6.5 Grendel - TAC vs. 8208 XBR - 123 gr. SMK HPBT

[sirriccus]

6.5 Grendel
20" Shilen HBAR 1/9
Hornady brass (once fired)
123 gr. SMK HPBT
CCI 450
2.2595" COAL
.0010" off lands

ETE = edge to edge
CTC = center to center

Ramshot TAC
Best group - .6862 MOA
Worst group - 2.2344 MOA
Accuracy node velocity - 2,383 FPS-2,429 FPS

IMR 8208 XBR
Best group - .5214 MOA
Worst group - 1.440 MOA
Accuracy node velocity - 2,463 FPS-2,518 FPS

No sign of execissive pressure or pushing near maximum charge. All shots were taken with 60 seconds between and in order of lightest to hottest charge. Example: Fired 1 round per charge, per target and only once all 5 were on paper would I continue to the next round of the same charge.

Ramshot TAC

25.5 gr. - 2,231 FPS AVG - 34 FPS EXTREME SPREAD
2,211 FPS
2,240 FPS
2,229 FPS
2,245 FPS
2,233 FPS
-----------
2.2715" ETE - 2.0075" CTC - 1.9173 MOA

26.2 gr. - 2,283 FPS AVG - 19 FPS EXTREME SPREAD
2,275 FPS
2,275 FPS
2,290 FPS
2,285 FPS
2,294 FPS
-----------
1.1505" ETE - .8865" CTC - .8467 MOA

27.0 gr. - 2,361 FPS AVG - 45 FPS EXTREME SPREAD
2,341 FPS
2,375 FPS
2,374 FPS
2,381 FPS
2,336 FPS
-----------
1.1965" ETE - .9325" CTC - .8906 MOA

27.5 gr. - 2,429 FPS AVG - 28 FPS EXTREME SPREAD
2,417 FPS
2,416 FPS
2,432 FPS
2,437 FPS
2,444 FPS
-----------
.9825" ETE - .7185" CTC - .6862 MOA

28.0 gr. - 2,478 FPS AVG - 35 FPS EXTREME SPREAD
2,462 FPS
2,462 FPS
2,487 FPS
2,484 FPS
2,497 FPS
-----------
2.6035" ETE - 2.3395" CTC - 2.2344 MOA

IMR 8208 XBR

26.6 gr. - 2,452 FPS AVG - 14 FPS EXTREME SPREAD
2,460 FPS
2,460 FPS
2,446 FPS
2,446 FPS
2,450 FPS
-----------
1.7725" ETE - 1.5085" CTC - 1.440 MOA

27.0 gr. - 2,463 FPS AVG - 29 FPS EXTREME SPREAD
2,474 FPS
2,468 FPS
2,465 FPS
2,467 FPS
2,445 FPS
-----------
.8100" ETE - .5460" CTC - .5214 MOA

27.4 gr. - 2,504 FPS AVG - 35 FPS EXTREME SPREAD
2,486 FPS
2,505 FPS
2,507 FPS
2,504 FPS
2,521 FPS
-----------
1.2490" ETE - .9850" CTC - .9407 MOA

27.8 gr. - 2,513 FPS AVG - 22 FPS EXTREME SPREAD
2,504 FPS
2,512 FPS
2,505 FPS
2,526 FPS
2,522 FPS
-----------
.9530" ETE - .6890" CTC - .6580 MOA

28.2 gr. - 2,562 FPS AVG - 5 FPS EXTREME SPREAD
2,565 FPS
2,564 FPS
2,562 FPS
2,559 FPS
2,564 FPS
-----------
1.4640" ETE - 1.2000" CTC - 1.1461 MOA

[ScoutH57]

I've never used TAC

I really like the 8208XBR with my .308 and 6.5 Grendel(123 AMAX) meters very well and has been very consistent for me.

27.8 Grains is my go to load with 123 Amax.

I don't have my data book with me but I believe my average muzzle velocity is aroound 2450 FPS out of an 18 inch Odin Works barrel.

[Mike Wood]

Thanks for posting. I too am shooting a 20" barrel, but with a slightly faster twist (Satern w/1:8.75). I am looking forward to working up a load with 8208 & 123 AMAXs once my brass stash accumulates enough.

[BluntForceTrauma]

Wow! Excellent detailed report. Thanks for taking the time!

