Rifle load development methods compared

[MCMXI]

Touching looks good. I get a lot of internet advice saying not to load at touch. Either in or out but not touch. I don’t necessarily subscribe to that but I understand the logic, particularly when you’re shooting long strings in a competitive format. The throat is changing.

Having said that, my .308 shoots its smallest at touch so that’s where I load them.

Have you done a primer test? If not, I’d take that load at touch and shoot some with different primers

I can see the logic of not trying to load at touch since if I can control +/- .001" for the COAL then I might be into the lands or off the lands or touching. Your comment about the throat changing as it heats up makes sense too. It seems intuitive to me that there would be less difference in case pressure and other variables at -.010" +/- .001" rather than .000" +/- .001" but intuition is often wrong. I'm going to repeat the test and then do a primer test after that. I'm still not getting consistently good/low ES numbers with new brass. I'm neck sizing the brass and deburring inside and out using the RCBS Trim Pro with a 3-way head. Powder is being weighed to the nearest .02gr but I'm not weighing bullets or brass. Perhaps a different primer will tighten things up.

 

[Varminterror]

The jump should increase as the barrel heats - in two directions. The bore gets larger and the shank gets longer as the metal expands, so jump gets (only a ridiculously small bit) longer.

I have also suspected that the “be off or in, but don’t kiss” is more about variability than any particular science. Ogives vary, seating depth varies slightly, heck, even some powder or carbon build up could hang on the lands. So being “in or out” would mean your load is developed to be “in or out,” so it wouldn’t take a pressure spike if ONE bullet were a little long, or take a dump if one were a little short.

 

[MCMXI]

More bullet seating data from this morning. I think I'm going to stick with .005" off the lands and do a primer test next as @Nature Boy has suggested. I'm not confident that I can control the COAL well enough to guarantee 0.000" jump but I feel that a COAL of +/- .001" is possible so I have more confidence being fully into or off the lands, but this bullet seems to shoot better with a bit of jump. I neck size the new brass and deburr prior to loading, but this time I only sized half the length of the neck since the bullet bearing surface doesn't need the entire neck. I can't say that it made much difference though. I'm more confident in the results from the last three groups compared to the first three. I need to shoot this rifle more but the AW trigger that I swapped in works way better.

I was pleased to see yet again that the clean/cold bore shift is basically non-existent with this rifle just like my other Accuracy International rifles. I had two Krieger barreled rifles and they were the same too. The barrel was quite hot for the last group but velocity and POI didn't change.

 

[Nature Boy]

0.005” off looks real good. Nice shooting

 

[MCMXI]

@Nature Boy, thanks. I'm using an Atlas bipod up front and a folded piece of leather at the rear and shooting off a bench for these tests. I can't say for sure if the outliers for the two right hand targets are shooter error or load related, or some combination of both.

I have the following primers on hand to test and will put some loads together this afternoon. There are so many things I should be doing instead.

CCI 450
CCI 400
CCI BR4
FED GM205M
FED GM205MAR

I also have some Winchester SRP but I'm not going to bother with those.

 

[Nature Boy]

I’m at the range too. My daughter told me after the match last week that the bolt was sticking intermittently on ejection so I took the left over rounds and shot them. Sure enough, about 30% took a rap with the palm at the top of the throw to break them loose.

Chrono says my average FPS has increased 42fps from the last time I clocked them. I did recently change powder lots so that’s my only theory.

Looks like I’ll be running another load test on ‘ol faithful

 

[Varminterror]

How do you guys prefer your primer tests?

I usually almost fully start over when I change primers, doing another Ladder/OCW/Velocity test whenever I switch primers. A little expedited in design, so more of a “rolling start” instead of a “standing start” to the load development, but I certainly don’t consider a primer switch to be independent.

But I do go back and forth.

Usually I don’t see significant change with a simple primer swap, but I’ve seen enough change occasionally that I’m not brave enough to consider it a drop in fit. In my match rifle last season, I started with WLR’s, but then switched to CCI BR2’s at about 600rnds. I gained about 20fps with equivalent loads, my ES/SD shrank slightly in the node, and my node shifted about .5grn. Woulda been a bad deal on match day if I hadn’t ran another round of tests.

