Please help me pick a load (300 PRC)

[markd657]

I tested 3 different configurations today for my 300 PRC.
- Barrel is 30" and has bout 200 rounds before the tests.
- Lapua brass, 1x fired, annealed (Annie), trimmed, chamfered, deburred.
- Brass is cleaned by an Ultrasonic Cleaner and neck is lubed with NeoLube2.
- Powder is N565, measured by FX-120i.
- Primers are seated with K&M seating tool (with Gauge).
- All bullets are seated at jam. Berger 220 LRHT.

Group A's (in photo)
- ES/SD and groups are not good so please ignore

Group B's (in photo)
- Primers BR-2
- Neck turned down to 0.012"
- Neck tension 0.0025"
- Decent ES/SD but does not group well.
- The groups were much tighter when the neck tension was 0.0035" and neck was not turned. But ES/SD were higher as well (with virgin brass).

Group C's (in photo)
- Primers 210M
- Neck has not been turned
- Neck tension 0.0035"
- Higher ES/SD but appears to group well

Do you think I can pick a charge in B and adjust seating depth to get it to group like C? Or should I try to get ES/SD down with C?

 

[moondog]

Right, wrong, or indifferent here is my experience over 2 barrels. I've tried about every 200 grain class bullet. Mine has favored the 215s in both, jammed .010. Loose the Neolube, tried it, no bueno. Dry tumble instead of wet to leave some Carbon in the neck. Try more neck tension, like way more. found out by accident mine likes more.I'm running H-1000 right at 3000

 

[Kracken McGraw]

I pick the little tight round cluster that C is making. Then you answered your own question when you said that group B was shooting better with a no turn neck and more tension also.

 

[OmegaRed]

A trap that we've all fallen into (or keep falling into) is trying to have ED/ES numbers correlate with group. It just doesn't. Often times my best ED/ES numbers are the WORST groups in a series of testing.

Pick the load based on target (POI, size, shape) consistency over multiple groups and multiple powder charges/seating depths. It's hard to tell where your POA is on these, but if you shoot at targets in succession over a waterline, it's easier to decipher when you have a load that is spitting shots or groups. I'm assuming this isn't a hunting gun with a 30" barrel? How much more accuracy do you need than C groups?

 

[Bill K]

Pick the load that is consistent for groups and also for the first cold shot, especially if your want this as a hunting load. Then just stick to it, as you rifle is showing you that is what it likes the best.
Dont' fret and chase your tail with other factors.

 

[Doom]

The reality is that 4 shots over a chronograph will give you a good feel for your velocity but as for determining differences in standard deviation you can't really make a good comparison. As for your groups C1 is nice but it may also be misleading. What I would do is start with that and see what happens as more shot data is collected.

 

[moondog]

I will also add that if possible, you should be doing your load development at 500+ yards. It'll show up better.

 

[RegionRat]

Maybe tell us what kind/type of shooting is intended?
If this is you starting into long range or mid range matches, then we should expect to need to do a lot more testing at distance.

If we are into a hunting rig, then I would take your best guess here and go test at distance.

Notice the word "distance" shows up in both contexts. It isn't that I am trying to tell you there is no value to short range testing, there certainly is.... But there is a cost to all testing and they don't all give the same return for investment.

This rig clearly shoots well enough at short range that your next tests should be much father down the trajectory if you want to be able to read results more clearly.

Not to dissuade you from the testing you did, but it is as @Doom says, statistically not significant at these sample sizes. Just eliminate the stuff you don't like with these sorts of tests, then expect to invest in the ones you take a risk on.

When your methods and component selections agree with your rig, then you will see the MV stats improve.

In the meantime, study the targets at distance and only use the chrono for safety and feedback on the workmanship and component selection issues.

