12fv build w/ pics

[DesertDug]

all current brass is Hornady. I do have some unfired virgin Hornady brass, and do plan on getting some (100 pcs) of Lupa brass with small primer pockets as I proceed with this project.

[CFJunkie]

There is nothing wrong with Hornady brass.
I suggest you try different large rifle primers.
I tend to favor Federal 210M large rifle primers because I am so anal about accuracy and have measured the results with about 4 different primers and found the 210Ms shoot the best in my .308s by a very small margin.
But just about any large rifle primer will work very satisfactorily and you may find your rifle has different preferences than mine do.

If you are concerned about the Hornady brass, measure the trim length and weigh the new brass before you prime them.
It will allay some of your concerns when you find that they don't vary very much case to case as long as the brass are all from the same lot.
Different machines can churn out brass with different lengths.

The Hornady brass will last you a minimum of 12 reloads if you don't constantly flirt with high pressure and will give you a known consistent base for your reloads.
Unless you shoot over 5600 rounds a year like I do, you can reload for several years with that initial batch of brass with good success.

[CFJunkie]

Update on 100 Lapua brass resize for Savage 12 FV 6.5mm. This is the 5th resize and the distribution is now closer to a normal distribution than after the last resize.
I'll be loading them tomorrow for a shoot on Wednesday morning.



# Lapua Brass - 5th Resize


1.914
0


1.913
2


1.912
9


1.911
17


1.910
35


1.909
22


1.908
7


1.907
6


1.906
1


1.905
1






1.91000
Median


0.00146
St Dev



My resizing die settings seem to keep the brass pretty close but there is a slight skew to the short side but not particularly concerning.

90% of the brass is still within +/- 0.002 of SAAMI recommended trim length.
98% of the brass is within +/- 0.003
of SAAMI recommended trim length.
The worst is short
of SAAMI recommended trim length by 0.005.

[DesertDug]

Range report. - small sample sizes
Bore sighted at 50 yards. Shooting hornady 129 gr American whitetails at avg 2804 of the 5 I measured. Box estimates 2920 fps.
It took 3 shots to get it on center and put 7 within 1".
Moved to 100 and groups all shoot within 1" with the factory loads.

Hand load predicted speed of 2608 fps avg. for 5 shots measured 11 fps slower at 2597 fps. With hi of 2622, lo of 2578, sd17 and es of 44.
Best 5 shot group
https://i.postimg.cc/BvB1Bxjf/IMG-1821.jpg (https://postimg.cc/xkqC0NG6)

this is a 5 shot group with the hornady 140 black box speed 2690, shooting avg 2688 for five shoots.
https://i.postimg.cc/y6jkSBkQ/IMG-1822.jpg (https://postimg.cc/7bCxpF10)nearest pnb atm (https://banks-nearme.com/pnb-near-me)

I am sure in the right hands this would shoot even better, and I will be able to measure my improvements.

[DesertDug]

# Lapua Brass - 5th Resize


1.914
0


1.913
2


1.912
9


1.911
17


1.910
35


1.909
22


1.908
7


1.907
6


1.906
1


1.905
1






1.91000
Median


0.00146
St Dev



.
CFJ, Will you adjust charge for each, or bullet seating depth?

[CFJunkie]

DeserDug,

That is a good start with a brand new rifle. You've done your homework and are getting the variations under control.
The one or two shots that are away from the group are probably either moving in or out on the scope ( best group) or a lapse in trigger control in the second group, but still that is a great improvement.
Shooting factory loads with less than match grade under 1 inch is an accomplishment.

I never expect to shoot a new riffle perfectly the first time I have it out at the range.
It takes me at least one range session to get comfortable with the feel of a new rifle and scope. Sometimes I never do and then I figure that the stock or the scope height doesn't fit my set up and begin to look for adjustments. Other times I love the set up and shoot the new rifle well. It is sort of a crap shoot so I don't expect any miracles and an happy when they happen.

To answer you question of how to adjust for the trim length:

I already sorted the first 25 into a set and will consider them 1.911 and load for that. Generally the first two rounds are to get the barrel fouled and warm it up so the rounds will group.
I set the charge based upon the power and bullet used to get close to 1.360 msec. and adjust seating depth to get exactly on 1.360.

The second set all fall in the 1.910 length and I'll set the charge based upon a different bullet but probably the same powder and do the same thing.

The third 25 will be a toss up between 1.910 and 1.909 but I'll probably choose 1.909 and set the charge based upon a different bullet.

The last one will also be a toss up between 1.908 and 1.907 with a couple of outliers but I'll use 1.908 and set the charge based upon the bullet used.

Each time I use the seating depth to adjust to exactly a exit time of 1.360.

There is about a 0.002 difference in seating depth or trim length to make a 0.001 msec. of exit time, so 0.001 trim length isn't as much of a problem as you might think.

[DesertDug]

So are you not concerned with a "jump to lands" measurement, because it's the exit time that dictates?

