Michael,

You've a plan. But I wouldn't order a custom riffing button for the .475 B&M. You have two of three rifles that engrave the bands and one that abraded the bands and PacNor should replace that barrel after they scope it cause it is defective.

well - that was an expensive barrel from Border, and seemingly it was ok and specs were right...

Well - soon Hatting will get the throatreamer and all the other stuff and we can start playing around
Dont know though whether we will be able to test accuracy with all different throat lengths, I think we first of all will test pressure/velocity and whether/when brass band shearing occurs...
Personally I beleive that we will end up with a throat in the .250" - 375" range - but we will see... Soon...

quote:

Originally posted by capoward:
Michael,

You've a plan. But I wouldn't order a custom riffing button for the .475 B&M. You have two of three rifles that engrave the bands and one that abraded then bands and PacNor should replace that barrel after they scope it cause it is defective.

Jim
Taking the stocks off both 475s this morning, getting some ammo loaded and sending what I have to Brian to get started on them. Not sending my expensive stocks==Cost more than the rifle!

Brian says PacNor offers in .474 1:10 and 1:16. Replacing the stainless barrel with the 1:16 just to check it out.

Zero doubt in the .474 band shearing here--Barrel!

Ulrik

I believe Brian told me that the 500 MDM was .375 throat. Works for me, very well.



With this all said, I am going to bow out of the conversation as I don't think I have anything I can add to it.

Michael

A record of some of your groups would be helpful, but it would take a lot of testing to differentiate accuracy before finding a point where things get noticeably/greatly worse. The point of shearing has got to be worse.

Michael, on the 0.375" freebore for the 500 MDM. You mentioned that right after talking to Brian.

A major topic of discussion is the “sufficient amount” of freebore to safely accommodate traditional hunting bullets. And I reckon Woodleigh FMJ and RN SN bullets are about as traditional of bullets as one can obtain for the .510 caliber.

My good buddy Sam Rose sent me a few Woodleigh bullets for measurement – and they arrived today – and I measured them up…a 535gr RN SN designed for the 500 Jeffery and a 500gr FMJ designed for the 500 Nitro Express…

Pictorially here is what two of the Woodleigh bullets – simulated in dimension is QuickDESIGN – look like fitted within the chamber of the 500 AccRel Nyati with its 0.255” freebore if seated & crimped against the upper edge of the seating groove using a 2.65” length case:

First is the 535gr .510 Woodleigh RN SN…


Second is the 570gr .510 Woodleigh FMJ


And here’s the minutia I collected for each bullet, the bullet seated in the 2.65” length case, and the seated bullet’s relationship to the chamber’s freebore/throat intersection and barrel’s bore diameter intersection:
535gr RN SN COAL: 3.392”
Measured Bullet Shank Diameter: 0.509”
Measured Bullet Length: 1.249”
Length of Shank Diameter of Bullet: 0.600”
Length Base to Bore Diameter of Bullet: 0.758”
Length Base to Upper Edge of Seating Groove: 0.507”
Length of Seated Bullet Protrusion: 0.742”
Length of Seated Bullet to Shank Diameter of Bullet: 0.093”
Length of Seated Bullet Shank Diameter to Freebore/ Throat Junction: 0.1765”
Length of Seated Bullet Shank Diameter to Barrel Bore Diameter: 0.3855
Length of Seated Bullet to Bore Diameter of the Bullet: 0.251”
Length of Seated Bullet Bore Diameter to Freebore/ Throat Junction: 0.0175”
Length of Seated Bullet Bore Diameter to Barrel Bore Diameter: 0.2275
570gr FMJ COAL: 3.394”
Measured Bullet Shank of Diameter: 0.509”
Measured Bullet Length: 1.357”
Length of Shank Diameter of Bullet: 0. 435”
Length Base to Bore Diameter of Bullet: 0.752”
Length Base to Upper Edge of Seating Groove: 0.613”
Length of Seated Bullet Protrusion: 0.744”
Length of Seated Bullet to Shank Diameter of Bullet: -0.178”
Length of Seated Bullet Shank Diameter to Freebore/ Throat Junction: 0.4465”
Length of Seated Bullet Shank Diameter to Barrel Bore Diameter: 0.6565
Length of Seated Bullet to Bore Diameter of the Bullet: 0.139”
Length of Seated Bullet Bore Diameter to Freebore/ Throat Junction: 0.1295”
Length of Seated Bullet Bore Diameter to Barrel Bore Diameter: 0.3395

Ok… that’s it. I’m done – with the heat and humidity here with no AC – I’m definitely done. Plus I’ve zero need to go any further – both bullets fit just fine in the [i]Nyati’s[/] 0.255” freebore chamber with plenty of available bullet jump with a spec length case and bullet’s seated & crimped in the bullet seating groove.

