max powder capacity

[cst]

Im new to the grendel....got a question while stuff is starting to get ordered....What is the average max capacity of powder the brass can hold with a 123gr. loaded before being compressed??( i ordred some Leverevolution..i guess similar to CFE)

Any difference between Lapua and Hornady in terms of volume?

[NightForce]

Any difference between Lapua and Hornady in terms of volume?

Great question and a matter of fact yes.

Even though this is not a load for the 6.5 Grendel, it clearly illustrates how the internal case volume affects chamber pressure...

A cautionary note on Laupa brass.

Many reload and the cases we load are generally what ever we have on hand. Most simply take out a reloading manual or two, do some reading and start with a load most likely in the middle of the recommended rage. What most of us never do is take into account the internal volume of a case which greatly impacts the bullets velocity and internal chamber pressure.

The following two photos are snapshots from the QuickLOAD program. The only difference is the internal volume of 28.8 grains and 30.5 grains. Take a look at the chamber pressure; 56,143 psi and 64,925...





I selected 4 empty cases by different manufacturers. All were cleaned thoroughly and trimmed to 1.750 then I inserted a new Remington 7 1/2 primer for consistency. I have a digital scale to after I recorded the weights I zeroed the scale and filled each case with water right to the top with a slight convex shape to each. I'm not quite sure what the "official" level is but by keeping this shape consistent I was introducing as little variation as possible.


Military LC-75

Empty Case Weight - 91.4 grains
Water Weight - 31.3 grains

Remington UMC

Empty Case Weight - 92.3 grains
Water Weight - 30.9 grains

Black Hills Match

Empty Case Weight - 97.2 grains
Water Weight - 30.1 grains

Lapua

Empty Case Weight - 107.7 grains
Water Weight - 28.9 grains

While I'm uncertain if the Remington UMC would be considered military cases I was surprised to see the Black Hills Match be 5 grains heavier. In general, commercial brass is thinner therefore yielding a slightly larger internal volume but this may not be true with Black Hills Match, at least in this case. The Lapua brass is what shocked the hell out of me! If I was at the recommended maximum charge weight using this brass I would easily exceed the SAAMI Maximum Chamber Pressure by quite a lot.

AND, my COAL is 2.350 instead of the 2.260 normally associated with this cartridge.....

[mseric]

A couple things concerning your Case Capacity tests.

You selected 4 empty cases. Were these cases New or used? Were they sized or unsized.

Quickload recommends that cases should be fired in "Your" firearm and left unsized.

In general, commercial brass is thinner therefore yielding a slightly larger internal volume

Although this is true with Military vs Civilian brass in 308 and 30-06 it is less true in the 223/5.56. In fact most "Military" 5.56 brass has more case capacity than it's Civilian cousin.

From Sierra.

The conventional wisdom to reduce loads with military brass is familiar to most reloaders and is generally good advice. The rationale here is that the military cases tend to be somewhat thicker and heavier than their civilian counterparts, which in turn reduces capacity and raises pressures. This additional pressure normally requires a one or two grain reduction from the loads shown in most manuals or other data developed with commercial cases. While this is most often the situation with both 308 Winchester and 30-06 cases, it is less true with the 223 brass. We have found that military cases often have significantly more capacity than several brands of commercial brass. Again, take the time to do a side-by-side comparison of the cases you are working with and adjust your load as needed. There may be no need for such a reduction with the 223. Know your components and keep them segregated accordingly.


I do not have any Hornady Grendel brass to check fired case capacity, so I can't answer if one has more capacity then the other. Compressing powder is nothing to worry about and shy away from as long as there is data to support the charge. Ball/spherical powders do not compress as well as rat-turd powders, but they can still be compressed although only slightly.

[cst]

So does anone have any actual numbers for the amount of grains in brass with a round loaded(123gr.) before compression????

[NightForce]

A couple things concerning your Case Capacity tests.

You selected 4 empty cases. Were these cases New or used? Were they sized or unsized.

Quickload recommends that cases should be fired in "Your" firearm and left unsized.

All cases were fired and left unsized for this test.

To ensure uniformity and consistency therefore eliminating as many variables as possible, I developed and followed a small test plan.

1. De-cap
2. Tumble
3. Trim to length (1.750)
4. Re-prime
5. Weigh each empty case
6. Zero the digital scale
7. Fill with water using an eye dropper
8. Record and publish the data.

