# Hole in Primer



## Cheetah (Aug 28, 2006)

I was shooting my 300 mag the other day with my handloads. One spent case had a tiny hole completely through the primer. I am using 250ccI primers . Anyone have any answers to why this occurred. About 25 of the other spent cases were OK. Thanks


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## dogdigger (Jan 26, 2004)

was the primer flat? it sounds like you had one that was pretty hot. maybe you got distracted on one and put a like to much powder in? if not i dunno

mark


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## SDHandgunner (Jun 22, 2004)

A pierced primer can be caused by several things. If the firing pin is defective it can cause a pierced primer. If the hole in the breech face is too large it can cause craters on primers or a pierced primer. If the primer itself was defective it can cause a pierced primer.

However most of the time a pierced primer is caused by too much pressure. This can be caused by either a load that is too hot or a powder that is temperature sensative. Depending on the powder that was used temperature (either ambient temperature or letting the cartridge sit in a HOT Barrel / Chamber before shooting it) can cause a pierced primer.

Case in point, many years ago I bought a new Remington VSSF in .223. I worked up my load (52gr. Speer Hollow Points with Winchester W-748 Powder) in 80 degree temperatures. The load was what I considered MAXIMUM but safe, and super accurate. A few weeks later when we were on the Cheyenne River Reservation shooting prairie dogs the temperature soared to 107 degrees. Yep all of a sudden I was blowing holes in primers (about 15 or 20 out of a box of 50). To keep shooting I had to keep my ammo in a cooler and not let a loaded cartridge sit in the hot chamber / barrel.

Without actually looking at the rest of the fired primers I am only guessing as to what is wrong, but it could be one of several things or a combination of things as well.

Larry


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## Cheetah (Aug 28, 2006)

Yup: I think you answered my question Larry. It was the last of 20 or so rounds with letting the barrel cool off every few shots. However barrel never completely cooled off. Also the day was about 85 degrees. Definately will have to remember that in future. My first time on this forum.........Thanks for the awesome advice......Cheers


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## SDHandgunner (Jun 22, 2004)

You are very welcome. If you don't mind me asking, what powder are you using? I have learned (and learned the hard way) that some powders are temperature stable and others are not. I have become quite anal about this and try to use ONLY powders that are in Hodgdon's Extreme Line which are said to be quite temperature stable.

Good luck.

Larry


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## VarmintHunter117 (May 28, 2005)

Larry good advice! I too have learned about temp sensitive powders... biggest that comes to mind is the old Winchester WAP... I still have some of this powder that was bought to load .400Corbon loads for my 1911A1.

big difference in pressure with temp increase! which caused a few pierced primers


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## SDHandgunner (Jun 22, 2004)

I would have to say that powder temperature sensativity is something I never thought of until I had a problem. The incident I had out shooting Prairie Dogs really drove the point home to me. I was hot and mad and said to my buddy I didn't come all the way out here to not be able to shoot, so I kept shooting. After I had blown about 20 primers (yeah I know, really DUMB on my part) I went to close the bolt on my Remington VSSF and as I cammed the bolt closed the gun fired (no I didn't hit the intended prairie dog either, but I also was fortunate in that I didn't hit something I didn't want to hit either).

What had happened was that the Remington vents the gases downward and the fouling created gummed up the trigger mechanism. I spent the next 2 hours in 107 degree temperatures removing the trigger assembly from my Remington Model 700, totally cleaning everything, reassembling everything and finally readjusting the trigger. From then on I kept my ammo on that trip in a cooler so I could shoot it safely.

When I returned from that trip I pulled the bullets on every single round I still had loaded with W-748 powder, took the powder to my brothers farm, poured it out on the ground and lit it on fire. Yep no more ball powders for me. Since that point I have only used powders that are said to not be temperature sensative.

I learned the hard way, and thank god no one was injurred.

Larry


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## Cheetah (Aug 28, 2006)

Hi Larry: I was using IMR 4350 Powder loaded 71.5 grains with Grand Slam 180 gr. bullets. I have been using this load now for about 15 years with super success. Um... did a little homework on this pierced primer thing and read that it can ruin your firing pin. I rechecked my brass and looks like only one pierced right through. About 3 others looked different than the usual convex dimple from the pin. Do ya think my pin is still OK after one piercing. I havent fired it since this happened.........Bruce


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## jimbob357 (Jan 2, 2006)

71 grains of IMR 4350 is max for a 180gr bullet in .300 Win Mag.

http://www.imrpowder.com/data/rifle/300 ... 5apr03.php

Was it a newer round can of IMR 4350? Since Hodgdon bought the IMR line, I've noticed that IMR 3031 and IMR 4064 is faster then it use to be.
I would back down a little and work up your load again.
Also the only other thing I can think of is that your bullet may have been seated deeper then normal?


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## Cheetah (Aug 28, 2006)

Actually it was a few years old ,can of 4350. Getting into the max loads. I see the IMR site says 71 gr is the max. However I have a Speer book which says 73 is the max. And a friend has a another manual which is even different max again. I have never seen so many variations in the max load of a particular powder/bullet weight?? I guess IMR is probably the one to follow since its their powder , but I think powder manf. lean on the low side of caution in their max loads. I asked a buddy who shoots H1000 in a 300 mag and he compression loads them like 4 or 5 grains over max. Says his cases have no signs of deformation at all. All in all my next reload session I am going to go to the IMR tables as I dont not have a death wish. This is a super forum...........but with huinting around the corner it will be winter before I get time to browse it........Thanks


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