Yep I’m done…

Jim,
I appreciate the work and the passion -- I also did this on the other end to make certain there were no known safety issues

I am where I am until we have proved data..

Micheal's results of stripped bullets with short throats is VERY interesting .. which leads me to the following..


I don't believe the throat on the Accrel to be the cause of the stripping -- frankly pressures in a jacketed bullet would be astronomical on soft jacketed bullets.. and i've shot everything in mine without pressure signs on reasonable loads.

it MIGHT be the cause of the large group sizes though..

but we'll see..

Hey Jeff,

Thanks.

Michael's band stripping issue with #2 of three 475 B&M rifles was/is definitely and interesting situation. Hopefully PacNor will share with Brian and Michael exactly what was wrong with that specific barrel.

LOL… reasonable loads, I believe with Ulrik and Tanzan we’re looking a maximum performance at safe pressure being the norm…

Ulrik and Hatting will hopefully commence their freebore testing process shortly so that the many questions we all have will hopefully be answered.

In meantime we'll just have ponder the situation…

I'm expecting to safely load to around 7000 ftlbs in the 500AccR.

RIP already exceeds that in the 49-10 (a ballistic duplicate of the 500AccR) so I don't forsee any problem. current loads on Ammo guide may be underloaded, since they do not press beyond the levels of the 49-10 even though they have a freebore that should allow considerable increase (7500ftlb?, 8000ftlbs?).

Someone please explain to me:
How and where is freebore and leade measured correctly??? For ex - from where to where do you measure the 1,25'' freebore ???

Freebore egins at the end of the case, where the external case diameter becomes the frerebore diameter and continues to where the riflings start to show. The riflings then grow up to their full rifling height at the end of the "leade".

However, you will probably need to do a chamber cast in order to measure or see this since the riflings begin with only <0.001" and typically take 1/4" before reaching the full height. The "lead angle" in degrees, typically between 1.5º to 2.0º forms a triangle with the height from the base to the hyupotenuse being the height of the rifling (0.011" for AccR?, would give about .42" freeborn)

quote:

Originally posted by buffalo:
Someone please explain to me:
How and where is freebore and leade measured correctly??? For ex - from where to where do you measure the 1,25'' freebore ???

Obviously if you’ve attempted to find the answer on the interest you’re as confused as just about everyone else. Things would certainly be easier if everyone used the exact terminology to cover the various sections of a Finish Chamber Reamer then folks like us wouldn’t have to ask the question.

Unfortunately ‘Leade’ and ‘Freebore’ are used interchangeably by both reamer manufacturers and magazine writers.

Perhaps to get us on the same page this annotated illustration will help – it is the Finish Chamber Reamer specification for the 12.7x68 / 49-10 cartridge generated from QuickDESIGN:



Note: Corrected Chamber Schema...

Hope this at least puts our discussion on the same page.

That is a nice picture, though someone watching should be warned that it is not drawn to scale. The neck chamfer looks like is is about half of the neck length while in reality it is only about 3% of the neck length.

I had a question or problem with the number totals. Probably related to jetlag but had forgotten that the bore difference is a diameter but the riflings are projections of a radius on each side.

So:
The length of the "leade" allows the angle to reach the height of the riflings. This is a standard trigometric function.

so the tangent of 1º30' (1.5º)
will equal the freebore to rifling height (0.011" diameter difference gives .0055" rifling height)
divided by the unknown length (x).

multiplying the equation by x and dividing by the tan gives
x=0.0055"/tan

Since the tan 1º30' is approximately .0262
the length of the freebore becomes
0.0055"/0.0262
which is 0.21"

So QuickLoad's 0.2291" figure probably used a .512" freebore diameter, needing a little more leade to get to the extra height.

