Barrel Whip?

[budlight]

.223 rem. I've gotten into AR's and the 223 is cheap fun shooting when you use all quality forgings and match grade barrels. We have lots of ground squirrels and I do out of state Prairie poodles.

My barrels lengths are 20 -24 inches and hand loading some of the highest BC 224 bullets. I recently bought a stainless light weight barrel which uses a .625 gas block size and gets down to .525 inches towards the end.

I've researched everything that I could find and wonder if the machinist might have made the end too small dia. It's still lots of meat compared to a .224 center. Using known very consistent 62 gr HPBT the groups have opened up at 200 compared to some of my other heavy barrel rifles.

I will post a barrel and rifle picture later. Thanks!

 

[birdiemc]

Just off the cuff here, every single barrel out there is going to act in a unique way. You can have 2 barrels made exactly the same at the exact same time from the same lot of steel and they will vary. There are so many variables just within the barrel that determine how a barrel is going to shoot, no 2 are identical. If you've read extensively on barrel whip you've likely come across the discussions talking about the barrel bulging as the bullet travels through it. Think snake eating a rat. The barrel flexes about the action, depending on weight, stiffness, etc. They all move, heavier barrels move less. Theres lots of things going on inside a barrel when fired.
All that to say a known good round in one barrel doesn't mean it will be good in the next.
It's likely that by turning down the end of the barrel to a thinner profile the barrel is not as stiff so its causing the barrel to flex differently than what you're accustomed to. But you should be able to find a load that pleases you.
My 2cents

 

[budlight]

Okay, what I don't know is most barrel whip started right after ignition, or out towards the end of the barrel where the velocity and in turn bullet rpm the greatest? Like what I have is like a Shilen Contour #1 lightweight out towards the end at the .550 size for 308 and smaller. Which I would think wouldn't matter that much with the low foot pounds of a 223.

The most accurate load with these superior BC 62 gr, is 24.6 gr of AR-comp powder using all L.C. brass trued and Rem match primers. Right at 3100 fps and a es of 8 fps tested at 84 degrees and 5000 elv.

rifle length piston AR

 

[milo-2]

I think I'd experiment some with loads before I made an assumption here.
I have friend who just built an AR with a Proof carbon barrel, he was unhappy too, a little coaxing and he backed off his powder charge and is now amazed with it.

 

[birdiemc]

I'll drag out the ballistics book I'm reading when I get home and regurgitate what he has to say, but whip starts at the time of firing, the whole barrel whips while the bullet is traveling down the bore