Help reading primers

[Lefty Trigger]

Been working on load development for my .223 bolt rifle trying several powders. I have been starting at the lower end and building single rounds in .01 grain steps to max and a couple of powders beyond max slightly. While loading 8208XBR I had a primer blow out the firing pin hole, quit there because I was .02 over max (was told to go .08 over max) (my fault! hint,..dont listen to friends for reloading advice) Ok so that got me checking closer on what I was shooting today and I noticed that ALL my primers are "cratered" even at the starting load? This powder is IMR 4064 and start was 23.0 through to 25.1 which is still under max. All primers are craters but they also start to flatten out at 24.5 and progressively flatten more till the end but no primer punctures. How do I read into this info? Primer cratering should not be used as a pressure sign?? Should primers flatten well below max?(depending on who's max I use)

Heres the load (data from Lyman book max is 25.5) (Hogdon max is 24.0)
.223 once fired 2017 Lake city brass full length resized with .002 shoulder bump
Redding bushing die with .002 neck tension
powder is IMR 4064 23.0gr to 25.1gr in .1 steps 22 total rounds (Satterlee load test)
bullet is Sierra 69gr HPBT matchking seated .015 from lands about 2.280 coal
primer is CCI 400 small rifle
Rifle is new Savage 10T-SR 1:9 twist
BTW Satterlee test put ideal load at 24.0gr at 2950fps

 

[chkunz]

The CCI 400 primers have a "thin" cup (0.020 in) and in my experience show more flattening than a "thicker" cup (0.025) primer. So you might want to take that into consideration. I am not saying that the thin cup primer is bad for the bolt action rifle, just that it may look different. But blowing a primer, any primer, is not good. Did you mean 0.1 grain increments? 0.01 grain increments would be very small.

 

[Rsadams]

Without pictures it's a guess..

cci 400 are known to be soft , they flatten easy... Even at low power charges...

Post some pictures...

 

[Lefty Trigger]

The CCI 400 primers have a "thin" cup (0.020 in) and in my experience show more flattening than a "thicker" cup (0.025) primer. So you might want to take that into consideration. I am not saying that the thin cup primer is bad for the bolt action rifle, just that it may look different. But blowing a primer, any primer, is not good. Did you mean 0.1 grain increments? 0.01 grain increments would be very small.

yes .1 sorry I fixed it.

 

[Lefty Trigger]

Heres some pics, best I could get stupid phone camera wont focus close up. First is starting charge, then mid way and final was the max I loaded 25.1 cratering is bad.

 

[mikeinct]

look at the edge..where the primer meets the brass case..Looks ok to me..if you have normal bolt lift..it is good..lots of rifles crater the primer w/o being in the high pressure zone..Sometimes it is the primer, sometimes the firing pin..If none are pierced ..You R Good Enough..ML

 

[Lefty Trigger]

look at the edge..where the primer meets the brass case..Looks ok to me..if you have normal bolt lift..it is good..lots of rifles crater the primer w/o being in the high pressure zone..Sometimes it is the primer, sometimes the firing pin..If none are pierced ..You R Good Enough..ML

No tight bolt lift ever. Guess I'll stop looking for cratered primers if these look ok.

 

[tn6br]

No tight bolt lift ever. Guess I'll stop looking for cratered primers if these look ok.

You need to have your bolt fixed. Firing pin hole is too large in relation to the firing pin call gre-tan

 

[rammac]

So which powder gave you the blow out, 8208 or 4064?

 

[Rsadams]

You can try switching to the CCI bench rest srp , it has a harder cup , so does the magnum primers , with the magnum you will have to use data for them..... I also don't see anything horrible with this primers.... Just crono them and let the targets tell you were the accuracy is... Remember a fast bullet isn't always an accurate one.. Also check the primer pockets when you installing primers if one feels loose , set it aside... I had CCI srp flatten on a load that was no where near to hot... I have a bunch of them so I keep useing them... I have seen loose pockets and split brass in once fired cases , it happens...

 

[Lefty Trigger]

So which powder gave you the blow out, 8208 or 4064?

8208 XBR had the blow out, my fault for taking advice and was over max but not by much. 23.8 was max charge and it blew out the firing pin hole at 24.0 grains. Still recorded incredible velocity at 3058fps and made a loud "whissss" freaked me out!

 

[Rsadams]

8208 XBR had the blow out, my fault for taking advice and was over max but not by much. 23.8 was max charge and it blew out the firing pin hole at 24.0 grains. Still recorded incredible velocity at 3058fps and made a loud "whissss" freaked me out!

Lol, ya that's bad don't do that...

 

[Texas10]

The cratering problem on your Savage could be caused by a poor firing pin fit to the bolt head. You might want to disassemble your bolt and clear out the piece that went up the firing pin hole. It'll many times jamb the firing pin. While you've got it out, measure the firing pin tip diameter with a good micrometer (no caliper). Then measure your bolt head firing pin hole diameter using a good drill index set as a pin gage, and report back the difference. More than .002 or .003 and you've got a fit issue.

