.223 Backed out primers

[Waywatcher]

I took 20 reloads to the (cold) range the other day in my .223 bolt gun.

They were full length resized following RCBS instructions, camming over just a bit. These are the first cases resized using this particualr die in this particular rifle. The cases were once-fired remington, the primers were CCI, the powder was Varget, the bullets were Hornady 75 hpbt.

Here's my results at the powder charge levels:

22.0, all 5 had backed out primers. None were flat.
22.5, 2 of 5 had backed out primers
23.0, 2 of 5 had backed out primers
23.5, 2 of 5 had backed out primers

All necks were sootier than normal, and I didn't see any high pressure signs. No flattened primers, no cratering, no sticky extraction, no gas leakage by the primers. So I'm thinking it was a little too much headspace.

I am thinking that the cases were "over resized" leading to excessive headspace. I had a .223 smallbase die before, and using the cam-over with that die did not give me backed out primers in the same rifle.

I ordered an RCBS precision mic gage for .223 to see what measurements I have. It should arrive tomorrow according to UPS.

I'm curious to see what kind of input and suggestions everyone here has. I'm sure I forget some information, but I should be able to provide more if necessary.

 

[rcmodel]

Not enough powder to re-seat the primer for one thing.
Backed out primers and sooted cases are a sure sign of low pressure loads.

Hodgdon shows a Varget Starting load with a 75 grain Berger as 22.5 grains giving 41,000 CUP.
MAX load is 26.0 giving 48,400 CUP.

It is also possible you are pushing the shoulder back too far in the sizing die for your chamber.
You don't need an RCBS precision mic gage to set the sizing die to get a properly sized shoulder.

Just back off the sizing die a little and size fired cases while adjusting the die little more each time until you can feel slight resistance closing the bolt.
That's as good as it gets.

rc

 

[hdbiker1]

I concur with rcmodel about the charge amounts and possible oversizeing. I use the RCBS Precision Mic because I reload for 5 AR's, so it makes it easier to measure fired cases and determine shoulder bump back. I also use one for the 2 .308's I reload for. The thing with the precision mic is, once you're sizer die is set up, you won't need it unless you acquire another gun or you lose the sizer die adjustment.

 

[NCsmitty]

Backed out primers and sooted cases are a sure sign of low pressure loads.

+1 to what rcmodel indicated, especially if the soot is running into the shoulder area.
Take the time to fit the sized case to your rifle's chamber with the sizing die.




NCsmitty

 

[243winxb]

Neck Tension/Bullet Pull- 35 to 45 lbs is Normal

Was the base of the bullets sitting at the neck/shoulder junction? Or seated long to get into the rifling? Does your expander measure .002" smaller than bullet diameter? Does a sized and expanded case neck expand .002" or more on seating a bullet?

 

[Waywatcher]

Thanks for all the replies and help!

Here's some more info:
Expanded neck size is at .245
With a bullet in (no crimp) it is at .247

I do not know how to measure bullet pull...?

Bullets are seated to std. COAL of 2.250 (my mags won't fit much bigger) so the base of the bullet is below the neck/shoulder junction.

There was no soot on shoulders, just necks.

I thought the Hornady load info was a bit timid; they show loads starting at 19.4 and max at 23.5.

I have some other loads already made with some changes--the brass & powder charge. Next time at the range I am going to try them: LC brass and Varget starting at 22.8, then 23.0, 23.2, 23.4 and 23.6. Unfortunately I had already full length resized this brass the same way, so I guess I will see if the new brass and powder charges change anything. Do you think the LC Brass might up the pressure a little bit over R-P commercial?

P.S. the temperature at the range was right around 0 degrees Fahrenheit and windy to boot.

 

[Waywatcher]

Take the time to fit the sized case to your rifle's chamber with the sizing die.

It wasn't a matter of time, I'm new to this and was following the instructions.

 

[243winxb]

Double check your scale settings just to be sure. Then up the powder charge. You neck tension is fine. You never know with new dies, don't cost nothing to check a few things.

