6mm cheat sheet info
- Thread starter whatwind?
- Start date
It would be very interesting to create a “case efficiency” by looking at capacity, powder charge, and velocity. I know each of these calibers would be more optimized with different powders, like varget for 6br, 4350 for 243, 4831 for 6-284, but still could be useful.
for instance, despite having 38% more case volume and burning 22% more powder, 243 only gains around 100fps over a 6br(2900 vs 3000fps) for a 105gr bullet.
for instance, despite having 38% more case volume and burning 22% more powder, 243 only gains around 100fps over a 6br(2900 vs 3000fps) for a 105gr bullet.
RegionRat
Gold $$ Contributor
@jpmimproved I often mused about such a study with some ballisticians who were also target shooters and hunters. It would take some resources to put good numbers behind such a study since you would have to sweep a few different bullet weight ranges and bbl twists for each of these calibers to fill out the picture. I have done a little of it myself by just using published information and found the bbl length is also an issue you would have to address. When some of the new heavier bullets came out, it changed the landscape for many of the smaller calibers like 6mm.
The muzzle energy with some bullet weights, bbl lengths, and powders, can take some designs from efficient to just average, but I like the study of such questions. In the end, if we look at muzzle energy divided by the potential energy of the powder charges, you can start to see where some of these designs really shine. It takes a lot of legwork to gather that data and format it so it is understandable.
In the short run, if you just look at it the way you did with a given bullet and the powder you burn to get a given speed, you can see the issue of how the muzzle energy and speed play to get an extra 100 FPS. It takes more homework and averaging to say if each design pays an equal price for any given speed change.
The muzzle energy with some bullet weights, bbl lengths, and powders, can take some designs from efficient to just average, but I like the study of such questions. In the end, if we look at muzzle energy divided by the potential energy of the powder charges, you can start to see where some of these designs really shine. It takes a lot of legwork to gather that data and format it so it is understandable.
In the short run, if you just look at it the way you did with a given bullet and the powder you burn to get a given speed, you can see the issue of how the muzzle energy and speed play to get an extra 100 FPS. It takes more homework and averaging to say if each design pays an equal price for any given speed change.
How does BRA or BRX weigh more than BR brass it was formed from?
Could they possibly be formed from a different lot, separated by years? Perhaps a one case sample, randomly selected?
The values are merely ball park numbers for QuickLoad. YMMV.
| Neck | Shoulder | H2O | |
| Cartridge | Length | Angle | Weight |
| 6mm BR Norma (Lapua) | 0.3362 | 30° | 39.02 |
| 6mm BR AI (Lapua) | 0.3374 | 40° | 39.80 |
| 6mm BRX (Lapua) | 0.2313 | 30° | 41.00 |
| 6mm Creedmore (Hornady) | 0.2775 | 30° | 53.70 |
| 6mm Dasher (Norma) | 0.2995 | 40° | 41.18 |
| 6mm International | 0.3764 | 26° | |
| 6mm HLS (Remington) | 0.3720 | 26° | 45.08 |
| 6x47 Lapua (Lapua) | 0.3000 | 30° | 47.88 |
| 6 XC (Remington) | 0.3032 | 30° | 49.64 |
| 6 XC (Peterson) | 0.3001 | 30° | 48.24 |
| 6x47 Rem (Remington) | 0.2868 | 23° | 31.10 |
| 6 PPC (Norma) | 0.2804 | 30° | 33.74 |
| 6mm AR Turbo (Lapua) | 0.1847 | 40° | 37.46 |
| 243 Win (Federal) | 0.2561 | 20° | 55.58 |
| 244 Rem (Remington) | 0.3755 | 26° | 57.02 |
Updated previous with case manufacturer in parenthesis and removed case weight to reduce confusion.
Shoulder Angle derived from body and neck diameters and shoulder length to the degree.
6 XC (Peterson) and 6mm Dasher (Norma) are unfired cases.
6x45 is 23°.
6-250 is the 6mm International and 26°.
Last edited:
Whatwind _
Howdy !
I DK whether you might want to add a 6mm wildcat ( mine ) to the list ? I call it " DEEP 6 " .
The chamber is cut by running a 6mm Remington reamer in " short ", for a nominal .466" base diam.
I use ( Norma ) 7X64 as the parent case.
Shoulder angle is 26* ( same as 6mm Remington ), and neck lg is 3.51" ( same as 6mm Remington ).
Shoulder as also same as 6mm Rem.
Case capacity is 51.2gr H2O
It's a great 1,000yd capble varmint/target cartridge ( IMHO ).
With regards,
357Mag
My batch of Hornday 6mm GT is 44.8g water. A second production run was 45.4g.
The 43 might be from the original resized 6.5x47.
The 43 might be from the original resized 6.5x47.
perhaps there should be a range then? say 43g to 45g. thats going to be the case with most cartridges.
You can ad a drop of dishwashing liquid to your water that your using
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