quote:

Originally posted by boom stick:
I think the BR class has a limit of 40 cal diameter.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by capoward:
KUR RIP,

Obviously you were intended to do something else today!

Jim,
Yes, I had to take three generations of mothers out to lunch today, along with son-in-law and granddaughter. 3-year-old Grandaughter picked place to eat, she is precocious, but stuck on Bob Evans for unknown reason. . Meal, flowers, and gift certificates were presented to Mom, Wife, and Daughter. Daughter is pregnant again. Boy this time maybe.

Great idea using the RCBS loading block upside down...gonna have to pull an old one out of the box to use myself...should be very handy.

I have a similar QD QD that I use for my two M77 SA Rugers.

Is it a Chucky Cheese token?

Ok...so if a 12.7x68mm MT falls into the DGBBBR 'Small Big Bore' Mitch Carter Class, does that mean that my 10.74x68mm MT falls into the DGBBBR 'Mini Big Bore' Mitch Carter Class?

No. You need to call it a 10.75 to make that class!.

If so guess that puts the 9,3 BH&M into the DGBBBR 'Micro Big Bore' Mitch Carter Class!

Correct, despit above..

So where tha heck does that put Colin's little 2-bore DR? Uh... maybe the DGBBBR 'T-Rex' Mitch Carter Class!!!

quote:

Originally posted by RIP:
Micro Big Bore: 9.3mm (.366") to 10.74mm(.422") 10.80mm (.425”) caliber
Mini Big Bore: 10.75mm (.423") to 12.67mm (.499") 10.82mm (.426”) to 12.95mm (.510”) caliber
Small Big Bore: 12.70mm (.500") to 14.83mm (.584") 12.97mm (.511”) to 15.75mm (.620”) caliber
Medium big Bore: 14.85mm (.585) 15.77mm (.621") to 25.37mm (.999") caliber
Big Big Bore: 25.40mm (1.000") and larger calibers.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by RIP:
Jim,
You got it all screwed up with some .02 mm gaps and your classes make less sense.
You would make the 404J (.423") a Micro Big Bore same as the 9.3 (.366"),
yet you make the 425WR (.435") into a Mini Big Bore same as the 50BMG!
This will never do.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Ok… I really know squat about how to compute the BC of a bullet so QD designed a simulated 361gr .500 ESP Raptor with Talon Tip to play around with QL, and QT. Both QL and QT identify the G1 Std ICAO of the 361gr .500 ESP Raptor with Talon Tip as 0.296 BC… for whatever that’s worth.

And playing a little further with QT, using RIP KUR’s velocity QT indicates 1902 fps and 4440 ft-lbs at 300yds.

And... extremely nice shooting RIP KUR. Now I wonder what you'll do with the 430gr MTH at 300yds.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by 416Tanzan:
Jim--

The 430 grain MTH was listed as 0.426 BC some time ago.

IMO, the Raptor needs to get within .100 points of that BC to be a competitor over 200 yards.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by RIP:
I took a "stay-cation" day and had the range to myself.
Quickly ripped off the 50-yard chronograph work.

The Barnes FXB-cannelured .500/375gr bullet showed a good load with H322 charge of 97.0 grains.
Velocity 2705.3 fps and ES of 32 fps for three shots and 0.585" group: ~1.1 MOA

The CEB load finished up very strong with tip installed.
360-grain(W350), 95.0 grains H4198: 2903.0 fps at 5 yards from the muzzle, with ES of 9 fps for three shots.

