Primers back out of shell!

poline · January 19, 2011, 09:51 PM

Two rds 37.0 gains each of H322, average speed 2,275fps, oal2.801
both primers backed out of Hornady brass .011 What does this mean?
Any thoughts or comments this forum would care to share would be appreciated. Thanks

dawico · January 19, 2011, 09:56 PM

What gun/ caliber/ and bullet are you shooting?

I have had some Hornady brass loosen up in the primer pocket prematurely if it helps any.

poline · January 19, 2011, 10:33 PM

Spanish FR 8, 308 cal, 150gain bullets

azar92 · January 20, 2011, 01:09 PM

My guess would be pressure is too low. There isn't enough force to re-seat the primer

Brian Pfleuger · January 20, 2011, 01:23 PM

Quote:

Originally Posted by azar92

My guess would be pressure is too low. There isn't enough force to re-seat the primer

Yep. That's only about a 33,000 psi load.

Doodlebugger45 · January 20, 2011, 01:30 PM

I also noticed that was an extremely low pressure load. However, if that's the cause, then how come we don't hear about primers backing out of the pocket with even lower pressured rounds like a 30-30?

Brian Pfleuger · January 20, 2011, 01:40 PM

I'd have to guess it's a relativity issue. That would be near max pressure in a 30-30. It's designed for 30,000psi. The 308 is designed for... 61k? 65k?

Doodlebugger45 · January 20, 2011, 01:57 PM

I don't disagree at all. It's just that I am trying to educate myself. Are the primer pockets different in a 30-30 than they are in a .308? Certainly the primer itself doesn't know it will be shot in one versus the other.

It just seems to me that pressure is pressure. If 30,000 is enough to keep the primer in one pocket, it would seem to keep it in another pocket if pockets are equal.

Hog Buster · January 20, 2011, 02:13 PM

The case heads could be expanding from too many reloadings, enlarging the primer pocket. Don’t know about Hornady, but Federal is notorious for that.

Brian Pfleuger · January 20, 2011, 02:20 PM

Quote:

Originally Posted by doodlebugger45

It just seems to me that pressure is pressure. If 30,000 is enough to keep the primer in one pocket, it would seem to keep it in another pocket if pockets are equal.

I'm guessing... again... but I think it has to do with the design of the case, maybe the chamber too.

That load is probably right in a border region of reseating the primer.

Here's my guess....

When I load case forming loads in my 7mm-08, the pressures are in the 20-25K psi range, maybe even upper teens. Those primers get reseated because the pressure is not enough to stick the case to the chamber and the case slides back against the breech. That's the whole point of the load.

Now, with a 30-30 load, the case is designed around that 30K psi range, which also happens to be right around the pressure required to stick the case to the chamber walls.

So, the 30-30 is probably sticking the case and stretching in the head region to reseat the primer on max loads and on lesser loads it's probably sliding back the whole case and reseating that way.

With the OP's load, I'm guessing he's right on the border. Enough pressure to stick the case but not enough to stretch the head region, maybe.

I'm not sure, it makes some sense to me, but I could be totally wrong.

700cdl · January 20, 2011, 03:15 PM

I'm leaning more toward a headspace issue. I've used quite a bit of brass that had been loaded real hot and thus my primer pockets expanded real bad, but I never saw one back out because of it. Have you ever loaded for this weapon before? If so were the loads a higher pressure load or lower pressure?

mehavey · January 20, 2011, 04:27 PM

Primers backing out (and staying out) on is almost invariably a sign of excessive headspace combined with low pressure. The reason you don't see it on deliberately-designed low-pressure cartridges (e.g., the 30-30) is because such ammunition headspaces on the rim and not the shoulder. (Even then you can have a headspace problem if the rim is too thin.)

misskimo · January 20, 2011, 04:41 PM

Might need to check your scale. 2200 fps is alittle low for 37 g. Suppose to be around 2500 per hodgdon load data site. Sounds to me that maybe you peaking pressure because of not enough powder
Might be wrong

Brian Pfleuger · January 20, 2011, 04:44 PM

Quote:

Primers backing out (and staying out) on is almost invariably a sign of excessive headspace combined with low pressure.

