458/338 Lapua Magnum using Ruger Hawkeye African platform endeavour

[Jefferry404]

Well, this thread, https://www.africahunting.com/threads/458-338-lapua-anyone-done-this.90956/
got me going and since winter is nearly up...
Will post here the preliminary information regarding the DGR configuration, etc and cartridges characteristics.
I am not a wildcat guy but with the dearth of 375, 416 brass, but the availability of the rifles, the Lapua brass seems to be
everywhere, thought this could work for a nice, standard action rifle.
Folks that might be interested in such, please chime in, particularly with the mag. box configuration, etc
Some preliminary targets:
-Shooting for an 8.5lb rifle with Lijia 1:12, 6-G with the Ruger Hawkeye barrel channel, then a 2nd taper to 0.750" diameter muzzle at 24" or so.
-balance around the action front ring or a tad further back. Weight and balance from 0.500"x5" tungsten rod in the buttstock
-LOP 13.75"
-use Alaskan Arms Ruger drop floorplate with either the Ruger magazine windowed, follower or custom magazine and follower
-complete quarter rib kit (qrib, banded sling swivel, banded front sight base) with either the Ruger Hawkeye folding sight or
2 leaf express sight and the NECG Ruger ghost ring peep sight. The boreline heights of the rear sight and peep sight are designed to be the same.

The chambering will follow the Wildcat Wizard's build (on another website) which is simple, economical but maybe a shorten 458 winmag throat.

component cost:
ruger hawkeye	$1,300
Lijia barrel	$490
Alaskan Arms drop box	$265
qrib kit	$650
NECG peep	$99
2 leaf express sight	$129
7mm front bead 3/32	$35
	$2,968

Estimated gunsmithing $1000-$1300.

Not sure if the Ruger platform is worth this amount of refinement, who knows...
Steve

 

[AZDAVE]

I can see where you are going with this. I have played with wildcats off and on for most of my life.

A couple things I would consider is that you will need to cut the lapua cases to a long action vs a magnum length action and resize the cases etc. So as long as you are good with that far be it from me to say don't do it.

What you might consider is that 300 PRC is made from 375 ruger basic brass. 375 and 416 Ruger brass is only made by hornaday and they do a run of brass on who knows what schedule. However there are at least 4 companies that I know of that make 300PRC brass. You might consider that as it would fit the action, wouldn't have to open the bolt face, wouldn't have to work possible feeding issues on mag follower and action rails that the larger 338 Lapua cases might present. etc

 

[Jefferry404]

thanks for the input.
the PRC necked to 458, not sure about the shoulder (did not want to increase dia). looks like same capacity as the 458 wnmag, with a bit higher pressure case. The Lapau shoulder is 30/1000 larger
For the 450gn TSX, would not need to trim the cases. For the 480gn DGX,S, just at the magazine length, might need to trim 50/1000.

 

[AZDAVE]

What kind of velocity are you looking for out of your wildcat?

The 375 ruger or 300 prc will have a bit more case capacity than the 458 WM. the case is 80/1000 longer and it doesn't have a belt. There will be plenty of shoulder on the case to headspace the round with.

 

[Jefferry404]

this would be a nominal load below. By nature, I am not a high velocity guy. Max. velocity
at the max. Lapua case pressure looks to be 2414fps. At the 450 Rigby max. pressure, 2300fps
So, either a high velocity 458 or a low pressure 458.
Steve

 

[Jefferry404]

this is 300PCR necked to 458, with larger shoulder (35 whelen neck to shoulder dimension), slightly shorter body. The red is the 300PRC case overlap with the 458 chamber. Is this enough headspace intersection for fireforming? (do not want to mechanically size the brass)

 

[AZDAVE]

It should be. That is a lot more than the 400 whelen and it headspaces off the shoulder

 

[AZDAVE]

The 338 Lapua verision would require a bit more gunsmithing but pressures would be lower. On the 300 prc side Lapaua make brass for it also

 

[Jefferry404]

thanks Dave,
I wish I was less of an engineer. When I go thru the wildcat process, the bang for the buck always seem less than the effort as I want big gain but... I ran the numbers thru on the 458/300prc and gets a bit more velocity at the same pressure than the 458 winmag.
458/300prc

the Lapua, other than the feeding work, seems to give enough increase in performance over the winmag (about 150fps more at 58kpsi pressure) and room to blast.
Steve

 

[AZDAVE]

Steve,
As a retired engineer I understand your thought process.

Just don't let the paralysis by analysis loop get you wrapped around the axle.

You won't go wrong with either.

Dave

 

[Jefferry404]

I have been retired for 9yrs. One reason I go thru these cerebral exercises is to keep the mind somewhat firm
The only wildcat so far is a 416 Cheytac and Manson had the reamer. I am considering a 505-408.
Steve