.308 Winchester
- Thread starter Two Shoes
- Start date
I’ll say listening to Hornady’s ballisticans (sp?) discuss a lot of their observations, one mentioned Varget being their go to powder in a bolt gun. That and powder and bullet combo made the biggest difference than anything. Meaning all the load development outside of that made less of a difference far as jump, charge weight etc.
(But that higher charge almost always trended to larger dispersion) also that 3-5 shot groups statistically mean next to nothing… you need like 20-30 shots to have data worth going off of due to the noise.
I’m posting this to just backup what you were saying about the powder and basically sounds like you’re right and I’m just a noob learning and so yeah.
I have used Varget in 308 with a lot of success over many years....
But it was the worst powder ever tried in a 16" 308 AR 10.
The S/D was 49.5 over just 6 shots with Varget being absolutely the most inconsistent powder ever tried in this rifle horrible stuff in this case.
But it was the worst powder ever tried in a 16" 308 AR 10.
The S/D was 49.5 over just 6 shots with Varget being absolutely the most inconsistent powder ever tried in this rifle horrible stuff in this case.
Attachments
Finally got out to try some N540 today.
Custom model 700, 20" lilja 1:9 with an m852 match chamber.
Lapua brass, cci br2, 168 smk at 2.800"
Custom model 700, 20" lilja 1:9 with an m852 match chamber.
Lapua brass, cci br2, 168 smk at 2.800"
Now you just have to test that 43.7 gr load over 20 shots or so to see if it'll repeat.
Yeah that's in the works. Hell has frozen over here today in Texas and it's a freezing cold 36 degrees outside. (Sarcasm) I'm trying to find the motivation but the wood stove in the house just feels too good. I think I've got fifteen more primed cases in the loading block ready to go.Now you just have to test that 43.7 gr load over 20 shots or so to see if it'll repeat.
I'm also going to work on a load for the LMT with once fired federal brass. Probably start around 42gr for that one.
The ten shot fell apart. I had three that I called my bad. But there's something else.
How critical is primer seating depth ? These cases have been primed a while, and I can not for the life of me remember what I primed them with. But seating depth was all over the map.
The groups I posted were all .008" deep. What I just shot was anywhere from .008" to .002". And the group reflected it. Sd doubled as well.
I'm out of prepped brass for this one. On to the gasser load.
How critical is primer seating depth ? These cases have been primed a while, and I can not for the life of me remember what I primed them with. But seating depth was all over the map.
The groups I posted were all .008" deep. What I just shot was anywhere from .008" to .002". And the group reflected it. Sd doubled as well.
I'm out of prepped brass for this one. On to the gasser load.
Primer seating depth can make a difference depending on what's actually going on with how the anvil is actually being seated. There is some leeway, but .006 variance is quite a bit, though that too depends on how much variance there is in the depth of the primer pockets.
Another aspect to getting consistent ignition is the variance in the primer compound that can upset SD's quite a bit. I was a skeptic about weight sorting primers, where there were a couple reloaders who ran a test for weight sorting that appeared to show a significant difference between the lightest and heaviest. I decided to run the test myself and sorted some CCI-400's for my .308 bolt gun. I took the lightest that weighed 3.36 gr and the heaviest that weighed 3.50 grs and used them in my best loads where my primer pockets are uniform and the seating depth was consistent at .004" below flush. The 3.36 gr primers produced an average velocity of 2,688 fps with an ES of 31 and an SD of 7.1. The 3.50 grs produced an average velocity of 2,695 with an ES of 15 and an SD of 4.7. These were for 10 shots and upon repeating 10 shots with those weights, it virtually the same . . . like I had to use 3.48 grs (had no more 3.50's) and got an average velocity of 2,695 with an ES of 14 and and SD of 4.8. While the ES and SD's were still pretty good on the 3.36's, they were all the same and so I'd really expect that. I should have mixed a batch with both weights to show what kind of SD one gets when mixing the lowest with the highest. Looking at data I've collected overs some years for CCI-400's with this load, I just don't get SD's or ES's that low when using unsorted primers. So, does it make a difference? Yes! But does it make enough of a difference to be worth the time it take to sort primers? I'd say NO! . . . for the vast majority of reloaders.
100 round groups or you are just spinning your wheels and have useless data. Lol
I just recently started paying attention to primer seating depth.Primer seating depth can make a difference depending on what's actually going on with how the anvil is actually being seated. There is some leeway, but .006 variance is quite a bit, though that too depends on how much variance there is in the depth of the primer pockets.