Tan,

Yes pictorially the drawing is distorted in the shown lengths vs. what their actual length are; otherwise it would be almost impossible to visually display the 45º angle of the Neck Chamfer in comparison to the 2.699” length of the Chamber. The Workitem Scale of the QD drawing is 1.32:1 which is then printed at a 1.5:1 scale – both of which distort the visual the visual length appearance of the Chamber Section vis-à-vis the total Throat Section of the drawing.

And yes there was an 'Oops' with the totals - I'd used an early draft of the 49-10 chamber specifications not the 'actual final finish chamber reamer specifications'... My bad - drawing corrected above...

Relative to the 500 AccRel Nyati, here are the Throat Dimension Lengths:
Throat Dimension Lengths:
Diameter Throat’ Freebore / Leade: 0.511”
Diameter Bore = 0.500”
Diameter Grooves = 0.510”
Length Neck Chamfer to Bore Diameter = 0.47853”
Length of Neck Chamfer = 0.0135”*
Length of Freebore / Leade = 0.255”
Length of 1º30’ Throat Angle = 0.21003”**

*Note:
Neck Chamfer Length computation based upon the 45º Angle Specification from Chamber’s 0.538” Neck Diameter at the junction of the Neck Diameter to the junction of the Neck Chamfer Freebore/Leade 0.511” diameter.

**Note: The QD Software rounds to the nearest x.xxxx” length…So:
0.2100” Throat Angle Length = 1º30’00.94” (1.50026) Throat Angle
0.2101” Throat Angle Length = 1º29’58.38” (1.499550) Throat Angle
0.21003” Throat Angle Length = 1º30’ (1.500) Throat Angle [presuming a perfect 0.500” bore and .510” groove diameters for the barrel] – obviously change either diameter and the Throat Angle Length changes – plus there’s the finish chamber reamer manufacturing tolerances to consider - and we have the additional tolerances resulting from the actual barrel chambering to consider…

It looks good.

I need to check UPS and see how the shipment is progressing.

Randall

.511" throat reamer arrived...
Now just waiting for the modified 500 AccR reamer from Manson...

quote:

Originally posted by buffalo:
.511" throat reamer arrived...
Now just waiting for the modified 500 AccR reamer from Manson...

Do you have a projected completion date for the modified reamer?

Jim,

The 500 AccRel Nyati has started and is already on order, correct? It would be nice if McGowen gets it by 1 Oct.

Tan,

The 500 AccRel Nyati is in production and has a projected completion date of 9/30/2012; Dave is expediting the order to accomodate your re-barrel timeframe with McGowen.

I'll notify you and Dan Wynne when the finish chamber reamer ships; it's shipping directly to Dan... It may or may not reach Dan by 10/1 but it should be pretty close.

What are the throatspecs on the 500 AccRel Nyati???

quote:

Originally posted by buffalo:
What are the throatspecs on the 500 AccRel Nyati???

The specifics are listed in my 21 August 2012 21:55 post... This page, just a few posts above...my response to 416Tanzan...

Basically they are:
Length/Height of Neck Chamfer: 0.0135" (45-degree angle SAAMI/90-degree angle CIP)
Length Freebore/Leade: 0.255"
Throat Angle: 1-degree 30-minute (1.500)

Also check my 18 August 2012 03:15 post... This page above... The 0.255" Freebore/Leade gives plenty of 'bullet jump' between the bullet' caliber diameter and beginning of throat angle for use with .510 caliber FMJ and RN SP bullets; zero issues with CEB, GSC, S&H, NF, or Barnes monometal bullet use...

excellent....

Was just emailing with RIP… He is currently on an impoliteness timeout from the AR Forums. He passes his regards to all and looks forward to his return later this month…

While we wait for some new reamers and test results, here is an old article on freebore that is on the web. I found it enjoyable reading.

Study Unit on Freebore

happy reading.

Thanks Tan for the article. I found the article very interesting in its pre-1976 composition; it would certainly be nice if the author would update the article to cover today’s SAAMI pressure levels, today’s powder availability, but especially today’s special bore-riding banded bullets.

