this is meant to be a compilation of designs, tips, rules of the road,,, and even case design.

This isn't even close to complete, but if someone wants to add in, it would be appreciated.

*at the same pressure, you should see a PERCENT increase in velocity equal to about 1/4 of PERCENT of capacity increase.
** exception -barring strong case differences ... for example, the 458 AccRel is only 2-3% larger than a lott, but it has a strong shoulder

* in many big bore cases, the crimping groove in -0.80 from the nose of bullet -- assuming a "Standard" hunting bullet

* an SD of .300 or higher is good in cup and core soft nose bullets - this means NOTHING with copper/brass bullets

*well designed monometal (copper/brass) are game changers

* a little longer length of pull is FAR better than shorter in terms of felt recoil, within reason

*big bore rifles should be a bit nose heavy for shooting off hand

*NEVER, NEVER, brace the toe of the stock on the bench or in bags when shooting from the bench -- it can break the stock

*a 3.35" case is cheaper to gunsmith into a standard length action than a 3.65

*most "hated" features (short neck, belt, rim, rebate, steep taper) are okay, if planned for

*4 tons of ME into the dirt is far worse than 1 ton into the vitals, with a good bullet

your thoughts/corrections?

I most humbly submit, as a truly UNQUALIFIED com-
menter, that: (1) rebated rims seem to cause much
annoyance, planned for or not, based on my reading,
(2) .280 sectional density for the new breed of bullets
seems to be the number, per MM and SR research.
(3) Longer LOP will though, more likely "catch" on
clothing as one mounts the gun, especially the more
clothing one is wearing.

i concur with the .280 ... or there abouts.. it's long been my conjecture that copper bullets get .02 on sd ...

quote:

Originally posted by jeffeosso:
it's long been my conjecture that copper bullets get .02 on sd ...

Sorry, I don't get this. Please help me out.
As to rebated rims I refer to all the 500 Jeffery stories.
The catching on clothing came from a gun fitter at www.woodcockhill.com as I recall.

quote:

Originally posted by D R Hunter:

quote:

Originally posted by jeffeosso:
it's long been my conjecture that copper bullets get .02 on sd ...

Sorry, I don't get this. Please help me out.
As to rebated rims I refer to all the 500 Jeffery stories.
..

i said .300 .. you said .280 for new bullets .. we agree --

i've built a couple 500 jeffe's .. and there are gun smiths that can make great ones...

but, like rebates and lop. too much or too little can be problems.. but no one complains about the rebate on the 460 weatherby...

the .425 WR is the poster child for how crappy a design cartridges with significant rebate are.

What Jeffe said otherwise, PLUS ONE!!

Thanks Jeffe, Now I am following you on the .02.

Here is a rule-of-thumb

For .40-.50 calibre, the .590" Rigby/Lapua and 460 Weatherby caseheads set the bar for versatility when velocites over 2500 fps are desired.

quote:

Originally posted by Idaho Sharpshooter:
the .425 WR is the poster child for how crappy a design cartridges with significant rebate are.

What Jeffe said otherwise, PLUS ONE!!

True, True, True. And look what WR did to the 98 action to make 'em feed!!!

quote:

Originally posted by 416Tanzan:
Here is a rule-of-thumb

For .40-.50 calibre, the .590" Rigby/Lapua and 460 Weatherby caseheads set the bar for versatility when velocites over 2500 fps are desired.

Hubel's belted 585 HE and RobGunBuilder's 600 OK crank things up even further...
And there's the wildly bigger stuff as well!!!!! Over .620" is artillery IMO though.
With what the .585" bullet is capable of I believe that anything bigger is "want"
not "need". Our good friend Michael458 says essentially that regarding the .500/
.510 bullet, and he has much experience to lean on with his 50's!

About action lengths - It does save huge bucks determining
the potential of what is called "regular length action".

Many regular actions with half days work can handle
3.65" cases easily. Enfields,Rugers, CZs, Savage, many others,
and many can handle 3.90" cases. And I know custom builders,
the high priced ones, got to make a living, but for
big bore nuts on a budget a little energy and brain work
can save a lot. Thank goodness fo MRCs PH in helping out..

And I'll be posting pics comparing bolt lugs from
actions guys look down on, to those that are considered
gold, that will surprize many.Ed

quote:

*at the same pressure, you should see a PERCENT increase in velocity equal to about 1/4 of PERCENT of capacity increase.

That could be interpreted as 1/4 of one percent.

Maybe it should say 1/4 of the percentage increase.

I use the math that every one percent increase in powder charge
is about a one percent increase in muzzle energy,
at regular rifle pressures to 65k, and
the velocity increase is the square root of that
energy increase. Simple example is say a 9% increase
in powder gives a 3% velocity increase.ED

quote:

Originally posted by SR4759:

quote:

*at the same pressure, you should see a PERCENT increase in velocity equal to about 1/4 of PERCENT of capacity increase.

That could be interpreted as 1/4 of one percent.

Maybe it should say 1/4 of the percentage increase.

I did, though I "wrote" the equation in English... Allow me to restate in a simple formula. where V is velocity and c is original capacity
ΔV≈(Δc/c)/4
Or
ΔV≈0.25(Δc/c)

these would be in decimal, but trivial to transform as percentage... I dare say most people automatically do thus.

Ed I think you meant capacity not powder in 9%≈3%

I meant both increasing together.. I assumed about 100% fill,
and just increasing capacity along with powder volumne to fill
it up, like going up from a 458Win to 458 Lott and on up to
a 458 African 3".

If you put a full 458 Win charge in a Lott case that
has more room you will lose a little speed, IE takes
takes a real small amount more powder to stay even.
And adding more above that then gets the gains in energy.Ed

quote:

Originally posted by hubel458:

Many regular actions with half days work can handle
3.65" CASES easily. Enfields,Rugers, CZs, Savage,
many others,and many can handle 3.90" CASES . Ed

Hi Ed,

Did you mean CASES or CARTRIDGES OAL ?

Meant overall loaded cartridge length.
Like the 585 loaded length is 3.90"
same as 505 Gibbs and any gun hand that handles
that does the 585.Ed

Thanks!