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.308? What do you load?

Mudflap621 said:
Surely, because a single 3 shot group is a respectable statistical representation.

Have you ever tried to reproduce an OCW test? What about try shooting it with more than 3 shot groups, 30-shot groups would surely up the statistical proof. Seems like every time ive seen it tried it comes up unrepeatable.

Take Lou Murdica for example. If you have never heard of him id suggest doing a little research as he is pretty well versed in ballistics. Lou has some of the most state of the art equipment and has done alot of testing for bullet manufacturers. He tests with rail guns in a tunnel which leads him to eliminate almost all outside influences. Ill attach a few of his findings here.

"Well, here's what I got today. I've got some more work I'd like to do and I'll see if I can get the Excel sheet uploaded here-- if nothing else I'll try to get it in a google doc or something.

Each dot represents a 5 round group MPOI (Scale is inches at 200yd). Each color represents a charge weight. I will be further breaking these into subsets of 1st, 2nd, 3rd, 4th, 5th, and 6th group of each charge weight. I'm about half way through that and I'll spoil it for you-- they don't repeat. These are less messy to look at, too.

This data set has the most resolution, but the gun was moved between some of the sets, so each set of 35 is referenced off of its own MPOI. Some 'global' position could be lost, but in my experience with other powder ladders, even over 3-4gr spreads the MPOI of the large data sets is within about a .08 MOA window in the worst cases.

Nevertheless, if you look at this below, you'll see 5 shot group MPOI of the same ammo varies in a .35ish MOA window... so even if my 'global' 35 shot group is .04 or .06 or .08 MOA in error, it's completely swallowed up by the randomness of 5 shot samples-- which has been my point all along. There are not many viable conclusions to draw from 5-shot groups, and the difference in dispersion performance or MPOI between two varied powder charges is not among them. These patterns repeat over and over. Noisy data until 15-30 rounds in... It's the same thing you learn in probability and statistics, it's the same rule of thumbs that every statistical process control/analysis people use... Somehow people think shooting is different I guess?
OCW.JPG



Sorry if I'm short, but I've had this play out already. I started with shoulder fired rifles & contoured barrels with me aiming them and had people claim I wasn't steady enough to have valid data. I switched to an accuracy fixture and 1.25" barrels and get told that it's too rigid to show OCW results. My data came to the same conclusion both ways... I've burned out barrels doing this and have people tell me I'm wrong with no supporting data, or refute large sample data with more small sample data. It gets old."

I’d also be interested in seeing more proof that SD and ES mean nothing. Im not the most versed on physics or ballistics but im pretty confident that a projectile with a large velocity spread will not be consistent at 1000 yards. IMO these numbers are some of the best representations of consistency. If you want accuracy you need consistency and the most effective and most reliable test is velocity testing. It eliminates a lot of variables that are present in POI testing.

BTW I'm not trying to say that harmonics are non-existent all im saying is that looking for POI shifts at 100 yards with an OCW test doesn't seam to be the best way and has been found to be unrepeatable.
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A good node for a load should be insensitive enough for a minor - up to a .3gr at least deviation in powder drop amount. It will be perfectly visible in a 10 rd group.

I played enough with that for now and a way going with 5 rd groups initially to find best spots and a subsequent 10rd batch loaded groups was the fastest way to proceed.
 
That post wasn't directed towards you and my point in the post was to bring light to that there are so many variables at play when trying to look for POI shifts and its inconsistency. The idea of the OCW is correct but the way of finding that node is flawed. IMO these nodes we seek seem to be directly linked to velocity sd and es. Historically my most consistent loads and groups always come from the loads with the most consistent sd and es. I think that for someone to state that velocity and its sd and es to have no affect on accuracy is incorrect.

I agree a good node should be forgiving and hopefully tolerant of a powder variation but that deviation isn't always shown at 100 yards and will most certainly grow with distance. This is another reason everyone strives for the low SD and ES as it shows a more consistent load.

If im shooting at 100 yards I can load up a 2 gr swing and keep same POI and roughly 3/4" MOA over roughly 25 shots. That's why, like Ive stated before, I really don't put alot of faith into using POI method. Now with that 2 grain charge difference I saw a roughly 170FPS difference in velocity. That is definitely not acceptable at distance although it will print decent groups at 100 yards.

You obviously do alot of testing and I enjoy going through your research. If your enjoying it and having fun and gathering data than that's awesome keep it up.
 
My input here.

My best reload was 180gr Barnes TTSX with 44.0gr of Reloader 15. Loaded mag length for M1A.

I could shoot 4" groups at 300 from a stock Savage 10FP when I was much less skilled at shooting than I am now.