Best 3-shot groups for it today:
50 yards: 0.606" about 1.2 MOA
100 yards: 0.448" about 0.4 MOA
300 yards: 1.069" about 0.3 MOA



This CEB bullet gets more accurate as range increases:







4th shot at 300-yard target above held "looser" hence flew higher?
Or I "pulled" it, it's a flyer.
5th shot: Used a reticle hold-over with the Leuplod 2.5X-8X scope, so it landed on the top target.
And maybe the breeze was more, drifted right, or I pulled it?
Here the pink streamer is hanging at "45-degrees of wind between lulls."

quote:

Originally posted by boom stick:
It's funny that these bullets are accurate yet accuracy is not as important with 7 projectiles lol
Close does count with these not that you want to get sloppy. Heart and lung shot and lights out.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by boom stick:
It's funny that these bullets are accurate yet accuracy is not as important with 7 projectiles lol
Close does count with these not that you want to get sloppy. Heart and lung shot and lights out.

quote:

Originally posted by boom stick:
With hunting there are many variables and it's good to know there is a margin of error or margin of oops or room for Murphy with these type of bullets. Not much but a lot more than others.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne

quote:

Originally posted by boom stick:
With hunting there are many variables and it's good to know there is a margin of error or margin of oops or room for Murphy with these type of bullets. Not much but a lot more than others. It could save your ass on an expensive hunt of a lifetime and prevent wounded animals and run offs.

quote:

Originally posted by capoward:
I thought it appropriate to resurrect the original thread to throw some new information into the mix.

Here’s some historical information:
Select Chamber Data:
Chamber Minimum Length: 2.669"
Brass Maximum Length: 2.657"
Shoulder Diameter: 0.575”
Neck Diameter @ Shoulder/Neck Junction: 0.531”
Neck Diameter @ Case Mouth: 0.531”
Freebore Diameter: 0.502”
Freebore Length: 0.252”
Throat Angle: 1º30min

Multiple-edited post-excerpts by RIP:
A la Doc M's MIB extractor head spacing research. Using the extractor of a Winchester M70 and the rimless-rim of the case for headspace on fireforming; Just touch off a standard .338LM in a 49-10 chamber… Mine were fire formed with a hot loaded 200-grain Nosler ballistic tip .338/200-grain bullet.

Lapua-brand .338 Lapua Magnum Commercial Brass:
New Unfired Case Length: 2.717"
Fire Formed Case Length: 2.707"
Fire Formed Case Trim Length: 2.647".
Fire Formed Case Capacity: 131.45grs water

And here’s some updated information:
Yesterday I picked up 50 pieces of ‘new unfired’ 338 Lapua Magnum (Lapua manufacture) commercial brass. A few months ago I picked up 200 pieces of ‘once fired’ 338 Lapua Magnum (Lapua manufacture) military brass with spent primer, half cleaned and half un-cleaned. This afternoon I had a chance the brass prepped as 12.7 x 68 Magnum brass.

Here’s what I’ve come up with…
Unfired Commercial brass – OAL: 2.717”, Shoulder Diameter: 0.543”, Neck Thickness: 0.029”
Once-fired Military brass – OAL 2.724”, Shoulder Diameter: 0.544”, Neck Thickness: 0.033”
(Note: Once-fired military OAL runs 2.722” to 2.724” length – the piece used for this comparison was 2.724” OAL.)

First Step: a single pass into my Hornady’ 338-500 Custom Expander Die – Second Step: 6 smacks* with a 3# hammer with the case within my Hornady’ 12.7 x 68 Hydraulic Case Form Die – and Third Step: a single pass into my Hornady’ 12.7 x 68 Full Length Resize Die:
U/F Com – OAL: 2.634”, Shoulder OD: 0.572”, Neck OD: 0.517”, Neck ID: 0.494”, Case Weight: 339.511gr with spent primer, Case Capacity: 123.458grs water– Case Neck OD with 500gr CEB BBW#13 FN Solid: 0.527”
O/F Mil – OAL 2.649”, Shoulder OD: 0.572”, Neck OD: 0.518”, Neck ID: 0.494”, Case Weight: 354.944gr with spent primer, Case Capacity: 108.026grs water – Case Neck OD with 500gr CEB BBW#13 FN Solid: 0.528”
* Hornady recommends 3-smacks but that only results in Shoulder OD of 0.5685”

And finally, the Fourth Step: create dummy cases by seating .500 caliber 500gr CEB BBW#13 FN Solid (DGBR W04 – these are the discontinued 4-equidistant band style) bullets, seated with 2 bands outside and bands inside the case neck – case mouth seated against lower edge of the 3rd band:
Unfired Commercial brass – COAL: 3.570”, Neck/Shoulder Junction Diameter: 0.527”, Neck Diameter @ 2nd Band W/I Neck: 0.527”
Once-fired Military brass – COAL 3.570”, Neck/Shoulder Junction Diameter: 0.533”, Neck Diameter @ 2nd Band W/I Neck: 0.528”
Dimensional Issue:
The neck/shoulder junction diameter of the once-fired military brass exceeds the minimum chamber specification and is an issue requiring resolution.

