case fill 30-06

S

Shadow9mm

New member
Trying to find powders for my 30-06, running into some problems. Here where I am starting

Once fired Winchester brass
Remington 9 ½ large rifle primers
Hornady 150g Interlock BT. At Ogive bullet touches lands at 2.613, bullets seated at 2.602. bullet seats into casing 0.397

Space remaining as measured from case mouth with MAX charge
Benchmark 49g 0.750 after loading bullet 0.371
Varget 52g 0.670 after loading bullet 0.291
Reloader 17 60g 0.409 after loading bullet 0.030

I plan to steer clear of benchmark and I am seriously doubting varget, there is just so much space left in the case.

My question come down to this How much does case fill affect accuracy and pressure/safety. I had heard of detonations with too low of case capacity.
 
Last edited:
My question come down to this How much does case fill affect accuracy and pressure/safety. I had heard of detonations with too low of case capacity.
Click to expand...

The detonation you are referring to is called SEE (Secondary Explosion Effect), and only involves small amounts of slow burn rate powders. This is normally not done by knowledgeable reloaders in the first place. When you are using suitable powders a little unfilled space is not a concern. Varget is such a suitable powder. Use published load data and don't worry about any unfilled case space.

Don
 
SEE is not only for slow powders. It just happens more easily with them. There is a brief description by P. K. Kekkonen on the Finish Gunwriter's site about a 200 milligram (3.1-grains) load of VV N320 (similar burn rate to Bullseye) that blew up a .308 being loaded for by a friend of his, almost costing the shooter his eyesight. This would probably be around 11% loading density with the fairly heavy cast bullets those guys like for subsonic loads to use with suppressors over there.


Shadow9mm,

The two issues associated with poor loading density are a big change in velocity depending on whether the powder is forward against the bullet (lower pressure and velocity) or back over the primer at firing (higher pressure and velocity) and also the issue of how much empty space has to be pressurized in the case to keep the powder burning well. In the 30-06, with lower loading densities (say 80%, plus or minus) it is common to find a magnum primer, which better pressurizes extra empty space than a standard primer does, will improve velocity consistency and mitigate some of the powder position-induced variation. If you get powder much past 90% fill, though, standard primers may do better and also that mitigates powder position variation.

The powder I've been buying for 150-grain bullet loads is Vihtavuori N135. It is very bulky relative to its energy content. It is faster than most powders popular for loading for the M1 Garand (my purpose), but that high burn rate produces low muzzle pressure with near maximum loads, and they turn out to be almost at military M2 Ball true muzzle velocity. The fill something like 93% of the case underneath a 150-grain Hornady FMJ loaded to Hornady's recommended 3.185" for that bullet.

It looks like you are trying to load for just 0.011" of bullet jump. That's enough to raise pressure over a jump of more like 0.030", so you may need to lower powder charge a little to allow for that. It won't be as much pressure increase as jamming the lands (usually about 20%) but you'll probably get 10% increase or so out of that short jump. Also, short jumps are not automatically most accurate. Read this Berger article for some insight on the matter.
 
Add in if its good cross check reloading data then your charges are not an issue.

Either get a or go by reloading manuals. Hornady and Sierra have the widest spread of listings.

R17 is a very good 30-06 power
 
Hornady 150g Interlock BT. At Ogive bullet touches lands at 2.613, bullets seated at 2.602. bullet seats into casing 0.397
Click to expand...

Pardon my ignorance, but what is your COL? When you say "bullet seated at 2.602" that's measured from where, to where??

Please help me understand your numbers, they seem very short to me, but I don't know where you are measuring from and to.

Case length is 2.494" max and COL is 3.340" max, for the .30-06.
 
44 AMP said:
Pardon my ignorance, but what is your COL? When you say "bullet seated at 2.602" that's measured from where, to where??

Please help me understand your numbers, they seem very short to me, but I don't know where you are measuring from and to.

Case length is 2.494" max and COL is 3.340" max, for the .30-06.
Click to expand...
I'm using the hornady bullet comparitor, and OAL case gague. I put a bullet in the tool and push till it touches the lands in the rifle and measure a few times. the bullet comparitor goes on my calipers and measures at the ogiv of the bullet since it is more consistent that the length of the bullet. lets me adjust my seating depth better. makes sure my loads are safely off the lands, and lets me play with seating depths to refine accuracy.
 
Unclenick said:
SEE is not only for slow powders. It just happens more easily with them. There is a brief description by P. K. Kekkonen on the Finish Gunwriter's site about a 200 milligram (3.1-grains) load of VV N320 (similar burn rate to Bullseye) that blew up a .308 being loaded for by a friend of his, almost costing the shooter his eyesight. This would probably be around 11% loading density with the fairly heavy cast bullets those guys like for subsonic loads to use with suppressors over there.


Shadow9mm,

The two issues associated with poor loading density are a big change in velocity depending on whether the powder is forward against the bullet (lower pressure and velocity) or back over the primer at firing (higher pressure and velocity) and also the issue of how much empty space has to be pressurized in the case to keep the powder burning well. In the 30-06, with lower loading densities (say 80%, plus or minus) it is common to find a magnum primer, which better pressurizes extra empty space than a standard primer does, will improve velocity consistency and mitigate some of the powder position-induced variation. If you get powder much past 90% fill, though, standard primers may do better and also that mitigates powder position variation.

The powder I've been buying for 150-grain bullet loads is Vihtavuori N135. It is very bulky relative to its energy content. It is faster than most powders popular for loading for the M1 Garand (my purpose), but that high burn rate produces low muzzle pressure with near maximum loads, and they turn out to be almost at military M2 Ball true muzzle velocity. The fill something like 93% of the case underneath a 150-grain Hornady FMJ loaded to Hornady's recommended 3.185" for that bullet.

It looks like you are trying to load for just 0.011" of bullet jump. That's enough to raise pressure over a jump of more like 0.030", so you may need to lower powder charge a little to allow for that. It won't be as much pressure increase as jamming the lands (usually about 20%) but you'll probably get 10% increase or so out of that short jump. Also, short jumps are not automatically most accurate. Read this Berger article for some insight on the matter.
Click to expand...
I have read the article, but i do need to re-read it, its been a while. I got a new rifle in a new caliber and am trying to find out what she likes. With a new gun or barrel I generally try to work up to a max load with a jump of 0.011 (I give 0.001 for margin of error at the closest distance). Once I work up a to max with no signs of pressure I start working my way back on powder and seating depth to find the most accurate load with the best performance since i know everything below max is safe.
 
Last edited:
Stick to the data in your loading manuals , as long as you are at or above the minimum charges listed and not above the maximum charges listed you will have no problems with mysterious explosions ...secondary or otherwise .
The labs have tested the loads and case fill has been taken into account .
If you are loading the Hornady 150 gr. Interlock BT then grab a Hornady Reloading Manual and follow the tested data given ...it has been tested for that bullet and will be safe .
Gary
 
I did check the hornady manual, I don't like how broad their manual is though. it lists 150-155 in the same group, BT and flat base together. gives a broad veocity range. they list start at 44.9 at 2500-2599fps, and a max of 53.6 in the 2900-2999 range. Its vague. I went though several manuals and compiled load data from several sources so figure out where to start.
 
You must log in or register to reply here.
Back
Top