If I was building a load for a stock bolt gun with no mods to specifically shoot only at 300 or under, I would do an OCW in 0.3gr increments starting .020" off the lands with 5 rds of each.

From that I would pick the charges that produced the smallest two groups and the smallest SD group.

I would then load two batches of ammo. One using the avg charge of the best group loads (i.e. if your small group loads are 44.5 and 44.8, load to 44.65). The second using the low SD charge. In both groups I would create 3rd lots varying the OAL by .003". Three lots longer (approaching the lands) and 3 groups shorter.

Shoot those and from there pick the best one, and load that until you shoot the barrel out. Hours behind the gun are what matter most.

Chasing SD for 300yds or less will likely not give the optimal result. The reason professional shooter like Eric Cortina chase SD is the long range makes the results better and they are going to use a tuner to tighten the load after OCW and OAL testing. This is a completely different animal from taking a stock gun and having fun a 300 pushing your own abilities.

Note I am not a long range shooter. I've only ever shoot to 600 and that is on AR platform 18" barrel battle rifles, not purpose built long range guns. I do however have the ability to load 308 and have a YouTube subscription :)
 
Mudflap621 said:
That post wasn't directed towards you and my point in the post was to bring light to that there are so many variables at play when trying to look for POI shifts and its inconsistency. The idea of the OCW is correct but the way of finding that node is flawed. IMO these nodes we seek seem to be directly linked to velocity sd and es. Historically my most consistent loads and groups always come from the loads with the most consistent sd and es. I think that for someone to state that velocity and its sd and es to have no affect on accuracy is incorrect.

I agree a good node should be forgiving and hopefully tolerant of a powder variation but that deviation isn't always shown at 100 yards and will most certainly grow with distance. This is another reason everyone strives for the low SD and ES as it shows a more consistent load.

If im shooting at 100 yards I can load up a 2 gr swing and keep same POI and roughly 3/4" MOA over roughly 25 shots. That's why, like Ive stated before, I really don't put alot of faith into using POI method. Now with that 2 grain charge difference I saw a roughly 170FPS difference in velocity. That is definitely not acceptable at distance although it will print decent groups at 100 yards.

You obviously do alot of testing and I enjoy going through your research. If your enjoying it and having fun and gathering data than that's awesome keep it up.
Click to expand...
Interesting because I have a few 30-06 and 223 loads that will show the same thing at 100 yards
Large swings in powder charge and getting that same POI/POA relationship.
Now I dont expect to have 1 grain swings in my reloads but its nice to know that I “should” get a reasonable impact in the same area? At least inside 300 yards
Note : these are moa ish loads when I can deliver
Now I cant off the top of my head tell you what 170fps deviation does at distance but do think it would be with in a certain “zone” of impact as the other shots with in the OCW node?
Lets say a no wind event 170fps should just print slightly lower at distance?

In the end you need to find what works for you and repeat. Thats the fun part
 
Mudflap621 said:
That post wasn't directed towards you and my point in the post was to bring light to that there are so many variables at play when trying to look for POI shifts and its inconsistency. The idea of the OCW is correct but the way of finding that node is flawed. IMO these nodes we seek seem to be directly linked to velocity sd and es. Historically my most consistent loads and groups always come from the loads with the most consistent sd and es. I think that for someone to state that velocity and its sd and es to have no affect on accuracy is incorrect.

I agree a good node should be forgiving and hopefully tolerant of a powder variation but that deviation isn't always shown at 100 yards and will most certainly grow with distance. This is another reason everyone strives for the low SD and ES as it shows a more consistent load.

If im shooting at 100 yards I can load up a 2 gr swing and keep same POI and roughly 3/4" MOA over roughly 25 shots. That's why, like Ive stated before, I really don't put alot of faith into using POI method. Now with that 2 grain charge difference I saw a roughly 170FPS difference in velocity. That is definitely not acceptable at distance although it will print decent groups at 100 yards.

You obviously do alot of testing and I enjoy going through your research. If your enjoying it and having fun and gathering data than that's awesome keep it up.
Click to expand...
I can most definitely say that I do observe non linear decency on both the seating depth and powder amount/burn rate. Different amount of powder or same seating does not translate into a same consistency of grouping averages. Seating depth is of course a major factor there. Yet I saw in a .223 experiments plenty of SD 4-8 groups of 10 with an abysmal spreads, up to 6-7moa.

From physics perspective it probably or definitely a factor of a pressure buildup rate during propagation of a projectile through the given barrel.

And, of course all that only makes sense while chasing that illusive 1/3 or 1/4 moa consistency. But, when you get it and see that sub 1 inch group at 300 - it feels nice.

