Garmin xero c1 pro velocity readings

[1raggedhole]

I’ve been playing around with my Garmin, and found something very strange today. Setup per the manual, and as I have done before. Testing 17hmr and 22lr loads out of three different rifles, four different loads. Every single one averaged at least 100 fps faster than the box. In my experience, this is very unusual for rimfire ammo out of rifles.
1. CCI A17, box and previous pro chrono results at 2650 fps:
Today w Garmin, both Ruger American target and Browning t-bolt 2760 fps and 2788 fps avg respectively.
2. CCI 17 v-max, box and previous pro chrono results at 2550 fps:
Today w Garmin, both Ruger American target and Browning t-bolt 2680 fps and 2730 fps avg respectively.
3. CCI mini mag 36HP, box states 1230 fps.
Today w Garmin, Kimber HS 1336 fps avg.
4. Federal Gameshock 36HP (745), box states 1260 fps.
Today w Garmin, Kimber HS 1352 fps avg.

Unfortunately I didn’t have another chrono at the same time to compare it.
I have read many others stating their Garmin is reading the same as other chronographs, so again I’m puzzled.
Anyone else seen something like this?

 

[Big_Daddy]

Without knowing what their equipment setup was for their "box" readings were, it is difficult to truly answer.

With certain 6.5 Creedmoor ammo, I have had velocities notably higher that the box data.

My data from today, using the Garmin, with 223's were very consistent with the #'s from previously recorded chrono #'s.

I will be interested to hear what others have to say.

 

[Rocketvapor]

Barrel length?
Take just a few and let someone shoot them over another Chrono.

 

[65swede]

Today I shot the same load past the Garmin in four .223 rifles. 28gr CFE223, Lake city brass, CCI400, 53gr vmax.
22" Tikka 8 twist 3300ish
24" savage 9 twist 3300ish
24" Rem Varmint Special 12 twist 3300ish
26" savage 9 twist 3500ish

Both the savages were suppressed, the other two were not. Great accuracy in all four rifles.

I shot both the savages on Friday and got the same results. I find it hard to believe 2" of barrel can make an additional 200fps.
Some barrels are just fast

 

[Coyotefurharvester]

Does your bench allow setting up the unit following the Garmin suggestions? I'm budgeting for my next purchase, the Garmin.

 

[Straightshooter1]

I’ve been playing around with my Garmin, and found something very strange today. Setup per the manual, and as I have done before. Testing 17hmr and 22lr loads out of three different rifles, four different loads. Every single one averaged at least 100 fps faster than the box. In my experience, this is very unusual for rimfire ammo out of rifles.
1. CCI A17, box and previous pro chrono results at 2650 fps:
Today w Garmin, both Ruger American target and Browning t-bolt 2760 fps and 2788 fps avg respectively.
2. CCI 17 v-max, box and previous pro chrono results at 2550 fps:
Today w Garmin, both Ruger American target and Browning t-bolt 2680 fps and 2730 fps avg respectively.
3. CCI mini mag 36HP, box states 1230 fps.
Today w Garmin, Kimber HS 1336 fps avg.
4. Federal Gameshock 36HP (745), box states 1260 fps.
Today w Garmin, Kimber HS 1352 fps avg.

Unfortunately I didn’t have another chrono at the same time to compare it.
I have read many others stating their Garmin is reading the same as other chronographs, so again I’m puzzled.
Anyone else seen something like this?

I have a LOT of data on various 22LR ammo and I can say with a lot of confidence that CCI Mini Mags and Federal Gameshock's can have ES's as wide as 60 to over 100 fps. I've got some data from other shooters who've recorded average MV of CCI Mini Mags at 1315 fps from a single box of 50 shots. So, I don't find the amount of spread you showing as any surprise.

 

[1raggedhole]

Does your bench allow setting up the unit following the Garmin suggestions? I'm budgeting for my next purchase, the Garmin.

Yes, I do not have issues getting 15 inches away from the muzzle (to the side and back)

 

[1raggedhole]

My OCD was preventing me from sleeping, so today I setup my old prochrono about 8ft in front and the Garmin on the bench. See pic of the data comparison. Basically the Garmin is recording slightly higher readings (avg +37 fps), probably closer to actual muzzle velocity, while the prochrono is slightly lower due to be 8ft away. This seems reasonable, and makes it pretty clear that this A17 ammo is very fast out of this barrel. Each shot for shot comparison is also quite close considering the old tech vs new tech.

 

[dgeesaman]

I had a lot of CCI 17HMR that shot a few hundred fps above its rated velocity. Some shot below the rated 2550. I just chalked it up to 17hmr being barely better than junk quality.