Reloading 6.5 Creedmoor

ToolAA said:

Need quick opinion on determining upper pressure limit. From what I've read one sign of overpressure is flattened primers. When I examined my fired cases at the highest charge I see only a slight flattening. I'm thinking ok I've got room to go up. Good. Then I compared my fired reloads to an unfired factory round and a fired factory round and I was surprised that all of the factory rounds look totally flattened and expanded into the chamfer of the primer pocket.

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From left to right:
1) Unfired factory round
2) Fired reload at my lowest test charge
3) Fired reload at my highest charge
4) Fired factory round

So this has me wondering two things obviously 10 factory rounds cannot be near the pressure max. Is using primer flattening even reliable? Second thing is that my hand loads were only neck sized so they were snug in the breech. Is it possible that being snug the primers just done push out like they may in a factory round which has a bit more play?

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I think your loads are fine so far and you have some room to experiment with a few more powder increments.

Two things will flatten primers:

One is excessive headspace, which will cause primers to take on a flattened appearance. The case is driven forward in the chamber by the firing pin until it hits the chamber shoulder, then the primer initiates. When the primer fires, pressure within the primer pocket backs it out of the case a distance equal to headspace. As the powder ignites and builds to working pressure, the primer begins to expand and 'balloon out' where unsupported by the primer pocket, but then the case head is driven back down against the bolt face, causing the expanded primer to flatten out and occupy the radius relief area at the outer edge of the primer pocket. This can look like high pressure, but really isn't. One clue is that if pressure were really this high, the primer indent is usually cratered too, but in the case of excessive headspace, it will be smooth and round.

The other thing that will flatten primers is high pressure, where the limit of elasticity of the primer cup material is exceeded and the cup deforms to fit all available expansion space. Pressure flattening will run from "mild", where the radius edges of the primer start to square up, to "moderate", where most free space is occupied and the radius edges are pretty much square to "severe", where the tool marks on the bolt face are impressed into the primer cup material and the cut begins to "crater" (extrude) back into the firing pin bore.

Cratering begins with lightly raised edges and becomes more apparent and sharper, until the yield strength of the cup is reached and "blanking" occurs, in which the small round firing pin indent is blown back into the firing pin bore and into the bolt body, leave a perforated primer cup.

I'd characterize your fired factory load primer as between moderate and severe, favoring moderate, as evidenced by the radius edges of the primer almost filling the crevice and the moderate cratering, but no impressions from the bolt face.

Yes, factory ammo is usually loaded on the hot side. As I had mentioned above, most consistent performance often comes at just below maximum, and another compelling reason is that the marketing department sets the bullsh!t bar pretty high and if they expect it to deliver what they say it will, it has to be loaded to maximum.

Accuracy with factory ammo is typically evaluated at 100 yards, and this is also where about 90% of it is fired. As long as we deliver velocities similar to what is marketed and groups are decent at 100 yards, most shooters are happy and done.

Federal is one ammo maker that seems to have broken the code, and it is pretty clear that they use the OCW method in loading their .223 and .308 match ammo. Federal Gold Medal .308s in 168 are typically so precise at 100 yards in so many rifles, if your rifle won't shoot them, there is probably something wrong with the rifle.

Wow! talk about digging down to the deeper levels. We certainly are fortunate to have you on this forum Ed.

Those should be sticky.

PowPow said:

Those should be sticky.

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Agreed. I started reading Ed's response and realized if I kept on going I would be late for work.

To take a complex subject like that and explain the technical nuances in an easy to understand way is valuable. The analogy of how a circular saw oscillates while cutting and how bores are machined made perfect sense.

More homework for tonight. Except this is homework I'll be looking forward to reading.

Found some H4350

I found some H4350 1 lb cans. Shipping and Hazmat make it expensive. But, there was no limit to how much you can order.

https://reloadingunlimited.com/product/hodgdon-h4350/

Alternatively, Reloader 16 is supposed to be the new hotness.

Well I got a chance to get back to the range and test some higher power loads. I was able to get 44 gr of powder compacted into the case. Those loads showed some primer compression and a very slight bolt face impression on the head so thats the max but it was not severe. I was pushing 2750fps but accuracy was crap.

I compared a sample of loads previously tested at 28° temp against loads tested at 50° temps and all differed about 30fps. Seems like a lot about 1.5fps per degree but I am going to try and find some data to compare other similar burn rate powders.

I did have two unusual groups that I could use some help deciphering.

Here are two groups where the first two shots looked like I had found a great node/load combination but then the next two shots were off considerably but were within 1/4 moa of each other.

