Pierced Primers

[vossman]

So I shot a few reloads today out of my new S&W M&P 15. It worked very well BTW.
Had 2 pierced primers, I am thinking they are flukes but wanted someone else to look at them. Load is .223 55gr FMJ Hornady, 25, 25.5 and 26 gr of Varget, Lake City Brass trimmed to 1.75, Rem SRP.
http://i1341.photobucket.com/albums/o759/vossman23/DSCN0880_zpsdcf819b5.jpg (http://s1341.photobucket.com/user/vossman23/media/DSCN0880_zpsdcf819b5.jpg.html)
Bottom row is 25 gr, middle is 25.5 and top is 26. Bottom primer was only slightly pierced, middle was pierced pretty well and I did not find any of the 26gr loads that had any damaged primers. I can see the primers flattening a bit with the higher loads. Too much pressure or maybe I need a different/harder primer? Pretty sure I could drop down to 24.5 and still get reliable function but IIRC 25 was the minimum.

[sabot_round]

Your minimum by the Hornady book is 22.8 gr of Varget. The max per the same book is 26.4 gr so your pretty close to max. Back it up a little bit and work your loads up. Are you looking for speed or accuracy?

[J]

What he said.

Most people load 5.56 light, to save money. Unless you are using it for 400m+ who cares? Save the powder and load more rounds. 23-24g Varget should do just fine. As long as it cycles the firearm, I like light these days for close range stuff.

[SA Friday]

Remington primer cups are fairly decent, but they have horrible standard deviations. Every time I've used them the velocities are all over place. The pressures had to be also. They have got to be burning powder without consistency. Try a different primer. I've had good luck with CCI and (believe it or not) Wolf.

You are loading pretty heavy on the powder. I haven't ever gone past 25.0 gr with Varget and a 55 gr bullet.

[vossman]

Both the Sierra and Speer book said 25 to start and 27 max. Good to know I can go lower, thx. Not really looking to do anything with these other than shoot. I have some 62 and 69gr that I want to use for 300+

[sabot_round]

If you're just plinkin, go with the lower loads and save some powder. If you need more data for Hornady bullets just shoot me a PM.

[vossman]

Thanks Sabot, I will start again at 23 and see what happens with the 55s. Appreciate everyones help too. V

[Zombie Steve]

Yeah, 25 grains of varget is not a hot load at all. Really accurate, though. I've shot that bullet with PMC and LC 73 brass, with and without mag primers... they always go over the chrono at 2,600 - 2,700 fps from a 16" barrel.

One thing that hasn't been mentioned is what OAL he was loading at. If the bullet is jammed into the lands (either because of seating depth, or if there's not enough neck tension they pull out when chambered), the bullet can't get a running start at the lands, and that ups pressure significantly.

If your OAL is somewhere around 2.210" - 2.220", load a dummy round, and chamber it. Let the bolt slam on it like normal. Take it out and measure again. It's usually a few thousandths longer (stops abruptly in the chamber, acts like a bullet puller). Growing .005" is pushing it. If it's more than that, I'd think your problem is neck tension. Are you crimping at all?

[vossman]

OAL measured 2.230, about the top third of the cannelure. .02 shorter than the two manuals had for OAL. I figured the Hornady bullet profile was a bit different so i used a Hornady ogive comparator and it matched a factory round to within .005.
I will try the slam test and see what I get, I did not crimp either. I am using the Forster Micrometer dies. If the bullet is pushing into the lands, I should see marks on it when I extract it right?

[Zombie Steve]

Well, you're doing what I would do... seat it to the cannelure. On the batch I was running, that meant 2.210". Not that uncommon to see one batch different than the next (mine were from 2009).

I don't crimp either, but if they really are getting yanked a bit, I suppose I would consider a light crimp, but that's kind of masking the problem. When you resize brass, what's the measurement inside the neck? Is this a bushing die (sorry, I'm a little ignorant of them, I just get by with regular old 2 die sets)? If so, I think neck tension is adjustable with different bushings, right?

One other question - did you fire anything else really hot lately? Have you looked at the end of the firing pin? If you pierced a primer before and didn't know it, the tip can get rough. They tend to pierce more and more regardless of pressures.

[vossman]

When I took the gun apart I looked at the firing pin to to see if it was sharp and it looked normal to me. Nice smooth round edge, nothing special. Today was the first time I shot it, put 40 PMC factory rounds through it then all 40 of the reloads through it. I shot one or two reloads by themselves to make sure they'd cycle first.
Did not check the case mouth dimension. I know I could not press a bullet in there by hand when I tried. I know I can now that they have been fired though. I will load up some dummys and see what I come up with. Thanks. V

[clocker]

Take it for what it's worth, but I don't see the other signs of over pressure on those cases. That leads me to suspect that your firing pin is out of spec or the primers are too soft. If you can find a different brand of primer, I'd try that as a next step in troubleshooting.

