we'll call it the 500 AR (as calling it the 500 BS would not have a good "connotation")

number 1 - I don't think this project is actually worth doing, UNLESS you have a 308 Ruger mkII laying around.

okay, here's my thoughts.
a rigby/lapua based 510 would have zero net advatange over a 495 a2 and will require a single stack mag in most guns. But yeah, you might could get 535 2100ISH.

but guys, that would be a LIGHT LIGHT LIGHT 500.

I guess if I could shoehorn a 3.15" 458 win into a mexican mauser, I probably could do the same with another and a 500 mbogo short... or 500 AR just to keep in the bend of it.

Let's see...

338 lapua brass
blown out
shortened
single stack (unless you do it on a ruger)
that could be loaded to 3.1



if you take this to a 24" barrel, you might could tread on 2200... and if you took the case to 3.35, you would hit 2300 MAYBE

I would then suggest that the actual cartidge be designed for 3.35, and then pushed in and the charge backed down for 3.1

So, what do we want to do?

I'll designed it and give it to BB if he wants to do this project.. and see the "fun" of taking it home....

rough costs
200 - reamer
80 - headspace gages
180 - dies
200 - barrel
350 - ruger to build it on
300 to 500 - install barrel, recoil lug, feeding

or about 1310 bucks to get it off the ground...


I can take this as an 07 project as, yes, 6.5 weeks into the year I am BOOKED.

<why am I doing this?>

jeffe

because you are a gun nut!!!

it can be named bsar (get it... bizare)

or just 500 boomstick no space

500 ar will do if you insist...

how about moving the shoulder forward some?...

Jeffe,
Very interesting concept.

I feel comfortable necking the .338 Lapua Magnum brass up to .458, and ending up 2.690" long for trim-to (max brass 2.700"). BUT, will the brass survive necking to .510???

As for blowing the body out, why not go a little more to .575" at the shoulder?

And why not keep the 20 degree shoulder of the .338 Lapua Magnum???

If only Lapua made a cylindrical basic brass with the same head as the .338 Lapua Magnum, and made it at least 2.5" long ... then I would want it 3.000" too:

L to R: Lapua, Norma, QualCart

neeevermind (gilda radner voice)

quote:

As for blowing the body out, why not go a little more to .575" at the shoulder?

trimming to rough length first might help...

Boomstick,

the neck is 1 caliber, BS.. that's the way it's "supposed" to be, in a perfect world... don't think it would matter if it was .510 or .45 ... and wouldn't give back enough case to make it worth arguing about.

Rip,
i just took the dim's to the shoulder of the 338 lapua improved... only gives back about .1deg ... need alot more shoulder to have a sharper shoulder (which I wanted, but it aint there).. I think if you annealed LAP brass, as is, stuck a .338 shanked .500 (under sized) in for fireforming on a stiff load it would take the brass all the way out...

of course jamison basic would be form DOWN, rough trim, fireform

jeffe

old school 500 nitro velocity...i like it!

Here's mine:

A bit different.
http://server5.pictiger.com/img/45146/computer-games-an...x-61-mmmaus_full.gif
(grrrr.)

try that again bwana...

Reason for the short neck was figuring on a 535g Woodleigh or similar length bullet, not wanting to eat up too much powder, and still get the .7" mouth-to-COL for cannelures and ogee.
The need for caliber-lenght neck gets less as caliber increases. My thought is that it has more to do with how much brass is holding your bullet. In the .264"-.338" range, a caliber's length is probably a good rule of thumb.
As for net advantages over Cartridge X, well, it can be built into a tiny package and throw some big horsepower, right in its own little niche. Whether that niche is something you want filled is purely personal.
If the 3.1" round really can send a 535 out closer to 2300fps from a 24", it would be more than one might want for realistic NA thumping (a la "monster 50AK" style) - and there's lots of cast load possibilities. Besides, a little SA rifle with a British DG stock setup and 3-leaf, barrel-band, etc., just does something for me.
If I had a 495 A² I'd mostly just be wishing it was a 500 A²!

Jeff, what is it about Rugers that preclude the need for single-stacks?
I've always seen this round in a SA M70.

BB,
rugers are wider than model 70s... and wider enough that you can perhaps, get rigby/lapua cases to stagger feed.

no point in discussing it.. rather, cussin it, as it won't work without spending cubic dollars

jeffe

Well, never heard that. Have never owned a Ruger, but that makes me think twice. I suppose the ones I've handled seemed to work, but the Ruger always seemed like a M70 wannabe (my own personal and ill-conceived bias, to be sure.)

Are you guys hijacking my 500 on the 416 Rigby basic case?
I just miked an unformed 416 Basic case and it measures:
oal 2.954
dia at base .584
dia at mouth.578
casemouth id .554
wall thickness .012 p/- .001

take a .510" slug plus .024 for double the case neck thickness = .534 + x for a shoulder has to equal .584
x = .025" per side
give me .010" taper and x = .020" for a neck/shoulder area

Soooooooooooooooooooooooooooooooooooooooooooooooooooooo...
I get a reamer cut for that set of dimensions and have them open up 416 Rigby dies to match.
CH4D will work with me using the reamer to cut the fl sizer and seater

Egad!

