Large Flash Hole

[alamogunr]

I was preparing to prime some .45ACP cases after sizing and happened to look down into the cases. I noticed that some of the cases had a larger flash hole. I removed those(there were 7 out of 50. These were miscellaneous range pick ups that I had either bought or picked up myself. These seven cases were all W-W or Winchester marked. I had already reloaded them a couple of times with fairly light loads. I hesitate to use them again with the large flash hole on the chance that I might decide to load some heavy loads.

I haven't examined any others besides this fifty.

Could the large flash holes raise pressures dangerously? None of the cartridge drawings I have specify flash hole size. I don't have any means of measuring it anyway.

[bruce drake]

Those are Winchester NT cases. The larger flash hole is for their Winclean primers which are supposedly easier to clean up afterwards with non toxic by-products. THeir flame isn't as large so they need the bigger primer hole to ensure a reliable ignition. Those NT primers aren't readily available but I haven't seen a difference in my reloads with regular primers.

Bruce

[runfiverun]

the bigger hole would allow more pressure to push against the primer itself.
but at 20k i wouldn't get all worked up about it.

[Hang Fire]

the bigger hole would allow more pressure to push against the primer itself.
but at 20k i wouldn't get all worked up about it.


Could be wrong but I think not. The flash hole size is imaterial in this instance, as the pressure once through FH would be the same force acting on the primer diameter.

As per Winchester: "Winchester .45 ACP brass had a flash hole much larger than normal. We quickly learned that those cases were from their new non-toxic primers, which contained no lead or other heavy metals such as barium and antimony. A check with Winchester and some independent tests showed that the larger flash hole was not a cause for concern. There was no difference in pressure or velocity when the same load was fired in cases with the large flash hole compared to an older case with the normal hole."

http://findarticles.com/p/articles/mi_m0BQY/is_5_51/ai_n13469620/

[alamogunr]

Thanks! I'll put these back in the block and continue loading.

[Larry Gibson]

As runfiverun mentions the larger flash hole will not raise psi's but will allow more psi to push against the primer theoretically. I routinely drill out flash holes to as large as possible (#28 drill) for use with cat's sneeze loads. I have pressure tested those cases in the .308W to a measured 40,000 psi with no apparent problems. The primers used in the flash hole drilled cases couldn't be differentiated from those with regular flash holes with the same load. The fired primers looked identical.

Larry Gibson