Gentlemen, I present... the ".220 REDLINE"
- Thread starter fredo
- Start date
Anyone know what the bullet OAL measurement is for the 85 gr Nosler RDF .22 Caliber bullet is?
1.135 in length. 0.498 BC. These are from Nosler. Nosler gives it an 8 twist recommendation.
Fredo -
Howdy !
I took a second look @ Homer Powley's "Expansion Ratio" table ( Guns & ammo 1974 Annual "Powley Papers" ). As an accurization of what I previously stated about expansion ratio....
- In a notional 28" lg .224" caliber barrel, a sample charge of 70gr powder would seem to suggest an
expansion ratio of 4.5 .
- This is a tad better than the 4.0 ER figure I previously quoted, for an earlier estimated 72gr charge
shot in the same length 28" .224" cal barrel.
The sample chart Homer provided, did not go lower than 4.0 on expansion ratio.
With regards,
357Mag
Howdy !
I took a second look @ Homer Powley's "Expansion Ratio" table ( Guns & ammo 1974 Annual "Powley Papers" ). As an accurization of what I previously stated about expansion ratio....
- In a notional 28" lg .224" caliber barrel, a sample charge of 70gr powder would seem to suggest an
expansion ratio of 4.5 .
- This is a tad better than the 4.0 ER figure I previously quoted, for an earlier estimated 72gr charge
shot in the same length 28" .224" cal barrel.
The sample chart Homer provided, did not go lower than 4.0 on expansion ratio.
With regards,
357Mag
Thank you for the info, 357 Mag!
I'm not terribly familiar with how your expansion ratio value estimates translate into projected performance. Would you be so kind as to explain?
Also, reckon the capacity of a finished .220REDLINE would be nearer to ~70grains, given the subsequent (minimal) loss of volume from the necking down process...
Sitting on "GO" here to get this in hand! Just waiting on a Cerakote batch job to wrap up to take the shine off that Brux. Working with some test loads will make for a nice breakup of the winter doldrums when I can't get away to chase coyotes. Once I get a mild firing on some brass, can measure capacity & get to to tweakin' QL parameters to help narrow down a load.
Won't be long now!
I'm not terribly familiar with how your expansion ratio value estimates translate into projected performance. Would you be so kind as to explain?
Also, reckon the capacity of a finished .220REDLINE would be nearer to ~70grains, given the subsequent (minimal) loss of volume from the necking down process...
Sitting on "GO" here to get this in hand! Just waiting on a Cerakote batch job to wrap up to take the shine off that Brux. Working with some test loads will make for a nice breakup of the winter doldrums when I can't get away to chase coyotes. Once I get a mild firing on some brass, can measure capacity & get to to tweakin' QL parameters to help narrow down a load.
Won't be long now!
Looks like Christmas is coming early this year!!!
'Smith just sent me this...
Merry Christmas, everyone!!!
Parker, get 'yer chinstrap buckled up...we're almost there
Chambers strait on the 4 jaw that's a big No No. how can the barrel pivot to dial in the bore. But besides that its a cool project.
fredo ,
Howdy, again !
Tehre's info abut " expansion ratio " and bore capacity written by individuals that are both more knowledgeable and more articulate than myself.
Until we can talk more on these topics, here's one sample read:
https://www.thefreelibrary.com/Bore+capacity+&+expansion+ratio.-a03578530
I DK whether you have P.O. Ackley's 2 volumne tretise " Handbook for shooters and reloaders " ?
If you do , please take a look @ pg 16 5 or so.... wherein he talks about " bore capacity ".
We'll talk, again, soon as I get the chance.
With regards,
357Mag
Howdy, again !
Tehre's info abut " expansion ratio " and bore capacity written by individuals that are both more knowledgeable and more articulate than myself.
Until we can talk more on these topics, here's one sample read:
https://www.thefreelibrary.com/Bore+capacity+&+expansion+ratio.-a03578530
I DK whether you have P.O. Ackley's 2 volumne tretise " Handbook for shooters and reloaders " ?
If you do , please take a look @ pg 16 5 or so.... wherein he talks about " bore capacity ".
We'll talk, again, soon as I get the chance.
With regards,
357Mag
fredo -
Howdy !
More on " Expansion Ratio ".....
The following is a quote from the " Guns & Ammo 1974 Annual " ( "Powley Papers " ):
..." Mr. Powley was also able to find a way to figure velocity for a given peak pressure.
It can be calculated from the following ( using the Powley Computer ):
1. Powder weight divided by bullet wt
2. Density of loading ( case capacity divided by powder wt )
3. Expansion Ratio ( ER )
" We already know figures Nos. 1 & 2, so the Computer next finds Expansion Ratio from the Case Capacity, Barrel Length and Calibre. Finally, extensive tables on the Computer give muzzle velocities for a very wide range of Expansion Ratios and Ratios of Charge to Bullet weights. "
Comment:
A wildcatter can use ER to compare various wildcat designs, trading off things like barrel length and case capacity for a given caliber; and seeing how projected muzzle velocity if effected.