Yeah, backing out .011 is definitely a headspace issue, staying there is a pressure issue, as you say.

poline · January 20, 2011, 05:00 PM

Can someone, please, define headspace?

jimbob86 · January 20, 2011, 05:03 PM

Quote:

Primers backing out (and staying out) on is almost invariably a sign of excessive headspace combined with low pressure.

I concur. That was the case with my Gew. 88 (Commision Rifle).

Brian Pfleuger · January 20, 2011, 05:10 PM

"Headspace" is the distance from the base of the cartridge to the breech of the gun. The 308 "headspaces" by touching the shoulder of the case against the corresponding point in the chamber.

What is happening (probably) with your rounds is that the shoulder is being pushed too far back by the sizing die. This results in the cartridge going too far forward in the chamber, leaving excess space between the base of the cartridge and the breech face.

There may be some more technicalities with your particular combination. I know nothing about the gun you are using.

k4swb · January 20, 2011, 05:22 PM

Never say always.

Primers almost always back out of the case. The case then slams backward into whatever it slames into (different things on different type firearms) and is slammed back into the case.
Not enough pressure to slam the cartridge backward hard enough and it isn't reseated. Too much pressure and it can be deformed/flattened on reseating.

Most things, not just firearms have tolerances in which they perform as expected. Above or below these tolerences and things act differently.

poline · January 20, 2011, 05:38 PM

700cdl

Yes, I have reloaded before, with H4895, with average fps begining at 2445fps going as high as 2588fps and no one primer backed out.

With the primers in question, all were average fps from 2275fps to 2365fps.
Two of the brass were Hornady and one was Federal.

mehavey · January 20, 2011, 05:58 PM

As K4SWB says, all primers back out.

They do so into the available headspace at the start of the ignition cycle after the firing pin pushes the case forward and ignites the primer. Pressure then builds to lock the thin-walled forward portion of the case to the chamber wall. If pressure is insufficient to stretch the thicker case wall near the rear head section back to the bolt bolt face (thereby reseating the primer), the primer stays backed-out.

Your H4895 loads developed the required pressure to stretch the case.
The H322 load did not.

This actually did you a favor as it showed that you're oversizing the case, and making you vulnerable to head separation after a [unspecified] number of firings.

I suggest you back the resizer out a turn or two, resize a few cases and check to see if they will chamber. Assuming they won't (squeezing the sides in will lengthen the case), then incrementally screw the die in until they just do. Lock it there and you have a custom sizing set-up for that rifle which will maximize your case life (and be a lot safer in the long run).

steve4102 · January 20, 2011, 05:59 PM

Your load tells the story. It is a weak load with low velocity compared to Hodgdon data. A weak load will cause the primer to back out even with proper headspace. Take a 30-30 or pistol round like 357 that headspace on the rim and fire them with primer only. Primers will back out and stay out, good luck getting the cylinder in the revolver to rotate.

Start with the simplest solution first. Your Load!! It is to low pressure and causing the primers to back out. Bump it up and watch the backed out primers magically disappear.

k4swb · January 20, 2011, 07:36 PM

Quote:

As K4SWB says, all primers back out.

Actually I said:

Quote:

Primers almost always back out of the case.

I've learned to not say always and never.

mehavey · January 20, 2011, 07:41 PM

"...into the available headspace..."

AKA: my qualifier concession to "almost always"

Jim Watson · January 20, 2011, 07:42 PM

Does it back primers out with a factory load?
If not it is the load. Maybe it is too light to "reseat" the primer. We are warned to segregate the brass used for VERY light loads with cast bullets because the case shoulder is being set back in firing.
Maybe you have sized the case too deeply and are setting the shoulder back in the loading die. Not every case/die/chamber combination works best with the die screwed down hard on the shellholder like the instructions usually say.

If primers protrude from factory or surplus loads, it is the fault of the rifle; having too much chamber headspace one way or another.

poline · January 21, 2011, 08:51 AM

(If primers protrude from factory or surplus loads, it is the fault of the rifle; having too much chamber headspace one way or another.)
No, the primers do not protrude from factory or surplus loads.