[rpm]

How are you loading these? I've noticed on some brass (PRVI Partizan in particular) that it requires significant force on my 550 to seat the primers to the proper depth, despite having been through the swager.

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[eneranch]

How are you loading these? I've noticed on some brass (PRVI Partizan in particular) that it requires significant force on my 550 to seat the primers to the proper depth, despite having been through the swager.

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I'm thinking that's probably NOT a good thing!!

[vossman]

I took my time with these. Tumbled, hand primed, single stage press, swaged primer pockets. Primers seated normally just below flush after swaging. SW didn't have any other SRP other than the Remington I am using so I will try again at a lighter load.
Remingtons are supposed to be pretty soft from what I understand, CCI and Tula are at the top of the hardness scale. I need to find a few of those or maybe some magnum primers.

[vossman]

Just as an update. I loaded some more rounds with these primers for my Rem 700 in .223. 24.5 grains of Varget and a 55 FMJ Hornady V-Max bullet. 1 more pierced primer out of 25 rounds. I have not pierced any other primers with this rifle with probably 500 rounds thru it. I think its time to call Remington and see what they say.

[Hoser]

Check your firing pin tip. It most likely has a sharp edge on it and when pressures go up they pop.

26 gns is not hot for Varget. I run out of room in the case before I run into pressure issues.

[sabot_round]

Check your firing pin tip. It most likely has a sharp edge on it and when pressures go up they pop.

26 gns is not hot for Varget. I run out of room in the case before I run into pressure issues.

I doubt that two different rifles have the same issue. I think those Remington primers are the culprit.

[vossman]

Remington sent me a shipping label an I sent them 2 of the cases with pierced primers. I will post if I hear back from them.

[RTillery]

Sounds to me like you could possibly be setting the shoulder back on your cases too far during resizing causing a headspace clearance. Getting your resize die set to the length of your chamber is a basic first step. If you have it screwed down to your shell holder, and the die is on the short side, and your chamber is on the long side, you may have a head space situation. Even if your chamber checks out perfectly with a headspace gauge, If you push your shoulder back on your case, you have excess headspace. What happens is the case is driven forward into the chamber by the firing pin, and there is clearance between the bolt face and rear of the case. When it fires, the brass grips the chamber, but the primer is pushed rearward by pressure in the case to fill the void. The firing pin is forward and the primer flows around it, punching a hole. Then the case stretches back to the bolt face flattening out the primer. Not to worry too much though, this is not that uncommon. A way to check is to fire a factory load and see if there is any signature on the primer. We measure this all the time in benchrest. We have a little tool we call a 'gizzie' usually made by the smith that chambers the barrel, that slips over the neck and registers on the shoulder. You take a fired case ( It is now the length of the chamber) and resize it as follows: Measure it with your gizzie, back off your resize die a 1/2 or 3/4 a turn from your shell holder. Resize and remeasure with the gizzie. It will probably have grown in length slightly. Screw the die down just a smidgen and try again until our measurement is just a thousands or two shorter from where we started with the gizzie. The round should chamber and you will have minimum headspace and maximum brass life. You can do this without the gizzie by just sizing and trying it in your chamber til the bolt just closes but it is harder to tell when you have it just right. We sometimes reload our PPC cases a hundred times or more so getting headspace set correctly is an art form. The object is to just barely kiss the case all over to create the slightest clearance possible and still chamber without drag. Getting your chamber dimension and your resize die "married" makes life good. I have seen three guns blown up because of having it wrong. Not pretty!! Good luck.

[Dalendenver]

I know that I am reviving an old thread but I didn't read where you ever found the solution. If you are using Rem 6 1/2 primers in a .223 you are using a primer that Remington says not to use, it is too soft for the floating firing pin. They say to use the 7 1/2 primers. CCI #41 primers are specifically designed for the AR with a thicker primer cup. Here is a good article on primers.

http://ingunowners.com/forums/ammunition-reloading/174704-choosing-right-primer.html

[<MADDOG>]

I know that I am reviving an old thread but I didn't read where you ever found the solution. If you are using Rem 6 1/2 primers in a .223 you are using a primer that Remington says not to use, it is too soft for the floating firing pin. They say to use the 7 1/2 primers. CCI #41 primers are specifically designed for the AR with a thicker primer cup. Here is a good article on primers.

http://ingunowners.com/forums/ammunition-reloading/174704-choosing-right-primer.html

I think the OP was answered, you just had to read through it... Good post none the less.