Rich

BB,
other than the first line have round tops, there's nothing to compare.. and they are totally different ways to get to the same place.

the current ruger (which IS in production) is available, every day, in lefty, right, SS, or blue

double square bridges
intergal return to zero machines scope mounts
3 position safety ON THE ACTION with is a surpreme mechinical lock out

SUCK trigger

and you can throw one on the top of EVERY one of them, and work the bolt.. it will CRF from the mag, and push feed from the top.

other than the triger SUCKS and the wood doesn't come up high enough on the righthand side of the stock, They are excellent actions...

solve the trigger for 80 bucks...

jeffe

Rich,
if you are making a full length one... or want this shorter one, go for it,... I won't be touching this project for at least a year in any event

jeffe

quote:

The need for caliber-lenght neck gets less as caliber increases

totaly agree!

quote:

Originally posted by RIP:
Jeffe,
Very interesting concept.

jeffeosso...

you actualy got rip to be happy with one of your (our) projects...??? are all the planets aligned or is it a full moon ouuuuuuuuuuuuu!

i guess i should be happy and not rock the boat

rip...i think the 500 a.r-b.s. needs adopting along with the orphaned 450 b.s.

i think i just rocked the boat

quote:

Originally posted by boom stick:

quote:

The need for caliber-lenght neck gets less as caliber increases

totaly agree!

Disagree -- This is 100% backwards to math. Though this is a relativilty PII (pursuit of irrelevent incrementals) area.

we over-rate what the case neck does/can do, and smaller cartridges have a several TIMES overlength neck.

*** this is the crux of my discussion.. the math part is boring and listed under this section

Recall that the purposes of the neck are to aid in feeding and to hold the bullet under recoil

What does this all mean? It means that we should fine the optimum neck length for a very large caliber and work our way DOWN with shorter necks to do the same job. I'll draw a line in the sand with the 550 express. It works perfectly with a single caliber "neck" but the 577 nyati requires a caliber+ neck (this might be a function of the crap brass, though). Since the 550 works so well with that, then everything else can be shorter to accheive the same results... that is, hold a bullet in the case!!

The smaller cases can get by with TINY necks.
**** math stuff now****

let's agree that on earth, in 1g then mass is a function of volume (and we don't need to go into the oddities of an accelerated object actualy weighs more as we are talking about near rest to ~50fps MAX inside the magazine)

The MASS of the bullet, as well as the SURFACE AREA of the interface between the case and bullet will determine the CoF (you can all it several things, but this is a handy enough label) required to hold the bullet in the case mouth under the forces to be encountered


you have the law of square/cubed working AGAISNT you on the MASS of the bullet but in you favour on surface area . and you loose this struggle when it comes to neck tension. Lets "pretend" that the section of the bullet inside the neck is cubic in nature, rather than a rod (just the part inside the neck) ...

(using cube to make math shorter) 1cmx1cmx1cm
If that the volume would be 1cm^3 (1cm*1cm*1cm) and had a surface area of 1 cm as well 6cm^2 (6*1cm*1cm)
and we then we DOUBLE the size to 2x2x2
the surface area becomes 24cm^2 (6*2cm*2cm) FOUR times the surface area)
the volume goes up EIGHT times or 8cm^3 (2cm*2cm*2cm)


As we agree that volume goes up EIGHT times, then the mass also goes up EIGHT times, requiring the CoF to dramatically INCREASE to hold the bullet in the case neck under the ~same~ FPS accel/decelerations typified during recoil. Yes, the recoil lb-ft generally goes up dramaticaly in larger calibers, but the FPS generally stays in the 17-25 range (pretty narrow)



full math shown below - they have a typo that should read 8cm^3 (2cm*2cm*2cm)
http://www.auburn.edu/academic/classes/zy/0301/Topic4/Topic4.html#square

jeffe

BS,
if you place this into two camps, Rip and I...
we both have excellent ideas, just not overlapping ones for the most part. This is one of those times were my struggle to keep the action and gunsmithing fairly cheap overlaps with superior performance of larger rounds

jeffe

quote:

Originally posted by jeffeosso:
BS,
if you place this into two camps, Rip and I...
we both have excellent ideas, just not overlapping ones for the most part. This is one of those times were my struggle to keep the action and gunsmithing fairly cheap overlaps with superior performance of larger rounds

jeffe

o.k.

so with my roughly cal neck short neck 404 that would work in a win mag action...how bout that?

that sure falls into that philosophy do it not? sorry...

i am starting to like the 500 a.r.-b.s. more...how much for a first run rifle if action donated?

quote:

Are you guys hijacking my 500 on the 416 Rigby basic case?

ID Sharpshooter, yours?

I guess if you make it first, and adverstise to one and all that you did it.

