Unexpected High Velocity with 6.5 Creedmoor

[Woodymyers]

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?

 

[Park ranger]

Not sure, but why don’t you load like 40.5 grains of your H4350 and a 140. That lot seems fast.

 

[TylerFromMS]

Why is going fast a bad thing again?

 

[INTJ]

The classic load for a 6.5 Creed is H4350/41.5, 140 ELDM, 2.8 COL.

The internal diameter of barrels vary and that affects speed. If you didn't have any other pressure signs, except for perhaps mild ejector marks, I'd just be happy with the extra speed and go shoot.

QuickLoad is only a rough approximation at best.

 

[Jerry Wick]

Seems to me the important questions are:

1. Are there overpressure signs with the fired brass? If not...2. Is the load accurate for the chosen use? If so, go with it. If not, reduce the better of the two some amount and hope for the best tomorrow. Sometimes last minute prep works out.

 

[MikeMcCasland]

Was it chambered with the SAAMI .199fb reamer? If so, what brass are you shooting? It matters a lot in a 6.5CM.

For instance, in my .199fb barrels, Lapua brass will "tune in" right around ~41-41.5gr. Alpha LRP brass is 40-40.5.

Same velocity on both, but brass alone will account for the difference.

 

[Bc'z]

Check your neck clearance.
If a bullet won't easily slide into a fired case necks will need to be turned to drop preasures and velocities to normal.

 

[6MMsteve]

Stabal is faster than what peeps think, I loaded some up under book loads and got bolt swipe and hard lift, it sneeks up on ya ol staball

 

[Sandstorm]

The high 2890 with the H4350 and 41.0 to 41.5 seems like the ticket to me.
Why you changed powers dont make sense to me...but whatever.
Seems like a fast barrel is all..and as mentioned before not a bad thing at all.

 

[Dave M.]

I load 6.5CM 140g ELD-M into starline SR brass, 42.3g of H4350 and I’m getting 20 shot strings with averages of 2885-2925 depending on temps with absolutely no signs of over pressure. Very accurate load from a 28.5” bartlien 5R barrel and a stolle panda action.
Dave

 

[LVLAaron]

Why is going fast a bad thing again?

Depending on the day of the week PRS guys like to shoot really high velocities, or really slow velocities. Whatever the last winner did.

 

[ROBARRC50]

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?

Curious what chrono are you useing? You verify velocity with drop at distance?

 

[LVLAaron]

FWIW My load when I had a 6.5 - Was the same. 42.4 and berger 140's. It ran about 2900.

Load it for the match and see how it does.

 

[338 Mollett]

I knew a guy in bomb disposal and WAS always in a hurry too.

 

[Woodymyers]

wow!!!!!! Thanks you guys. To answer in general: I am not unhappy with the speed. Just very unexpected. Good points, should have mentioned but trying not to write a book. ya,. no bolt swipe, primers look fine, just going about 100 fps faster than i predicted. First time ive seen this. Unusual and wanted some opinions. Thank you. Will load without any changes. Didnt want to chance a mishap. My buddy told me to quit worrying, but in this gig when something dont work how i thought i want to know why!!!! You guys are awesome!! Thank you

 

[LVLAaron]

wow!!!!!! Thanks you guys. To answer in general: I am not unhappy with the speed. Just very unexpected. Good points, should have mentioned but trying not to write a book. ya,. no bolt swipe, primers look fine, just going about 100 fps faster than i predicted. First time ive seen this. Unusual and wanted some opinions. Thank you. Will load without any changes. Didnt want to chance a mishap. My buddy told me to quit worrying, but in this gig when something dont work how i thought i want to know why!!!! You guys are awesome!! Thank you

Quickload is a great tool. Many powders are off by... a considerable amount. VV powders for example. QL isn't anywhere close to anything I've done with VV. Not uncommon for it to be off by 100fps - bad QL data, case volume, etc all make a difference.

You'll like the 43.4 area. It feels like a lot but in my experience with 4350 is the hotter you load it the more accurate it gets, and doesn't show a lot of pressure signs.

 

[Jvance513]

Have had great success with creedmoors. Factory and full blown bench guns that I compete with. My factory gun shoots consistent 5-7” groups at 1000 and squeaks the occasional 3 when conditions are right. My custom bench creed has shot me a few in the 2’s and a ton of 3” groups. Both my factory gun and custom gun run 42.00 of H4350. Purely luck that it fell that way but the node usually runs 41.7-42.1 in all the ones I’ve had. My BAT shoots a 140 hybrid at .017 jump and my savage shoots a 142 eps at .035 jump. Load something with a hybrid around .020 jump and it’ll compete.

Edit. All of this is with lapua SRP brass
And sized with a .290 bushing gives me around 32-35 lbs if seating force on a K&M

 

[Sandstorm]

My BAT shoots a 140 hybrid at .017 jump

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

 

[Fast14riot]

QL is great for getting you in the ballpark of powder charges, but after that, look at the brass, target and the load. That is real data, not simulated.

Whi cares about the faster velocity. If YOUR pressure signs are in check, run it. Look at your target and brass.

 

[Straightshooter1]

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?

I use QuickLoad a lot, but not for determining an initial powder charge as you did. It's common that the burn rate in QL is much lower than what one finds in the real world. So, one needs to first find what kind of velocity they're getting from a particular lot of powder for the particular gun and make adjusts in QL (like the burn rate) to match that velocity before its predictions are anywhere close to what can be expected in the real world. To get start data for adjusting QL , it's not a good idea to start with loads that are at the high end as you can easily find yourself in that predicament of running into pressure issues. Once the adjustments are made, one can get better predictions on various amount of that particular powder use as well as different bullet performance as they relate the particular gun. 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.