Primer piercing but weird

[cohunt]

FYI, CCI mil-spec primers are the exact same as the magnum primers except that the anvil is moved back just a bit in the cup to make them more "strike resistant" to floating firing pins --they use the exact same cup, primer compound, and amount of compound as the magnum counterparts, in fact the brisance is the same too-- its just the anvil placement that is different (confirmed with cci a while back)

 

[tdot]

I think it's crazy guys are looking for thicker cups. The primers are already more than strong enough. A cci 450 or a rem 71/2 or fef 205m has enough strength to wreck a brass in one firing. They seldom fail if the pressure is within spec. Afterall primers is one tool we have to observe pressure in our loads. And a blanked or pierced primer is one of those signs that says you just stepped on the pedal way too hard. Sometimes by accident but alot of times on porpose.
Basically if you can't make reloads the fall within the safe pressure max that are set by the manufacturers then you should stop reloading. It's not safe for you or those around you. You know who I'm talking about. Goes like this. ( My 7-08 imp shoots 3400 fps with a 168 vld.)
There special little case somehow beats down magnums with twice the powder capacity. There is one variable we have to all adhere to when reloading, pressure. You go over the max and things fail.
Shep

For my use, it was nothing to do with not being able to stay within pressure. I could only find small primer Lapua brass for a Rem 260 I'd just bought used. The builder of the rifle had sent one piece of fired brass with it. From inspecting that brass, it was pretty obvious the firing pin needed to be bushed. I didnt have time to send the bolt away to a Smith to do that work before hunting season. So from a little research on the interwebs my safest options were thicker cup or staying with a large rifle primer brass. I found the latter, before I'd fully researched the issue with cup thickness and I've never looked at the issue again.

 

[Bret GRAVELINE Graveline]

This used to happen frequently with the 17 remington, according to legend Remington came up with the 71/2 a little thicker but harder as well, making the switch always solved that problem although a time of two accuracy suffered to some degree but not always, be sure to disassemble the boot and clean, with the 17 the pearcing produced a small billet that did at times end up in the bolt, plus you will get some carbon blow back, need to keep the striker and spring clean.

 

[emp1953]

According to cohunt's chart, dimension "C" for small rifle is shorter than dimension "C" for large rifle. So the primers should seat deeper before bottoming out. If the OP is bottoming out the primers then a firing pin issue is less likely. More likely the change in brass brought a change in case volume and an increase in pressure. Either rework the load in the new brass as suggested by 25WSM, or reload and shoot only the older brass. Any change in any of your components changes the characteristics of the load and should be approached as a brand new load.

 

[25WSM]

Trg That's just weird that 5 million remingtons are shooting all over the world but all of yours need bushed. I have bushed a bunch of them over the past 15 years or so. The small firing pin size definitely helps from blanking primers. And all my bench guns have the small firing pin. But not so I can run more pressure. Just for for the insurances during a match I don't blank one and get a piece in the bolt and have a d/q. Bottom line if you are blanking primers in your unbushed bolts regularly you are over pressure. If it was a Remington problem of blanking primers on normal loads it would be a 5 million gun law suit. I know I don't want hot gas blowing in my eye all the time.
Shep

 

[25WSM]

How can you look at one fired piece of brass given to you and determine your bolt needs to be bushed. You have no idea how hot the load was on that brass. Most remingtons will leave a small crater around the dent which means to much pressure on a normal bolt. But given the slop on remingtons firing pin you just live with it or pay to fix it.
Absolutely false that most Remington clones do this. Custom clones of a 700 are not going to have a loose firing pin fit. Most give you the option to have the small pin diameter also. This small pin will definitely help not to blank primers.
If your clones are that loose send them back. But I highly doubt they are.
Shep

 

[bigngreen]

Trg That's just weird that 5 million remingtons are shooting all over the world but all of yours need bushed. I have bushed a bunch of them over the past 15 years or so. The small firing pin size definitely helps from blanking primers. And all my bench guns have the small firing pin. But not so I can run more pressure. Just for for the insurances during a match I don't blank one and get a piece in the bolt and have a d/q. Bottom line if you are blanking primers in your unbushed bolts regularly you are over pressure. If it was a Remington problem of blanking primers on normal loads it would be a 5 million gun law suit. I know I don't want hot gas blowing in my eye all the time.
Shep

Its a well known and documented issue, look how many guys do that job as a main stay in their shops!

 

[25WSM]

As I stated that they are loose. And are really only an issue if you start pushing pressure. I'm sure with tolerance stacking you get a real loose one. So no I am not denying they are like that but just confirming that blanking primers is an overpressure related event. This thread is about that.
Shep

 

[bigngreen]

As I stated that they are loose. And are really only an issue if you start pushing pressure. I'm sure with tolerance stacking you get a real loose one. So no I am not denying they are like that but just confirming that blanking primers is an overpressure related event. This thread is about that.
Shep

Its not always pressure, just did one with verified pressure loads, amazing a bushed firing pin completely fixed the issue with below 55k pressure loads and now it runs right in the pressures it should without false pressure signs.