Another aspect to getting consistent ignition is the variance in the primer compound that can upset SD's quite a bit. I was a skeptic about weight sorting primers, where there were a couple reloaders who ran a test for weight sorting that appeared to show a significant difference between the lightest and heaviest. I decided to run the test myself and sorted some CCI-400's for my .308 bolt gun. I took the lightest that weighed 3.36 gr and the heaviest that weighed 3.50 grs and used them in my best loads where my primer pockets are uniform and the seating depth was consistent at .004" below flush. The 3.36 gr primers produced an average velocity of 2,688 fps with an ES of 31 and an SD of 7.1. The 3.50 grs produced an average velocity of 2,695 with an ES of 15 and an SD of 4.7. These were for 10 shots and upon repeating 10 shots with those weights, it virtually the same . . . like I had to use 3.48 grs (had no more 3.50's) and got an average velocity of 2,695 with an ES of 14 and and SD of 4.8. While the ES and SD's were still pretty good on the 3.36's, they were all the same and so I'd really expect that. I should have mixed a batch with both weights to show what kind of SD one gets when mixing the lowest with the highest. Looking at data I've collected overs some years for CCI-400's with this load, I just don't get SD's or ES's that low when using unsorted primers. So, does it make a difference? Yes! But does it make enough of a difference to be worth the time it take to sort primers? I'd say NO! . . . for the vast majority of reloaders.
I still don't sort them.
I've noticed my most consistent groups and sd have been with primers at .002-.004 deep in my 300winmag. Most of my seating depths right now are just luck of the draw with certain shell holder/brass/cartridge combinations.
Using my rcbs hand primer for the winmag I get a dead nuts .004" seat. Priming in my press gives me a consisten .002"
I also have a Sinclair hand priming tool that I used to adjust different seating depths all the way up to .008"
Past .004 I start getting unexplained fliers and more vertical groups.
The best loads today with the 308 were .008 deep. I don't know. I'm going to shoot for a consistent .004-.006 and roll with it.
The Sinclair Hand Priming Tool is a very good tool that can produce pretty consistent results . . . in terms of how far below flush primers are seated. The thing is, different brands of primers have different cup dimension, where they'll be different in cup height (without the primer that tends to set higher than the edge of the cup). Then you also have differences in primer primer pocket depths from one brand of brass to another.
For example:
* My .308 SRP Lapua brass primer pockets are .121" deep.
* My .308 SRP Peterson brass pockets are .129" deep
* My .308 SRP ADG brass pockets are .125" deep
* My .308 LRP Lapua brass pockets are .128:
(cup heights here don't include the anvil sticking up higher)
* CCI 400 cup height is .109"
* CCI 450 cup height is .113"
* Federal 205M cup height is .1075"
* Remington 7 1/2 cup height is .110"
* CCI 200 cup height is .118"
* Federal 210 cup height is .117"
* Remington 9 1/2 cup height is .119"
* Winchester LRP cup height is .121"
If I want to seat my primers to the ideal where the cup in just touching the bottom of the primer pocket, for my .308 LRP Lapua brass at .128" deep and using the Federal 210" that are .117" in height, that primer will be seated .011" below flush. No, the cup doesn't have to be touching the bottom of the primer pocket to get good ignition, but it does help with consistency.
The problem with various brands of brass is they don't have very consistent pocket depths. You may have consistent seating depth as measured from the base of the case, but the space between the primer and the bottom of the primer pocket can vary a lot with the consistent seating depth. Again, for the vast majority of reloaders, it really just doesn't matter for the very small improvement in SD's that this helps with.
Last edited:
The problem with all the measuring is that nothing is consistent.
None of the brands case heads are even flat....high spots and uneven on all.
Even the new Lapua to fired LC.
So nothing to accurately measure from as exact....just close somtimes but with lots of variation from case brands, inside the same brand, primer pocket depth, flatness, diameter, and flash hole size and possibly burrs.
Then there are the primers...no two mixtures that make up the detonation are exactly the same, its a blended mixture, not to mention the physical differences between the anvil and cup variations in composition and size.
Can not measure or weight anything exactly to come up with anything but a general conclusion, that might have some bering on the real outcome.
