Grendel Case Volume

[JASmith]

I feel remiss in not asking this question before. Excuses - I have calculated the volume from QL, measured my own brass, and searched the web.

I have discovered that the volume seems to range anywhere from 35.5 gr water to a tad more than 37 gr water when filled to the top of the case neck. This range is enough to make the difference between comfortable loads and ones that stress bolts and possibly dangerous loads.

I would like to build a concise summary based on fired cases that we can all use. The challenge is the variability in both brass and chambers. This means the table will have at least these column headings:

• Brass Head Stamp (Including Caliber if not originally a 6.5 Grendel case)
• Barrel or Reamer Source
• Measured Volume

Please share your measured volumes using the format above. By all means, include individual measurements since those will help with the statistics.

I am hoping to consolidate the contributions starting about a week before Christmas. If enough new measurement data comes in after then, I will update the table at an appropriate time.

And, yes, I will be happy to incorporate case volumes from folks like Von Gruff who have tweaked the Grendel chamber to boost performance a bit.

Thanks!

[cory]

I was looking through some old data and I found one I measured. I believe I taped off the bottom so this will include the primer pocket.

AA
6.5 Grendel (PF)
38.5gr

[maverick5582]

6.5 Grendel
Manson Reamer AA print
AA Brass
1.515" case length
36.5 grains

[Drifter]

Link: http://bulletin.accurateshooter.com/...-first-report/

[JASmith]

Drifter,

Thanks for the link -- it is a good read. They seemed to use unfired, or fired and sized cases. Do you know if they did any measurements on as-fired cases? That would most closely approximate the volume codes like QL use.

[mseric]

CSS 6.5 Grendel barrel

AA Brass, fired case capacity= 36.3gr

IMI 7.62 x39, 3x FiredBrass Conversion= 33.7gr

[sneaky one]

It does depend on the trim OAL also-on the brass, guys!

[mseric]

Forgot, both IMI and Grendel brass trimmed to 1.514

[mseric]

JAS I have an 18" AA 2009 vintage Shaw barrel. All cases trimmed to 1.520"
WW - 34.1 gr
Lapua- 35.8 gr
PPU - 35.7 gr

Is that fired, unsized cases?

[mseric]

That is once fired and sized fired and sized for the Lapua and PPU. The WW is FF'd 7.62x39 fired twice and sized. I don't think there would be any point in measuring them as fired because the reason you measure is to tell you the volume of the powder space. Also I used the same spent primer when measuring the lots. I did 5 cases and averaged.

From the Original post.

I would like to build a concise summary based on fired cases that we can all use.

This would mean fired and not Re-sized.

[JASmith]

This would mean fired and not Re-sized.

Right on!

We use the fired case volume since that is the closest we can get to the volume of the case when it is pushed hard against the chamber. That volume helps define the interior ballistics environment.

[pds]

Precision Firearms upper
AA case (fire formed unsized)
36.0 gr.

[A.D.D. AR]

AA hunter upper of 2009 vintage: (still waiting on my satern barrel, ha ha)
2x AA/lapua brass (not re-sized yet)
case length= 1.515''
average= 36.26 gr water


3x Hornady brass (not re-sized yet)
case length= 1.520''
average= 35.96gr water

-mike