 

[NCsmitty]

If you use LC cases, they are usually a bit heavier and a bit less case capacity than commercial brass, and will probably work better by increasing the pressure a little. They should show less soot on the neck.




NCsmitty

 

[243winxb]

Bullets with different bearing surfaces & construction have an effect on pressure also. Longer or harder=more pressure. When you change any component in reloaded, reduce the powder charge and work up again.

 

[Funshooter45]

The cold temperature can have a big impact on the pressure. You were shooting loads that were already on the low pressure side to begin with. If it was around zero degrees, then that is a big drop in pressure. I have noticed the same thing with pistol loads. Especially loads that were on the mild side, but clean this summer, have become sooty little devils when it's 30 degrees. No matter the hype that powder companies put out there, it's basic physics that when temperature decreases, the pressure will also decrease.

 

[Waywatcher]

Update!

I got my RCBS Precision Mic today.

Measured some factory ammo, some factory fresh brass, and some of my full-length-resized brass.

Here are the dimensions:
--Factory ammo (not fired) measured a perfect zero on the Precision Mic.
--Factory fresh LC (never fired or sized) measured just below zero to -0.001
--Brass that had been resized in my RCBS FL Die had was measuring at -0.004 to -0.005.

(Shoulder was getting pushed back too far creating excessive headspace.)

So, as it turned out the die was over-resizing the brass when following RCBS's instructions. So I tried resizing brass with no cam-over whatsoever and was still getting -0.004. Not good at all.

I gave RCBS a call and they agreed to send me a new sizing die. (Long story short!) They had me check my shellholder too, to make sure it is ok, which it is.

 

[243winxb]

Sometimes on firing, the brass will spring out in the body area right behind the shoulder and not forward. This pulls the shoulder back/shorter cartridge headspace. This will give you a false reading using your tool. When you use your FL sizing die, set it up by placing a shim of .008" between the shell holder and the die. Size some brass and see if it will chamber. If it does not, use a smaller shim. I use a soda can of about .004" thick as a shim, put a hole in the middle for the decaping pin. When i close the bolt, i can feel slight resistence. Excessive headspace must be over .009" IMO. Then brass may come apart with case separations.

 

[Waywatcher]

Thanks for the reply.

I am not talking about any fired brass, which I think is what you're talking about.

All my measurements (above) were on either factory fresh ammo or factory fresh brass.

 

[243winxb]

When you get a true measurement of your chamber fired brass, you might see that factory brass is a lot more undersized . Even when neck sizing only, it might take 3 firings till the brass will no longer chamber. (maximum loads). Longer with light loadings.

 

[Waywatcher]

I imagine you're correct that factory ammo is undersized.

Brass sized on my current RCBS FL sizer die are even more undersized, by 0.004 to 0.005 shorter!

That is why I called RCBS and they are sending me a new sizer die.

 

[243winxb]

Like RC said in post #2

Just back off the sizing die a little and size fired cases while adjusting the die little more each time until you can feel slight resistance closing the bolt.
That's as good as it gets.

For a bolt action, works great, but i like the shim to control die adjustment more precisely

 

[Slamfire]

Backed out primers are not necessarily evil. It just means that your load is not stretching the case to the bolt face. How can that be bad? Why is case stretching good?

I recommend that you set your case shoulders back about .003”. Typically cases are not meant to be stretched more than .006”. If the case is stretched above that you can expect case head separations.

Use cartridge headspace gages to set up your sizing die and you won't have any oversizing or hard bolt closure issues.


Another reason not to over size your brass is the potential of peening. Given too much of a running stretch, it is possible that when the case head hits the bolt face, peening could occur between the lugs and receiver seats. But it is highly likely that you would have several thousand case head separations before any peening happened in the chamber, and that would be a clue that something is out of tolerance.

Attached are pictures of some of my 30-06 brass, fired in a SAKO Finnbear . The load was 150 SMK 47.5 grains IMR 4895. This load is probably 40,000 psia, maybe less, velocities below. The front of the case expanded, holding the cartridge in place. Pressures were not high enough to stretch the case and stuff the primer back in.

