Where to go from here? 308 Win with Berger 168 gr Hybrid

[JFrank]

Well I'm not sure what I learnt from today. Except maybe I'm crap at shooting my 308.

I decided to try a seating depth test with 43.90 gr of Varget.

o 30 thou jump => 2.246” 4 rounds (3x loaded)

o 40 thou jump => 2.236” 4 rounds (3x loaded)

o 50 thou jump => 2.226” 5 rounds (2x loaded; 5 rounds to finish of 2x loaded brass)

o 60 thou jump => 2.216” 4 rounds (2x loaded)

o 70 thou jump => 2.206” 4 rounds (3x loaded)

o 80 thou jump => 2.196” 4 rounds (3x loaded)

With 50 thou jump I can clearly hear the powder in the case when shaking the cartridge. Not so by 70 thou jump.

Shot on Saturday 18 May 2019. Here's the data. Pic of target attached. Brass seems ok re excess pressure signs.

o 30 jump: 2607, 2594, 2601, 2573 Avg 2593.8 SD 14.82 ES 34. Group: W 0.42 MOA, H 0.60 MOA. Avg vel at target 2432, SD 11.3

o 40 jump: 2588, 2588, 2581, 2577 Avg 2583.5, SD 5.45, ES 11. Group: W 0.64 MOA, H 0.87 MOA. Avg vel at target 2430, SD 3.1

o 50 jump: 2576, 2599, 2595, 2587, 2606 Avg 2592.6, SD 11.55, ES 30. Group: W 0.30 MOA, H 0.79 MOA. Avg vel at target 2446, SD 9.9

o 60 jump: 2580, 2619, 2596, 2590 Avg 2596.3 SD 16.54 ES 39. Group: W 0.21 MOA, H 0.85 MOA. Avg vel at target 2448, SD 15.7

o 70 jump: 2604, 2586, 2608, 2621 Avg 2604.8 SD 14.45 ES 35. Group: W 0.49 MOA, H 0.6 MOA. Avg vel at target 2442, SD 11.0

o 80 jump: 2620, 2611, 2619, 2592 Avg 2610.8 SD 12.97 ES 28. Group: W 0.47 MOA, H 0.70 MOA. Avg vel at target 2458, SD 3.9

Best groups were 30 jump and 70 jump. (I knew I pulled one shot of the latter right.) Lowest velocity variance was from 40 jump. Previously I had done 3 shots at 43.90 and an estimated 58 jump (see post 1) and gotten very encouragingly low velocity variance. 60 jump today wasn't anywhere as encouraging.

Suggestions? I'm thinking a little more powder with 30 jump and maybe trying seating a little longer. Either that or just shooting my .223!!!!!

(Velocities recorded by the Two Box Chrono aren't comparable one day to the next due to box placement. The avg velocity at target from the Shotmarker should be however. As a reference, 43.90 gr of Varget at last outing was producing 2464 fps at 100 yd target.)

Dang’
Where’s all that vertical comin from?
Have you considered a Sierra 168 bthp? Much easier to tune in fact you could probably get a great shooting recipe in one or two trips to the range.

 

[Billy 30-06]

At this point I would stop load development with these components and go to something else." Like 168gr SMK and H-4895." Your gun is telling you it doesn't like what you're feeding it. I have found Varget not to be the best powder for the 168gr bullet in the .308 with a 26" barrel. It's OK to experiment with seating depth after you found a good load but it's going to be hard to beat .010" from the lands. I found if it won't shoot @ .010" jump you need to work with a different powder or bullet. With a good load .010" difference one way or another won't make any difference that you can measure.
Billy

 

[SGK]

@sjk I agree with you and have had similar discussions with Adam. Powder Charge is all about velocity seating depth will change the grouping.

I don't think they're independent but the philosophy isn't a bad one. Everyone needs some sort of strategy/theory/plan to work to else decisions have no basis and you've got noting to compare results with.

Only thing I would slightly dissagree with you on is the 100 and 200 yard comment about grouping. 100 yrds can be a bit to close and the bullet can still be unstable before it goes into its sleep mode. 140 yrds would be a better close range indicator.