Group A 42.8g

Load data velocity is the column far right


Group C 43.6g

Again velocity column far right


I was extremely careful and patient while shooting. Making sure I was lined up exactly on the diamond. Letting the trigger break on it's own. There was no significant wind and I fired all shots round robin. Also was very careful controlling the powder charge removing or adding single grains to get my balance scale exactly in the middle. I would guess i was able to hold a tolerance of +/- 0.05 g or better.

The only thing I can think if is that maybe the chamber was getting hotter as I was testing. This seems more likely on group A but I had fired 5 shots before even getting to the first A group shot and that theory doesn't seem to correlate to group C where the StdDev was 7.

For now, Im going to settle on 44.5 grains this should give me about 2650 fps at 65° temps. The two test loads on either side of this test also had pretty good groups less than 0.6 Minutes. So Im thinking i've found a decent accuracy band.

If I can make sense of the group A pattern I may test it again.

ToolAA said:

....I did have two unusual groups that I could use some help deciphering....

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I seriously doubt these groups are a product of the load.

The vertical spread is almost certainly a handling problem, and could be due to improperly adjusting your parallax. If you think of your scope's parallax adjustment as a "focus", you're probably not tuning out all of your parallax.

Disregard any range markings on the parallax turret, they are seldom correct. If your parallax adjustment isn't correct, you will see your crosshair move against the target as you move your eye behind the scope. Every time you settle down on the gun, you head must come back to exactly the same spot, or a parallax error will cause you to think your crosshair is not where it really is, so you move the rifle to fix it and the bullet moves out of the group.

Usually when we see two distinct group centers like this, I'll find a parallax adjustment error in the shooter's scope. Because they are almost perfectly stacked in a vertical direction, I suspect your stock doesn't support your head in a consistent position. The other thing about improperly adjusted parallax is that you'll get a few good groups, then some bad ones, then come good ones as you just happen to put your head back in the same place, or not.

Another possibility is your shoulder pressure and/or rear rest, although that usually strings them up and down to varying degree, which is what leads me to looking for a parallax error. You will also see splits like this when your bipod is loose on the swivel stud.

E.Shell said:

If you think of your scope's parallax adjustment as a "focus", you're probably not tuning out all of your parallax.



Disregard any range markings on the parallax turret, they are seldom correct.

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Yup that is exactly how i thought the parallax adjustment worked. It makes sense now that you explain it.

It's also good news in that I maybe both of those groups would have been extremely tight and that means my accuracy band is perhaps even a little wider than I first assumed.

Thanks again.

Today I got a chance to test again. I adjusted bullet seat depth to see if it had any impact on group size.

First thanks for the pointers Ed. I really focused on keeping a very consistent cheek weld. I cant say I was perfect but it seems like I had much tighter groups today all around. Even while warming up the cold barrel with a few factory rounds and with 15mph winds.

However I think I may be at the limit of my skill level with respect to holding the rifle steady, while testing. I had three separate pairs of shots which were almost through the same hole, maybe off by half the bullet diameter at most then the next shot would be about 0.4" away.

Best group seemed to be -0.040 from the lands.

Shot 4 may have been off related to my shooting skill or maybe not. Either way thats the recipe I'm going with for now 42.6g of A4350. with 0.040 jump. Over 20 shots today the mean velocity was 2660 with an SD of 15.6

Time to start making rounds for class.

Glad your getting it all worked out, it is a long process but the rewards are aweome.

Help with first attempt at OCW

So I finally got a chance to test some of my reloads at 100 yards at the AGC.
Temperature 69 degrees.
Shooting a Savage 10 FCP-CR 24 inch barrel with a Vortex Viper PST FFP scope.

Bullets are Hornady 140 gr BTHP, Primers at CCI BR-2, Powder H4350, and the brass is once fired Prime.
My scope was zeroed a little low so my groups are a little high.
I believe I have a node around 42.9 gr (avg velocity 2782, SD 16), a scatter group around 43.5 gr (avg vel 2867, SD 3).
No signs of over pressure.

So questions:
1) Should I look for a higher node above 44.1 gr? All of the tables say less than 42 gr for maximum safe loads.

2) Should I just fine tune the load around 42.9 gr?

3) Am I wrong to be running loads higher than Hogdon's and Hornady's recommended loads?

dbledoc said:

So I finally got a chance to test some of my reloads at 100 yards at the AGC.

Temperature 69 degrees.

Shooting a Savage 10 FCP-CR 24 inch barrel with a Vortex Viper PST FFP scope.



Bullets are Hornady 140 gr BTHP, Primers at CCI BR-2, Powder H4350, and the brass is once fired Prime.