I believe it might have been fired in my SAKO, based on this data from my spreadsheet.

[SIZE="3"]SAKO   24" Barrel   				
							
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 190grs ≤ WWII ≤ 195grs	17-Aug-06
		 			OAL 3.290"	T = 85 °F
Ave Vel =	2703	 			
Std Dev =	26.41	 			
ES =	80.66	 		 	 		
High =	2739	 					
Low =	2659	 		 		 	
N =	10	 			 		
 Accurate about 2" High, mild load, backed out primers[/SIZE]

Incidentally that is one good reason why primer flatteness is a unreliable indicator of combustion pressure. On dry cases in dry chambers, the case stretches over the backed out primer and stuffs it back in the pocket.

I “discovered” this after I started lubricating my Garand and M1a ammo. Lubricated cases had rounded primers but dry cases of the same charge had flattened primers. Either lubricated cases produced less combustion pressure, which is absolutely absurd, or something else was going on.

What was happening was that with lubricated cases, the front of the case could not grip the chamber, the case was not being stretched, the whole case slide back to the bolt face not allowing the primer to back out.

Incidentally, since my cases were not being stretched, my Garand and M1a ammunition does not have case head separations.

 

[ole farmerbuck]

Not to butt in here but I use 28.5gr BL-c2 / 40gr v-max with Luapa brass and CCI BR primers. Most of the primers swell and I cant deprime without loosening the shell plate on my LNL. Yep, had headspace checked (was minimum). I dont have any trouble with any other primers. The primers are not backing out.

 

[clutch]

Try neck sizing your fired brass. Back out your sizer a thread or two and try again. It is a bolt gun so as long as you shoot this ammo in that gun, you should be good to go.

Clutch

 

[Waywatcher]

Use cartridge headspace gages to set up your sizing die and you won't have any oversizing or hard bolt closure issues.

Nice pictures, thanks! As I mentioned above, I got my headspace gauge in the mail today. The problem I was having was mostly excessive headspace with a little low pressure, too.

My excessive headspace was caused from my sizer die pushing the shoulder back quite a bit too far. Even with no cam-over.

I never experienced any hard bolt closing; my resized brass was much too small!

 

[Waywatcher]

Try neck sizing your fired brass. Back out your sizer a thread or two and try again. It is a bolt gun so as long as you shoot this ammo in that gun, you should be good to go.

Clutch

Thanks for the response! I have read into neck sizing, and decided it's not for me. What I do plan to do in the future is to resize fired brass in my FL sizer die just enough to push the shoulder back just 0.001 to 0.002 using my Precision Mic for measurements.

 

[W.E.G.]

 

[Waywatcher]

Yep, thats the one! Thanks for the pic. It works well.

 

[Waywatcher]

Another update.

I got out to the range yesterday with some factory ammo, handloads, and the precision mic. The temp was about 15 degrees fahrenheit this time.

So here's some more data for some analysis:

--The Factory ammo mic'ed at a perfect Zero before firing, but after firing measured about -0.001 to -0.002. Is this odd? Shoulders moving slightly backwards...? No backed out primers on factory ammo.

--The handloads (LC Brass) mic'ed at a -0.005 before firing, and after firing ranged from -0.005 to -0.002 inches. This made more sense to me. Very few backed out primers. (I think 2 out of 25, and not very far, these are the brass that was inadvertantly sized down to -0.005; overall much better results than Remington commercial brass.)

Also, I got my new FL sizer die from RCBS and threw it on the press to see what it sizes to. The old one sized the brass to -0.005. The new one sizes to -0.002 on the mic which seems much more reasonable.

Shot my best group with this rifle ever too, 5 shot group at 100 yards was less than 0.75"! The magic recipe was 23.2 grains Varget, LC Brass, CCI 400 primer, Hornady 75 HPBT. (Well within all accepted data I have seen.)