Brian Litz did quite a bit of work in this area for Modern Advancements in Long Range Shooting vol II. Worth reading.

 

[SGK]

Dang’
Where’s all that vertical comin from?
Have you considered a Sierra 168 bthp? Much easier to tune in fact you could probably get a great shooting recipe in one or two trips to the range.

At this point I would stop load development with these components and go to something else." Like 168gr SMK and H-4895." Your gun is telling you it doesn't like what you're feeding it. I have found Varget not to be the best powder for the 168gr bullet in the .308 with a 26" barrel. It's OK to experiment with seating depth after you found a good load but it's going to be hard to beat .010" from the lands. I found if it won't shoot @ .010" jump you need to work with a different powder or bullet. With a good load .010" difference one way or another won't make any difference that you can measure.
Billy

Hmm. My HPS ammo is 168gr Sierra MK (Viht N540 powder). I have several hundred of these Bergers though and I thought the Hybrids were meant to be easy to tune (at least with respect to seating depth). And my 8lb jug of Varget isn't even half gone. Ugh.

 

[Billy 30-06]

Hmm. My HPS ammo is 168gr Sierra MK (Viht N540 powder). I have several hundred of these Bergers though and I thought the Hybrids were meant to be easy to tune (at least with respect to seating depth). And my 8lb jug of Varget isn't even half gone. Ugh.

They may be easy to tune but if your rifle doesn't like them or Varget you don't want to burn up your barrel trying to get them to shoot. Some barrels don't like the new lots of Varget. I have a 8lb lot of Varget that won't with anything in my .308.
Billy

 

[SGK]

If you don't have heavy bolt. Stay @ .0030 jump and shoot another OCW in .1gr increments up to 44.5gr

Finally got to shoot this today. See attached target. It started to absolutely bucket down with rain when I shot the 44.0 and 44.1 gr charges (and was rather squally ahead of that for the 43.9). Once the rain stopped things were dead still, although I was shooting at a sopping wet target.

44.2 gr looks nice and likely close to the limits of my ability. 44.4 had better velocity consistency but worse grouping (maybe I was getting tired and fed up).

If I feed 2461 fps at a range of 300 ft into Ballistics AE I get a muzzle velocity 2626 fps.

I don't see any signs of excess pressure on the cases. The only thing I noticed was that from 44.2gr onwards the sidewall of the cases seemed markedly dirtier.

(I can't wait to shoot my forthcoming 6mm Creedmoor to get a reference for what a good rifle can do. Dana English finished it up last week. Defiance Deviant Elite action, Bartlein barrel, Bix 'n Andy Tacsport Pro trigger and Manners stock.)

 

[Bc'z]

44.2 looks real nice.

 

[SGK]

Yeah the problem is, statistically, a 4 shot group provides zero confidence. All I can say is it isn't yet a bad one.

 

[Bc'z]

Yeah the problem is, statistically, a 4 shot group provides zero confidence. All I can say is it isn't yet a bad one.

Load 10 and have a look see

 

[SGK]

This is loading to my best estimate of “touch”. Limited bearing surface in case neck. Safe?

 

[barefooter56]

This is loading to my best estimate of “touch”. Limited bearing surface in case neck. Safe?

SGK,
There was a video of Bryan Litz discussing the bullet seating depth testing of the BERGER Hybrid Target bullets ( include the ELITE HUNTER bullets in this also) on this website. But I have not been able to find it for awhile now. In it he states that the ' general rule of thumb" for bullet seating depth testing with these bullets is to start your bullet seating depth testing at .015 OFF THE LANDS. Then WORK BACK INTO THE CARTRIDGE CASE IN .005 INCREMENTS . When you find a bullet seating depth that shows promise and you want to try to "tweak" it . Test .002 to either side of that CBTO. There is about a .060 range that you find the bullet seating depth accuracy node in most cases. HOWEVER , there are exceptions to every rule. So moving the bullet closer to the lands starting at the .015 OFF THE LANDS MAY be what your rifle likes. You have no way of knowing which one works for YOUR RIFLE until you test. Any bullet seating depth testing should be done using the starting load published for the bullet/powder/cartridge combination being loaded. Once the bullet seating depth accuracy node is found. Work the powder charge back up slowly checking for pressure signs and accuracy until your highest , or a velocity accuracy node that works for you is found.

