM

I suspect it might have just been a flash hole burr, and would not worry about it.

300magman · July 2, 2011, 10:15 AM

I actually have a good indicator on these cases, it was indeed a lot more metal that had to be removed.

I can tell this because all of the brass had cone shaped primer pockets with the flash hole being the deepest point of the cone. Most of the primer pockets (once reamed with the uniformer) have a shiney ring of freshly cut brass around the outside edge of the primer pocket....depending on how much was removed it varied from a slight ring, to a thicker ring that came close to reaching the flash hole. But on the few exceptional cases, the entire bottom of the primer pocket was shiney, indicating a lot more brass being removed.

crowbeaner · July 8, 2011, 06:25 PM

You'll find that almost all caliber brass and MOST brands will have those variations. All due to the drawing process and the fact that the mfg. is making brass as fast as they can to keep up with demand. Lapua and Nosler seem to have the least variance, but at much more costly prices.

July 1, 2011, 11:55 AM	#1
300magman Senior Member Join Date: September 12, 2008 Posts: 714	Primer Pocket Reaming Sorry for another newbie question.....but, I was giving 100 pieces of new 45/70 Starline brass the full treatment and when I got to uniforming the primer pockets (using a Holland Primer Pocket Uniformer, chucked up in a drill) I noticed that a few pieces of brass didn't conform to the rest. Most of the brass needed about 2 seconds of low speed drilling to sink the uniformer full depth, but a few pieces needed several times that amount of drilling. I'm just wondering if that is caused becaus there was too much brass left in the primer pocket during the brass's creation, OR if the primer pocket was simply located too near to the head of the brass and after being drilled this much, might now be too thin to be used safely. Is this a fairly normal issue to encounter with brass? and should I be worried about the safety of these pieces of brass?

July 1, 2011, 12:06 PM	#2
Missionary Member Join Date: June 2, 2011 Posts: 78	Greetings Been along time since I bought a supply of Starline 45-70 and I do not remember any great primer pocket differences. You would be better off measuring with a dial caliper differences. You may just not be rotating the drill press handle with the same amount of force.. Mike in Peru

July 1, 2011, 12:27 PM	#3
Shootest Senior Member Join Date: February 9, 2011 Location: Just outside Cleveland, Ohio Posts: 722	I suspect it might have just been a flash hole burr, and would not worry about it.

July 2, 2011, 10:15 AM	#4
300magman Senior Member Join Date: September 12, 2008 Posts: 714	I actually have a good indicator on these cases, it was indeed a lot more metal that had to be removed. I can tell this because all of the brass had cone shaped primer pockets with the flash hole being the deepest point of the cone. Most of the primer pockets (once reamed with the uniformer) have a shiney ring of freshly cut brass around the outside edge of the primer pocket....depending on how much was removed it varied from a slight ring, to a thicker ring that came close to reaching the flash hole. But on the few exceptional cases, the entire bottom of the primer pocket was shiney, indicating a lot more brass being removed.

July 8, 2011, 06:25 PM	#5
crowbeaner Senior Member Join Date: June 4, 2007 Location: Upstate SC Posts: 1,943	You'll find that almost all caliber brass and MOST brands will have those variations. All due to the drawing process and the fact that the mfg. is making brass as fast as they can to keep up with demand. Lapua and Nosler seem to have the least variance, but at much more costly prices.