 

[Varminterror]

Btw - I’m living a vicariously through you guys today. I was supposed to be shooting today to practice for a match next weekend, which is a single day practice match for a bigger 2 day match in 2wks...

Unfortunately, I brought something home from Mexico with me, and I’ve been “voiding” it by all means possible for the last ~50hrs. Down 9lbs, despite a focused effort to replace fluids. 100-102 fever, chills, sweats, headache, shortness of breath, dizziness, body pain, all the fun stuff...

On the upside, my wife said my fever delirium Friday night was entertaining, apparently I thought someone was chasing us and I didn’t know where she was leading me, so I kept asking, every few seconds, in a panic, where are we going? What time is it? Why are they after us? Went on like that for 2hrs she said, and I’d jump out of bed every time she touched me.

So yeah... I’d rather be on a firing line somewhere, so I wish you good shooting, fellas!

#dontdrinkthewater

 

[MCMXI]

How do you guys prefer your primer tests?

@Varminterror, sorry to hear that you got a bug in your system and hope that you make a speedy recovery.

I'm simply copying @Nature Boy with his approach. I've got 25 rounds loaded up with 38.0gr of Varget, COAL of 2.763" (2.108"_bc) and the five primer types listed above. I'm hoping that they all shoot well, or at the very least see some clear trends. Of course the wind is howling now so I won't be shooting today unless the winds drops significantly. I'm probably looking for small differences and don't need to be worried about other variables that might affect the results.

 

[MCMXI]

Chrono says my average FPS has increased 42fps from the last time I clocked them. I did recently change powder lots so that’s my only theory.

Yep, that seems like a good assumption. What's the change as a % of your original velocity? Sometimes it seems that there's no end to this. Even when a great load is developed, and you seem to have certainly done that, there's always a bit more tweaking. I noticed in an email last week from MSHA that they have 24" and 26" 6BR barrels for my AX in stock. I was tempted for a few moments but then I came to my senses and realized that I have so many rifles to work up loads for and I don't need to add to more complexity.

 

[Nature Boy]

Yep, that seems like a good assumption. What's the change as a % of your original velocity? Sometimes it seems that there's no end to this. Even when a great load is developed, and you seem to have certainly done that, there's always a bit more tweaking. I noticed in an email last week from MSHA that they have 24" and 26" 6BR barrels for my AX in stock. I was tempted for a few moments but then I came to my senses and realized that I have so many rifles to work up loads for and I don't need to add to more complexity.

About a 2% increase.

I’ve seen others say that when they get a new barrel they buy enough powder and bullets of the same lot to cover the life expectancy of the barrel. I just can’t see myself doing that

 

[Varminterror]

I’ve seen others say that when they get a new barrel they buy enough powder and bullets of the same lot to cover the life expectancy of the barrel. I just can’t see myself doing that

It’s a lot easier to do so when you’re shooting a short barrel life cartridge. Stocking up on enough components to kill a 308win costs a lot more than a 6 Creed, for example.

I took this pic last year before I started into that barrel. I only got 1471rnds on it, didn’t even make it through all of the Bergers. Only fired about 60 of the ELD-M’s in that barrel. Also ended up using Hornady brass in deference to the fact Lapua announced 6 creed brass - but couldn’t find any all season - but I did use 500pc of Hornady to kill that barrel (and correspondingly changed to BR2’s instead of the pictured 400’s). But other than a few tinkering sessions with the ELD’s, it was one lot of bullets, one lot of powder, one lot of primers, and one lot of brass killed that barrel.

I wish I would have done the same again for this barrel. I suppose I still can, although it’ll be less exciting since the brass is no longer boxed, and one of the big boxes of Berger’s is already empty.

 

[Nature Boy]

How do you guys prefer your primer tests?

I usually almost fully start over when I change primers, doing another Ladder/OCW/Velocity test whenever I switch primers. A little expedited in design, so more of a “rolling start” instead of a “standing start” to the load development, but I certainly don’t consider a primer switch to be independent.

But I do go back and forth.

