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I've been reloading my 223 and 308 and always filled the cases up and sometimes compress loads with a drop tube.
But i have noticed with 303, 6.5x55 and 7.5x55, there is lots of room left but the max load has suggested not to load anymore.
I have some understanding of why the case should be reasonably full but need some more experienced people to tell me a bit more.
Any experts on this topic?
Use a slower powder
define "lots of room left" from my understanding of things the fuller the better to be sure BUT above say 70% is pretty normal and fine...IF you get less than 50-60% fill you can get flame from primer flash over top of powder which causes issues and a chance of secondary explosion....which i belive is when it goes baboom...had that with low charge of 760 in .270 years back with loads done for me by sports shop....I had to point rifle at sky and lower onto target to prevent it happening...wasnt flash I tell you.
You should have about 90 % full cases for good results, as suggested above use a slower burning powder which will fill the case more than the faster powders. The danger with a lot of space is poor ignition and possible high pressures.
Put the primer in first helps for me:XD::P;)
Sorry couldn’t help myself :ORLY: these others seem to have better advice :thumbsup:
With the 6.5x55 at least book loads assume you have a swedish m1896 action. The m 38 is quite a bit stronger and modern rifles stronger again.
Quite true my load for my Tikka in 6.5 x 55 is full, can't hear the powder, but I use a slow burning powder and it has a stronger action.Quote:
Originally Posted by Marty Henry
Follow the book to the letter and you will be safe.
If you have to use a drop tube with the .223 and .308 you are using too slow a powder, AR2206H is a good powder for both cartridges,Quote:
Originally Posted by lee308
the 303 6.5x55 and 7.5x55 are some of the earliest smokeless cartridges, The early smokeless powder was less powerful and bulkier
than modern powder as long as you don't go over max loads or under start loads you will be fine,
AR2206H works well in the .303 use 174 - 180 grain bullets they fit the throat better than lighter bullets
Yes, I go over the max load a bit for my 308 with 2206H for sure. but worked up to it though. Lapua thick brass didn't help.Quote:
Originally Posted by shooternz
If there is lots of space left in the case it can cause inconsistent ignition.
Picture a case only half full of powder. Depending on the angle of the rifle/cartridge, all the powder within the case could all go to one end or the other, or sit with more at one end than the other etc etc etc. This can cause inconsistency in ignition between the powder & primer. For example in a half full case - sometimes powder will be right up against the primer, and other times all the powder might be at the front of the case with a big gap between powder & primer.
The less the powder can move around in the case, the less potential there is for inconsistency caused by difference in the powder column & how it is ignited by the primer.
Can Cause mis fires or hang fires if you’re running primers which aren’t the hottest
Especially if you are using small primers in larger cases such as 308 etc
Q: What happens when your case has lots of room left?
A: Nothing.
But it is considered poor practice, even though no manufacturer, despite trying, has managed to replicate the "secondary explosive effect" or "flashover" or "detonation"
This is a myth that has been perpetuated for a long, long, long time.
Using bulkier/slower powder is good advice. alternatively top up the case with corn meal or dacron.
Ive had loads of win 760 that were done for me by sports shop..110grn projectiles and I asked for about 3000fps....if I didnt tip rifle to sky before squeazing trigger they went BA...BOOM it was VERY off putting and did terrible things to accuracy and flinchyness.... Ive remade same loads with a little more powder in them and they are lazer beams without issue...either the powder he used was ???damp/old n stuffed....or the lack of powder was causing it....that they would work if muzzle pointed skywards first suggests the second...
Cute picture. But no. The primer isn't a little spark at the end of the case, it will fill the entire case with flame.Quote:
Originally Posted by ChrisW
And I'd be interested to see any evidence of the powder-location-vs-accuracy theory.
little spark.....funny story,years ago I had quite a few cases loaded that I pulled apart (might even have been the dud loads mentioned above) so I ended up with primed cases that needed to be resized.....how to deprime them in town???? oh I know ,place muzzle against my good polarfleece vest and simple fire off the cases one at a time,no noise no bother EXCEPT it burnt /melted round patches on my good vest!!!!flame had travelled some 21". plenty plurry flame there LOL.
