Range report: 260 Rem CBI and 123gr A-Max

Rifle:
Savage 110 Long Action
Criterion 26" .260 Rem 8 twist SS varmint contour barrel
Savage 112 BVSS centerfeed stock, converted to staggerfeed
Nikon Monarch 5-20x44

Environmentals:
Partly cloudy
Temp 85°F, Dewpoint 53°F, ~32% humidity
675' ASL elevation, density altitude ~2400'
Partially shaded (tree) shooting bench
Rifle shot off bags
100 yards

Load specifics:
2x Nosler brass, neck sized with Lee Collet Die
WLR primer
Hornady 6.5mm 123gr A-Max
COAL 2.84, 0.010" off lands

Notes: I really need to bed my action/stock and don't have any velocities for these loads...my ProChrono & Miles Gilbert Bedrock kit are supposed to arrive tomorrow but I'm out of town on business so today was my range day. The bench also wasn't the most conducive to great accuracy, especially given my marginal but improving form.

Varget
38.5: 3 shots, 0.5" group. Two shots touching, one pulled high/left
39.0: 3 shots, .425" group. Two shots in one hole, one pulled high/right
39.5: 3 shots. 2 shots touching, one called flyer 1.5" high
40.0: 3 shots, 0.64" group, horizontal stringing. Showed pressure with Sticky bolt & brass flow

H380
42.0
42.5
43.0
43.5

All groups were garbage with sticky bolts, which was disappointing considering 41.5gr H380 with a 120 Nosler BT is my whitetail load and shoots very well out of this barrel, as well as my 22" 9 twist Remmy 700 Mountain LSS. Did not try the 43.5gr load due to sticking bolt @ 43.0gr.

RL17
44.0: 3 shots, 0.7" group. First two shots touching, third pulled .6 right
44.5: 3 shots, 0.61" group. First two shots touching, third called flyer .6 low/right
45.0: 3 shots, 0.46" group.

H4831SC
47.0: 3 shots, 1"+ group
47.5: 3 shots, 0.63" group. First two touching, third called flyer left
48.0: 3 shots. First two shots one ragged hole, got excited and pulled the third 1.25" up/right in a called flyer. This load looks to be VERY promising.
48.5: 3 shots, 2" group with vertical stringing
49.0: 3 shots, 0.5" group, ejector marks.
49.5: did not test due to pressure @ 49.0

My next test will further explore 48.0gr H4831SC +/- 0.5gr, RL-17 44.5 +/- 0.5gr, and Varget 39.0 +/- 0.5gr, thankfully with velocity data!

I tried the 123 amax in my 6.5 Lapua and they shot well. I went with the 140 amax because I could it was more consistant at long range - 700-1100yds. Seemed like it was easier to load for too. Every charge I tried worked well. I suspect bedding will help with your flyers quite a bit. Nice looking rifle, I always liked the BVSS stock.

Were those 4831sc loads getting a little compressed? I start getting the crunch at about 47gr but that could be due my chamber and the seating depth required.

Yeah, there was a little compression with the 4831SC loads...but not as much as my 223 loads with Varget and 75gr bullets.

I found pouring the powder slowly into the funnel, then tapping each case on the bench about 10 times, settled it enough to where there was minimal compression. I actually could shake each loaded case and hear powder moving in all the SC loads except 49.5gr, which I didn't shoot.

Had very limited time to load over the last couple weeks, but wanted to test out the new ProChrono today.

Looks like 48.0gr H4831SC pushes the 123gr A-Max to 3000fps from my 26" Criterion barrel using RP .260 brass. This load had an ES of 20 and a SD of 8. This load also exhibited the best accuracy of the 5 loads I tested today with no pressure signs despite being a little compressed; think I'll probably work +/- 0.2gr either side to try and find a sweet spot.

38.5gr Varget provided average velocities of 2867fps with ES of 37 and SD of 18; 39.0gr Varget averaged 2893fps with an ES of 18 and SD of 9.

My next range trip I'll likely explore W760 and RL17 along with fine-tuning the 4831SC load.

Try some Nosler brass in your 260. Far better quality than the RP. I learned that the hard way when I had my 260 barrel.

Quote:

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Originally Posted by GaCop

Try some Nosler brass in your 260. Far better quality than the RP. I learned that the hard way when I had my 260 barrel.

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I've got 50 rounds of Nosler brass (that's what I used for the initial 123 A-Max workup), but I didn't have any time to clean/prep it prior to yesterday's range trip.

I'm thinking about dropping the c-note on 260 Lapua brass, or maybe reforming WW 7mm08 brass into 260 in the interest of 'cheapness'.

Reforming 7mm/08 works great. I did that until I could afford Lapua.