[CFJunkie]

I have already determined that some bullets like to be seated out further than others.
I have over 6,000 rounds through 6.5mm Creedmoors with about 10 different bullets, all measured and documented so I have a pretty good database of what works for my rifles and powder-bullet combinations.

I do begin choosing the charge for each powder-bullet combination based upon the bullet's 'preferred' seating depth. Based upon the trim length variations, I make the adjustment around that depth by making slight adjustments in seating depth.
The seating depth adjustment rarely is more than 0.008 to 0.010 to tune to the precise exit time once I have chosen the powder charge to get within the exit time range for the preferred seating depth. Most times it is only a few thousandths.

When I started testing the theory several years ago, I would set up a set of loads with their exit times 0.005 msec. apart so I could document the difference in group size average.

As you already know, a 0.1 grain change in powder charge causes about 0.005 to 0.006 msec. in exit time depending upon the powder, so it was a convenient method of creating loads.
Turns out that the increments were pretty small and my shooter variations often masked the differences at those tiny increments.
I quickly concluded that the differences in exit times really showed obvious results when they were 0.020 msec. or more off the exit time goal and the biggest differences were apparent when the shock wave got closer to the muzzle.

[CFJunkie]

DesertDug asked about whether I loaded for jump for this rifle in post #47. I had a good idea of where the various bullets would perform based upon my results with my other two Savage 6.5mm Creedmoor rifles.
When I bought the 12 FV 6.5mm Creedmoor ‘bargain rifle’ for $320, I didn’t even bother shooting the Sierra 140 gr SMK #1740 bullets because they shot so poorly in my other two rifles and I didn’t bother with Berger’s 140 gr Long Distance #26409 and Hybrid #26414 because they didn’t perform much differently than the 140 gr Berger #26401 Match bullets. I still had 200 of them and didn’t want to spend another $60 a box to buy more of the LD and Hybrids hoping for a miracle.
For the 12 FV 6.5mm Creedmoor results since inception, I did an analysis of the effects of seating depths for all the groups shot with the 35 in.-lbs. torque settings so the results would not be skewed by the poor performance at 45 in.-lbs.
The results are shown in O.A.L. measurements because the ogive to tip measurement varies for each bullet type.
The 130 gr Hornady ELD-M #26177 data was limited by having only one half-box of bullets left when I started data gathering with the 12 FV 6.5mm Creedmoor rifle.
The column headings - except for the last two columns - are in increments of thousandths away from SAAMI recommended O.A.L. of 1.910.
Normally I like to keep the jump around 0.015 to 0.020 to minimize the chance of getting the bullet touching the rifling. (The poly tips on the TMKs and ELD-M bullets add to the bullet overall length but the ogive determines the jump.)
“Avg Diff” is calculated difference in group average at each depth range by the using the average minus the best load average at the seating depth (underlined).
Group Averages by Bullet by O.A.L. Range - 35 in. Lbs. Torque
-----------------------------------5-10 11-20 21-30 31-40 41-50 51-60 Avg Diff. Jump for best load avg.
Hornady ELD-M # 26177 130 - 0.374 - 0.024
Sierra TMK #7430 --------130 ----------------------------- 0.393 0.341 0.024 0.005
Berger Match # 26401--- 140 - 0.378 0.386 ----------------------------0.026 0.056
Hornady ELD-M # 26331 140 - 0.404 0.415 -------------0.401 --------0.008 0.024
Sierra SMK #1742 -------142 - 0.370 0.379 -------------0.357 --------0.013 0.014
Hornady ELD-M # 26333 147 - 0.387 0.337 --------------------------- 0.042 0.024

As you can see, the 130 TMKs like to be seated out so the jump for the best load average was shorter than I normally try to achieve.
The 140 gr Berger Match bullets are baffling. They seem to shoot better with a longer jump than expected.
(I even remeasured those bullets to see if I made an error in measuring the bullet depth into the chamber on this rifle. I didn’t.
Then I checked the best load for that bullet that I shot in my 12 LRP and found that it also had a long jump, so I have concluded that it is the bullet not my measurements.)

[DesertDug]

I was able to measure OG of chamber distance and the load I had shot which was OAL 2.821" measures a jump to lands of 0.048".

I was thinking this is a large jump. If I want to load some up closer to the lands, say 0.038", 0.028" and 0.018' to lands and I have all my cases already trimmed to 1.190". Can I adjust the load to remain in correct exit time by adjusting the powder weight? Do I add .2 grains of powder for additional 0.010" in OAL?

[CFJunkie]

That's the way you do it. However, a 0.1 change in powder charge for H4831 SC will usually change velocity by about 6+ fps equivalent to a seating depth increase of 0.016. It is going to be hard to adjust by 0.010 jump by changing powder charges by 0.1 if the trim length is the same.

A 0.1 grain increase in powder charge for H4350 will change velocity by about 6+ fps. and will require a seating depth increase of 0.017.