The IDEA of the 500/416 on basic brass was floated around here YEARS before you came along. In fact, it was discussed only days before you started your thread!! (check out this post from January...here ) I chuckled when I read your thread because it was just re-hashing a recent thread here...I thought maybe you were joking. Maybe you still are? Or maybe you just didn't know what the 470 Mbogo is, and therefore that the 500 Mbogo we had been talking about is exactly what you suggested.

It was probably considered by others long before it was ever discussed here too.

[Although, I admit, I still don't think its really worth messing around with...I prefer a beltless case too but this is really re-inventing the wheel, when a 500 A2 covers it all handily]

There is almost nothing that is truly new in wildcatting.



Cheers,
Canuck

quote:

Originally posted by boom stick:
i am starting to like the 500 a.r.-b.s. more...how much for a first run rifle if action donated?

Does this mean you might actually "do" something in all this? Like fund/build/own one of these rifles? I see a lot of posts (and credit taking), but I haven't seen the boom-stick rubber hit the road yet.

Cheers,
Canuck

quote:

Originally posted by Canuck:
Does this mean you might actually "do" something in all this? Like fund/build one of these rifles? I see a lot of posts, but I haven't see the boom-stick rubber hit the road yet.

Cheers,
Canuck

Money talks, BS walks...




Just funnin' you BS.

with my new job i should have more spending money this year...but i am buying a new house so the cash the next few months will be tied up, escrow closes the 28th...funny i admit i am not afraid to laugh at myself...you saw the smoking jacket...

p.s. people with big dreams and little money are people too

quote:

with my new job i should have more spending money this year...but i am buying a new house so the cash the next few months will be tied up, escrow closes the 28th...funny i admit i am not afraid to laugh at myself...you saw the smoking jacket...

Get them to add a grand or two to your mortgage so you can get one of these bad boys built!

its too late to make changes but i would have bought the big screen tvs that were there the same way but did not want to make the mo. pmt. any bigger

quote:

Originally posted by boom stick:
its too late to make changes but i would have bought the big screen tvs that were there the same way but did not want to make the mo. pmt. any bigger

Life has a way of interfereing with plans and dreams!!

Jeffe,
Take a gander at page 414 of Ken Howell's book, Custom Cartridges:

As a recent convert to small shoulders, I had ignored this ".500 Van Horn Express" previously.

Gil Van Horn did a 2.5 inch ".510 Van Horn" on the .460 Weatherby case shortened.

Apparently the ".500 Van Horn Express" was done about 30 years ago, as a "short .510/.416 Rigby," by turning the belts off of .460 Weatherby brass:

2.5750" brass length
40 degree shoulder
0.375" neck length
shoulder diameter = 0.5750"
neck diameter = 0.5320"

The Weatherby-belted ".510 Van Horn" was a 2.5" version that was supposed to move a 600 grainer at 2300 to 2400 fps using 90 grains of IMR-3031

Thanks for the Jamison basic brass idea. I'll bet he can build it like Lapua does too, as he does the .408 Chey-Tac.

Van Horn had a .423 and .416 Van Horn based on the full length .404 Jeffery case (as with the .460 G&A).

And they say that Art Alphin designed the .416 Dakota for Dakota Arms???

I now see the .460 G&A as a great cartridge and ask the forgiveness of all the small-shoulder proponents I have antagonized in the past.

so this will be a tad better than the 500 van horn express with $1.62 brass

Well, the .500 AR do have a better neck.

I will be rooting for a full length one with Jamison Brass.

Might as well do three of them :

.500 AR 2.5"
.500 AR 2.7"
.500 AR 2.9"

well, dang it... i don't like being a decent designer a generation too late...


2.7" case would offer 10-15 gr more....

anyone got an icon for popped ballon?

jeffe

j, what does that mean...

this is stil a great idea and with good avaliable brass



hows this...did you mean bursting your ego?

2.7" anyone?

that takes us close to 3.4 or so

jeffe

whats wrong with the idea as is? it is not on lapua brass?

Jeffe,
I sure like the 2.7" best.

That would be unique.

Given a .5000" parallel-sided freebore length and a freebore diameter of 0.5105" or 0.5110" (bullets are 0.509" to 0.510") with 1.5 degree leade:

It could be used for any bullet and in all but the shortest of actions (seat long for 3.8" box, or seat short +/- trim brass 0.100" for the 3.4" box ... depending on the length of the bullet nose, etc.). That freebore would allow the use of any milsurp 50 BMG bullet and the Hornady 750 grain A-Max

I would add that to the HA!/DOA line, then I would neck it down to .475 AR (as distinct from your .470 AR).

.307 Lapua Chui
.337 Lapua Simba
.377 Lapua Mbogo
.427 Lapua Kifaru
.457 Lapua Tembo
.475 AR 2.7" ... could be a .477 AR Mbogo
.500 AR 2.7" ... could be a .507 AR Mbogo

.477 ARM and .507 ARM: Two strong ARMs, made with Jamison Basic Brass instead of Lapua.

.477 Jamison AR
.507 Jamison AR

This may JAR me into activity.

That would sure simplify the HA!/DOA line, to Seven cartridges only, all with brass length of about 2.7", Lapua or Jamison.

Thanks for the idea.