Unexpected High Velocity with 6.5 Creedmoor

[Ray123]

That's way more velocity than I've ever gotten out of H4350 and 41.7 gr behind a 140 gr bullet 2750 fps to 2770 fps max 24" barrel ...had to go to RL 26 to get that kinda of velocity. I'd verify the velocity over another chronograph... just to be sure...cause you'll know at long range when the BC and velocity you dialed, don't match up to the impact of the bullet.

 

[BlueWater]

26 in. Bartlien barrel chambered in 6.5 creedmoor onto a defiance ruckus action ... made sure we were not in the lands and cases were cut to 2.10 inches.

@Woodymyers , is this a 6.5 Creedmoor chambered to SAAMI spec?

According to SAAMI, TTL = 1.920" - 0.020". (Myself, I generally trim to 1.910".)

 

[Jvance513]

Would that happen to be around the 2890- 2920 node.?
I used to push my 140s with 42.4 RL16

The BAT runs around 2840ish and my factory gun is around 2780 with the 142s in my a 26” barrel.

 

[Owens85]

Would that happen to be around the 2890- 2920 node.?
I used to push my 140s with 42.4 RL16

That's my exact load for my 28 inch barrel with rl 16 and is right at 2900 fps. Pushing a 140 vld

 

[209jones]

For myself, if it isn't showing any pressure, good SD & ES, and it is actually shooting well at desired ranges, to eliminate doubt, I'd run 5 cases 5 times, at warm air temps, to check for loosening pockets. If it passes that test, continue on.

 

[PhilC]

It's common that the burn rate in QL is much lower than what one finds in the real world. <snip> But, even then, QL is not precise and one should understand it really only gets you a good ballpark idea to help shorten the load development process.

I have consistenly found this to be true when using bullet manufacturer's published load data in QL for comparison.

 

[Ringostar]

built a rifle for a friend wanting to get into PRS. Last minute thing. Spun a 26 in. Bartlien barrel chambered in 6.5 creedmoor onto a defiance ruckus action. No time for barrel break-in so using Quick load I worked up a load i thought he could shoot for the match. 140 berger hybrids, 42.4 grains of h4350 seated out to 2.9 inches. according to quick load should have produced a muzzle velocity of 2803 fps. It did not. I would have thought it would be a little slower with a new barrel and all but we got right around 2900 fps second shot on. I think the average was right at 2896 after 30 rounds. We stopped, came home, unseated a few rounds and weighed the powder, made sure we were not in the lands and cases were cut to 2.10 inches. All good. Fiddled with quick load and looks like to get that velocity we were over 73000 psi. After agonizing over the results with no solution or explanation i can think of i decided to try a different bullet, different powder, different seating depth. Went by the hornady book for 135 grain a-tips using Sta-bal 6.5. guess what???? Backed off to colder load. Without going into the details should have gotten 2700 fps. nope, 2800 fps. I cannot think of what could possibly be causing these speeds. 100 fps above what it should be. Is the barrel rifling cut smaaler than normal? What could be causing this? I have eliminated all I can think of. checked barrel with bore scope, cleaned before first shots and in between powders, muzzle brake is for 6.5 and used on different gun with no problems, loaded over 100 thou otl on second group, etc. What am i missing?

So how did the load work out?