24 May 2007, 04:13
bartscheComet tails

Being somewhat lazy today I put my target at 50 yds.While shooting some 55 gr. Rem. FMJs I noticed comet tail witness marks on the target.I have never taken notice of this before but on a little contemplation it is understanable; Fast spin, short range and molten or near molten lead presenting a centrifical deposit. Any body out there familiar with this?

roger
One of our deputies found a great deal on some 5.56 55gr fmj ammo with an A-Merc headstamp and several others bought cases of it. Apparently nobody shot any of it till the day we held carbine requal. At 25 yards we had several targets with pronounced comet tails and keyholes and bullets falling to pieces before they hit the target.

We finally decided that the bullets were plated and couldn't take the stress of being fired in the faster twist barrels on AR15's.
24 May 2007, 20:38
bartsche
These were conventionall jacketed FMJs. The swirls or comet tails were lead color grey.
Maybe of some interest same target; One of the Varmint Nite Mare bullets hit the end of a target staple. Were the staple was pushed through there there was a straight cut out ending in about a 5/16 dia. hole that was surrounded by lead mist for about 5/8 of an in dia. Imagine how fast that bullet was being deformed and sheding its lead.

roger
My buddy complains about "comet trails" with his 264 WM. Funny thing, groups never change.
I personally think the phenomina is a result of atmoshperic conditon, rather than bullet deterioration. It seams to happen when the humidity is in the most high level. Curiously, it seems to be more apparent while shooting flat base bullets, as oppossed to tapered base, or boat-tail bullets. It is neat to see though.
25 May 2007, 20:31
bartschequote:
Originally posted by ldkier:
I personally think the phenomina is a result of atmoshperic conditon, rather than bullet deterioration. It seams to happen when the humidity is in the most high level.
Don't doubt you for a minute, but where I'm shooting in Southern CA the humidity generally is low and was wed.

roger