R700/308/168/CFE223 inconsistent results

[Ned Ludd]

You are not alone in observing that CFE223 can sometimes produce unacceptably high ES/SD values. It is a double base ball powder, which sometimes do yield markedly more velocity than their single base counterparts. However, velocity is not everything, and the extra velocity obtained using double base powders sometimes comes with additional concerns such as high ES/SD and/or very abrupt transition into over-pressure as the ambient temp increases.

If it were me, I would also follow the plan you suggested and try H4895, or re-visit Varget. I have had very good results with H4895 under 168 Hybrids. I would also suggest narrowing down the number of variables in your tests. If you continue testing across such a wide range of variables using 10-shot groups, you might burn out your barrel by the time you find an acceptable set of components. I have always obtained satisfactory results using straight Fed210s (i.e. not 210Ms). As has been noted, the ES/SD values obtained using 5-shot groups can often suffer from small sample size issues. Nonetheless, increasing sample size to 10 shots will burn out a barrel faster and cost quite a bit more $$$ in terms of components and time. Is that really worth it when you can always run a 20-shot string to "validate" what you believe to be a finalized load once the development process has been completed? I agree that using the smaller sample size can sometimes be frustrating or even misleading in terms of ES/SD. However, people have been developing highly successful loads using such an approach for a long, long time, so it obviously can work.

 

[AckleymanII]

I have a palma chamber in my Krieger. 45.8g of XBR 8208 with a Winchester primer with the 168g Sierra in lapua brass shoots bug holes, .020 off the lands.

With this load, you could quit worrying about extreme spreads and start worrying about how you are going to get the Carbon out of the barrel. burns hot as Hades!

 

[6bra1k]

again you are doing this backwards. you are looking at data instead of targets.
data backs up targets not the other way....
..all the data in the world means nothing if the group still suck

 

[ScottMcc]

Thanks for the feedback everyone. Ackley, what vel do you see with that load of 8208? 6bra, I have to disagree a little. I think competitive ld shooters strive for single digit es and sd numbers. With the es of 95 fps I saw with the fed 215m, poi will vary probably 1/2 inch at 100, getting rapidly worse with distance. I haven't gotten good groups with cfe, but I also haven't seen any reliable velocity with it either. Reloading manuals say they use a magnum primer with certain ball powders like 748 and blc2, allegedly because they are denser and harder to light. I was hoping to find a primer that magically lit off cfe to produce better consistency. Instead I found nothing at all better about magnum primers. I'm baffled as to what if any difference there even is. I did determine CCI br2's were good, and I happened to recently acquire a brick of 1k, so they will become my new standard. So the next goal will be to take advantage of my new redding seating die, and play again with known accuracy powders.

 

[6bra1k]

one last time and then no more comments
you are doing load development backwards
load for groups, fine tune for group and then look at data
this is not science in a lab. this is real world shooting.

 

[D-4297]

I've read all the comments , and there are a few things I may add to this . As several have said ; SD /ES is not the Be All / End All , to shooting with accuracy . It does have it's place in the grand scheme of things , as I have found SD to be my "yard-stick" to measure my improvement in Case prep . The better ; and more consistent my Case prep became , the more consistent my SD became with it . Neck Tension ; as we refer to it , is also crucial to creating consistent SD . I call it by the correct name , of Interference Fit . Meaning the difference between the diameter of the bullet , and the Inside Diameter of the neck . Finding the correct Interference Fit , or Neck Tension for your rifle is but part of the issue . Seating depth also plays a part in variations of SD. There are many ways to "set-up" a round to shoot consistently , and accurately , and many paths to get down that rabbit hole .

Personally I would try to find a velocity node , that makes small round groups at one hundred yards , and then start adjusting seating depth to make the group smaller . As Ned , and others have suggested , Varget , or 4895 are proven powders for this bullet . And you might also take a look at IMR 4064 . This powder was loaded for Decades in the Federal 168gr Gold Medal Match round , that won more than it's share of championships . Newer isn't always better . Just newer . My .02 worth .

 

[JFrank]

Thanks for the feedback everyone. Ackley, what vel do you see with that load of 8208? 6bra, I have to disagree a little. I think competitive ld shooters strive for single digit es and sd numbers. With the es of 95 fps I saw with the fed 215m, poi will vary probably 1/2 inch at 100, getting rapidly worse with distance. I haven't gotten good groups with cfe, but I also haven't seen any reliable velocity with it either. Reloading manuals say they use a magnum primer with certain ball powders like 748 and blc2, allegedly because they are denser and harder to light. I was hoping to find a primer that magically lit off cfe to produce better consistency. Instead I found nothing at all better about magnum primers. I'm baffled as to what if any difference there even is. I did determine CCI br2's were good, and I happened to recently acquire a brick of 1k, so they will become my new standard. So the next goal will be to take advantage of my new redding seating die, and play again with known accuracy powders.

I think you may have better luck changing powders, im 308 e br-2 is a pretty decent primer to build around.

 

[ScottMcc]

one last time and then no more comments
you are doing load development backwards
load for groups, fine tune for group and then look at data
this is not science in a lab. this is real world shooting.

