Case fill and consistency

[MuleyFever]

I have heard people say that loads are more consistent when the case has a higher fill %. Any truth to this?

I ask because I may try loading a quite mild load for my wife but wondering if it will be harder to get good consistent accuracy.

 

[packer58]

Iv'e always believed that a nearly full or full case would have a more consistent burn but have no scientific evidence to back it up.

I know this doesn't help you .........just my thoughts

 

[amassi]

Yep always easier to find a 95% fill

 

[WeiserBucks]

I don't have any hard evidence, but I believe 100% that high case fill is better. I certainly don't mind a mildly compressed load.

 

[A382DWDZQ]

I don’t know if this was the goal, but I just pulled some hand loads for a 43 spanish with hardcast loads and they were topped off with what I assume was cream of wheat and it was pretty tightly packed. They would have been about 25% filled with powder and about 75% CoW. My assumption is that this keeps the way the powder burns consistent, but I know there are also loads marked as most accurate in the load data that are in the 85-90% full range. I have heard RL17 is a powder that likes to be at or over capacity.

 

[MuleyFever]

I just looked up the 6.5CM at Nosler and every load marked as most accurate in 90% or under.

 

[packer58]

I just looked up the 6.5CM at Nosler and every load marked as most accurate in 90% or under.

Keep in mind that the base of the bullet takes up a certain % of total case capacity, so with a 90% capacity load there may not be much empty space for powder slosh ....depending

 

[A382DWDZQ]

Keep in mind that the base of the bullet takes up a certain % of total case capacity, so with a 90% capacity load there may not be much empty space for powder slosh ....depending

This is a good point, however with Nosler at least, they seem to be adjusting for that because on the charts for their different weights, the "CASE HOLDS XX.X Gr. WATER" is adjusting upwards the lower the bullet weight.

 

[z987k]

Keep in mind that the base of the bullet takes up a certain % of total case capacity, so with a 90% capacity load there may not be much empty space for powder slosh ....depending

The load density takes into account the seating depth of the bullet.

 

[83cj-7]

My ES and SD numbers are usually very low when running a full case or compressed charge with slow burning powder. That said, I had worked up a reduced load for my .300 WM with a 150 grain bullet and H4895 and it was very accurate with single digit ES. I’ve said this before and I stand by it, consistent neck tension makes consistent loads.

 

[Laelkhunter]

I have read that a full case will produce a more consistent load. Has something to do with the powder settling in the case after it is chambered and when getting ready to fire it. I have also heard that loads with lower volumes could be dangerous due to the powder possibly bunched up at the bullet, and air space near the primer, the primer flash hits across the top of the entire powder charge, and not a progressive burn as a full load would produce. If you are looking for a reduced load, make sure you don't reduce the powder charge less than recommended minimum published loads.
If you are trying to load light loads for reducing recoil purposes, consider going to a lighter bullet and using a recommended starting load. Generally a lighter bullet will produce less recoil than heavier bullets. Also, a slip on recoil pad works wonders in reducing the felt recoil.

 

[Mack84]

I have heard people say that loads are more consistent when the case has a higher fill %. Any truth to this?

I ask because I may try loading a quite mild load for my wife but wondering if it will be harder to get good consistent accuracy.

It’s true to my experience

 

[Lawnboi]

I aim for a full case that is not compressed.

 

[SamsonMan22]

The only full or slightly compressed loads I work with are 308s using IMR4064. Everything else I actually find better results with a little wiggle room for the powder. I used to shoot for slightly compressed but I had a 300wm that hated powders that gave a full load. I ended up trying h4350 because I had some on hand and that gun shot amazing with quite a lot of powder slop in the case. It was still a fairly high % on case fill but nowhere near full. The only complaint I had with the load was lower velocity compared to something like h1000

 

[packer58]

The load density takes into account the seating depth of the bullet.

This is a good point, however with Nosler at least, they seem to be adjusting for that because on the charts for their different weights, the "CASE HOLDS XX.X Gr. WATER" is adjusting upwards the lower the bullet weight.

Yes, load density and case volume are two very different things. I had a brain fart and was thinking volume and talking density.

 

[rayporter]

just test your load. if it shoots ok nothing else matters.

some powders do well with light loads and some are not at all suited to low charges.

 

[MattB]

I used H4895 to approximate .223 energy in my daughter’s .243 and that load was very accurate. The fill percent was low in comparison to the maximum load (~78%), not sure how that translates to % of case fill.

My advice would be to not make something a problem until it actually becomes a problem.

 

[Pharmseller]

Find a powder that shows a higher % of case fill at the low end of the powder charge range.

I did this with Varget in a couple of .30-06s, worked great.




P

 

[Harvey_NW]

I've always heard that, but in the last few year of shorthanded components I have a few loads that have less than optimal case density, and haven't noticed any difference. I pretty much only shoot Hodgdon extreme powders though.

 

[wind gypsy]

I've seen it said yet you see lots of faster burning powders with less than full cases performing very well in many competition loads. EX: H4350 behind 230 bergers in 300wsm, 180 hybrids in 7 SAUM, varget in 6.5x47 rather than h4350. Those faster powders seem to do very well as far as getting a consistent load.