 

[BallisticsGuy]

The way I'm reading this is you have an established powder charge you use. And this charge works in your lrp brass. Then when you put that same charge in your srp brass it pierced the primers. If this is what you are trying to say then it's probably that the srp brass has less volume and therefore creating over pressure. You just can't take a load that works in one brass and put it in another and expect it to work. You need to work up the load for your new srp brass. You just can't mix and match any components up and expect it to work. Always drop back down on charge weight and work back up to a safe load. Pierced primers are almost always caused by too much pressure. A loose firing pin fit can do it if you run too much pressure. A firing pin protrusion of 50 to 65 thousands. Different guns will have different specs on this.
Try backing down the charge weight and working back up to max.
Shep

Case volume on the new cases came out as +/-.2gr of water across 10 cases. I'm 99% confident it's nothing to do with volume and it's nothing to do with pressure. I actually did start low and work up and it was core sampling them at a pretty low and known safe charge weight which is why it's such a mystery. Cup thickness hadn't ever bitten me before probably because I almost never use CCI non-magnum SRP's, just 450's, #41's or BR4's.

I shoot a lot of small primer brass in cartridges that can use both, 308 Lapua Palma, 6.5x47(SRP only), and 6.5 Creedmoor Lapua SRP. All of my rem 700 or 700 clone actions have had to get the bolts bushed. I've sent them all to Gre-Tan. My RPR and Sako TRG didn't need bushed, but my 700 actions did. All I use are the CCI mil spec srp's. With very reasonable loads, a 700 action even shooting the CCI 556 primers, can pierce. I recommend doing both (having the bolt bushed and run mil-spec primers) if your loads are edging to the warm side.

Kinda thinking it's just stuffing too much firing pin in there. The hole it's making is pretty wide. Excess metal stretch right near that edge is what I'm thinking. A narrower striker is seeming like a necessary item. Thanks for the Gre-Tan tip.

The small firing pin size definitely helps from blanking primers. And all my bench guns have the small firing pin. But not so I can run more pressure. Just for for the insurances during a match I don't blank one and get a piece in the bolt and have a d/q.
Shep

I'm thinking if I want to use non-magnum primers I'm going to need the bolt bushed and striker narrowed. Such is life. I'll just go ahead and switch to CCI magnum SR primers for a double layer of prevention. Preventing DQ's and DNF's is exactly the point.

 

[25WSM]

If you read in post 7 I did say almost always. Nothing in our sport is 100 percent. And I do bush firing pins from time to time when needed. Most of the time it's just not. I blanked the first primer of my life last yr during a match. It was with my custom action with the small firing pin on a small primer. I got lucky the piece that went back into my bolt did stop me from finishing my relay. I have no idea still as to what caused it. I don't run over pressure in my rifles and don't care to. I work up to my rifles max and then go down to my accuracy node and that is where it stays. For some reason my brass last a long time there too.
Shep

 

[bigedp51]

Right now I've got CCI 400's being ventilated. I've got some 450's and some #41's and some BR4's on hand. I actually run BR4's in the other rifle that uses both LRP and SRP brass. I wonder if that's why I've never encountered the issue before.

Try the primers with thicker .025 cups and see if you still have the same pierced primer problem.

The CCI 400 and Rem 6 1/2 with a .020 cup thickness are designed for lower pressure cartridges like the 22 Hornet. The large rifle primers with a cup thickness of .027 you were using are .007 thicker than the CCI 400 primers you are using now.

Trying the thicker primers with a .025 cup is far cheaper and faster than having your bolt bushed.

Below is a pierced CCI 400 primer that shows no signs of overpressure with a cup thickness of .020. And when the primers were switched to Rem 7 1/2 with a cup thickness of .025 the pierced primer problem was solved.

 

[del2les]

Back in the mid 90's, I ran into this with a couple of 222/223 varmint loads, and the only change was the primer. Loads I had used for years at safe pressure in my rifles, began to piece primers about 1 in 5. While preparing for a week long P-dog shoot in South Dakota at the Jamboree, I ran out of Remington 7 1/2 BR's and loaded the last hundred or so with a CCI 400 primer.

After a few days, I began to shoot the ammo loaded with the CCI400's, and shortly found myself piecing an occasional primer. I ceased shooting those loads and finished the trip using the 243's.

After arriving back home, I pulled bullets to weigh the powder charges, and after several, I found my powder weight was the same as usual. By now, my bulk order of Remington BR's had arrived, so I loaded as before and no piercing issues since.

 

[BallisticsGuy]

Below is a pierced CCI 400 primer that shows no signs of overpressure with a cup thickness of .020. And when the primers were switched to Rem 7 1/2 with a cup thickness of .025 the pierced primer problem was solved.

Precisely what my primers and case heads are looking like. Nice round shoulders, no swipes on the case head, butter smooth primary & final extraction. Just a hole in the primer. I'll run the magnums anyway. I had to stop load development after only 4 charge weight increments of .5gr and I'd like to see if there's another node just a little closer to 3k fps so I don't have to re-do my DOPE cards or have 2 sets of them. That node should be another .5-1gr up. If not, I'm sure the 39.5 will stay tight with the new primers.

I'm sure you all care by now so I'll spill it on the load. I initially didn't reveal details because I wanted people to focus on something other than the charge weight which I'm extremely confident is entirely safe.

RL-23, 6XC, Peterson brass, 115 DTAC's .010 off. Started at 38.5 and ran up to 40gr in .5gr increments. I've gone decently above that on LRP brass. Bottom right 38.5, bottom left 39, top right 39.5, top left 40. I wasn't at my most steady. Was occasionally shaking like a dog poopin' razor blades for some reason. Probably low blood sugar. I'm pretty sure the windage dispersion on the 40gr set was me.

What impresses me is the barrel has 1800 rounds of .243AI 115gr's at 3200fps through it. It was set back and re-cut to a 6XC. Still grinding out the one-hole groups. I will end up having to re-do this test run of course with the new primers and I'll do it from prone instead of a bench. I'm way more steady that way even when my blood sugar is low.