.308 Win load development - help - images attached

[Socal]

So I am attempting to develope "the perfect load" for my freshly built .308 Win. Its a Surgeon short action with a 24" Krieger SS MTU contour - 1-11" twist, Nightforce NXS 5.5-22x glass with NF rings all sitting in a AICS 2.0 stock. So for my load development, I started with three bullets, 155 gr Lapua scenars, 168 gr Sierra Match Kings, and the 175 SMK's. I am using Lapua cases, fully prepped, all using Varget for powder. I initially loaded 15 of each bullet ( 3 different powder charge weights, 5 each) for a total of 45 rounds to test today, so it looked like this:

QTY. Bullet Powder weight

5 155 Scenar 41 grains

5 155 Scenar 43 grains

5 155 Scenar 45 grains

5 168 SMK 40 grains

5 168 SMK 43 grains

5 168 SMK 44 grains

5 175 SMK 40 grains

5 175 SMK 42 grains

5 175 SMK 44 grains - Started to see some signs of pressure here, flattened primers.

All were loaded with Varget, The SMK's were loaded to COAL of 2.800 and the Scenars were loaded to 2.795" All were shot out of new lapua brass with Wolf primers.

I shot at an indoor 100yd range so there was no wind, mirage, etc. I started with a clean barrel, fired 2 fouler shots and proceeded shoot groups for the first bullet wait (3 groups of five) after this I cleaned the barrel lightly, let it cool and repeated this process for the other two bullet weights.

I am now wondering where to go next, It seems that my rifle likes the 175's moreso than the others, the 175's showed the most consistently tight groupings, although two of them I knowingly pulled the shots, resulting in the two flyers.

I have attached the target, anyone with any advice, please feel free to chime in whether it be advice as to how I should proceed or whatever.

Thanks in advance!

[smokshwn]

I would try a ladder test with each bullet.

be advised the link here has some horrible music that can't be shut down so mute your speakers.

http://mikeswillowlake.com/ladder%20test.htm

[Socal]

I would try a ladder test with each bullet.

be advised the link here has some horrible music that can't be shut down so mute your speakers.

http://mikeswillowlake.com/ladder%20test.htm

Thanks for that link, very interesting!

[Caspian_45]

You need to chrono the ammo too, or the tests will not be complete. A chrono will tell you a lot of things about your loaded ammo. ES, SD, average velocity, etc. You can play with over all length too.

Finding an accurate load for your rifle will be a long and frustrating, but fruitful experiance.

[Sandro]

You need to chrono the ammo too, or the tests will not be complete. A chrono will tell you a lot of things about your loaded ammo. ES, SD, average velocity, etc. You can play with over all length too.

Finding an accurate load for your rifle will be a long and frustrating, but fruitful experiance.

check your runout with a gage, anything out of 0,003 will create a flyer...I use the sinclair gage, i neck turn my cases too. check this link.Neck Turn

[smokshwn]

All that is great advice, but doing the ladder first will save you a ton of wasted rounds down range. Once you have found that node using Audett's method you can then continue working on other aspects of the load but you will bypassed many variable in the beginning, saving you a lot of work.

[Religious Shooter]

You need to chrono the rounds and then dump the #'s into a ballistic program to get a better picture.

Personally I try to get 1MOA as a fast as I can safely push it.

I'd aim for 2800-2950+ fps with the 155's.

You can try to tighten up the 155's performance by using the fired casings. In my experience, neck sizing (only) and using fired cases tightened up my group by about .25 MOA. When neck sizing you should try different bushings to see if it helps.

Doing the above with the 155's will usually mean 4-6,000 rd barrel life on a .308.

If you want your barrel to last longer, stick with the 175's.

Varying the length can also help. On my .243 messing around with the COAL alone gave a .1-.2 MOA improvement.

YMMV.

[Socal]

ya, I have a lot to learn it seems. My question is, does the ladder test still work at 100 yards? Right now most all of my groups are sub-MOA, with some being sub half-MOA but I am looking for every last bit of accuracy. Is ther an order I should do things, eg. first determine correct powder charge, second play around with COAL, third play with neck tension, fourth, different components etc...

[smokshwn]

The ladder test will still work at 100, the node and deviations will just be more difficult to distinguish because the difference will not be as evident.

Edited January 18, 2010 by smokshwn

[Socal]

I found this last night http://optimalchargeweight.embarqspace.com/#

looks promising to me due to the fact that they specifically mention it being used with great success at 100 yds to develop sub moa loads at distance.

[Big Bore]

I would try a ladder test with each bullet.

be advised the link here has some horrible music that can't be shut down so mute your speakers.

http://mikeswillowlake.com/ladder%20test.htm

You weren't kidding about the music.

[fastshooter03]

What throat do you have?

What reloading stuff?

Definitely get some chrono info.

Try some other powders? Benchmark is popular with some guys here.