But, going back to thread topic- sometimes it just does not seem to work, at all.
 
paul73 said:
I can most definitely say that I do observe non linear decency on both the seating depth and powder amount/burn rate. Different amount of powder or same seating does not translate into a same consistency of grouping averages. Seating depth is of course a major factor there. Yet I saw in a .223 experiments plenty of SD 4-8 groups of 10 with an abysmal spreads, up to 6-7moa.

From physics perspective it probably or definitely a factor of a pressure buildup rate during propagation of a projectile through the given barrel.

And, of course all that only makes sense while chasing that illusive 1/3 or 1/4 moa consistency. But, when you get it and see that sub 1 inch group at 300 - it feels nice.

But, going back to thread topic- sometimes it just does not seem to work, at all.
Click to expand...
Old timer at a club I belong to was a “science” guy for the military
He says his basic job was to test thevtesting.
Says he did a lot with mann accuracy devices, bullets , powders among other things.
He said sometimes whats on paper does not translate into good or bad and sometimes in science “we fudge with the math” till it looks right.
He said in all his testing and knowledge he said almost all good results came from
A powder charge that consumed the capacity of the case ( with in safety magins if chamber pressure) and a quality bullet ended in very good results down range.
When asked about seating depth
He said , “ well our testing was always done at max COAL to fit and chamber/magazine in the platforms it would be used in “
Then said
Some bullets like jump some dont.
 
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Mudflap621 said:
If you want accuracy you need consistency and the most effective and most reliable test is velocity testing.

BTW I'm not trying to say that harmonics are non-existent ..
Click to expand...
The underlying concept for harmonics is the same for OCW - tuning the load to the barrel - versus barrel tuners - tuning the barrel to the load.

I have never even heard of Lou M., but I do follow Brian Litz and Eric Cortina. I also have read Franklin Mann’s A Bullet in Flight and have all the data and ballistics from the famous Houston Warehouse studies.
I just don’t think velocity itself should be the ‘be all, end all’, that’s the gist of my point. For my precision loads, I save every group and overlay them on top of each other. For statistics, I also agree ‘more is better’ and I never shoot anything that I consider to be a ‘good group’ unless it is 10- shots or more. And then consistent on the next time(s) out, which is why I use Varget for my rig.

And I never would proclaim to use a OCW load that didn’t have respectable stats numbers/values. And unlike Dan Newberry, who has been doing it and interpreting such targets for years, I don’t do OCW at anything less than 300 yards, for when I saw Dan doing at 100 yards and interpreting the targets, I admit to being like, … What, huh? But then again, as he says in his videos, he knows that cartridge and load to the nth degree.

You and I are trying to reach the same place - we just go about a differently. If we differ on a topic, in that case, I’ll agree to disagree. But whatever … the OCW method works for me.

Tight groups!
 
mac1911 said:
Old timer at a club I belong to was a “science” guy for the military
He says his basic job was to test thevtesting.
Says he did a lot with mann accuracy devices, bullets , powders among other things.
He said sometimes whats on paper does not translate into good or bad and sometimes in science “we fudge with the math” till it looks right.
He said in all his testing and knowledge he said almost all good results came from
A powder charge that consumed the capacity of the case ( with in safety magins if chamber pressure) and a quality bullet ended in very good results down range.
When asked about seating depth
He said , “ well our testing was always done at max COAL to fit and chamber in the platforms it would be used in “
Then said
Some bullets like jump some dont.
Click to expand...
I'd say the old guy knew his stuff. A case full of powder has no voids that can vary by how it's "shook" as it is chambered.
Also, I don't know if any bullets "like" to jump. There are bullets that tolerate it better than others, though.
 
PatMcD said:
I'd say the old guy knew his stuff. A case full of powder has no voids that can vary by how it's "shook" as it is chambered.
Also, I don't know if any bullets "like" to jump. There are bullets that tolerate it better than others, though.
Click to expand...
This old timer is one to talk in half riddles and generally the answers are burried between the words of his riddles.
Often he rolls around to practice more with known good rifle and ammo things will get better.
He used to show up with all these data sheets and pictures. Often it was pictures of him next to some sort of contraption measuring stuff.

Another thing he always said is you only need to spin a projectile fast enough to stabilize it any faster gives inconsistencies in the bullet a chance to show its face.
He said at one point they took some known grossly defective jacketed bullets
He said you could see the difference in the jacket thickness around the bullet. He said under normal conditions they where fine but as they increased rpms the bullets began to do all sorts of wobbling and tumbling and eventually got the jackets/bullets to come apart mid flight.

