Need comments regarding load test results, group size, fps, etc. 308

according to my quickload calculations, my 42.5 load (2.800) is at around 54500 psi
I could technically load it to 45.1 at 2.875 at 61877 psi (but that's too close to max but we are talking theoretical values) 2740fps
Must not do the mistake of using that powder charge at 2.800 though, because that would bring it to 66510, a 4633 psi jump just for that 75 mils. Quite surprising.
max at 2.800 is around 44.1 2718 fps
So, there is a technical possible gain of 20 fps by seating 75 mils out, with the same pressure.

That's just theory, but I will load 3 of each at 43, 43.5, 44, 44.5, and 45 just to test pressure and speed, and then see where I need to work closer to max for a 1000m load.

Should hopefully shoot those next friday.
 
With the OAL measurement to the lands you provided, at 2.800" there is way too much jump.

You will get better results if you find a solution such as changing to a 2.970" magazine to load them longer like others have suggested.
 
I can hand feed any oal. Mag doesnt bother me.
My issue is that if loaded too long there is not enough left in the mouth for proper initial pressure

Cant fix it all at the same time, ill start playing with loads, and then play with oal...
 
Kryogen said:
I can hand feed any oal. Mag doesnt bother me.
My issue is that if loaded too long there is not enough left in the mouth for proper initial pressure

Cant fix it all at the same time, ill start playing with loads, and then play with oal...
Click to expand...



The 175gr TMK between 2.910" and 2.950" COAL should be a good starting point.

With the OAL length to the lands you provided, that's nearly .250" of jump at 2.800"

Way too much and it will make the throat even longer over time.

With a free bore like this, you may want to load the heaviest bullet your barrel can stabilize, the closest to the lands as possible.
 
I wonder...

ht tps://www.youtube.com/watch?v=9mgqkCgER90"]https://www.youtube.com/watch?v=9mgqkCgER90
 
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well I loaded a few more at 2.950 (that forster die is awesome, I just dialed in 150 thou, seated one, tadam, 2.950, no adjustment, dead on.)

Loaded at 43/43.5/44/44.5/45

According to Ql, the ones with 45 are only 57464 psi at 2700 fps (because of the reduced seating depth)
Avvording to QL, max load would be 46(61 707 psi). Maybe I'll load some at 45.5 and 46 just to see.

I'm 150 thou out, and I am testing stronger loads. Will report when I have results.

KABOOM-expositions-13710481-800-600.jpg
 
cant fit 45.5 + a bullet in there, forget it.
Wont really be able to put more than 45 grains in there
Will report friday.
 
46 is a compressed load for me. When I put the powder in I keep the funnel on and vibrate the case some. It compact the powder. I saw a video on YouTube of a guy using an electric toothbrush against the case so the vibrations help the powder down the case.
 
Thats an idea.
The compressed load starts at around 43.5 with that oal so i figured that i was starting to push it at 45.5
 
ok well I tested 45.5, 45.6, 45.7, 45.8 using that vibrator technique.

Just for fun because I don't think that I'll start vibrating my powder loads all the time.
Will shoot tomorrow and report. maybe I won't even get there if I get pressure signs anyway
 
Ok, so here are the results.

So far, with my .5 grains increments, it seems that the best group was at 44.0 (.6 MOA at 200Y)

Gave me a FPS of 2727. ES:13, SD:7.3 (not fireformed brass yet though).
Ql gives me around 60 600 / 62 000 max PSI for that velocity so that would leave me a little margin of safety
44.5 is max at 62 000 PSI so I wouldnt load there always as brass life will suffer.
45.6 was 2826 FPS at 68 871 PSI. (11% over max, started to get firm marks and harder lift)

I start to get some extractor marks at around 2750 fps, and above 2800 I get clear marks, and anything above 2800 comes with increased bolt lift tension, and max I tested was 45.6 with a clear extractor mark and harder bolt lift, so I stopped there. (2826 fps).

Sooo, I'll keep it at a max of 44.0 at around 2725 FPS +- 60 000 PSI. That's where the rifle appears to shoot the best anyway.
(depending on the burning rate adjustments, I get from 60 to close to 62 at 44.0). Worst cast is 62 000 at 44.1, which makes sense considering that anything higher gives me pressure signs....

Sweet spot appears to be somewhere between 43.5 and 44.1 (2700 to 2750 fps)
43.5 gave me .6 MOA also at 200Y, so my next test will probably be 35 rounds, 5 rounds of each between 43.5(ES26) and 44.1(ES13) then compare groups.

Next tests will be done with fireformed brass so neck tension should be more uniform.

Makes sense?
Also, I really wonder if it makes any difference to load .100 away from lands compared to .250 away. I'm still .100 away anyway.
Once I find the best load, I'll note the pressure, and then I'll try to get that same pressure at mag length with that pressure, and see what shoots better....
 
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Kryogen said:
Also, I really wonder if it makes any difference to load .100 away from lands compared to .250 away. I'm still .100 away anyway.
Click to expand...

Maybe not so much with accuracy in this case, but this is probably the only way you can load all that powder in the case and still have safe pressure levels. Looks like you found your sweet spot.
 
So if my rifle can take it, it's worth it loading longer and with more powder so I can get more FPS with the same pressure anyway? So if I find a load that works at 2.950, there is no point trying to find a load that works at 2.875 unless I want to load mag length?
 
Ok, I loaded 35 once fired lapua cases now, from 43.5 to 44.1
Neck tension was much more uniform with the 1f cases vs new, seating bullets felt the same.
Velocity was lower with the 1f cases, so results cannot be directly compared. Cases were larger, and neck tension was lower.

Last test had best group at av 2725 fps with 44.0 grains

But, with my 1f brass the fastest I got is av 2710 with 44.1 grains. So far 43.9 shot best but at 1 moa. (Es 6, sd 2.5). Other groups are all around the place at 1-2 moa.

So, that makes me think that I will need to continue that ladder up until I can get back to the 2720-2730 fps range where I got my best group last time. I appear to get velocities that equal to my last loads -.5 grains (new brass).
Soooo, I will load 44.2 to 44.6 and compare and report.

So far I cant really seem to get this bullet and powder to shoot small groups reliably. Thats weird because the 168 grain match bullets all shot good groups with a .250 jump
 
I think anything in the 2700 fps range is a nice load. The Federal Gold Medal 175 grains comes out at 2600 fps. I'm getting 2800 fps right now with 46 grains and Winchester cases but I did notice partial flattening of the primers. They still have a radius, but they're not as round as before firing. I will likely scale back my load to around 2700 fps. Problem is I'm getting better groups at 2800, might have to tolerate the over pressure, not sure if it's worth it in the long end. I've just annealed all my case necks. I'll see if that has an effect on over pressure before I scale it back down.
 
Im my rifle with 175TMK, with 2.950 OAL, IMR 4064, WLR, max SAAMI load out of a 26 inch rifle is around 2750 fps in my rifle, with 44.9 grains so anything over that is over max.

At 2.800, max is 43.0 for 2714 FPS
24 inch drops to 2675 max at 2.800

Unless you are seating longer than 2.800, or use a barrel longer than 26 inch, anything over 2715 fps is over max.
 
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