Case Creation Comments/Issues:
Fire forming cases vis-à-vis Hydraulic case forming:
Untrimmed Case Length: Fire Forming: 2.107”
Untrimmed Case Length: Hydraulic Forming Die U/F Com: 2.634”
Untrimmed Case Length: Hydraulic Forming Die O/F Mil: 2.649”

The fire-formed brass requires length trimming to function properly within the 12.7 x 68 Magnum chamber; this is not required with hydraulic case forming – except that the military brass should be trimmed to normalize case length after hydraulic forming.

Case capacity:
Untrimmed Case Length: Fire Forming: 131.45grs water
Untrimmed Case Length: Hydraulic Forming Die U/F Com: 123.458grs water
Untrimmed Case Length: Hydraulic Forming Die O/F Mil: 108.026grs water

Difference of 7.992grs water between Fire-Formed vis-à-vis Hydraulic Formed 12.7 x 68 Magnum brass; both using new unfired Lapua manufacture commercial 338 Lapua Magnum brass. The Lapua manufacture 338 Lapua Magnum military brass is 15.433gr heavier and 15.432grs water less capacity than the Lapua manufacture 338 Lapua Magnum commercial brass.

Final Comments:
Hydraulic case forming is a viable option for creating 12.7 x 68 Magnum cases from 338 Lapua Magnum commercial or military brass. That said, the greater case capacity of the fire-formed brass as well as the potential of normalizing the wall thickness from the case shoulder through the case mouth areas of the military brass may outweigh the ease of creating these cases via the hydraulic case method.

So there it is.

Oh yes, please note that ‘Tornado’ has been dropped from use within the 12.7 x 68 Magnum terminology.

quote:

Originally posted by capoward:

quote:

Originally posted by RIP:
Resized 49-10 brass that is 2.656" average length after second full power load and second resizing:

129.9 grains water gross/overflow water capacity

This is within one drop of the concave to convex meniscus change.
I do not care to be any fussier than that.

Looks like I shall get another firing before I have to trim.
At least 3 firings between trimmings.

Thanks RIP...I've updated the earlier post.

Ok...so your 1st trim length after fire forming was 2.647" and after two full powder loads and a second FLR resizings you have a 2.656" length...a case length growth of 0.009" which equals 0.0045" after each full load firing. So it appears that case trimming is required after every 4th full power loading...though it's actually every 4.888 full powder loadings.

RIP is the neck wall thickness staying at 0.0135" per side, or 0.027" gross, or is it beginning to thin out?

quote:

Originally posted by RIP:
Jim,
Neck wall thickness seems to be about .0135" at midpoint of neck: midway between neck-1 (at shoulder) and neck-2 (at case mouth).

However it is as thick as .0170" at neck-1,
and as thin as .0100" at neck-2.

Overall: Excellent.
It all works well, no inside-neck reaming, no outside-neck turning required.
All well within the tolerances of commercial brass, and Manson chamber reamer, and Hornady Custom dies.

Overall brass movement/growth is slight and leads to thinning at the case mouth, to make trimming after each third or fourth firing easier.

I shall say it again: There can be no better "Five Hundred" or "Fifty" than the 12.7x68mmM/49-10.

Since you have revived the older 49-10 thread, I feel compelled to copy new additions to 49-10 knowledge to this more recent 49-10 thread highlighting the wonderful CEB bullet accuracy.

Jim
"Life's hard; it's harder if you're stupid"
John Wayne