Usually I don’t see significant change with a simple primer swap, but I’ve seen enough change occasionally that I’m not brave enough to consider it a drop in fit. In my match rifle last season, I started with WLR’s, but then switched to CCI BR2’s at about 600rnds. I gained about 20fps with equivalent loads, my ES/SD shrank slightly in the node, and my node shifted about .5grn. Woulda been a bad deal on match day if I hadn’t ran another round of tests.

The sequence is worth a discussion. I've heard some long range bench rest guys say they do the seating depth test first. I don't know what's best. I'm just trying to isolate the variables.

BTW, feeling better today?

 

[Varminterror]

BTW, feeling better today?

Thanks for asking. Much, much better today. Still down 8lbs and feeling weak, so not “normal,” but my fever’s been gone since yesterday evening, and I seem to be back in control of my own destiny again. I suppose if I have to be sick, then I prefer “hard and fast” over “light and lingering,” but it was a rough ~60hrs.

Re: primers - I worry too much that the “charge optimization work” done towards one powder & primer combination won’t be optimized for the next primer, so I do another ladder/OCW/velocity curve when I change primers, but usually smaller span, and focused around where I expect one or two nodes to fall. Naturally, part of that is the nature of how I shoot. 100yrd targets can lie about 1000yrd groups, so I’d rather have a .4moa load with 4fps SD than a .2moa load with 20fps SD. 100yrd BR shooters would be foolish to follow that logic.

 

[MCMXI]

@Nature Boy, I completed a primer test this morning under near perfect conditions. I think I'm looking for difference that are beyond my abilities as a shooter to show. The Federal primers produced the two smallest 5-shot groups but I have the feeling that I'd get different results every time I ran this test simply due to the shooter. I did notice that the first shot of every group was the fastest. For example, the Federal GM205MAR group had the following velocities: 2842 fps, 2822 fps, 2822 fps, 2814 fps and 2817 fps. The ES would have been 8 fps if not for that first shot. I think the SilencerCo Omega 300 has an issue since I saw similar results with the 6.5 PRC fiasco.

All primers looked good, no pressure signs with heavy bolt lift, no pierced primers etc. I had no preconceptions with this test other than expecting the CCI 450 primers to shoot better after yesterday's results. Oh, and expecting the BR4s to be better than they were. The funny thing though is that there are no losers in the test with the worst group being 0.548 moa! The differences could easily be due to differences in neck tension, bullet weight, case capacity, etc.

Anyway, what are your thoughts on the test?

 

[Nature Boy]

CCI 450 and the Fed 205M had no vertical shape to them. I’d say those are the two that will work the best.

 

[Nature Boy]

100yrd targets can lie about 1000yrd groups,

That’s the reason for my posting this thread.

There are guys that do load development at 1,000 yards because that’s where they compete. There are others that also compete at 1,000 yards that say you can develop a load at 100 that works at all distances.

My point is that whatever you do at 100 needs to be validated at the distance you compete at. For me it’s mostly 600. The fella that I got this method from shoots at 1,000.

Glad you are feeling better. I could tell you some similar tales. One involved turtle soup, the other was chicken sushi in Tokyo. I’ll spare you and anyone else the gory details

 

[MCMXI]

My point is that whatever you do at 100 needs to be validated at the distance you compete at.

I'm going to load 10 each with the CCI 450 and Fed GM205M primers and shoot at 400 yards and 700 yards to see how they do.

 

[MCMXI]

It would be interesting to compare our "known" good loads to the Optimal Barrel Time theory proposed by Chris Long. I've tried his approach a number of times with only one successful load coming out of it. I find his anecdote below so ridiculous that I have a hard time taking anything else he says seriously. He can move a 3" diameter guy wire enough to see a wave travel along it ... whatever!

"I remembered one visit to a very tall TV tower in central Maine many years ago. I was killing time waiting for some event to happen (I don’t remember what) and was playing with some truly immense guy wires keeping the 1400-foot tower up in the clouds. These wires were about 3 inches in diameter, and were at least 1000 feet long, and under tremendous tension. I remember grabbing the wire near the dead man anchor, and giving it a shake as hard as possible. I watched the s-shaped wave disappear into the overcast, only to appear a few seconds later, hit the anchor point, can go back into the clouds, and so on until it died out. I played with this like a 2 year old for quite a few minutes."