That said, I’m ready to go! I own an original Powley Computer that I purchased from either Herter’s or Brownell’s back in the late 1960’s… I also own the new Powley Computer equivalent – that being the computerized QuickLOAD v3.6…

Back to the article… I do believe that we need to work of the terminologies used in the article so that we – meaning everyone participating in this thread (at least) – is using the same definitions when discussing the overall throat dimensions of the chamber.

Pacific Tool &Gauge refers to Leade as being that chamber space between the Neck Chamfer and the ]i]Throat[/i].

Dave Manson Precision Reamers refers to Freebore as being that chamber space between the Neck Chamfer and the Throat Angle.

This article refers to Freebore being that space between the bullet’s ogive [regardless of where the bullet’s groove diameter ends] and the Leade [with Leade referring to the throat angle].

So what are we to use for definitions on this thread?

The only other issue that I identified with the article is its reference to a “zero freebore” without further explaining what was being referenced. I’m presuming it referred to a target rifle where the bullet’s ogive is touching the rifling… Or was it referring to some turn of the 20th century rifle chambers comprised of the Neck Chamfer and an extremely shallow [< ½ degree] of throat angle which in itself resulted in sufficient bullet jump between the seated bullet and the bullet actually engaging the rifling so as to not have astronomical pressure levels?

Just saying…

Meself, I found the discussion of 2-bore to 3-bore lengths of freebore as examples where accuracy might be expected to go haywire to be very suggestive. And then those solumn reminders that once the metal was removed, there was no going back!

Very true.

The other very cogent piece of information - though not stated as bluntly - is 1st to design your freebore for the intended magazine length of the predominate rifle being used and 2nd to the predominate bullet length/weight being used. Anything else falls into the exception category - such as longer/heavier bullets or a longer magazine length which could have easily been accomodated with a throater reamer.

One thing that I found very interesting when measuring the Woodleigh 535gr RN SN vs the 570gr FMJ bullets - both have the exact length of bullet length above the seating groove - is that the shorter-lighter 535gr RN SN bullet actually had far less freebore than the longer-heavier 570gr FMJ due to the actual shape of the 535gr bullet carrying the caliber diameter of the bullet above the seating groove much closer to the meplat while the caliber diameter of the 570gr bullet stopped short of the seating groove...

Kind Sirs and Madams of the Extraordinary League of Big Bores:

Thanks to 416Tanzan for the link regarding the layman's primer on "Free-bore."
Like capoward, I too have been troubled for decades by the nomenclature used variously to describe rifle throating.

The concept of measuring free-bore length from the starting point of transition of full bullet diameter to ogival taper,
and thence to ending point at the start of leade,
is a good one if talking about EFFECTIVE-FREE-BORE.
But that ignores the leade/throat-angle contribution to effective free-bore.

This ALSO of course depends on the particular bullet used, AND the COAL, and is not a good method for discussions aimed at describing how to cut the chamber,
for use with many different bullets.

Also the above primer made no discussion of free-bore diameter except to indicate it was bigger than bullet diameter.

The A-square manual, ANY SHOT YOU WANT,
has an interesting and succinct discussion of throat.

IIRC correctly it points out, as antiquated, the old method of big bore rifle throating that uses only a leade, what capoward is calling "throat angle."

The recommended modern method pointed out is to include some "parallel-sided free bore" between the chamber neck and the commencement of the rifling "leade."

Of course, between the chamber neck and the parallel-sided free-bore is that tiny segment,
like a "collar" at the end of the neck of the chamber,
which we have called the "chamfer." This is the step-down from neck diameter to throat diameter,
usually, but not always, at an abrupt 45-degree angle.

THROAT of a rifle chamber includes all these:

1. Neck/collar chamfer length: tiny but not insignificant (CIP calls "neck" a "collar").

2. Parallel-sided free-bore length: This should not be muddied by association with the term "leade."

3. Parallel-sided free-bore diameter: No ambiguity there.

4. Leade: Well associated with the "throat angle" moniker, and fully specified by the angle of taper from initiation at the end of parallel-sided free-bore to termination at the line where the rifling lands finish rising to bore diameter.
Any measurement of "effective-free-bore" length would have to include the leade.