Using either computed ER values or those found on a reliable table of expansion ratios, the case designer can see whether certain chosen project goals might be obtainable.
For example: Say the wildcatter wants to make a .224" cal wildcat w/ higher velocity potential than the .220 Swift fetures, when shooting 55gr bullets ( as a reference ).
Homer Powley listed the expansion ratio for a 24" barrel .220 Swift as 5.6 . The wildcatter then runs computation on the Powley computer ( example ) for a .224" cal case w/ 70gr H2O case capacity.
He finds that even w/ a longer 28" barrel, his wildcats' forecasted ER will be 4.5 The wildcatter likes the calculated vel seen on the computer for his design, and decides to accept the probable lower barrel life the 4.5 ER portends. Another wildcatter might reach a different conclusion, based on his own particular interests, thoughts; opinions.
Let's talk, again!
With regards,
357Mag
Howdy !
More on " Expansion Ratio ".....
The following is a quote from the " Guns & Ammo 1974 Annual " ( "Powley Papers " ):
..." Mr. Powley was also able to find a way to figure velocity for a given peak pressure.
It can be calculated from the following ( using the Powley Computer ):
1. Powder weight divided by bullet wt
2. Density of loading ( case capacity divided by powder wt )
3. Expansion Ratio ( ER )
" We already know figures Nos. 1 & 2, so the Computer next finds Expansion Ratio from the Case Capacity, Barrel Length and Calibre. Finally, extensive tables on the Computer give muzzle velocities for a very wide range of Expansion Ratios and Ratios of Charge to Bullet weights. "
Comment:
A wildcatter can use ER to compare various wildcat designs, trading off things like barrel length and case capacity for a given caliber; and seeing how projected muzzle velocity if effected.
Using either computed ER values or those found on a reliable table of expansion ratios, the case designer can see whether certain chosen project goals might be obtainable.
For example: Say the wildcatter wants to make a .224" cal wildcat w/ higher velocity potential than the .220 Swift fetures, when shooting 55gr bullets ( as a reference ).
Homer Powley listed the expansion ratio for a 24" barrel .220 Swift as 5.6 . The wildcatter then runs computation on the Powley computer ( example ) for a .224" cal case w/ 70gr H2O case capacity.
He finds that even w/ a longer 28" barrel, his wildcats' forecasted ER will be 4.5 The wildcatter likes the calculated vel seen on the computer for his design, and decides to accept the probable lower barrel life the 4.5 ER portends. Another wildcatter might reach a different conclusion, based on his own particular interests, thoughts; opinions.
Let's talk, again!
With regards,
357Mag
fredo -
Howdy once again !
Say... I hope the response I sent immediately prior to this one did not sound smart-aleky.
My intent was to simply use numbers/values that we were already talking about as the sample exercise,
in-lieu of using other numbers for a different wildcat.
Another use for expansion ratio: Say you run some numbesr through the [ Powley ] computer, and you are not seeing the projected velocity you were "shooting for". I don't have one in front of me, and don't recall how high the velocity tables on a Powley Computer go ?
My point:
IF you weren't reaching a point near the velocity goal, you'd adjust expansion ratio ( ER ) via either choice of a larger capacity wildcat and/or increase barrel length. You'd have a good sense of what ER zone needs to be reached, to meet your need. ER can be used then, to help skewer the necessary case capacity;
which can then be used as useful input on potential candidates for the parent brass
With regards,
357Mag
Howdy once again !
Say... I hope the response I sent immediately prior to this one did not sound smart-aleky.
My intent was to simply use numbers/values that we were already talking about as the sample exercise,
in-lieu of using other numbers for a different wildcat.
Another use for expansion ratio: Say you run some numbesr through the [ Powley ] computer, and you are not seeing the projected velocity you were "shooting for". I don't have one in front of me, and don't recall how high the velocity tables on a Powley Computer go ?
My point:
IF you weren't reaching a point near the velocity goal, you'd adjust expansion ratio ( ER ) via either choice of a larger capacity wildcat and/or increase barrel length. You'd have a good sense of what ER zone needs to be reached, to meet your need. ER can be used then, to help skewer the necessary case capacity;
which can then be used as useful input on potential candidates for the parent brass
With regards,
357Mag
snert
Silver $$ Contributor
I will be thre for a week starting Next friday...tell me ahead of time cause all my stuff has moved to PAP, you and lil' P are on trigger detail...I'll roll tape
Speaking of which, have last years chuck whackin' footage on a DVD for ya. Hope to get up in the next few weeks and hand it over. Besides, we gotta go coyote calling together already!!!
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