In some cases even seating the bullet to the published magazine length of the cartridge you are loading. Then working the powder charge up has been found to work with these HYBRID bullets due to their jump tolerance. These are a different animal from the VLD bullets. Hope this helps.

 

[SGK]

Hi Phil, you'll see post 38 covered a lot of ground vis a vis seating depth. Subsequent advice I received here was to stick with 30 jump and increase powder charge. (Results in post 46.) I hadn't tested closer to touch because I had feared a lack of bearing surface in the case neck. With these bullets and with my Forster Datum Dial Kit, my best measurement of max CBTO (i.e. to touch) is 2.276". Before I tested anything closer to touch (20 jump, 10 jump and touch or whatever) I wanted some confidence that the limited seated bearing surface was still ok/safe. I had heard a good rule of thumb was one calibre width of seated bearing surface minimum. I haven't attempted to actually measure the amount shown in the pic.

If the seating depth node is 60 thou wide then I shouldn't bother with anything other than continuing to increase powder charge.

 

[Martin52]

Finally got to shoot this today. See attached target. It started to absolutely bucket down with rain when I shot the 44.0 and 44.1 gr charges (and was rather squally ahead of that for the 43.9). Once the rain stopped things were dead still, although I was shooting at a sopping wet target.

44.2 gr looks nice and likely close to the limits of my ability. 44.4 had better velocity consistency but worse grouping (maybe I was getting tired and fed up).

Did you settle on 44.2 gr and 0.030 jump ?

I have just re-tested Berger 168 hybrids in my 30 inch palma barrel, 11 twist, 0,085 fb. COAL is 2.910.

I am using Lapua palma brass, 43.5 gr Varget, Federal 205M primers, 0.010 jump and that produces a very tight group although I suspect this a low node. I might have to re-test with increased powder.

In my last tests I changed my routine. I first shot a lower charge weight for group, then increased the powder charge at the seating depth that produced the best group and that got me to 43.5gr/0.010 jump. It's the reverse of what I usually do.

Martin

 

[Don_Parsons]

I see you found the standard happy spot SGK...

Lots of bullets shot out of the mid size cases seem to like the 2700 ft-per seconds ish... A old guy shared this with this fall after I've been shooting for 40 plus years... Ha

I thinking he was talking about the heavier bullets that is...

I found 4 different combinations for both of my 308's in your range,,, super accurate...

My favourite load of all is the 178gr ELD-M'S at 2680 Lapua Palma Brass 1.990 case trim,,, seated 2.857 COAL,,, CCI BR II 450...
42.8 Varget.

I liked the 168gr bullets,,, my rifle started grouping better once I added the 1 gram of heavier bullet... There or about that is...

Thanks for sharing your information as I'll do my next test this winter...

Cheers from Don

 

[SGK]

Hi guys. Unfortunately I have been away from all this for quite a few months, grappling with divorce and also avoiding the hot SFL weather. The former is behind me now and the latter is slowly cooling so I'm keen to get back at it. After the testing results in post 46 I did decide to seat bullets longer to see what happened. I managed to shoot another series on June 22 and need to dig out the target.

o Shot 8 of 10 44.4 gr @ CBTO 2.256 ~20 jump. Avg 2641.5, SD 17.12, ES 48. Group: w=0.68 MOA, h=1.01 MOA.

o Shot 5 of 10 44.4 gr @ CBTO 2.66 ~10 jump. Avg 2646.4, SD 13.69, ES 35.

o Shot 10 of 10 44.4 gr @ CBTO 2.276 ~touch. Avg 2648.1, SD 13.48, ES 36. Group: w=0.59 MOA, h=0.94 MOA.

o 5 rounds 44.5 gr @ CBTO 2.276 ~touch. Avg 2654.8, SD 13.72, ES 37.

o 5 rounds 44.6 gr @ CBTO 2.276 ~touch. Avg 2669.6, SD 15.96, ES 45.