The biggest part of clumsiness here seems to be having to specify "parallel-sided free-bore" so as to distinguish it from "Leade"/"throat-angle."

I would like to move that we simplify to just this for specifying the throat of a rifle chamber:

1. "Neck Chamfer": Specify angle and neck-2 diameter of the chamber where taper/chamfer starts, and throat diameter where it ends.
"Collar Height" could then be calculated simply,
and used as the tiny length it adds to the overall free-bore length,
ignoring any specific bullet ogives and COAL of ammo when simply specifying a chamber's throat.

2. "Free-Bore": Adopt a modern convention that this means "parallel-sided free-bore." Specify a length and a diameter, and the primary bullet diameter it is to use.

3. "Leade": Specify the angle.
The length of leade then follows from free-bore diameter and bore diameter.

I think it is high time that we take the "leade"
in establishing standard throat nomenclature,
here at the "League of Extraordinary Big Bore Afficianados."

May I hear a second?

All in favor type "Aye."
*********************************************

PS

I now have an urge to build a .510-caliber 500 Mbogo Short.

It will be like the 49-10 but slightly wider in neck diameter and slightly longer in neck length.
Brass length will be 2.700" Maximum.
Final specs depend on measuring the necks of brass made from 500 Mbogo-3" shortened to 2.700" after necking down,
I could also try the .338 Lapua Magnum brass,
and see how neck thickness is there, using .510"-caliber bullets:
aka
50-bore/.510-caliber/.338 Lapua Magnum Improved of 2012
aka
"50-12"
aka
12.9X69mm
aka
12.9X69 50-12

500 Mbogo Short free-bore: 0.255" long, .511" diameter,
thanks to the consensus on the 500 Accurate Reloading Nyati.

Oops... I'll second! And - Aye

And...Welcome back!

Based upon my playing around with QD and QL - You're upcoming 500 Mbogo Short will be the perfect cartridge for a 3.6" magazine' rifle. LOL... The only thing that would make it better would be for it to be in true .500 caliber as that's where the very best & greatest variety of DG bullets are located!

Regarding the .338 Lapua Magnum brass - I doubt you'd lose even 0.005" in neck thickness from fire formed brass between the .500 caliber chamber and a .510 caliber chamber.

Hi Jim,

I hope you don't think this rude of me to beg:

Your excellent graphic capabilities might add a simple generic diagram showing the non plus ultra throat nomenclature for a rifle chamber.
No numerical specifications to clutter it up,
other than label the segment indicated
maybe 1,2,3 and a legend indicating what each numbered segment is called?
Whatever you can do or say goes on the labeling.

Maybe you could start another thread with a drawing and get comments before finalizing official nomenclature?

I am out of this thread now.

Ron "Rest In Pieces" Rip

Hey Ron,

It'll take a few days but I'll see what I can come up with.

RIP, I like your new picture logo "500 Mbogo." An absolutely great and under-utilized cartridge design.

Of course, I like your 500Mbogo Short, too, though it is not a true "short". It's more of a 500 Mbogo Lapua. A 2.7" case is probably not going to fit in a "standard length" action. the 2.65" 500 AccRel Nyati pretty much pushes the envelope.

Capo-- Yes, a picture would be nice.
As for .500" bullets versus .510", I figure that it is simply a matter of time before CEB comes out with a .510" Raptor. In the meantime, we still have the GSC 450 grainers and 475 grain non-con (still not on the website?). As long as there are 500 NE and 500 Jeffries around, there will be .510" hunting bullets.

quote:

Originally posted by 416Tanzan:
RIP, I like your new picture logo "500 Mbogo." An absolutely great and under-utilized cartridge design.

Of course, I like your 500Mbogo Short, too, though it is not a true "short". It's more of a 500 Mbogo Lapua. A 2.7" case is probably not going to fit in a "standard length" action. the 2.65" 500 AccRel Nyati pretty much pushes the envelope.

Capo-- Yes, a picture would be nice.
As for .500" bullets versus .510", I figure that it is simply a matter of time before CEB comes out with a .510" Raptor. In the meantime, we still have the GSC 450 grainers and 475 grain non-con (still not on the website?). As long as there are 500 NE and 500 Jeffries around, there will be .510" hunting bullets.