I think it is note worthy that I have had a load of 36.0 gains of H322 with an average fps of 2,265 and the brass involved was LC 77 and WCC 09 and neither of these primers backed out. My thought being that this military brass has less volume and is thicher causeing greater pressure and thus reseating the primer. Also proveing that it is better to seperate the brass by headstamp.

January 19, 2011, 09:51 PM	#1
poline Senior Member Join Date: January 27, 2009 Location: Richmond,Va Posts: 292	Primers back out of shell! Two rds 37.0 gains each of H322, average speed 2,275fps, oal2.801 both primers backed out of Hornady brass .011 What does this mean? Any thoughts or comments this forum would care to share would be appreciated. Thanks

January 19, 2011, 10:33 PM	#3
poline Senior Member Join Date: January 27, 2009 Location: Richmond,Va Posts: 292	oops Spanish FR 8, 308 cal, 150gain bullets

January 20, 2011, 01:40 PM	#7
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	I'd have to guess it's a relativity issue. That would be near max pressure in a 30-30. It's designed for 30,000psi. The 308 is designed for... 61k? 65k? __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

January 20, 2011, 02:13 PM	#9
Hog Buster Senior Member Join Date: October 26, 2009 Location: Pointe Coupee, Louisana Posts: 772	The case heads could be expanding from too many reloadings, enlarging the primer pocket. Don’t know about Hornady, but Federal is notorious for that. __________________ Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson

January 20, 2011, 05:10 PM	#17
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	"Headspace" is the distance from the base of the cartridge to the breech of the gun. The 308 "headspaces" by touching the shoulder of the case against the corresponding point in the chamber. What is happening (probably) with your rounds is that the shoulder is being pushed too far back by the sizing die. This results in the cartridge going too far forward in the chamber, leaving excess space between the base of the cartridge and the breech face. There may be some more technicalities with your particular combination. I know nothing about the gun you are using. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

January 19, 2011, 09:56 PM	#2
dawico Senior Member Join Date: October 18, 2009 Location: Lampasas, TX Posts: 326	What gun/ caliber/ and bullet are you shooting? I have had some Hornady brass loosen up in the primer pocket prematurely if it helps any.

January 20, 2011, 01:09 PM	#4
azar92 Senior Member Join Date: April 16, 2009 Location: Utah Posts: 209	My guess would be pressure is too low. There isn't enough force to re-seat the primer

January 20, 2011, 01:30 PM	#6
Doodlebugger45 Senior Member Join Date: April 15, 2009 Location: Wyoming Posts: 1,717	I also noticed that was an extremely low pressure load. However, if that's the cause, then how come we don't hear about primers backing out of the pocket with even lower pressured rounds like a 30-30?

January 20, 2011, 01:57 PM	#8
Doodlebugger45 Senior Member Join Date: April 15, 2009 Location: Wyoming Posts: 1,717	I don't disagree at all. It's just that I am trying to educate myself. Are the primer pockets different in a 30-30 than they are in a .308? Certainly the primer itself doesn't know it will be shot in one versus the other. It just seems to me that pressure is pressure. If 30,000 is enough to keep the primer in one pocket, it would seem to keep it in another pocket if pockets are equal.

January 20, 2011, 03:15 PM	#11
700cdl Senior Member Join Date: December 6, 2010 Posts: 216	I'm leaning more toward a headspace issue. I've used quite a bit of brass that had been loaded real hot and thus my primer pockets expanded real bad, but I never saw one back out because of it. Have you ever loaded for this weapon before? If so were the loads a higher pressure load or lower pressure?

January 20, 2011, 04:27 PM	#12
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,896	Primers backing out (and staying out) on is almost invariably a sign of excessive headspace combined with low pressure. The reason you don't see it on deliberately-designed low-pressure cartridges (e.g., the 30-30) is because such ammunition headspaces on the rim and not the shoulder. (Even then you can have a headspace problem if the rim is too thin.)

