Need a sanity check - new barrel and factory ammo

[kthomas]

Recently got a new 18" 6.5 Creedmoor barrel for my Mausingfield for hunting. The barrel is a Benchmark, in a contour very similar to 3B. This barrel was chambered with the intent of shooting Hornady 143 ELDX precision hunter ammo. Today I took it to the range for the first time, and decided to chrono the velocity of the barrel with different factory ammo.

Velocity was taken with a magnetospeed V3, attached to a SiCo Omega suppressor (which had a suppressor cover on it).

I first took 8 shots with factory Hornady140 AMAX ammo:

Max velocity - 2696 fps
Min velocity - 2616 fps
Avg - 2664
S.D. - 24.9

After that, I took the magnetospeed off to pull back the suppressor cover to allow it to cool. Suppressor cover and magnetospeed went back on, and I got the following results:

5 shots with 143 ELD-X precision hunter:

Max velocity - 2509 fps
Min velocity - 2476 fps
Avg - 2492
S.D. - 14.2

5 shots with 130 Prime ammo:

Max velocity - 2890 fps
Min velocity - 2858 fps
Avg - 2873
S.D. - 12.5

I know there will be a difference in velocity with different ammo, especially different grains. That is obvious. But the differences I am seeing are huge. It's a 414 fps spread between the fastest and the slowest - which seems huge to me. Also keep in mind that this is an 18" barrel.

I should've performed this same experiment with the suppressor off. I have a feeling it may be one of the following:

1. The magnetospeed has to be on an increased sensitivity in order to work with the suppressor - maybe this threw it off?
2. In hindsight, I probably shouldn't have mounted the magnetospeed to the suppressor cover - I should've left the suppressor cover off. The suppressor cover may allow the magnetospeed to slide back and forth during recoil, affecting the velocity measurement being taken.

I want to hear thoughts from the group. I'll retest next time out. But am I the only one that finds these velocity spreads to be extreme and very unlikely? What would cause these big discrepancies?

 

[_Windrider_]

Recently got a new 18" 6.5 Creedmoor barrel for my Mausingfield for hunting. The barrel is a Benchmark, in a contour very similar to 3B. This barrel was chambered with the intent of shooting Hornady 143 ELDX precision hunter ammo. Today I took it to the range for the first time, and decided to chrono the velocity of the barrel with different factory ammo.

Velocity was taken with a magnetospeed V3, attached to a SiCo Omega suppressor (which had a suppressor cover on it).

I first took 8 shots with factory Hornady140 AMAX ammo:

Max velocity - 2696 fps
Min velocity - 2616 fps
Avg - 2664
S.D. - 24.9

After that, I took the magnetospeed off to pull back the suppressor cover to allow it to cool. Suppressor cover and magnetospeed went back on, and I got the following results:

5 shots with 143 ELD-X precision hunter:

Max velocity - 2509 fps
Min velocity - 2476 fps
Avg - 2492
S.D. - 14.2

5 shots with 130 Prime ammo:

Max velocity - 2890 fps
Min velocity - 2858 fps
Avg - 2873
S.D. - 12.5

I know there will be a difference in velocity with different ammo, especially different grains. That is obvious. But the differences I am seeing are huge. It's a 414 fps spread between the fastest and the slowest - which seems huge to me. Also keep in mind that this is an 18" barrel.

I should've performed this same experiment with the suppressor off. I have a feeling it may be one of the following:

1. The magnetospeed has to be on an increased sensitivity in order to work with the suppressor - maybe this threw it off?
2. In hindsight, I probably shouldn't have mounted the magnetospeed to the suppressor cover - I should've left the suppressor cover off. The suppressor cover may allow the magnetospeed to slide back and forth during recoil, affecting the velocity measurement being taken.

I want to hear thoughts from the group. I'll retest next time out. But am I the only one that finds these velocity spreads to be extreme and very unlikely? What would cause these big discrepancies?

My thoughts are this, and i think you touched on the culprit. Dont use the cover and as far as sensitivity i dont think thats an issue but you can always increase it. If you know someone and can borrow a labradar to compare id suggest that as well.

 

[st1650]

I had a box of factory 143 eld-x that was way slower (ie 2600 instead of the usual 2700ish out of a 26in tube) not sure if it was a bad lot or maybe my magnetospeed battery was really low and it was a cold day but I was just shooting at 100y that day to test a couple of things and I didn’t bothered to check at 600 yards if it was actually that slow or just a bad chrono reading.

 

[kthomas]

My thoughts are this, and i think you touched on the culprit. Dont use the cover and as far as sensitivity i dont think thats an issue but you can always increase it. If you know someone and can borrow a labradar to compare id suggest that as well.

I've never used the magnetospeed with a suppressor cover before, and not sure why I chose to do it that way today.

Next time I'll do it without the suppressor cover. I'll also take readings without the suppressor.

I just don't believe those numbers that were recorded today.

 

[OREGUN]

Meh, looks normal to me.

Try it without the cover but I don’t think it’s unusual velocities. Heavy ones are slower, lighter are faster and they’re all in the ballpark for factory 6.5.

Put the velocities in your kestrel and see where you are on the plate at 600 yds.

 

[kthomas]

Meh, looks normal to me.

Try it without the cover but I don’t think it’s unusual velocities. Heavy ones are slower, lighter are faster and they’re all in the ballpark for factory 6.5.

Put the velocities in your kestrel and see where you are on the plate at 600 yds.

The velocities recorded for the 140's was exactly what I was expecting. I thought the 143's would be low to mid 2600's. But the Prime 130's being ~2900 fps out of an 18" barrel really caught me off guard.

But, maybe I'm way off base and this is actually what it is. I've had all of this ammo for a while, and have shot it through other 6.5 Creedmoor barrels. I don't remember having such big velocity spreads from this ammo in my other barrels. But I could be mistaken on that.

 

[acudaowner]

we reject your lies of sanity ...

 

[_Windrider_]

The velocities recorded for the 140's was exactly what I was expecting. I thought the 143's would be low to mid 2600's. But the Prime 130's being ~2900 fps out of an 18" barrel really caught me off guard.

But, maybe I'm way off base and this is actually what it is. I've had all of this ammo for a while, and have shot it through other 6.5 Creedmoor barrels. I don't remember having such big velocity spreads from this ammo in my other barrels. But I could be mistaken on that.

I absolutely love PRIME. I’m so sad we will never see it again

 

[kthomas]

I absolutely love PRIME. I’m so sad we will never see it again

It's good ammo for sure. I still have a few left in my gun room.

However, I've never had the correct chambers to really get the optimal precision out of that ammo. All my chambers have either been cut for AMAX's, ELD's or Berger Hybrids. I think the Prime really needs its own dedicated chamber to really squeeze all the precision out of it.

 

[kthomas]

Recently went out to the range to retest this, all testing was done without a suppressor. Here are the results:

130 Prime:

Max velocity: 2829 fps
Min velocity: 2804 fps
Average: 2814 fps
SD: 9.4

140 ELDX:

Max velocity: 2675 fps
Min velocity: 2643 fps
Avg: 2658 fps
SD - 12.6

140 AMAX:

Max - 2681 fps
Min - 2651 fps
Average: 2665 fps
SD - 9.8

143 ELDX precision hunter:

Max: 2504 fps
Min: 2477 fps
Average: 2485 fps
SD - 11.2

Similar results, with a bit better consistency amongst all ammo. The 143 ELD-X precision hunter seems pretty slow, wonder if the lawyers really got to Hornady on this one. Thinking about picking up some 123 ELDM projectiles to load up for hunting.