AAC Data Info

[PBWalsh]

Quick session today testing out the Garmin Xero chrono and a few different loads. Data was surprising with the AAC 77 OTM having both the lowest average group size and SD of the three match ammo types tested. Currently, the BMC 75 BTHP is my go to match ammo, but that’ll change after seeing this data set.

Shot 10 rounds of each for group 1, then a second 5 round group. Avg. Group is an average size of both group 1 and 2. All velocities shown.

Barrel used is a BRT 16” Optimum. Atlas CAL gen 2 bipod/rear bag for shooting. Trijicon VCOG 1-8 SCO optic. ~55-60*, mild to no wind, 100y.

Seems like this is a great buy at $0.62/round. I just ordered 500 more rounds of it. Just sharing for info, I know there was some issues with the first roll out. I’ll chrono some rounds when the shipment gets in to test consistency.

The Garmin? Super intuitive and easy. Highly recommended.

 

[PBWalsh]

Quick update. Shot some more yesterday and got higher velocities. Data shown is from a 10 round shot string.

Min: 2589.9
Max: 2674
Avg: 2629
ES: 88.1
SD: 22.6

DOPE:
300y - 1.6
388y - 2.5
436y - 3.3
517y - 3.7

Of note, my Hornady 4DOF app adjusted to 2630 fps called for 5mils of adjustment at 517y. Unsure about that, but 3.7 mils after adjusting for splash stack two rounds nearly on top of each other, center hit.

Anyone have ideas as to the data discrepancy?

 

[bfoosh006]

Quick session today testing out the Garmin Xero chrono and a few different loads. Data was surprising with the AAC 77 OTM having both the lowest average group size and SD of the three match ammo types tested. Currently, the BMC 75 BTHP is my go to match ammo, but that’ll change after seeing this data set.

Shot 10 rounds of each for group 1, then a second 5 round group. Avg. Group is an average size of both group 1 and 2. All velocities shown.

Barrel used is a BRT 16” Optimum. Atlas CAL gen 2 bipod/rear bag for shooting. Trijicon VCOG 1-8 SCO optic. ~55-60*, mild to no wind, 100y.

View attachment 8370378

Seems like this is a great buy at $0.62/round. I just ordered 500 more rounds of it. Just sharing for info, I know there was some issues with the first roll out. I’ll chrono some rounds when the shipment gets in to test consistency.

The Garmin? Super intuitive and easy. Highly recommended.

Do you happen to have the Lot # on the 77gr OTM ?

And thank you for sharing.

 

[PBWalsh]

I should’ve wrote it down and kept up with it but the whole lot immediately went into mags. I’ll start tracking the lot numbers. Just ordered another 100 on Monday. For the price and consistency so far, this may be my “do all” round. Not just a match round.

In comparison, the AAC 55 FMJ produced an average of 2914, ES of 145, SD of 43.4. Wolf Gold has had the lowest SD of the “55 FMJ” loadings at 17.3 and PMC at 25.5!

 

[bdickers]

Quick session today testing out the Garmin Xero chrono and a few different loads. Data was surprising with the AAC 77 OTM having both the lowest average group size and SD of the three match ammo types tested. Currently, the BMC 75 BTHP is my go to match ammo, but that’ll change after seeing this data set.

Shot 10 rounds of each for group 1, then a second 5 round group. Avg. Group is an average size of both group 1 and 2. All velocities shown.

Barrel used is a BRT 16” Optimum. Atlas CAL gen 2 bipod/rear bag for shooting. Trijicon VCOG 1-8 SCO optic. ~55-60*, mild to no wind, 100y.

View attachment 8370378

Seems like this is a great buy at $0.62/round. I just ordered 500 more rounds of it. Just sharing for info, I know there was some issues with the first roll out. I’ll chrono some rounds when the shipment gets in to test consistency.

The Garmin? Super intuitive and easy. Highly recommended.

what caliber is this?

 

[bfoosh006]

BTW, what is BMC 75gr BTHP ?

Badlands Munition Co ?

And for the above post... 5.56

 

[tucaz]

i have some aac 77gr otm data to add;

magnetospeed on the muzzle, 3000 feet elevation 60-70 degree

16" chomelined FN average 2710
16" LWRC IC A5, ave 2660
18" LWRC DMR, ave 2625
12.5" centurion, ave 2450


also the 75gr saber black tip...
12.5" centurion, ave 2500

IMI 77gr ran 2475 in the 12.5 centurion

 

[PBWalsh]

BTW, what is BMC 75gr BTHP ?

Badlands Munition Co ?

And for the above post... 5.56

My barrel is marked 5.56 yes. BMC is Badland Munition Company using a 75gr BTHP from Hornady.

@tucaz 3000’ of elevation difference really gives your barrels some extra velocity it seems. Or maybe the FN barrel is just “fast”.

 

[tucaz]

My barrel is marked 5.56 yes. BMC is Badland Munition Company using a 75gr BTHP from Hornady.

@tucaz 3000’ of elevation difference really gives your barrels some extra velocity it seems. Or maybe the FN barrel is just “fast”.

it is a little curious because the the LWRC and the FH barrel both shoot xm195 at nearly the same fps, yet have a large difference on the heavier bullet. need to run IMI 77gr thru the FN some time to compare.

here is a fast barrel for ya, my buddy has an 18" douglass 223 barrel that we chorno'ed IMI 77gr at
2818
2871
2861
2871
2903!

talk about a fast barrel.

and; i had to edit the list. it wasnt an 18" BA barrel, it was an old LWRC 18" DMR upper tha thad 8000 rounds thru it!

 

[PBWalsh]

One thing I noticed and learned on the last session: TRUST YOUR DATA.

I sent a round at 517y and everything felt good, trigger, recoil management, follow through, etc.

Splash was high, maybe .3-.5 mil. I checked the Garmin and it showed that round moving at about 40-60fps faster than the norm. Sent another with the same hold and had a center impact.

Sometimes it IS the arrow and not the indian. Believe the bullet yes, but trust your data/dope far more.

 

[tucaz]

One thing I noticed and learned on the last session: TRUST YOUR DATA.

I sent a round at 517y and everything felt good, trigger, recoil management, follow through, etc.

Splash was high, maybe .3-.5 mil. I checked the Garmin and it showed that round moving at about 40-60fps faster than the norm. Sent another with the same hold and had a center impact.

Sometimes it IS the arrow and not the indian. Believe the bullet yes, but trust your data/dope far more.

i’m pretty amateur at distance shooting, i do it alot but soooo much to learn and skills to acquire BUT i have experienced the same thing. i’ve be on a certain steel target and have hit hit hit miss (high or low) and wondered wtf!

figured it was a hot or low pressure round or atleast hoped it was