January 20, 2011, 04:41 PM	#13
misskimo Senior Member Join Date: September 26, 2009 Location: Kotzebue Alaska Posts: 120	Might need to check your scale. 2200 fps is alittle low for 37 g. Suppose to be around 2500 per hodgdon load data site. Sounds to me that maybe you peaking pressure because of not enough powder Might be wrong

January 20, 2011, 05:00 PM	#15
poline Senior Member Join Date: January 27, 2009 Location: Richmond,Va Posts: 292	Can someone, please, define headspace?

January 20, 2011, 05:22 PM	#18
k4swb Senior Member Join Date: July 11, 2009 Posts: 389	Never say always. Primers almost always back out of the case. The case then slams backward into whatever it slames into (different things on different type firearms) and is slammed back into the case. Not enough pressure to slam the cartridge backward hard enough and it isn't reseated. Too much pressure and it can be deformed/flattened on reseating. Most things, not just firearms have tolerances in which they perform as expected. Above or below these tolerences and things act differently.

January 20, 2011, 05:38 PM	#19
poline Senior Member Join Date: January 27, 2009 Location: Richmond,Va Posts: 292	700cdl Yes, I have reloaded before, with H4895, with average fps begining at 2445fps going as high as 2588fps and no one primer backed out. With the primers in question, all were average fps from 2275fps to 2365fps. Two of the brass were Hornady and one was Federal.

January 20, 2011, 05:58 PM	#20
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,896	As K4SWB says, all primers back out. They do so into the available headspace at the start of the ignition cycle after the firing pin pushes the case forward and ignites the primer. Pressure then builds to lock the thin-walled forward portion of the case to the chamber wall. If pressure is insufficient to stretch the thicker case wall near the rear head section back to the bolt bolt face (thereby reseating the primer), the primer stays backed-out. Your H4895 loads developed the required pressure to stretch the case. The H322 load did not. This actually did you a favor as it showed that you're oversizing the case, and making you vulnerable to head separation after a [unspecified] number of firings. I suggest you back the resizer out a turn or two, resize a few cases and check to see if they will chamber. Assuming they won't (squeezing the sides in will lengthen the case), then incrementally screw the die in until they just do. Lock it there and you have a custom sizing set-up for that rifle which will maximize your case life (and be a lot safer in the long run).

January 20, 2011, 05:59 PM	#21
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,955	Your load tells the story. It is a weak load with low velocity compared to Hodgdon data. A weak load will cause the primer to back out even with proper headspace. Take a 30-30 or pistol round like 357 that headspace on the rim and fire them with primer only. Primers will back out and stay out, good luck getting the cylinder in the revolver to rotate. Start with the simplest solution first. Your Load!! It is to low pressure and causing the primers to back out. Bump it up and watch the backed out primers magically disappear.

January 20, 2011, 07:41 PM	#23
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,896	"...into the available headspace..." AKA: my qualifier concession to "almost always"

January 20, 2011, 07:42 PM	#24
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,543	Does it back primers out with a factory load? If not it is the load. Maybe it is too light to "reseat" the primer. We are warned to segregate the brass used for VERY light loads with cast bullets because the case shoulder is being set back in firing. Maybe you have sized the case too deeply and are setting the shoulder back in the loading die. Not every case/die/chamber combination works best with the die screwed down hard on the shellholder like the instructions usually say. If primers protrude from factory or surplus loads, it is the fault of the rifle; having too much chamber headspace one way or another.

January 21, 2011, 08:51 AM	#25
poline Senior Member Join Date: January 27, 2009 Location: Richmond,Va Posts: 292	(If primers protrude from factory or surplus loads, it is the fault of the rifle; having too much chamber headspace one way or another.) No, the primers do not protrude from factory or surplus loads. I think it is note worthy that I have had a load of 36.0 gains of H322 with an average fps of 2,265 and the brass involved was LC 77 and WCC 09 and neither of these primers backed out. My thought being that this military brass has less volume and is thicher causeing greater pressure and thus reseating the primer. Also proveing that it is better to seperate the brass by headstamp.