My scope was zeroed a little low so my groups are a little high.

I believe I have a node around 42.9 gr (avg velocity 2782, SD 16), a scatter group around 43.5 gr (avg vel 2867, SD 3).

No signs of over pressure.



So questions:

1) Should I look for a higher node above 44.1 gr? All of the tables say less than 42 gr for maximum safe loads.



2) Should I just fine tune the load around 42.9 gr?



3) Am I wrong to be running loads higher than Hogdon's and Hornady's recommended loads?

Click to expand...

Im no Ed but based on his responses to me it seems that The main emphasis is on consistency in velocity. However your velocity numbers look good and inline with what Ive read from Siper's Hide.

I haven't seen too many people load above 43.5 grains of H4350 with a 140 grain bullet. Not to say you can't, but running 2900 fps out of a Creedmoor cartridge seems to be pushing it; especially in a 24" barrel. I run the Hornady 140 as well with 43.1 grains of H4350, federal primers and nosler brass. It comes in at 2830. Good luck with your endeavor.

Any particular reason not to use VV N-150?

I just got a Savage Axis in 6.5 Creedmoor and will be reloading soon. This is some good info, but I'm going to have to re-read it a couple times to absorb as much as possible before I start.

CapoGreg said:

I just got a Savage Axis in 6.5 Creedmoor and will be reloading soon. This is some good info, but I'm going to have to re-read it a couple times to absorb as much as possible before I start.

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Ive got and Axis II in 6.5 it's a great light and accurate hunting rifle.

Need some help with Ballistics Truing.

Last weekend during Ed's class I got to really see my hand loads in action. Truth be told they performed OK. I was probably operating at the limits of my rifle skills, which was the main reason for attending the class. Shooting from 100 yd zero out to 460, 555, 600, 700, 737, 800, 880, 1010, 1140 and 1203 yards gave me some really valuable load data. However something's been bothering me for a week because I still don't understand how the actual shooting data doesn't match the ballistics software projections.

After we shot all targets we compared the projected scope elevation adjustments with the actual elevation adjustment required to hit the target. In my case the required adjustment increased from .3 mrad to .5 mrad as we moved out to max distance. Seeing the data, Ed suggested that the velocity setting in the software may be incorrect. So I reduced it by about 2% and the curve then matched very tightly to the recorded elevation adjustments.

Ok so my velocity was incorrect. Problem solved. However Ed whipped out his fancy Doppler radar chronograph and we all tested 3 more rounds. My data was 2707fps which was actually slightly faster than the 2690 value I had been using. So the variable causing the difference could not have been velocity.

Yesterday I went back out and shot some more at 200 yds. I had my own Chrono. 25 rounds had a MV of 2737 with an SD of 19. Considering it was 85° yesterday that seems to match closely with the Doppler Radar data from last week. So the velocity is correct.

I had recorded the weather conditions last week when we zeroed and when shooting. So cross that variable off. Scope height was correct too.

Yesterday I tested to see if the graduations of my scope were accurate. At 200 yds 1mrad should translate to 7.2" if target impact elevation. For 18 rounds it was spot on. Varying +/- .2" between groups but at 5mrad my shots were exactly 36" high which is perfect. So cross scope calibration off the list.

Now I'm left with adjusting the Ballistic Coefficient. I dropped it down about 3% and I get a curve that again matches the shot data. Here is the problem. I wasn't using the manufacturers number. Bryan Litz publishes a well respected list of actual tested ballistics G7 data. The exact bullet I'm using Nosler .264 Custom Competition 140 gr is one that he has tested so in theory I should have been using the most Accurate ballistic coefficient number out there.

This leads me to my final questions:

1) Is there any other variable that I should be looking at that could account for the differences I was observing?

2) Is it reasonable to assume that actual production bullets can have varying coefficients.

3) If no other variables can be found incorrect is it OK to simply adjust BC until the curve matches my data?

By the way I'm not obsessing over this. I have learned so much in the past few months. It's very been rewarding for me, so my goal is really to continue on this educational journey.

Got some Nosler 140g RDF's and had my first chance to test them out at the range today. Generally pleased with the results at 100yds. Hopefully I get a chance to test at 500yds next week.







I'm using the exact same load as I was using with the 140g custom competition but the RDF's are firing about 40fps slower.

So this happened today. Got some 147 eld-m to try. Threw some H4350 behind them and headed to the range. This five shot group was shot at 200 yards. The “flier” pushed the group out to a shade under 1/2 moa. The exact load was 42.5 grains with an OAL of 2.830”.