For the record, the 38.0gr load above is nowhere near one of the nodes described by Chris Long's method.

24" barrel nodes: 0.8160 ms, 0.8948 ms, 1.0221 ms, 1.1016 ms, 1.2282 ms, 1.3084 ms, 1.4343 ms.

The load above has a barrel time of 1.151 ms according to QuickLOAD after I've adjusted the powder Ba value to match actual barrel velocity. Charge weights that match the nodes for the given COAL are 36.1gr (1.229 ms) and 39.3gr (1.101 ms). 36.1gr only produces 54ksi, and 39.3gr produces 70ksi. The accuracy node I found appears to be just about in the middle of the nodes predicted by the OBT method.

 

[Varminterror]

Yeah, travel enough and you’ll run into it. I got hit by (I suspect) oysters in New Orleans about 6 years ago so badly that I had to get IV fluids, and couldn’t fly home for an extra 4 days. Thankfully this one wasn’t so bad.

To your point of “developing a load at 100yrds which works at all ranges,” and only doing limited long range “validation/confirmation,” it might go without saying, different disciplines might start at the same place, but might end very differently. For example - precision rifle games never measure anything, only impacts. So if I find a 1/4moa “ish” load at 100yrds with a low ES, and it’s still “ish” at 600-1000, I check the box and go home. Maybe I tweak seating depth, maybe not - just depends on my group shape. That wasn’t my experience in 600/1000 BR, where I felt like I was in a black hole of load development, from which there was no escape.

I’ve been surprised, a bit, to see how similar are our load work-up methods (in principle, if not exact process), based on your recent posts. But I do expect we start down the same road, then I find some satisfactory early result and stop churning and start burning, while I expect your needs for F-class likely burden your process to further refinement than what we have for precision rifle games.

Maybe I’m wrong about that? But as an example, I didn’t do any seating depth tests this season, and other than 9 shots on ONE stage I can’t reconcile, every miss has been mine at 6 matches so far, out to 1000, and the 100yrd results are posted above. Maybe it’s cheating to have experience with the bullet already, but all I did was buy a new lot of H4350, BR2’s, and Hornady brass, seat them 6thou off, and charge weight test first via 100yrd velocity and OCW, then confirm with 600yrd ladder. Done. It’s a big load off of my mind to have that luxury, instead of chasing tiny groups and perfectly center mass impacts. Frustrating to balance a 22lb rifle in an 8” PVC pipe union suspended by ropes, but not frustrating to do the load work.

 

[Walkalong]

100yrd targets can lie about 1000yrd groups, so I’d rather have a .4moa load with 4fps SD than a .2moa load with 20fps SD. 100yrd BR shooters would be foolish to follow that logic.

I would have to agree.

 

[Nature Boy]

I’ve been surprised, a bit, to see how similar are our load work-up methods (in principle, if not exact process), based on your recent posts. But I do expect we start down the same road, then I find some satisfactory early result and stop churning and start burning, while I expect your needs for F-class likely burden your process to further refinement than what we have for precision rifle games.

Satisfactory to me is when I feel like I’m not leaving any accuracy on the table, but there are limits.

I don’t weigh primers. I don’t turn necks. I don’t measure BTO on bullets. I’m not buying custom bullets. I’m also not checking concentricity anymore.

I was able to clean an entire match last weekend and not do any of the above.

The load work I’m doing has paid off but that’s only part of it. I packed more sand in the ears of my rear bag. That was huge. I’m also becoming a better wind reader. That’s even bigger.

 

[Walkalong]

I’m also becoming a better wind reader. That’s even bigger.

Absolutely!

 

[JFrank]

Here’s a lesson in mirage reading,
My HG 1000 yard target from last weekend at Deep Creek MT.
My target puller( pit crew) says I was on a roll until the sun came out then shots started hitting lower and lower

 

[JFrank]

Here’s the same in reverse “ E Gads