Range report,the good,t he bad and the ugly.

[Cornbread]

Headed back to the range to try out some 100 gr ballistic tips and partitions with 8208.
18" BHW 1/8 .

New Lapua brass ,CCI 41, 2.250 coal loaded from 28-29.5 in .3 grains.
Apparently the rifle does not like this combination. 1 1/2-2" groups, ugly.
I could have gone higher as I have seen 30 ish grains as max but the results were so poor I decided not too. Looking at the other powders listed I may try some benchmark.Anyone have some experience with this combination? The other powders I see listed are a little too temp sensitive for my liking.

I did load some 123 Amax at 28 grains and 2.250 to confirm some recent load development. I was a little frustrated at this point and just ripped off 4 shots as fast as I could regain a solid sight picture. Didn't even peek at the chrono.




This load has been sub moa with both the Amax ans SST.

Next I tried some 120 gr Ballistic tips with 8208. same specs as above. Worked up to 28.1 grains. From 27 grains up the loads were running 1 1/2. At 28.1 it tightened up.



I was seeing some slight swipes but decided to go to 28.4.



This load was hot in new brass as the swipes were fairly heavy. I'm going to repeat and see what once fired brass does.

At 28.1 the loads chronoed 2455. 2530 at 28.4 [edit., corrected numbers].

[LRRPF52]

What chamber do you have?

A jump from 2465fps to 2515fps with only a .3gr increment is 50fps.

Can you list your charges with all the velocities?

[reddrock]

looks like you are on to something, my 20 in barrel likes xbr with 95 v-max and 100 gr ballistic tip,cfe with the ttsx, and ar comp with the 123 gr sst.

[Cornbread]

Here is the raw data. 18" 1:8 BHW 264 LBC chamber

120 BT

27.5 8208 2411,2430,2407 2416 avg 23es
27.8 8208 2440,2430,2430,2435 avg 10es
28.1 8208 2456,2454,2457, 2455 avg 3es
28.4 8208 2515,2538,2537 2530 avg 23es

I don't know where I got the 2515 avg at 28.4 from originally,my bad. Yes you can see a big spike in velocity and the swipes were pronounced.

100 BT

28 gr 8208 2537,2488,2498 2507 avg 39es
28.3 8208 2539,2543,2505, 2529 avg 38es
28.6 8208 2567,2578,2552 2565 avg 26es
28.9 8208 2617,2609,2630,2624 2620 avg 21es
29.2 8208 2626,2646,2634 2636 avg 17es
29.5 8208 2649,2640,2618 2635 avg 31 es

100 PT
28.3 8208 2523,2489,2513 2508 avg 34 es
28.6 8208 2547,2547,2521 2538 avg 26es
28.9 8208 2573,2552,2602 2575 avg29es
29.2 8208 2583,2591,2606 2593 avg 23es
29.5 8208 2650,2625,2611 2628 avg 39es

[LRRPF52]

Hera is the raw data. BHW 264 LBC chamber

120 BT
27.5 8208 2411,2430,2407 2416 avg 23es
27.8 8208 2440,2430,2430,2435 avg 10es
28.1 8208 2456,2454,2457, 2455 avg 3es
28.4 8208 2515,2538,2537 2530 avg 23es

I don't know where I got the 2515 avg at 28.4 from originally,my bad. Yes you can see a big spike in velocity and the swipes were pronounced.

100 BT

28 gr 8208 2537,2488,2498 2507 avg 39es
28.3 8208 2539,2543,2505, 2529 avg 38es
28.6 8208 2567,2578,2552 2565 avg 26es
28.9 8208 2617,2609,2630,2624 2620 avg 21es
29.2 8208 2626,2646,2634 2636 avg 17es
29.5 8208 2649,2640,2618 2635 avg 31 es

100 PT
28.3 8208 2523,2489,2513 2508 avg 34 es
28.6 8208 2547,2547,2521 2538 avg 26es
28.9 8208 2573,2552,2602 2575 avg29es
29.2 8208 2583,2591,2606 2593 avg 23es
29.5 8208 2650,2625,2611 2628 avg 39es

When I see those kinds of jumps in speed with the same charge weight increase, I take notice. Great data. Look at that ES on the 28.1gr XBR load under the 120gr NBT.

[Cornbread]

This is why I allways tell people you really need a chronograph for reloading. Especially with a round like the grendel where you are going to be above saami pressure before the primers and brass start showing pressure. You can see the velocity spike at 28.4 with the 120 BT. With the 100 BT you can see the velocity spike the flatten out after 28.9 grains. Suprisingly with the 100 PT you see a fairly linear velocity increase to 29.5. I would say this is probably due to the smaller bearing surface on the shorter partition. Fwiw Nosler lists 29 gr max with the 100 gr and 27.5 with the 120. Going to retest the 120's with 8208 and the once fired now Lapua. For the 100's I'm. Going to try another powder.

I can tell you that most guys don't crimp. I have seen a noticeable drop in es since using a medium crimp with the Lee factory crimp die. I assume this is due to it evening out the neck tension. The 120 BT really didnt tighten up until 28.1. Even with a not so temp sensitive powder like 8208 I would be worried about dropping out of the node. I may put some rounds in fridge/freezer over night to test.