Sounds like too much primer. I don't know about 760 my chart shows it on par with 2209 which is relatively slow. Manual also shows you should be cracking that speed quite easily with a full case of it.Quote:
Originally Posted by Micky Duck
My theory would be that the Primer was pushing the projectile out of the case and into the lands before the powder had sparked off
Take that for what it cost ya.
S.E.E has been observed in artillery size tubes, afaik never in small arms.
With the 6.5x55 in particular I was finding I could get marvelous accuracy with the 120/123 gr bullets and a healthy dose of 2209, but with a few grains less in the 140gr bullet size I just could not get the same sort of accuracy until I changed powders [in this case to VtVh N560] and filled the case back up.
Possibly just fell out of the accuracy node rather than being related to case fullness?Quote:
Originally Posted by jakewire
Not to sure what you mean as, being a totally different bullet required a different work up, definitely wouldn't have run the 140 with the load I had in behind the 120 Nosler, I just just couldnt get it with 2209 , changed powder, fuller case again and away. May have been just coincidence.
Could have also been the rifle didn't particularly like the heavier bullet/ 2209 combo
Ah I see, my mistake, I read that as a couple of grains less powder and the accuracy fell off :)
Lol.Quote:
Originally Posted by mimms
If you want ultimate consistency then you want to minimize variables, and powder being able to slosh around in the case is just another variable. Im not talking about the powder failing to ignite, im talking about ensuring the powder column within the case is relatively consistent for maximum consistency. Its generally accepted that loads where the case is almost full with powder often perform better than those with more free space.
Is it due to the consistency of ignition and the way the powder burns? Is there the potential for powder sprinkled along the bottom of the case, or all packed up the front, only half filling it up to burn with less consistency than a case that is packed full?
Point of diminishing returns with all things "consistent". I'm not arguing that consistency isn't good. I'd like to see evidence.Quote:
Originally Posted by ChrisW
Got any? "lol"
And I am all about the down-range, I don't want "ultimate consistency" i want "effective". I don't weigh cases, trim meplats, re-point projectiles, blah-blah-blah, not doing so will introduce inconsistency to my loads.
But I have a 99% chance of connecting the shots when i take em, so they're consistent enough
It is common knowledge that a cartridge which is full/almost full of powder will often perform with better consistency than a case with lots of free space within it. You can come up with your own conclusions as to why.
Generally loads with a 90+ % fill rate will be more accurate. Im not about to go and dredge the internet to back this up.
According to quickload the less powder in the case, the lower percentage gets burnt in a given barrel length (eg .308 with 35gr powder may only have burnt 80% of the powder in a 16” barrel whereas with 42gr you might have a 99% burn rate. If you are burning different amounts of powder every shot due to not all the powder being burnt, then that’s inconsistency
@mimms I ran some quickload data which should demonstrate this point fairly well.
First up we have a "normal" .308 load. Its a 165gr btsp in front of 45gr ar2208. Its got 104% case fill capacity, so will be a slightly compressed load. This should burn consistently. Note quick loads predicts a 98.55% powder burn out of a 24" barrel.
Attachment 120594
Next up we have a cartridge with "lots of room left in the case". Iv just halved the powder charge for demonstration sake. This load has everything the same as previous but only 22.5gr ar2208. Case fill capacity is only 52.2%. This one burns inconsistently with only a predicted 68.89% of the propellant being burnt in the same 24" barrel. This percentage could go up or down slightly depending on how the powder was clustered inside within case. Accuracy and/or consistency of FPS could (not will) suffer. Either way its an inefficient load.
Attachment 120595
The reason for the complete burn (in well packed cases), and the consistency that comes with that is that all the powder is packed neatly into a column, that cant move around much if at all, so more of it burns, and burns more consistently.
I have experienced this first hand developing a load for a 3855 using 4227. Starting at 15 gr and checking for unburnt powder. Plenty at 15, less at 16, none at 19. Case was still only about 70% full and nice tight groups.
Deffinately had the same thing with my swede. TBH that rifle only suffers from an inconsistent shooter (me). It has no nodes. The only thing a swede hates is a slightly loose projectile like a prvi partizan fmj rn. Other than that one projectile i could consistantly nail tight groups if i concentrate.Quote:
Originally Posted by Sakoswarosorted
But i did notice it got distinctly easier switching to 2213sc and filling up the case more.