If your still using H4831 SC powder, I suggest you try 2.837 (a jump of 0.032) with an additional 0.1 grain load and 2.855 (a jump of 0.014) with adding another 0.2 grain to your original load. The next increment would put you into the rifling and I wouldn't attempt that. You could always simply adjust the seating depth leaving the charge the same and sacrifice a few fps if you want to see if you get any added benefit of using a few thousandths shorter jump.

If you are now using H4350, then you need to adjust to make 0.017 increases in O.A.L. for each 0.1 grain increase in charge.

[DesertDug]

great thanks, will adjust setting depth and load charge to see how it effect groups. Still using H4831sc for the time being.

[DesertDug]

https://i.postimg.cc/T1v8NCRS/ED6-CE9-A7-2069-4-AC6-AED6-437-A24-F1-D0-B2.jpg (https://postimg.cc/cgh5r7tM)

[CFJunkie]

Nicely done.
Your rifle build looks great and works great.
Good work!

[DesertDug]

Got to the range again yesterday. Loaded up the same load of h4831sc in 1.90" trimmed cases.
OAL of 2.821 for a jump to lands of 0.048". 8 rounds, group of 3 and 5
OAL OF 2.837 for jump of 0.032" 15 rounds shot in groups of 5
OAL2.855" for jump of 0.014" 10 rounds groups of 5.

88 deg temps with wind from 8:00 at 4.7 miles. 100 yards

All groups shot well. All at or less then 1" even with called pullled shots. My form seems to be the biggest issue still.
Best group measured 0.0646 with the 0.014" jump.

From looking at the groups I do not think there is a clear winner, what do you nuts think?

https://i.postimg.cc/3w5kgFMY/IMG-1831.jpg (https://postimg.cc/XrLNWF7z)

https://i.postimg.cc/mgQLGxqW/IMG-1832.jpg (https://postimg.cc/5X2dwrbs)
https://i.postimg.cc/KYG2S1Bt/IMG-1833.jpg (https://postimg.cc/75WcSYBL)

[CFJunkie]

You're showing a lot of improvement, DesertDug

Although all the groups are showing the dreaded :"4 in - 1 out" effect that always haunts most of us, you have two groups that are under 0.9 and would be a lot better if the one shot was with the other 4.
I used On Target to measure the groups and got some interesting data.
Your second images right group is 0.833 and the third image left group is 0.766 even including the 1 out shot.

--------- Left --Middle--Right -- Average
Image 1 1.107------------------1.107
Image 2 1.147 1.241 0.833 ---1.074
Image 3 0.766 1.126-----------0.946
--------------------------Overall 1.037
Even with the 1-out shots causing some disruption of the group sizes, the averages would indicate that the results are improving slightly as you move toward a jump of 0.014 at 43.0 grs.
6129

6130

If the 1 out shot was in with the others, your average groups sizes would be a lot smaller.
With the 1 out group moved in with the others, the group sizes are indicative of what a rifle might do if you could keep the one stray shot from ruining your groups.
You know from my June 4th session results that I reported on another thread how one lapse of concentration can cause an anomaly that messes up everything.

--------- Left --Middle--Right -- Average
Image 1 0.866 -----------------0.866
Image 2 0.541 0.723 0.833 ---0.699
Image 3 0.453 0.705 ----------0.579
--------------------------Overall 0.687
With the I out shots moved, the averages still show that the results favor 0.014 jump at 43.0 grains slightly and that indicates that the trends are in the same direction.

I think you have some data you can work with both with load development and with technique improvement.

Although you can't erase the errant shots, you can get an idea of what might be possible.

[DesertDug]

new barrel shipped. :biggrin-new:

Hope it shoots as good as the stock one.:o

Need to get the barrel nut and lug ordered. I guess I need to go with e/arther brown since they have them in stock and have head gauges as well. They will be in black while the barrel is in SS. Should have had these ordered already from sharpshooters supply, oh well...

Gonna be at the lease and will shoot up the H4830 loads I had ready to test at the range with the factory barrel but never made it there. Will not be bench results.

[DesertDug]

Shot the h4350 loads with the stock barrel. 100 yards prone out the back of my pick-em up truck.
41gn h4350 with 143 gn edlx case grime 1.914" w/ cci primers. COAL of 2.851" to achive an exit time of 1.360 ms at the 12 th refraction and a 0.018" jump to lands.

This is will be the last test loads done on this barrel as the new one should arrive tomorrow.
Load looks promising.

Shot two groups of 5, one group of 10, and one group of 15. These are the three group of factory cases that I did not mix together.


https://i.postimg.cc/VsVdNm8w/IMG-1848.jpg (https://postimg.cc/ThnR781N)cute unique baby boy names 2015 (https://treetop100babynames.com/)

[DesertDug]

One group was sup 1 moa
https://i.postimg.cc/v8NtwJ2g/IMG-1855.jpg (https://postimages.org/)

[CFJunkie]

Pretty darn good shooting out of the bed of your pick-up. Those are all kill shots.

Let us know how the new barrel does. I hope it does at least that well but I'm sure it will probably do better.