416Tanzan,
Though I tried to excuse myself from your thread,
not responding to the thread owner would be impolite, eh?
Yes, underutilized, but at least the 500 Mbogo-3-Inch has drawn blood on cape buffalo, twice.
And the 500 Mbogo-Short (2.700") is only a silly 1.27mm or 0.050" longer than the 500 AccRel Nyati (2.650"), but shorter than the 500 Jeffery (2.750") by the same amount.
500 Mbogo Short (12.9x69/50-12) is only 1.09mm longer than the 12.7x68/49-10 (2.657").

With the 500 Mbogo Short, I cannot think of a bullet I could not use with it in a standard M98.
3.5" box works for 500 Jeffery.
It will work for the 500 Mbogo Short.
will stamp/engrave barrel for two types of brass:

"500 Mbogo Short": 500 Mbogo brass from Quality Cartridge

"50-Bore/.510-Caliber/.338 Lapua Magnum Improved of 2012": .338 Lapua Magnum brass

I rest my case, my brass case.

quote:

Originally posted by capoward:
Hey Ron,

It'll take a few days but I'll see what I can come up with.

To my knowledge, the freebore is the length section between the chamber neck chamfer and the start of the rifling.(THE GROOVE DIAMETER IT IS).You can shoose if you want the walls to be straigh (Weatherbys, Remingtons) or angled (Winchester). The general misimpretation here is if the section is straigh sided it is called a freebore and if it is angled it is refered as "no freebore".
Personally I don't care what do you want to call it because I don't take any notice of it. The rationale is that the BULLET JUMP is far more important. If you insert a straigh face rod "gauge" of the exact groove diameter as far as it goes into the barrel it will get stopped when it reaches the rifling. The diameter of the rifling itself at this point will be equal to the diameter of the "gauge". End of story.

To measure the bullet jump follow my instruction;
1) drill the bottom of the case through the primer and tap it 3/8" UNF or M10 if you live in Metric country.
2) cut a bolt 1"-1.25" long that will match the thread and drill through a hole and tap it with 1/4" UNF --M6?.
3) degrease the case and the bushing, apply Loctite or equivalent on the outer thread of the bushing and into the inner thread of the CASE and screw the two together
4) make sure the bushing is fraction bellow the bottom of the case. Let it cure solid
5) get a threaded rod to match the bushings inner thread
6) lubricate and resize the case, just keep in mind there is a 1.25" long bushing inside while doing so
7) screw the seater die and set the bullet of choice into the case to the present COL length and MARK THE BULLET AROUND CASE MOUTH WITH NEEDLE.
8) measure through the hole in the bushing and find how far is to the bottom of the bullet
9) cut the threaded rod 1/8" shorter make a slot for a screwdriver to fit on one end and round a little the other end
10)screw this rod down into the case until you reach the bottom of the bullet, if done correctly the rod will be 1/8" bellow the bottom of the case and the NEEDLE MARK at the same place
You have now dummy cartridge ready for the next part of this excercise.

1) get a brass rod or a cleanning rod and make the face straight or by screwing an addaptor in the case of a cleanning rod.
2) get 2 lock collars 1/2"-3/4" long with side screws that will close fit the rod of choice and all faces of these collars will be true with the holes in them!
3) chamber the dummy cartridge and close the bolt and stand the rifle up on the butt.
4) slide the two lock collars on the rod of choice and insert the rod into the barrel and rest it on the bullet nose.
5) push hard onto the TOP LOCK COLLAR AND LOCK IT IN THE PLACE
6) remove the rod with top collar locked in its place and the bottom collar sliding free
7) remove the dummy cartridge
8) insert the same kind of bullet nose first (offcause) into the barrel chamber until it will contact the rifling and there will be some resistance.
9) insert the rod with the two collars and hold the bullet in place with the help of rod (pencil)
10)rest the rod of choice on the nose of the bullet and press the FREE BOTTOM COLLAR ONTO THE MUZZLE AND LOCK IT IN PLACE

THE DIFFERENCE BETWEEN THE TWO COLLARS IS YOUR FREE BORE PARTICULAR BULLET JUMP. and I don't give a fuck what anybody wants to call it.