With that it appears some primers will have less S/ D over a few shots with certain powders, at a certain pressure in your particular hand load...But each primer cup, each primer mixture, consistently, and weight varies, each anvil varies.
Then ya have case volume inconsistencies and neck tension inconsistencies, plus bullet inconsistencies, and powder burn inconsistencies.
Hopeless for exacting...but when it comes together and you aquire low S/D keep doing what your doing.
I never worry about primers just seat them.
I been running a odd ball little AR 15 cartridge called the 338 Spectre with a 16" barrel. It runs single S/Ds with almost every bullet 160 gr to 350 gr. Super or subsonic ...completely loaded on a Dillion progressive.
Depending on case LP primer or SR primer, different brands with no difference still single digit S/D. Kind of incredible but its high load density and 100 % burnt according to QL with a moderate Lee factory crimp die.
Notice the 350 gr is machined on my lathes to make it a bore ride, another variable.
All these different primers SR & LP and 4 different cases but not mixed with every bullet from 160 gr to 350 gr subs all single digit S/Ds fired in an AR 15 auto loader, sub or super, and accurate with them all.
Unusual...maybe, but all these variables seem to make little difference in this cartridge.
So I'm not gonna worry about primers, unless I notice a difference...just seat em and go.
But if all that measuring and weighing works for anyone keep on doing it.
But maybe it's cartridge volume balanced to bore ratio, to powder volume, to % burnt, rather than primer that makes the difference.
My 6 Dasher is like that too...just seat the primer, no other concern needed.
None of the brands case heads are even flat....high spots and uneven on all.
Even the new Lapua to fired LC.
So nothing to accurately measure from as exact....just close somtimes but with lots of variation from case brands, inside the same brand, primer pocket depth, flatness, diameter, and flash hole size and possibly burrs.
Then there are the primers...no two mixtures that make up the detonation are exactly the same, its a blended mixture, not to mention the physical differences between the anvil and cup variations in composition and size.
Can not measure or weight anything exactly to come up with anything but a general conclusion, that might have some bering on the real outcome.
With that it appears some primers will have less S/ D over a few shots with certain powders, at a certain pressure in your particular hand load...But each primer cup, each primer mixture, consistently, and weight varies, each anvil varies.
Then ya have case volume inconsistencies and neck tension inconsistencies, plus bullet inconsistencies, and powder burn inconsistencies.
Hopeless for exacting...but when it comes together and you aquire low S/D keep doing what your doing.
I never worry about primers just seat them.
I been running a odd ball little AR 15 cartridge called the 338 Spectre with a 16" barrel. It runs single S/Ds with almost every bullet 160 gr to 350 gr. Super or subsonic ...completely loaded on a Dillion progressive.
Depending on case LP primer or SR primer, different brands with no difference still single digit S/D. Kind of incredible but its high load density and 100 % burnt according to QL with a moderate Lee factory crimp die.
Notice the 350 gr is machined on my lathes to make it a bore ride, another variable.
All these different primers SR & LP and 4 different cases but not mixed with every bullet from 160 gr to 350 gr subs all single digit S/Ds fired in an AR 15 auto loader, sub or super, and accurate with them all.
Unusual...maybe, but all these variables seem to make little difference in this cartridge.
So I'm not gonna worry about primers, unless I notice a difference...just seat em and go.
But if all that measuring and weighing works for anyone keep on doing it.
But maybe it's cartridge volume balanced to bore ratio, to powder volume, to % burnt, rather than primer that makes the difference.
My 6 Dasher is like that too...just seat the primer, no other concern needed.
Attachments
Since you're here, how many firings on your sig hybrid cases now ? I'm up to 4 on mine. I've shot up to 47gr of varget in them but settled at 45 for my current load. Which isn't too crazy. I know you lean on yours pretty good. I'm curious how many firings they're capable of before that steel head decides it's ready to check out.
All these things with variability you mention are all true. And because of that is why I tend to be so skeptical about claims that I haven't seen any testing done. But when several good independent tests are run and the outcomes are the same, I'll then accept the theory. . . especially when my own tests end up with confirmation.
Aside from that, I'm just someone who likes to understand the details that are going on, as I've got an insatiable curiosity about things. And I understand that not everyone shares this mind set, and that's OK by me.
And I think you're right where if you don't find any difference for something for your cartridge or your cartridge simply meets your standards, there's really no point in pursuing it.
Similar threads
