[BillyJack04]

Just wondering if any of you guys shoot light loads such as a 40gr bullet. The twist rate is 1 in 7, in the 556. I have been told when shooting the light loads, through this fast twist rate, that they have the potentional to break apart as they exit the barrel. I'm just wondering if anyone has had this happen to them.

Thanks

 

[SkyPup]

I shot two hundred rounds of Remington 45 grain hollowpoints when I first got my rifle and they were outstandingly accurate with zero problems.

Have not shot any since then though...

The potential is there though if the bullets are subpar with the copper coat.

 

[nycstripes]

Its not always about the weight of the bullet itself. Its how its constructed. Sometimes a light varmint weight copper jacket can be over-rotated from the high rate of twist in some AR barrels. More than the twist can effect this though even though it has the length and weight that correlates with the rate of twist of a particular rifle.
The smoothness of the interior of the barrel, the bullet jacket thickness also play a part in this scenario.
There's no magic list that tells you what bullets may come apart in a given rifle.
I was shooting my 1in8 twist Armalite in the NYS Highpower Leg Match at Camp Smith a while back and I had 75gr A-Max's come apart like you describe on the 600 yard line which cost me some valuable points. I switched to Sierra 80gr Match Kings and never looked back.
The Hornady A-Max is a match bullet, but its built like a varmint bullet with a very thin copper jacket.
The Sierra is a little tougher and would have to be pushed much harder than a 223 is capable of to repeat this event.
In the short answer, you'll have to see for yourself. The indicator is that when you fire a round, its followed by a second audible pop ahead of the barrel. The second sign is a missed target...
Hope this makes it more clear for you.

 

[Buck Rogers]

Yes, federal premium 40gr noslers and wincherster 40gr ballistic silvertips will both just about shoot ragged hole 5 shot groups at 50 yards. I'm convinced they would if I was a better shot.

Search my profile for threads I've started and you'll find one about how much my sig likes the light varmit loads, with some target pics. I have heard it theorized that it isnt bullet weight so much as bullet length, so the light varmit rounds with the plastic tips are unusually long for their wieght, and that might explain it. Also, both these rounds are very very high quality, I mean they're over $1 a round, so its not that surprising that they're accurate.

I've had ALMOST as good of luck with 55gr fiochi, for close to 1/3 the price of the high dollar stuff.

EDIT:

http://www.sigarms556.com/viewtopic.php ... ght=#42377

 

[restoring]

I only tried one light weight round, a 40gr and it spun apart coming out of the barrel.

The jackets were separating as the round came out of the barrel.

This was right after buying our first 556 a few years back thus I don't honestly remember the brand.

We've stuck with 55gr and up (mostly in the high 60's and 70's) ever since.