I remember someone asking why test that knowing the jackets where not concentric.
He laughed and said “cause someone was getting paid for this info plus what a manufacture considers a defect might very well be just fine for GI”
 
i think i finally found a well working node for my 308 AR barrel. targets 2 and 4.
now will need to load several sets of 10 to test it better.

gotta say - this one gave me grief, it took way more time than ALL other rifles together to finally find this one. i updated the picture to show how groups spread out again with more powder.
proves that any barrel has a working node, even if one is more difficult to find than others.

308.jpg
 
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that rifle is a royal pain in the ass. for now it looks like the 2.808" with 42.6gr is still what works best, for what it is. 10rd groups were again way inferior to 5rd ones.
i will try later to get some sierras in 168gr to see if they will do any better - those were hornady eld match.
42.4 should not have differed that bad from 42.6gr. but it did. rifle was locked very well and shot slowly, so, it is not my hastiness, it is what it does...
probably just a time to have my peace with it and let it be.
308_2.jpg
 
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If youre not using a tuner, I would load to 42.5 even though you might give up a little on group size because at 42.8 your POA/POI really shifted up significantly. How was SD across these loads?
 
xtry51 said:
If youre not using a tuner, I would load to 42.5 even though you might give up a little on group size because at 42.8 your POA/POI really shifted up significantly. How was SD across these loads?
Click to expand...
i adjusted scope up at last 2 groups. SD is between 19-12. yeah, it is quite a some bullshit up there...
 
paul73 said:
Can anybody comment- what are those bullets? They look like a sierra match, somewhat. Are they any good?

www.midwayusa.com

Speer Match Bullets 30 Cal (308 Diameter) 168 Grain Hollow Point Boat

Speer Boat Tail Bullets are designed for long-range shooting. Shooting at extreme range requires a special kind of bullet. Speer Target Match...
www.midwayusa.com www.midwayusa.com
Click to expand...
They may be fine, but nobody I know in the accuracy sports use Speer bullets.
That being said, I'd try them to see if they work in YOUR rifle.
 
PatMcD said:
They may be fine, but nobody I know in the accuracy sports use Speer bullets.
That being said, I'd try them to see if they work in YOUR rifle.
Click to expand...
What are the accuracy guys running these days. I know to old bench shooters and they are still loading lapua’s they bought by the 5 gallon bucket YEARS ago. They are not very active anymore but do come to the range.
 
paul73 said:
I tried 150 and 177, was nothing that good. 155 - may be. Will be next.
Click to expand...
I have been running nosler 155s for old military rifles they do better than most.
They do particularly well in the M1a and 308 M1. With my M1a scoped I was getting right on top of moa . I will add
My M1a shot best with FGMM 175s

Using a light bullet like 125-135s I would reserve for specific use. Like 200 yard matches. I load mine at lower velocities that your attempts mainly because im just looking for enough stability and accuracy at 200 yards.
If I where loading for XTC in one of my 30 call rifles I would probably shoot 168s in that 2650 ish velocity range and see what happens.
 
paul73 said:
i think i finally found a well working node for my 308 AR barrel. targets 2 and 4.
now will need to load several sets of 10 to test it better.

gotta say - this one gave me grief, it took way more time than ALL other rifles together to finally find this one. i updated the picture to show how groups spread out again with more powder.
proves that any barrel has a working node, even if one is more difficult to find than others.

View attachment 603155
Click to expand...
When I look at this picture I see a lot of vertical movement? Are you comfortable behind this rifle. Its almost as if your shifting your head around but it could just be the load?

Anyhow I would place that rifle with your best loads in the hands of a known VERY GOOD consistent shooter and proof it out that way. I have one guy I know I can hand him a rifle and ammo and if the rifle and ammo are good he will proof it out.

Few things I learned from the older guys
If its not you or the gun itself
1. Vertical string - try more powder
2. Horizontal string - could be to hot but these guys say they will lean on shooter/equipment for the horizontal groups
3. The group shifter - you get 2 touching on the right 3 touching on the left
One guy says hot loads and causing mechanical shifts in your scope or beading?

Me after all you went through: I would have completely disassembled the rifle
Dismounted to scope and be looking for anything out of place , clean it , put it back together and make sure there is nothing going on in the bore/throat
Shit I would have bought a new barrel already , lol
 
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I think the 155's are working so well in the M14/M1A's because they get an optimum case fill and flat shooting higher velocity out of powders with a good burn rate, and all without over-gassing the rifle. Rotational speed of the bullet is probably still in that sweet spot too. This should translate well to bolt action, but with a bolt gun you have the flexibility of pushing the load a little hotter if that nets a better result.