Unless you suspect your neck or case prep, or your primer seating/ignition system is to blame, then you are not closing the loop by agonizing over chrono values unless you are willing to burn a lot more money and time on alternate component testing. YMMV

 

[markd657]

Right, wrong, or indifferent here is my experience over 2 barrels. I've tried about every 200 grain class bullet. Mine has favored the 215s in both, jammed .010. Loose the Neolube, tried it, no bueno. Dry tumble instead of wet to leave some Carbon in the neck. Try more neck tension, like way more. found out by accident mine likes more.I'm running H-1000 right at 3000

Yeah I had just turned the neck so no carbon residue remained inside the neck so I had use Neolube. I did a test with my 6.5 CM a while back and shooting with carbon inside the neck improved my ES/SD about 10-15% compared to wet tumbling (with SS pins) and applying dry wax.
Regarding neck tension and ES/SD, for the N565, I tested BR-2 with both low and high. Low produced better ES/SD but worse group. I can try higher neck tension with the 210M.

 

[markd657]

A trap that we've all fallen into (or keep falling into) is trying to have ED/ES numbers correlate with group. It just doesn't. Often times my best ED/ES numbers are the WORST groups in a series of testing.

Pick the load based on target (POI, size, shape) consistency over multiple groups and multiple powder charges/seating depths. It's hard to tell where your POA is on these, but if you shoot at targets in succession over a waterline, it's easier to decipher when you have a load that is spitting shots or groups. I'm assuming this isn't a hunting gun with a 30" barrel? How much more accuracy do you need than C groups?

sorry that's not a good target. I'll upload a new one with the POA's tonight.
This is not a hunting gun and it weighs 25 lbs. I'm not competing, just learning to reload with it. I would like to see if I can get it to shoot 0.5MOA at 1000 yards. So the C groups look good for me. I am trying to see if I can reduce the ES/SD of C.

 

[markd657]

I will also add that if possible, you should be doing your load development at 500+ yards. It'll show up better.

Maybe tell us what kind/type of shooting is intended?
If this is you starting into long range or mid range matches, then we should expect to need to do a lot more testing at distance.

This rig clearly shoots well enough at short range that your next tests should be much father down the trajectory if you want to be able to read results more clearly.

I'm not competing or hunting but I would like to see how accurate I can get this rifle to shoot at 1000 yards.
But 1000 yard distance availability is limited at the moment. Maybe when BLM lands open. There's local range that I can set paper target at 400 yards that I plan to go soon. However, a load that works at 400 yards may not work at 1000 yards correct, unless ES and SD are really low?

Unless you suspect your neck or case prep, or your primer seating/ignition system is to blame, then you are not closing the loop by agonizing over chrono values unless you are willing to burn a lot more money and time on alternate component testing. YMMV

I have tried 3 different bullets, 3 different powders and 2 different primers. I still have some powder + primer combos that I have not yet tried. although I would like to see if I can get C's ES and SD down to where B's are before testing the remaining combos. I'd like to see if it's my process or there's a variable that I can adjust to lower ES/SD.

 

[moondog]

This is 600 yard load development with mine. 30" 9twist, H1000, Fed210m 215 Hybrids jammed. 007

 

[markd657]

This is 600 yard load development with mine. 30" 9twist, H1000, Fed210m 215 Hybrids jammed. 007

impressive. curious why did you choose the 215 gr and not the 220 gr?
and what ES/SD did you get in the end?

 

[moondog]

Tried the 220s, did some load development and couldn't get them to shoot inside the 215s

 

[Coyotefurharvester]

Statistics wise I don't think there is real difference between b and c es/sd, you have shots that didn't register? +,- error in the chronograph and just not alot of data. Did you need to turn brass because of neck clearance? Wouldn't comparing new brass to fired brass be meaningless if your not ever going to shoot new brass in competition/hunting and at some point all your brass will be fired multiple times?

 

[LCazador]

Yeah I had just turned the neck so no carbon residue remained inside the neck so I had use Neolube. I did a test with my 6.5 CM a while back and shooting with carbon inside the neck improved my ES/SD about 10-15% compared to wet tumbling (with SS pins) and applying dry wax.
Regarding neck tension and ES/SD, for the N565, I tested BR-2 with both low and high. Low produced better ES/SD but worse group. I can try higher neck tension with the 210M.