I'm sure you know what you're talking about. The original point of my thread was to understand why I was seeing such wide spread in my cfe loads, not necessarily 'why can't I get good groups'. Was there a better primer to try? Is the powder itself flawed? Just trying to understand cfe specifically. I have 8 pounds of it, it meters well, and it delivers extra velocity. Now from my experience and other's input, I am certain cfe itself is the limitation. So I will use it for now on just for plinking and the Desomma plate range at ben avery. Thanks, scott.

 

[ScottMcc]

I did some more barrel burning experiments today with different powders this time. All 10 round groups with the same Hornady 168 ELDM at 2.850." All with BR-2 primers and lapua brass, plus one group with Lake City. I have a near infinite supply of LC 7.62 nato brass, but they have not delivered accuracy or consistency. I select by date, weight (176.0 to 177.0 gr), trim, neck turn, deburr, etc etc. Lapua has been much better, but I threw in a set of full-prepped LC anyway for comparison. I already had the varget, 8208 and 3031, and a bud at work came through with the Imr 4895. I will try H4895 as soon as I can find some. I did the same routine as before - get back on target before chambering the next round, fire quickly, cool the barrel with a neck towel, plus 4 passes with a dry bronze brush between groups. Ambient temp was 90F, light breeze at my back.

POWDER_______CHARGE______AVE
IMR3031________40.5__________2672_27_10.1
VARG LAPUA____42.5__________2655_31_9.9
VARG LC_________42.5__________2675_51_16.9
IMR4895_________41.5__________2667_44_13.3
XBR8208_________41.5__________2678_44_12.4

3031 was a nice surprise. My can is probably 25 years old, but it worked well. Lake City brass really does produce higher pressure and more velocity, but worse statistics, as I have seen in the past. 8208 produced the best group, which would have made two very good 5-round groups too. Next I will try bumping Varget up to 43.0 grains, with berger 168 vld's and hybrids, plus sierra 168 mk's and tmk's.

 

[Sniperhandle]

8208 XBR powder is excellent if you can find it right now. Are you clearing your data between your 10 shot strings?

 

[Sniperhandle]

Another powder I have had excellent results with is N140.

 

[Larryh128]

I really wonder if part of the inconsistent #s are from not brushing your case necks? Do you brush them? If not give it a try.

 

[ScottMcc]

8208 XBR powder is excellent if you can find it right now. Are you clearing your data between your 10 shot strings?

I have a labradar, so I start a new series for each group. Larry I stand the cases up in a plastic bin and spray them with dillon case lube so that some gets into the necks. I am sizing with a redding bushing die with a .335 bushing, so the expander on the decap stem just barely drags. But then I tumble after sizing long enough to get all lube out of the inside.

Does anyone have 308 loading data for AA 2495? I have a chance to buy 2 pounds.

 

[Ray123]

I have a 308 r700 with 24" 5R barrel and the HS Precision fiberglass stock, all original except for timney 2 stage trigger. Roughly 1360 rounds total. I'm loading large primer lapua brass with 168 Berger hybrids and Vld's with 46.5-47.5 grains of cfe223. By the books that is barely a starting load, yet I get well over 2800 fps on the Labradar. I have also tried Varget and 8208, but cfe223 gives me 100-150 fps more and meters a lot better. I have tried oal's from 2.800 to 2.870 with seemingly no change in accuracy or pressure. It has surprisingly long freebore, considering the twist is only 11 1/4. For case prep, I sort by weight, +- .5 grain, with a light neck turn. I decap and neck size on a rock chucker, then prime, powder, and seat on a Dillon xl750 with dillon seat die. Runout is typically 0 to .010 at the tip. For load development I weigh every charge on a dillon electronic scale.

My problem is inconsistency in the numbers. One group of 5 will show es of 14, sd of 8, then the next 5 will be something like 44 and 23. I have tried Rem 9-1/2, 9-1/2M, and Fed 210 primers. I saw identical velocities between the two rem primers, but they were both good for about 50fps more than the Fed primers.

Questions -

Would 10 shot groups be worth the effort for more reliable data? If so, how do you go about a 10 shot group to control barrel temp?

Reloading books used to recommend magnum primers with ball powders like blc2 and 748. Is cfe223 harder to light?

I have a deal pending for CCI LR Benchrest primers. I will also try Fed 215's when I can find some. How do you guys rank primers for consistent es and sd?

scott

AR 10 18" H380 47.5 gr 168 Speer match LC brass and LC primer 10 shots ave 2512 fps S/D 5.5 over 10 shots. 147 gr FMJ 48.5 2600 + fps 3.5 S/D over 5 shots with LC primed brass....H 380 meters great & very low S/D with cheap LC brass. Lower velocities than some but very consistent for long range vertical. The 10 shot group was .850 by 1.1" with a 14× scope and bad eyesight. CFE223 has a mostly produced large S/D and quite often split groups...3 shots here and 2 shots a short distance from the 3 shots, opening up a tiny 3 shot group to 1" or even 1.25" with CFE223, but it was fast and better with 155 match bullets at 3100 fps than 168 at 2900 fps...it reached 3150 fps on a hot day but accuracy was too inconsistent, from a 27" bolt gun with a match barrel.