16" .308 loads

[dbooksta]

I can't get the 1:8 16" bbl to perform with any heavy bullets.

As a benchmark I shoot 168gr FGMM and my barrel will group .75MOA.

But I've tried 208gr A-Max, 210gr VLD, and 220gr SMKs, all with ample velocity to spin stabilize, and they all group wider than 2MOA. It's embarrassing!

For example, using LC brass, 40.9gr Varget and 2.90" COAL is supposed to be an OBT load for 16". I get about 2330fps from that but still 2MOA at 100 yards!

[dogtown]

This shoots 1/2 MOA for me:

175SMK
Lapua Brass
Fed 210M
45gr Varget
COAL 2.805" (off the top of my head)


Obviously, don't jump right to that charge weight, back off a bit and work up - it's fairly hot.

Something you should try is a box of DTM .308WIN - that also shoots 1/2MOA for me and it's not hot at all.

[dbooksta]

I can get good performance out of these lighter bullets. Just yesterday I tested an OBT load (150gr SMK, 46.0gr Win748, CCI250 primers, 2.740" COAL) that shoots tight and is efficient in 16" barrels.

But you can get more energy out of a high-twist short barrel using heavy bullets, so I'm particularly interested in whether anyone has found an accurate load for bullets that are 200gr+, and if not why these barrels can't be made to perform there.

[ShadowPeo]

Send a PM to Russ with a link to the thread, he may have a better idea

[Seddo]

I did some testing today with my covert.

CALIBRE 308 Win
Case Lapua
Powder 2208
Primer Fed GM
Projectile 178gr Amax


CHARGE AVE ES 50M GROUP MOA NOTES BEST 2 MOA
43.0 2426.5 51.0 0.510 1.1
43.2 2421.7 4.0 0.925 2.0 pulled one right 0.068 0.1
43.4 2434.7 32.0 0.600 1.3 0.068 0.1
43.6 2449.5 27.0 0.580 1.3 pulled one right 0.170 0.4
43.8 2448.0 8.0 0.580 1.3 0.015 0.0
44.0 2468.3 20.0 0.570 1.3 0.105 0.2


CALIBRE 308 Win
Case Lapua
Powder BM2
Primer Fed GM
Projectile 178gr Amax



CHARGE AVE ES 50M GROUP MOA NOTES BEST 2 MOA
39.0 2333 20 0.61 1.33
39.5 2352 10 0.195 0.42
40.0 2382 9 0.158 0.34
40.5 2400 16 0.85 1.86 pulled one right 0.125 0.27

All groups were 3 shots. As you can see from the few really good 2 shot groups I had a bit of an issue with the creep in the tripper. I will try and adjust that out tonight.

Next step for me is to load up the best BM2 and 2208 load and I will take them to the range Saturday and shoot them in a 600y f class match. I will do a few of the subs too, 100.7moa to get to 600y from my 50m supersonic zero assuming 1050 fps.

Sorry, I don't know why the test isn't showing how I copied it in.

[Seddo]

Here is the best one

40gr BM2, 178gr A-Max, 2382fps ave, ES 9fps.

[mefly2]

Without a chronograph ... what velocity can I expect out of 149gr factory / military loads?
Old shooter with a new rifle and just want to break me in with some of the less expensive ammo until I am dialed in ... then will use federal match ammo.

[dbooksta]

2550-2600fps.

[Seddo]

I shot the 11gr TB and 208's on a 600y f class target today and all but 2 hit, the 2 misses went over the top and had a crack so they went supersonic. I tried them after I finished a run 600y run with supersonic 178's so the barrel was pretty warm, it took about 8 subsonic rounds before the first one went high and then the second one was after 15 when I stopped shooting them.

I tried to chrono them but the low battery light was flashing, I got 989, error and 300 so I will have to try them another day.

I used 104moa for the first shot and then worked it back to 99moa, that was from my 50m supersonic 50m zero (subs printed 5.75").

All in all a good day, I just wish I had taken the metric hex keys to take the creep out of the tripper. I will do it before I head to the range tomorrow to chrono.

[dtanut]

Hey guys, getting ready to start reloading for my SRS 22" .308. can't decide between 168 and 175 SMK and between Varget and Reloader 15. Can you guys enlighten me on what combo these rifles like the best

Thanks