You turned the neck so no carbon residue remained inside the neck? Explain please. After neck turning you will need a tighter bushing so you can restore the neck tension lost by the neck turn. Do you have a bushing die and did you change bushing? If you are going to shoot at a grand you need to consider extreme spread and standard deviation as part of your load testing. In my opinion bad ES and good groups do not equate to a good 1K load. It's good ES with great groups that count!

 

[markd657]

Statistics wise I don't think there is real difference between b and c es/sd,

they could be the same. but with this barrel, I could never get 6-7 FPS SD groups in one sessions like I did with B, until I turned necks to 0.0012" and lowered the neck tension.

you have shots that didn't register?

the lab radar misbehaves sometimes.

Did you need to turn brass because of neck clearance?

I did it mainly to reduce the neck thickness variations. Also, Jack Neary said "turn them thin to win" LOL. so I don't think it would hurt.

Wouldn't comparing new brass to fired brass be meaningless if you're not ever going to shoot new brass in competition/hunting and at some point all your brass will be fired multiple times?

if you are referring to my "virgin brass" note. that's to indicate that the higher ES/SD found with virgin brass could have caused by deviations in the brass (lengths, shoulder lengths, etc) and might not be solely due to the higher neck tension.

 

[markd657]

You turned the neck so no carbon residue remained inside the neck? Explain please.

I only turned the outside of the necks. But I don't see anyone using dry lube or left over carbon to turn neck so I ultrasonic cleaned the brass (and all carbon is gone) then used Imperial Sizing Die Wax to do it.

After neck turning you will need a tighter bushing so you can restore the neck tension lost by the neck turn. Do you have a bushing die and did you change bushing?

yes I changed bushings to account for the new neck thickness. I have various sizes from 0.329 to 0.335.

If you are going to shoot at a grand you need to consider extreme spread and standard deviation as part of your load testing. In my opinion bad ES and good groups do not equate to a good 1K load. It's good ES with great groups that count!

absolutely.

 

[LCazador]

So with all that said, you need to look for a powder that will give you good ES with good groups. Then I would work on great groups with that powder. Neck tension and seating depth should come into play solely as a refinement of that load work. For 1K work I'd be testing at 300-500 yards minimum if that what your shooting range dictates. This testing should include wind flags and a wind meter. Your final testing should be at 1K of course. By the way I still didn't get your explanation of your neck turning eliminating carbon inside the neck. Brush necks before you neck turn that's all that's needed . Use die wax for turning necks and fireform after neck turning.

 

[markd657]

So with all that said, you need to look for a powder that will give you good ES with good groups. Then I would work on great groups with that powder. Neck tension and seating depth should come into play solely as a refinement of that load work. For 1K work I'd be testing at 300-500 yards minimum if that what your shooting range dictates. This testing should include wind flags and a wind meter. Your final testing should be at 1K of course. By the way I still didn't get your explanation of your neck turning eliminating carbon inside the neck. Brush necks before you neck turn that's all that's needed . Use die wax for turning necks and fireform after neck turning.

What I meant was that I used the Ultrasonic Cleaner to clean the carbon before turning the necks while loading for that last range session. As I now know, I didn't have to wash the carbon off. I only needed to brush the inside.

Regarding powders, I have tried the following combinations for this barrel. Most of these were done while fire-forming the brass:

1. N565 + BR-2 + 220 gr LRHT (lowest ES/SD but groups are not great)
2. N565 + BR-2 + 215 gr HT (good groups but consistently high ES/SD)
3. N565 + 210M + 200 gr LRHT (best groups but not so great ES/SD at high NT - haven't tried low NT)
3. H1000 + BR-2 + 220 gr LRHT (good groups but higher ES/SD than 1 at both low and high NT)
4. N570 + BR-2 + 245 gr LRHT (a lot of vertical strings)

How do you try different powders? Do you try them with all bullet + primer combinations or do you pick what you think is the best bullet and primer and try them with each powder?