I ordered half a dozen firing pins from Savage and cherry picked the best fit to fix my Savage. I think they were like a couple of bucks each. Might have to sign a waiver to buy if your not a FFL. No big deal. You can also buy a new bolt head from Savage or aftermarket. Lastly you can have your bolt head bushed to a tighter fit. Not terribly expensive and someone here will provide a link to the shop that does that.

Using a BR4 or CCI450 primer with a thicker cup will help too. Or back off the charge weight and find a lower accuracy node.

8208XBR is a good powder for that bullet in the 223. Try the 69 g TMK too. Great B.C.

 

[Lefty Trigger]

The cratering problem on your Savage could be caused by a poor firing pin fit to the bolt head. You might want to disassemble your bolt and clear out the piece that went up the firing pin hole. It'll many times jamb the firing pin. While you've got it out, measure the firing pin tip diameter with a good micrometer (no caliper). Then measure your bolt head firing pin hole diameter using a good drill index set as a pin gage, and report back the difference. More than .002 or .003 and you've got a fit issue.

I ordered half a dozen firing pins from Savage and cherry picked the best fit to fix my Savage. I think they were like a couple of bucks each. Might have to sign a waiver to buy if your not a FFL. No big deal. You can also buy a new bolt head from Savage or aftermarket. Lastly you can have your bolt head bushed to a tighter fit. Not terribly expensive and someone here will provide a link to the shop that does that.

Using a BR4 or CCI450 primer with a thicker cup will help too. Or back off the charge weight and find a lower accuracy node.

8208XBR is a good powder for that bullet in the 223. Try the 69 g TMK too. Great B.C.

I have some 450 magnum primers but not sure how much to change the load to use them. The only loads I found for using the magnum primers was Benchmark powder and while it shoots good I get better results with the 8208 and 4166.
I have the Hornady 68gr HPBT match bullets and they are more consistent length than the 69gr Sierra's they are also longer and make the loads hotter. The Sierra bullets vary in length by as much as .007 maybe I got a weird batch?

 

[riflewoman]

Thin cup primers don’t work well for the 223. Remington developed the 7-1/2 Primer for the 222 223 and 222Magnum way back in the 60s to eliminate the results you obtained. The firing pin fit isn’t the best but it’s workable. You’ll get better results with Rem 7-1/2; CCI 450, 41, BR4; Winchester SR primers. There’s some imports that are good too but I don’t use them.

 

[SmokinJoe]

Would not recommend the WSR primers, the current ones are pretty soft. The others recommended should be good. Actually, I have used Fed 205's in some of my fairly hot varmint rounds for quite some time with good results & never a failure. Would strongly recommend that you get your firing pin bushed by Greg Tannel, makes a very big difference on what you see & what the primers will tolerate.

 

[krink85]

I had the similar results a few weeks ago in my .223 with the same powder and primers (75gr projo). "Pressure" signs showed up at 23.3gr which caught me off guard because I started at 23.1. I cautiously shot all the way up to 25.1 where the same "signs" were showing but nothing else except that the primer was just a touch flatter than before. I was using an AR and not a bolt gun so I cant comment on bolt lift, but there wasn't any recoil difference that I was able to feel. Reading the replies makes me cautious to keep using that primer in my AR. I really don't have much substance to answer your questions but its always nice to know that you aren't seeing a crazy or odd problem and that it has an easy-ish fix.

 

[Texas10]

IIRC, AR's require a magnum primer to prevent slam fires. CCI 41 or CCI450. The problem is the free floating firing pin will have enough inertial upon locking into battery position that it'll often dent the primer. Sometimes it'll be enough to fire if the cup material is too thin. That's why all AR ammo is loaded with magnum primers.

 

[M.Stilley]

IIRC, AR's require a magnum primer to prevent slam fires. CCI 41 or CCI450. The problem is the free floating firing pin will have enough inertial upon locking into battery position that it'll often dent the primer. Sometimes it'll be enough to fire if the cup material is too thin. That's why all AR ammo is loaded with magnum primers.

I have heard this hearsay a lot, but I have NEVER seen this in ~10000 reloads of my own, and thousands more witnessed using regular small rifle primers. If you run an AR until it's so dirty that the firing pin doesn't freely move, then maybe...

 

[bloc]

You need to have your bolt fixed. Firing pin hole is too large in relation to the firing pin call gre-tan

I agree: the firing pin hole is too large wrt the diameter of the pin.

I ran into the same problem with a Savage .204 using CCI primers. I got deep cratering and, in one or two instances, a slightly pierced primer! The primer edge radius was fine, the bolt opened without issue, the cases were not stretched.

I tried Tula and Federal Match primers with the same load. With Tula primers, the problem was mostly corrected. The problem was gone with the Federal Match primers.