168gr Amax Development

[1stmar]

I think this would make a good sticky...

[browninghunter86]

Is IMR 4064 very temp sensitive? If I were to get a lb or 2 of different powders to try which would y'all suggest for top accuracy? 4064,4895,748.....

Here in South GA temps are very hot and can be fairly cool during fall/winter

[Unclenick]

Not as sensitive as IMR 4895, IME. Powder sensitivity is less important than barrel temperature as a pressure factor, anyway, and I would give it lower priority as a consideration than finding something that shoots well. If the groups are tight over several load steps and you center the load in the middle of those steps, then you have wiggle room for temperature anyway.

[Jimro]

I use 4064, but a lot of the guys I know who are much better shots than I use Reloader15.

Either powder will serve, I think that Re15 is the powder used by more competitors in 308 and 223 now.

If you don't mind keeping a log book of changes including temperature, there are still some folks who use 4895.

I would not choose 748 for an accuracy load unless you needed a ball powder for use on a progressive reloading press. And in that case I chose Power Pro 2000 MR for my 223 match load, and I am happy with the performance (PowerPro2000MR is pretty temp stable based on measurements someone else took over at snipershide).

Jimro

[browninghunter86]

I may try to get some RL15 again and some 4064 to give a try with. I hope this new barrel shoots. If not I do not know what to try since all the other guns I shoot I can can shoot well

Could it be the reverse that I may need to increase trigger pull weight to help me shoot better? I believe the Savage is set lighter than my remington 770 which I can shoot well

[browninghunter86]

Ok got new barrel on and went to the range to shoot.


Load 1= 43.6gr and each load increases by 0.3gr up to 46.3

[1stmar]

I'm thinking load 9 and 10.. Start with those, no?

[Thor2j]

I'm not sure why you only shot one of each. Won't tell you anything.

[browninghunter86]

Thor2j read first few posts in this thread

[1stmar]

Bh86, did you rebarrelling that yourself?

[browninghunter86]

no I had it done by John Whidden here in south Ga. Excellent work

[Jimro]

Try 8,9, and 10 at 100 yards.

Jimro

[browninghunter86]

Here is groups from this morning to verify 45.7-46.3. Shot @100 yards off bipod. I think I rushed/pulled the 2nd shot in group 2 but oh well. Also shot 1 shot each of 44.3,44.6,44.9 on another target at 100 and had same POI so in theory that is 3% below my high node

[Unclenick]

Note: Composed before last post.

Below are plots of the vertical and the horizontal. This doesn't have the classical Audette form, but the vertical trend is to be most stable at shots 8, 9, and 10. For the Horizontal it is at shots 8 and 9. Shot 10 shifts left (minus direction) significantly. About what you'd expect from a 3:00 to 9:00 gust of wind (same as a 9:00 to 3:00 momentary lull) of around 7 mph. If you didn't have that it may still be a shooter error. Hard to tell.

The horizontal follows a definite trend, like heat walking, but that could also be gradual wind pick up. Since I wasn't there, I don't know. It should be a total of about 10 mph change at 90 degrees to the gun. More if the wind is off 90 degrees.

If it's not wind, cooling the barrel between shots should help. Doing a complete barrel carbon removal (Boretech C4 or Gunzilla with overnight soaks or Slip 2000 Carbon Killer for faster action) then breaking the barrel back in with thorough copper and carbon removal between each shot (Boretech Eliminator will do both for fresh single-shot fouling) then degreasing all hydrocarbon traces (Bore Scrubber or Windex) then firing one shot, then recleaning and degreasing between each of 9 more shots is claimed by some to settle the gun in a cold bore position. I don't have proof of this, but 10 shots can't hurt much of anything but your time budget and you get to group those ten to see where your clean, cold barrel zero is as compared to its POI fouled or warm.

Bottom line is to start shooting groups with 8, 9, and 10 round robin style on three targets to see what happens.

[Unclenick]

Well, looks like you beat me to it with the new target. Try running a larger shot count per group next time to verify your middle group isn't random error. I like to use 15 to anchor the group center, but even 5 significantly reduces the uncertainty. This new barrel is obviously a lot more promising than the original.

[Jimro]

Nice, I would go ahead and load up 20 rounds of 46.0 and call it good. I think you did pull that shot on the middle group. But it looks like you've dialed in an OCW node where a +/- 0.3 gr difference in powder charge will still give you sub MOA performance.

Now it is time to play with seating depth to see if you can't tighten the group a tad (your choice), once I get to sub MOA for a tactical rifle I call it good and go shoot.

Jimro

[browninghunter86]

Nick shot 1 in my first target was cold bore shot. Didn't seem to shift hardly any from all the other shots.