I have some 6.8 SPC Remington cases of different manufactures that I put through this same test....

[LRRPF52]

I personally work out for myself how much powder capacity there is by filling the case to the shoulder neck junction, then dumping it out and seeing what the weight is. I then subtract 10% of that load for a starting load.

LVR is around a raw max of 33.0gr, so a start load makes sense at 29.0gr under a 123gr SMK/Scenar/A-MAX/NCC/SST.

Determine your velocity trend per charge weight using no more the .3gr increments with LVR, and put them over a chronograph or Magnetospeed. Once your velocity trend departs from 12-31fps, you're probably in a place you don't want to be.

When I do get around to testing LVR, I will load strings of fire like this under the 129gr SST:

28.1
28.4
28.7
29.0
29.3
29.6
29.9
30.2
30.5
30.8
31.1


Bwild97 has a max load of 32.5gr under the 123gr SST that produced 2740fps from a 24", and the COL he used was 2.275", with Fed205M primer. He worked up to that of course, so please don't take that load and go right to it.


I think LVR appears to be a very suitable powder for the 129gr and 130gr bullets, in addition to 120-123gr.

[Drifter]

So does anone have any actual numbers for the amount of grains in brass with a round loaded(123gr.) before compression????

It's gonna vary by powder, brass, and COL requirements for a particular chamber. These numbers will be ballpark for example only, but it might be ~28gr of 8208 powder, and ~31gr of CFE to avoid compression. That being said, I haven't experienced any problems with compressed loads as long as the load (pressure) isn't excessive. Look at data on Hodgdon's website, and you'll see some charge weights with a "C" shown, meaning compressed. Whether compressed or not, excessive loads beyond max for a particular barrel can be dangerous. In other words, just because a load isn't compressed doesn't mean that it's safe. As always, start low and work up loads carefully. And just because a shot or two is fired without ill effects doesn't mean that a particular load is safe. Learn to recognize the signs of pressure, and use of a chronograph is strongly recommended if you plan to approach max loads.

[rasp65]

According to the calculations that I use, a Lapua case with a volume of 35.8 gr of water, 123 A-Max seated to 2.26" will reach 100% density at around 28.9 gr of LVR. When measuring water capacity of cases I add a small amount of detergent to the water(mixed separately in the container I use the eyedropper from) to relieve the surface tension.

[Nukes]

QuickLOAD cautions 'Do not use with Hodgdon Extreme Powders.'" Except for a smidgen of VV N540 (for the 130 grain Sciroccos in the 6.5 Grendel), all the powders we use are Hodgdon Extreme Powders. Alas!

[LRRPF52]

In my .260 Rem, case volumes are significantly different. I started out using 7mm-08 Winchester brass necked down.

Then Lapua started making .260 Rem, and the case volume is much less in it than the previous. Pressures will go way up if I were to use the same load of H4350 in the Lapua brass, so I had to work up loads again.

With the Grendel, it seems that most brass is fairly close to each other, but using sensible starting loads 10% less than max published loads will get you started off on the right track to developing a load.

[NightForce]

Rarely do I need software that won't run on Mac OSX, but when it isn't offered, it is usually ham radio or ballistics software.

May I prevail on you, Nightforce, to do a comparison related to the 6.5 Creedmoor?QuickLOAD cautions 'Do not use with Hodgdon Extreme Powders.'" Except for a smidgen of VV N540 (for the 130 grain Sciroccos in the 6.5 Grendel), all the powders we use are Hodgdon Extreme Powders. Alas!

Yes of course!

I saw this sort of late but will be glad to ryn the numbers for you tomorrow....

[Nukes]

You are most generous to do so—a scholar and a gentleman! Many thanks.

[NightForce]

QuickLOAD cautions 'Do not use with Hodgdon Extreme Powders.'" Except for a smidgen of VV N540 (for the 130 grain Sciroccos in the 6.5 Grendel), all the powders we use are Hodgdon Extreme Powders. Alas!

Are you loading to a COAL of 2.825 in all cases?

Like you, I try to load my accuracy stuff out to about .010 to .015 from the lands but I don't see your chamber's maximum cartridge length listed using Berger 140 grain Match Hybrid Target projectiles.

[NightForce]

Nukes,

I took a shot and used a COAL of 2.825 from my new Nosler manual.

[NightForce]

I added these to the list of possibilities and the pressures are under max listed of 63,091psi. I don't adjusted the Pmax pressure, it's what ever the program provides.