The next step is to udjust your COL (Cartridge overall length) to suit your desire.
1) measure the difference between the two locked collars on the rod
2) check your present COL against the length of your magazine
3) use the dummy cartridge inner threaded rod to push the bullet out to the desired length. Remember you have some 1/1/8" of the thread to play with
4) place the dummy cartridge in the shell holder and udjust the seater, The bullet is supported from inside of the dummy case by the threaded rod so you can screw the die in without dislodging the bullet.

You can repeate this with any bullet using the same dummy case just remember while resizing. If you need a target accurate precize fit you would have to use the same bullet from the dummy case for the entire proccess.
Pyzda

Ron you look way to relaxed in that picture!

Pyzda thanks for the information - definately a good way to find out exactly what chamber specifications were used if you're unaware. Might be easier for some than doing a chamber casting.

Hey Ron,

Recognize this:

Edit Added: Oops with label taken care of!

Tan, Ulrik, and Ron,

Here you go guys – the perfect BBW#13 bullets for your 500 AccRel Nyati/Hatting and 500 Mbogo Short:

quote:

Originally posted by michael458:
I received some interesting .510s today, some Sam had ordered and I sneaked a few around the corner on him! HEH HEH........... If I was a .510 sort of chap, I think I would be looking very very seriously at this matched pair!

And LVSP:

quote:

Originally posted by michael458:
Sam's new 475 BBW#13 NonCon HP. If I was doing 51--this is the bullet, with its matching 510 Solid. LVSP 1450 FPS

Edit Added: Looks like you guys are going to have to hope that CEB starts manufacturing a 375gr BBW#13 HP NonCon Lever Gun bullet - then you'll be able to use the Talon Tip and fit within/feed from your magazine. This combo might be easier to get than the 450gr GSC HV bullets.

Hey Tan I just thought, while you’re traveling you might want to try and pick up some of the 450gr .510 GSC HV bullets if you’re serious about bear hunting SoCal this fall/winter – dear old Condor zone lead free (<1% lead content) bullet zone you know so it’ll be copper only, no brass.

wow,

no BRASS bullets in CALIF either?

Yes, I'll have to order some GSC's. Supposedly they are in the US now. I tried to order some a couple of months ago thru CustomBrass... but they didn't have any (yet/anymmore).

Anyway, those 475's will make a great all around bullet with a talon. Hopefully, I'll be able to get them into the Ruger magaine and feeding.

I've noticed that the Ruger magazine box bangs up a bit when fired, so that I need to bang out the front bit and maybe epoxy on a piece of metal like what I remember seeing RIP do. I should have about 3.4" to work with without much prolem, but getting more may require careful working on the magazine box.

Jim
Nice.
"50-12" for short, 500 Mbogo Short,
as with "30-06" (30-bore of 1906), so with "50-12" (50-bore of 2012).
40-07 = .395 Tatanka
50-08 = 500 Mbogo 3"
49-10 = 12.7x68/49-10

Neck diameter may need correcting to give a little better shoulder.
Depends on what the brass actually measures when formed, sized, loaded with bullet.
I could also go only +.003" of chamber neck over loaded brass neck diameter, like I did with the 500 Mbogo 3".
The 49-10 is +.004" of chamber neck over loaded brass neck diameter.

Qual-Cart necks were a little thinner out there at the long end too.
Shorter Lapua brass was thicker.
Can also do inside neck reaming if I want to thin necks after fire forming to uniform, and eliminate any "dreaded donut" by reaming,
if that should rear its ugly head in the 50-12.

Reamer specs not finalized for neck of 50-12, but they will be the same for N-1 and N-2.

Examples previously by me:

49-10 loaded brass neck diameter (N-1 and N-2): .527"
49-10 chamber neck diameter (N-1 and N-2): .531"

500 Mbogo-3" loaded brass neck diameter: .532"
500 Mbogo-3" chamber neck diameter: .535"
(same N-1 and N-2)

Will see.

I frankly don't believe the length of the lead or freebore has anything to do with the bullets stripping the rifling. Has anyone looked at the hardness of the brass used for the CEB bullets? Have these same bullets ever been manufactured with Brass of differing hardness? Tested? I have only seen such stripping once before when very soft brass was used inadvertently. Perhaps this has already been covered but I just though I'd ask.-Rob