It has about 30 rounds through it so I think I am going to give it a scrubbing this weekend.

I know everyone has their "magical" method to everything but Whidden told me with new barrels he shoots 20 rounds then scrubbs the heck out of it and does it this way for first 100 shots. Then after that he lets accuracy dictate when he cleans. Also told me to use JB bore paste or IOSSO every 150 rds to really clean carbon out

[Unclenick]

Everyone's got their own theories about break-in or even not to break-in. Varmint Al just runs 50 strokes with Flitz before every firing for the first time, and will repeat with JB if the bore still seems to foul. No shooting required.

I don't consider break-in a critical issue in most instances. I do know that some barrels will burnish and foul less if you clean them completely between shots for the first 10 to 20 rounds, though most of the improvement seems to happen in the first 10 if it's going to happen at all. Others, and I've had a couple, start as bad foulers and stay that way right through any break-in ever devised, and staty that way until you do something more extreme, like firelapping. The jury is still out with me on getting the barrel to take a set with the first few rounds (Howa's distributor's theory).

The idea behind cleaning between every round is that fouling from the previous round collects on and covers a surface that is grabby and that needs to be re-exposed for burnishing by the next shot. I've never figured out the advice to fire multiple rounds between break-in cleaning or to graduate from cleaning every round to every two or three then every five, etc. It seems to me all that does is guarantee the roughest spots are well protected from burnishing as you go on to subsequent rounds before cleaning. Maybe someone else sees something going on there that I've missed, though.

[browninghunter86]

I did run bore snake with oil a few times before first firing just to make sure nothing was in the barrel.

when I clean it I will see how dirty it is from only firing this few rounds. I read an artilce somewhere(can't remember where online) before that said to reduce fouling at any time during barrel life......shoot one and clean to remove fouling and repeat until you shoot 1 and you see fouling has been reduced from previous one shots

Like we stated before some have a "ritual" they do. Many match grade barrels don't really require this breaking in like a factory barrel does since they are hand lapped and really high quality

[browninghunter86]

If JBM ballistics/Nikon Spot On is accurate with all weather and other variables I could possibly put in with my target from 200 yards my 8,9,10 load hit 2.5" high and at 100 yards they hit 2.5" high. It is saying that is a 232 yard zero and the velocity is 2825 fps

That sure does seem fast!!!????

[Jimro]

It is a tad on the hot side, but then again you are shooting a grain over where I stopped my Varget load workup. As long as you don't see pressure signs in your rifle, then you are good to go.

Jimro

[Unclenick]

Drop tables are a notoriously imprecise way to determine velocity. 100 fps just makes 1/3 moa difference at 200 yards for your bullet in that velocity range, but just 50 fps makes a significant difference in pressure when you're near maximum. You'd need to fire some large shot count groups to get averages accurate enough to be sure what you are seeing is real and not an artifact of randomness.

I don't recall if you said what length the new barrel is?

[browninghunter86]

Nick--it is 26" 1:10 twist

the QL data you helped me with using this bullet was for shorter barrel but the and OAL of 2.880" and the new load OAL is 2.800" but out of a longer barrel

[Unclenick]

Have you measured the fired case capacity out of the new chamber yet? Should be a little smaller since the gun is tighter.

If I use QL's default setting of 56 grains case capacity, I get a load that's 10% compressed and produces 67,900 psi and 2868 fps. Should be a real cruncher to assemble and a throat burner to shoot. But even at that velocity, for the round to be 2.5" high at both 100 and 200 yards I have to zero at 257 yards and the sight centerline has to be 2.3 inches above the bore centerline, which is way high unless you've got a spotting scope mounted up there. So something is amiss with that information.

If I take the predicted behavior of the 46.3 grain load and look at barrel time and tweak case capacity to land it right on one of Chris Long's Optimum Barrel Time points, it suggests a second sweet spot would appear at around 42.5 or 42.6 grains. Might be interesting to see if that proves to be true.

One other factor is that real ballistic coefficients from real guns often aren't a perfect match to published data. Since your rifle is now shooting pretty tightly, you should be able to safely shoot through a chronograph at 100 yards to record ten velocities to average, then repeat at 200 and use that data with the JBM site's calculators to better get the BC you have with your gun an load. You're kind of getting to that point with the load data where you want some actual velocity data to see what sort of ballistic efficiency you're getting from your gun and how fast your lot of Varget is burning as compared to average so pressures may be better estimated.

[browninghunter86]

Trim to length: 2.005", OAL 2.880"(2.160" ogive), Fed 210M primers, WW brass, H20 of fired brass in new chamber 56.67 gr, Temp 82 F

I am thinking about getting the Alpha Master Chrony. I can not afford a really expensive unit at this time