Nick

Edited January 19, 2010 by fastshooter03

[Socal]

What throat do you have?

What reloading stuff?

Definitely get some chrono info.

Try some other powders? Benchmark is popular with some guys here.

Nick

Not sure bout what throat I have. How do I find this? Should I get the reamer specs for my barrel from Krieger?

I am using a Dillion 550B and Redding Competition Micrometer dies. Lapua cases, Wolf primers, Varget, and the bullets discussed above. I will definately get some chrono info, not quite sure why that didnt come to mind at first. I imagine many people would look at those groups and be fairly satisfied, all the groups are right around MOA and over half are well within sub moa. The 175 SMK groups are under .5 MOA but I am an absolutel perfectionsit, I know this rifle is capable of more. I want a clean 1 hole group at 100 hahaha I am on a mission.

[twodownzero]

Need a lot more powder with the 155s. They don't work until you get them over 2900 fps out of a 24". That means 46.5-47+ grains.

[fastshooter03]

<!--quoteo(post=1136121:date=Jan 18 2010, 07:34 PM:name=fastshooter03)--><div class='quotetop'>QUOTE (fastshooter03 @ Jan 18 2010, 07:34 PM) <a href="index.php?act=findpost&pid=1136121"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec--><!--sizeo:2--><span style="font-size:10pt;line-height:100%"><!--/sizeo--><!--fonto:Comic Sans MS--><span style="font-family:Comic Sans MS"><!--/fonto-->What throat do you have?

What reloading stuff?

Definitely get some chrono info.

Try some other powders? Benchmark is popular with some guys here.

Nick<!--fontc--></span><!--/fontc--><!--sizec--></span><!--/sizec--><!--QuoteEnd--></div><!--QuoteEEnd-->

Not sure bout what throat I have. How do I find this? Should I get the reamer specs for my barrel from Krieger?

I am using a Dillion 550B and Redding Competition Micrometer dies. Lapua cases, Wolf primers, Varget, and the bullets discussed above. I will definately get some chrono info, not quite sure why that didnt come to mind at first. I imagine many people would look at those groups and be fairly satisfied, all the groups are right around MOA and over half are well within sub moa. The 175 SMK groups are under .5 MOA but I am an absolutel perfectionsit, I know this rifle is capable of more. I want a clean 1 hole group at 100 hahaha I am on a mission.

If Krieger did the chambering job then they should be able to tell you what throat length the reamer they used has.

You can also tell somewhat by loading a bullet into a sized empty case say 3.100" OAL and see if it hits the lands. If it does hit, sand the land marks off the bullet and seat it deeper and keep repeating until the marks go away. That will get you close but if you want something more exact you can get the Hornady(Used to be SToney Point) guage that goes into your chamber with a special threaded case and the bullet you want to measure when the bullet ogive touches the rifling.

Hornady Lock n Load

I found out with my DPMS 308(that has about .200" freebore), that it shot pretty much the same with all the different loads and bullets. I attributed this to the long throat.

I would expect nice 5 shot clusters with the setup you have with just about any load if it has a 308 match chamber.

One thing you can try is loading the bullet out further then mag length to see if that decreases the flyers and group size.

Nick

[inkedshooter]

Just like the others have said.... chrono. I know guys that will weigh each bullet, weigh each case, measure case length, case and neck diameter, get the powder measurement exact to the last grain, etc etc etc... before developing a load. You've got a great rifle that's probably going to be picky on what round you shoot through it. Post pics of your rifle!!

[Dave.O]

If your loading on a 550, are you dropping powder with the powder measure on the press? Or, are you weighing each and every charge?

It's been my experience with Varget that it won't meter that well out of a charge bar.... YMMV..

I like to load all my longrange ammo on a single stage press, and I use a RCBS chargemaster to throw the powder. I keep the powder to the .1... If all charges call for 45.1, that's where the scale stops.. It can be boring, but, worth the work when you start shooting farther than a 100yd..

I also shoot the 155 scenar.. Out of my rifle they don't have to move as fast as some have them moving.. I have them moving right at 2800, and they shoot real well in my local 600yd F-class matches..

There is alot of good info here in this thread, you have to pick and choose what will work for you..

[Bret Heidkamp]

The 175 SMK groups are under .5 MOA but I am an absolutel perfectionsit, I know this rifle is capable of more. I want a clean 1 hole group at 100 hahaha I am on a mission.

I hate to say this but you are selecting the wrong bullet (and the wrong caliber, actually) to shoot at 100 yards. Forget about the 175 smk, that is a long range bullet. Use a flat base spire point lighter weight benchrest bullet, not a heavy boat tail. Look at what the bench guys shoot at 100 and 200 yards. The bullet you are shooting is not stable until about 200+ yards.

Your load work (and ladder tests) really needs to be at 300 yards for the 175 smk or you won't get results that are easy to interpret. The ladder won't have enough vertical separation.