[Mike Wood]

Even though it was barely over 1 MOA, with that low of an ES (should it be consistently repeatable in the single digits over more batches of that load), would the 28.2 gr load of 8208 be better at 500-1000 yards than say the 27.8 gr 8208 group that was almost half MOA?

[sirriccus]

Proving that minimum ES does not always result in minimum PoI.

I thought that was pretty interesting too. I would have assumed it would have.

Okay this could be one problem with your group sizes. Every time you shoot your changing your POA and your NPA. Fire all the rounds of one charge at one POA then go onto the next. It will keep you in position and give you better results.

On the other end, one of your best groups, but worse ES.

It's referred to as the Round Robin Method. It is intended to reduce shooter induced error.

Do you know what your looking for? Can you post pics of your targets? Your group sizes aren't going to be very helpful, but we may be able to see a node in there.

Both had very abvious accuracy nodes. I'll post the pictures here shortly.

Also, why are you testing two different powders at the same time? Work on one powder, see if you can get the results you want. If not, then try a different powder.

I had already done the testing with TAC, but felt as if there was more accuracy to be had with my setup so I continued on with it as well as started up with 8208 XBR. which I'm glad I did because it seems to be more consistent across the board for my setup. I will further dig into both accuracy nodes and do more testing with COAL.

[sirriccus]

I've never used TAC

I really like the 8208XBR with my .308 and 6.5 Grendel(123 AMAX) meters very well and has been very consistent for me.

27.8 Grains is my go to load with 123 Amax.

I don't have my data book with me but I believe my average muzzle velocity is aroound 2450 FPS out of an 18 inch Odin Works barrel.

Seems to be the end of my accuracy node, but it shot fairly well for me too.

[sirriccus]

Thanks for posting. I too am shooting a 20" barrel, but with a slightly faster twist (Satern w/1:8.75). I am looking forward to working up a load with 8208 & 123 AMAXs once my brass stash accumulates enough.

My pleasure. I've got some Hornady 123 gr. ELD-M's I'm looking forward to play with. Should be a great option for my setup.

[sirriccus]

Wow! Excellent detailed report. Thanks for taking the time!

No problem. I'd be doing it regardless so I might as well share with some like minded individuals.

Even though it was barely over 1 MOA, with that low of an ES (should it be consistently repeatable in the single digits over more batches of that load), would the 28.2 gr load of 8208 be better at 500-1000 yards than say the 27.8 gr 8208 group that was almost half MOA?

That's a really good question. I honestly have no idea.

[sirriccus]

Left target TAC / right target 8208 XBR

[1911man]

Great report, looks like you found some good info here. I love that tight spread on that 28.2 grain XBR load. Maybe if you shoot it a few more times you might find that it actually groups a little better than your testing today.

I have found 27.5 grains of TAC to be extremely accurate with both the 120 SMK and 123 AMAX in my rifle.

[sirriccus]

Great report, looks like you found some good info here. I love that tight spread on that 28.2 grain XBR load. Maybe if you shoot it a few more times you might find that it actually groups a little better than your testing today.

I have found 27.5 grains of TAC to be extremely accurate with both the 120 SMK and 123 AMAX in my rifle.

Appreciate the advice. I will revisit that today.

[sirriccus]

UPDATE: Did further OCW testing with accuracy node from previous work up. Here are the results.

Best group - .4847 MOA - 2,486 FPS AVG
Worst group - .9684 MOA - 2,512 FPS AVG

IMR 8208 XBR

27.0 gr.
1.0545" ETE - .7905" CTC - .7550 MOA

27.2 gr.
.7715" ETE - .5075" CTC - .4847 MOA

27.4 gr.
.9320" ETE - .6680" CTC - .6380 MOA

27.6 gr.
1.1340" ETE - .8700" CTC - .8309 MOA

27.8 gr.
1.2780" ETE - 1.014" CTC - .9684 MOA

28.0 gr.
1.0885" ETE - .8245" CTC - .7874 MOA

IMG_0633.JPG

[Mike Wood]

Why no 28.2 of 8208 again?

[sirriccus]

Why no 28.2 of 8208 again?

I forgot my fouling shots so I ended up using the highest charge and lowest charge (10 rounds total) for that purpose. I will revisit the 28.2 gr. charge again Sunday to see what she's got in her.