o Still no signs of excess pressure

I will post the target when I find it - things got a little disorganized moving house. Given there were no signs of excess pressure I decided I may as well keep climbing the powder load. I have loaded but not yet shot the following. 2.276 is approx "touch" in my rifle.

o 5 rounds with 44.7 gr Varget at 2.276” ~touch 4x loaded

o 5 rounds with 44.8 gr Varget at 2.276” ~touch 4x loaded

o 5 rounds with 44.9 gr Varget at 2.276” ~touch 5x loaded (annealed)

o 5 rounds with 45.0 gr Varget at 2.276” ~touch 5x loaded (annealed)

Quickload suggests can go as high as 46.3 gr when seating for 60 jump

I don't mind 'exploring' with this 308 as I'm finding the entire exercise a great learning curve. I expect much better results from my custom build 6mm CR for which I have the first rounds loaded (a simple 1-shot per increment powder ladder at 'touch' to look for pressure signs).


EDIT: target added

 

[jsthntn247]

I used to run them, seated out about as far as yours are, in Lapua large primer brass at 46.2gr of Varget.

 

[SGK]

I added the target from my last outing to post 54

 

[JFrank]

Hi guys. Unfortunately I have been away from all this for quite a few months, grappling with divorce and also avoiding the hot SFL weather. The former is behind me now and the latter is slowly cooling so I'm keen to get back at it. After the testing results in post 46 I did decide to seat bullets longer to see what happened. I managed to shoot another series on June 22 and need to dig out the target.

o Shot 8 of 10 44.4 gr @ CBTO 2.256 ~20 jump. Avg 2641.5, SD 17.12, ES 48. Group: w=0.68 MOA, h=1.01 MOA.

o Shot 5 of 10 44.4 gr @ CBTO 2.66 ~10 jump. Avg 2646.4, SD 13.69, ES 35.

o Shot 10 of 10 44.4 gr @ CBTO 2.276 ~touch. Avg 2648.1, SD 13.48, ES 36. Group: w=0.59 MOA, h=0.94 MOA.

o 5 rounds 44.5 gr @ CBTO 2.276 ~touch. Avg 2654.8, SD 13.72, ES 37.

o 5 rounds 44.6 gr @ CBTO 2.276 ~touch. Avg 2669.6, SD 15.96, ES 45.

o Still no signs of excess pressure

I will post the target when I find it - things got a little disorganized moving house. Given there were no signs of excess pressure I decided I may as well keep climbing the powder load. I have loaded but not yet shot the following. 2.276 is approx "touch" in my rifle.

o 5 rounds with 44.7 gr Varget at 2.276” ~touch 4x loaded

o 5 rounds with 44.8 gr Varget at 2.276” ~touch 4x loaded

o 5 rounds with 44.9 gr Varget at 2.276” ~touch 5x loaded (annealed)

o 5 rounds with 45.0 gr Varget at 2.276” ~touch 5x loaded (annealed)

Quickload suggests can go as high as 46.3 gr when seating for 60 jump

I don't mind 'exploring' with this 308 as I'm finding the entire exercise a great learning curve. I expect much better results from my custom build 6mm CR for which I have the first rounds loaded (a simple 1-shot per increment powder ladder at 'touch' to look for pressure signs).


EDIT: target added

I hate nasty Lawyer’s especially when they work for my ex wife.

here’s a super simple 308 ladder test with 155 gr just .002 off the lands. The node is 44.2
So I can start seat testing at 44. and work up Or 44.2 and let er eat.
I colored some Bullets at different depths took it to 550 and let er eat.
1 1/2 vertical at 550 will do just fine in a hunting rig. I’m done..

 

[Bc'z]

I hate nasty Lawyer’s especially when they work for my ex wife.

here’s a super simple 308 ladder test with 155 gr just .002 off the lands. The node is 44.2
So I can start seat testing at 44. and work up Or 44.2 and let er eat.
I colored some Bullets at different depths took it to 550 and let er eat.
1 1/2 vertical at 550 will do just fine in a hunting rig. I’m done..

I double dog dare you to run 44.3

 

[JFrank]

Oh man not a double dog dare!
Hell why not? But if I hurt my shoulder again I’m goin need help packin deer out da bush.