[Socal]

ROUND 2!

I loaded all the rounds in fully prepped 1x fired Lapua cases, trimed to 2.005, neck sized with a .336 redding comp busing die. Using Wolf primers, Varget, and 175 gr Sierra SMK's. Target shot at a 100yd indoor range, chrono 10ft ahead.

I loaded ammo ranging in charge weight from 42 grs to 45 grains of Varget in .3 gr increments, giving me 11 sets total, three cartridges per set for a total of 33 rounds. I followed the Instructions to the OCW method ( http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134)

and tried to be as "scientific as possible". I shot two fouler shots and proceeded with my testing allowing 2 minuted between shots. It was fairly cool (59f) so barrel heating wasn't an issue. What I found was interesting. Around 42 grs the groups were wide open and as the charge weight progressed the groups tightened up. I know the OCW method is used to help select a "forgiving" node that will allow for some vairance in your loads, location, etc and still maintain a consistent POI, but I couldnt help but notice the group size.

The best groups by far came from the 45gr Varget, measured just above .25 MOA. I checked everything I know how to see if there were pressure issues with this load but couldnt find any - no hard bolt lift, no excessive head / case expansion (measured with calipers) and the primers were flat, but no flatter than the loads with the 43.8 grs.

Is this a common load, or too hot???

Now that I am at this point, where should I turn next to squeeze the last bit of accuracy out of this rifle and which powder charge looks good?

Here are the chrono data:

ES SD AVG HI LO

42.0 16 8.718 2520 2526 2510

42.3 17 8.544 2543 2552 2535

42.6 10 5.033 2558 2563 2553

42.9 42 23.692 2576 2603 2561

43.2 23 12.288 2579 2593 2570

43.5 12 6.928 2607 2615 2603

43.8 7 3.606 2631 2635 2628

44.1 2 1.155 2654 2655 2653

44.4 53 26.627 2664 2692 2639

44.7 18 9.018 2679 2688 2670

45.0 3 1.528 2708 2710 2707

Pics of the groups are below. As you can see, 44.1 and 45 grs both had insanely low velocity variations. When I charted this, there is actually a pattern of peaks and valleys, but the peak and valleys turn steeper as the velocuty / charge weight increases.

Thanks in advance!

This is becomming addicting!

Edited February 2, 2010 by Socal

[Chris]

After looking at those targets, I would go with the 44.7gr charge. You can also start at 44.4grs and work your way up to 45.0 at .1 or .2gr increments and see if groups and spreads get any better. You can try loading a bit longer also, this should tighten up the group some as well.

44.0-45.0grs is a very common load with Varget and lots of people use it to great success.

The group below is at 200 yards. I'm loading at 2.830" with 165gr AMAXs and VV N150 @ 2760fps.

Edited February 3, 2010 by Chris

[kgunz11]

Chris, you mean the 168 Amax?

If you read on Dan Newberry's forum about the OCW theory, you'll see many of us found a common accuracy load at 44.7 gr of Varget. Of course different lots will perform differently, but it's just one of those loads many rifles like.

I've worked OCW loads up for over 20 rifles now and I am convinced the theory is sound. I think you should go back and read it again. Group size means little to nothing, it's all about barrel harmonics and where your bullet exits the barrel in the "whip cycle". You want 3 charge weights that impact at the same place on the target. You then tweak the seating depth, neck tension, or both to tighten the groups.

I've seen many folks that have great shooting loads when the temps are 70* and then fall all apart when it's 40*. The OCW, when done correctly, gives you some room so that wont happen. I like not having to sort brass, the OCW makes that possible. I've got several tests on Dan's forum that I've done to help others. Below is a picture of an OCW using Berger bullets that I tweaked the seating depth on to tighten the group. I loaded up 3 rounds at this powder charge and .3gr each side of it and shot them at 500 yards. All 9 rounds went into a group 2.5" tall and 3.5" wide even though they were different charges. I'll be shooting steel at distance this week and I'll take some pics of the groups. This was shot out of my DTA SRS in 7WSM.

This is 2 of 3 targets shot in an OCW with my 7-08 hunting rifle. Notice the POI on the target is in the same place between both powder charges. I still have the target around here somewhere so I can probably get you a photo of the 3rd target too.

[JWS61]

Socal,

Have you thought about using Bench Rest Primers? I know that Wolf are pretty good but I still see a smaller SD with CCI BR or Federal Gold Medal. If you still want to use Wolf or want to go the extra step with even a BR primer, weigh all of them and sort them by weight and use only similar weight primers for a given lot of reloads. This will shrink your SD and group size even more. This does take time and patience but like most things you get out of it what you put into it. Also the weighing and sorting of brass and bullets will help too.

Have Fun,

Jeff

[Flexmoney]

Barrel wear thread drift moved here: http://www.brianenos.com/forums/index.php?showtopic=103176

- Admin.

[gunther]

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[gunther]

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