I see there is some discussion of varying velocity not having that much effect on POI in terms of calculated bullet drop. While that may be true, the barrel dynamics may be different enough to magnify the effect. Maybe not a big deal in something with a bull barrel, but this is especially true for those of us stupid enough to F around with vintage competition- especially vintage sniper out to 600 yards. No heavy, free-float barrels for this; and slight changes in velocity can really open up the groups which aren't going to be awesome anyway. I think the best to be had is a hair under MOA with a new or new-ish barrel and the rifle and load optimized. Fall out of that narrow optimal load 'band' and the groups can spray out to 2.5+ MOA quite easily. When carefully developing the load I try to hit SD's in the single digits and an ES in the mid-teens or worst case below 20 fps so that once I crank out match ammo in bulk the loads are still not going to be the limiting factor in my scores. I will F up scores well enough on my own, thank you.
 
mac1911 said:
When I look at this picture I see a lot of vertical movement? Are you comfortable behind this rifle. Its almost as if your shifting your head around but it could just be the load?

Anyhow I would place that rifle with your best loads in the hands of a known VERY GOOD consistent shooter and proof it out that way. I have one guy I know I can hand him a rifle and ammo and if the rifle and ammo are good he will proof it out.

Few things I learned from the older guys
If its not you or the gun itself
1. Vertical string - try more powder
2. Horizontal string - could be to hot but these guys say they will lean on shooter/equipment for the horizontal groups
3. The group shifter - you get 2 touching on the right 3 touching on the left
One guy says hot loads and causing mechanical shifts in your scope or beading?

Me after all you went through: I would have completely disassembled the rifle
Dismounted to scope and be looking for anything out of place , clean it , put it back together and make sure there is nothing going on in the bore/throat
Shit I would have bought a new barrel already , lol
Click to expand...
My vertical spread is almost always higher than horizontal unless it's a rifle in dire need of some TLC. With irons, it's going to be my eyesight. Especially true with poor light which is usually the case at my 'home' range. With my scoped rifles, I'm usually shooting sub-MOA with the modern ones and MOA-ish with the vintage. Highest spread will be vertical. I think that vertical spread is due to flaws in technique. I can shoot a sub-half MOA group with the 6.5 ManBun at ~25X scope power and at that point the spread is pretty much equally distributed.
 
My skills and equipment are no where near these guys but I like to at least learn and get ideas. This is is a decent series to watch I think. Touches on a lot of things and I apply some stuff when I can ir where it fits.
I only own 1 rifle capable of even getting to 1/2 moa and 2 that can deliver 1 moa when I an shooting well.
 
mac1911 said:
My skills and equipment are no where near these guys but I like to at least learn and get ideas. This is is a decent series to watch I think. Touches on a lot of things and I apply some stuff when I can ir where it fits.
I only own 1 rifle capable of even getting to 1/2 moa and 2 that can deliver 1 moa when I an shooting well.
Click to expand...
well, i do not expect 1/2+moa from that 308 barrel, to be frank - it was not really ever anticipated, as i got that aero/wilson upper for, what, a $460 something, i think.
it seems to be intact, but, i may take it apart, why not, it is not difficult. as of swapping the barrel - dunno, i am not there yet. scope is apollo primary arms 18x - same i have on a 6.5CM AR10 build - it is also solid.

with my ar15s i started my loads with hornady eld bullets also, and it just did not work well. in 6.5CM those hornadys are excellent. here in 308 they were supposed to be ok - but, who knows.

i had an another semi-decent result with that same seating depth of 2.808" and 44gr varget - but it prints the extractor really quite a lot at that pressure.
speed at 44gr was not excessive - merely 2560fps, but, i did not like the printing, so wanted to back off with the load a bit. i may step it back up. 42.6gr gives almost exact 2500fps for 168gr.

plus, that flier to the side is what it 'just does', i think - and in a groups of 10 it shows up every time. if it is mechanical - it is not clear what it is, as it is just an AR - and all seems to be tight, and i did shoot that upper from 3 different lowers. as of swapping the barrel - dunno, it is easy, of course, but, i am not there yet. plus my rifles safe is full, got 9 in there, i cannot fit no more and do not want to sell anything. :)

1650026787962.png

Plus, I still think the ELD hornadys are just not for an every barrel. the same load of 42.6gr varget on the 168gr SMKs is supposed to push `em to 2650fps - i get merely a 2500fps. wanna try that too.
 
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While I'm more of a mid-timer, my go to bullets for .308 are Barnes TSX and TTSX. Not cheap, but they hit like freight trains and go where you want them to. I haven't had a target round I could group better than TSX. That's probably my limitation and I don't shoot competition long range so I'm more interested in terminal ballistics.
 

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