.50's based on the .338 Lapua case...

[Guest Tiff]

I would really like to own a .50 BMG, but the more I look into it, the more I realise that without destroying my ISA accounts it's just not going to happen

 

So apart from the SSK range of cartridges, what other .50 cal versions are based on the .338 Lapua case?

 

I know the idea behind the Whispers is a sub 600 yard, silent sniping round with a heavy payload....however I don't really need that on the range

 

I was thinking more along the lines of a .338LM case immediately necked up to .510 and not cut down at all.

 

So does such a round exist and how fast do you think a 750grain A-Max could be launched, out of such a round?

 

Or have I just lost the plot completely

[Ronin]

Think your chasing an unicorn here mate.

 

Maybe better to chop in the 338 and save pennies for custom build .50 - cheaper than factory by my reckoning.

 

(50 Barnard action, barrel and Mcree or similar stock)

 

 

Know where there is a barrelled .50 Barnard for sale......

 

 

Bear in mind the .50 is also cheaper (by a bit) to shoot than the 338 if you use surplus ammo.

 

Personally I would forget .50 and think seriously about .375 CT, .416 Steyr or .408 CT.....

 

All three offer more than the .50 ballistically..

 

 

Again just my 2p

[Guest Tiff]

Just been in the gunroom and made this approximation of what I'm thinking of:

 

750 grain A-Max, .510-338 LM & .338 Lap Mag

 

I will try seating the bullet in the morning.....

[Guest Tiff]

Think your chasing an unicorn here mate.

 

Maybe better to chop in the 338 and save pennies for custom build .50

 

 

You mean unicorns don't exist, I'm heart broken

 

The .338 is here to stay...particularly since it's got a nice new 30-338 barrel on it

 

I know a .50 at moderate velocities is not going to be overly impressive ballistics wise. But how moderate would it be with 75+ grains behind it?

 

More of a 'fun' gun, than a serious long range contender. Also with most of my 'local' ranges (i.e. 300 miles away Lydd and Senny) only offering targets to 1,200 ish, do I really need a full .50BMG?

[littlefraggle]

Have a look at .338 Edge. .338 bullet in 7mm Rem UltraMag case. Plenty of stuff on interwebnet about it. Just sold ours - very sad.

[Ronin]

Quite well documented on the webthat there are issues with some Edge builds - over pressure , accuracy problems. Hsten to add this is not with all personally think that the lap mag is the better of the two

[1967spud]

what about the cheytac is that a consideration

[Guest Tiff]

what about the cheytac is that a consideration

 

 

I'm working off the Sako TRG 42 as a base action, so it's .338LapMag cases I have to work with....

 

As an aside, Kirby Allen in the states has produced a .510 Allen Tactical using a necked up .408CT case. With the .750grain A-Max hes getting 2,450fps with a 26"+ tube.

 

I hadn't really thought about headspace/extraction issues, but surely if the .510 whisper (shortened .338LapMag case) works well in the TRG, wouldn't a longer version? I believe they only shortened it for optimal volume, since it only uses 30+ grains for subsonic loads.

 

I know its a bit of a wacky idea..but I'm hoping my new 30-338 should get me to the 2,000yard mark, with my .338 LapMag getting me near there anyway. So I'm not really looking for another long range performer....More something different and also relativly cheap for 1,200 tops.

 

Ronin I agree about the Edge...Having owned a rifle in its parent case (the .300RUM) the brass is simply terrible to start with - with Remy stuff being useless and Nosler very very soft. Pushing it as hard as they do (mostly out of remy 700's) is just asking for trouble IMO.

[sean c]

If you did get it to work then that would be a sight to behold with tracers. Home made rainbows to go with that unicorn.

[Guest Tiff]

If you did get it to work then that would be a sight to behold with tracers. Home made rainbows to go with that unicorn.

 

 

Just ran a few figures using a 750grain A-MAX at a very modest 1,500 fps and the drops/drift in MOA are:

 

range drop drift (10mph)

100 zero zero

 

600 43 4.3

 

1000 87 7

 

1,200 112 8.3

 

So nothing outside of dialling in to 1,200yards using a 5.5-22x56 NXS on a canted base.

 

Please keep you ideas/view coming...I've probably missed something obvious on why it won't work!

[brown dog]

Please keep you ideas/view coming...I've probably missed something obvious on why it won't work!

 

 

at 1500fps MV, you'll be building a round that'll be transitioning sonic/subsonic pretty damn early in its flight (at a guess, 3-400m? you can do the crunching ) rather pointless if it turns out to behave like mad-woman's-that which promotes growth and vigour when transitioning; I'd build something that got to the target supersonically; or went the whole way subsonically; designing something that transitions halfway to the target is just setting yourself up for failure.

[Guest Tiff]

at 1500fps MV, you'll be building a round that'll be transitioning sonic/subsonic pretty damn early in its flight (at a guess, 3-400m? you can do the crunching ) rather pointless if it turns to behave like mad-woman's-that which promotes growth and vigour when transitioning; I'd build something that got to the target supersonically; or went the whole way subsonically; designing something that transitions halfway to the target is just setting yourself up for failure.

 

That's a good point....speaking to people who shoot the 750 grain A-Max subsonically say it still maintains a B.C. just over 1.0 So even at 1,500fps at the muzzle it will only go subsonic past 800-900 yards. Also from people I've spoken to who shoot the .50 Spotter (shorter than the BMG, designed for artillery as an aiming gun) say the A-Max deals very well with the transition in the trans-sonic zone. That would of course depend on if 1,500fps is achievable?

 

Please keep the ideas coming.

[Ronin]

Thinking and typing aloud (possibly not good)

 

 

However, how about reversing the Snipe Tac idea:

 

 

338 parent case - .375 calibre bullet.

 

375/338LM

 

Think that the .408 may also fit a little better than the 510, with a more pronounced shoulder.

 

408/338LM

 

 

Just musings.

 

 

Problem with either of these is bullet availability,

[TC]

like mad-woman's-that which promotes growth and vigour

 

 

Not heard that since my first pistol instructor 20 odd years ago, thankfully not commenting on my group

 

TC

[sean c]

I don't know if Ive gone slightly crazy but what about going the opposite direction and necking down the case to 6.5mm, i don't know if it's been done before or is safe to do but it was going around in my head all day.

 

Just running the figures though jbm gives you.

 

MV= 3700fps (as a guess)

Bullet= 139grn scenar.

Zero= 100yds.

Standard atmosphere at sea level.

 

Range Drop Drift (Drop and drift in MOA)

600 6.6 2.4

1000 15.2 4.4

1500 31.3 7.7

2000 57.5 12 (only just super-sonic)

 

Now if that did work then it would be A) tough on barrels B ) amazing.

[Ronin]

linley scenario is bullets would not reach target unless you used solids.....

[Guest Tiff]

Hi Sean, it has been done, but as Ronin said its mostly a cooper jet that comes out....7mm is about as small as you can go witht he .338LM case - as Kirby Allen has done with his and wildcat bullets. Its a nice idea, but 300-400 rounds is the max you would get, even with solids

 

I don't need to go any smaller, since I reckon not much will beat my 30-338 with 240's at 3,100+ (will find out when a try it for the first time in the morning!)

 

I like the idea of using .375 or .408 bullets, but can see a world of pain ahead sourcing bullets....particulary any that will work at subsonic velocity and twist issues.....Also not sure if the B.C. gained over a .338 will make it work as well as 1.0+ of an A-Max.

 

Please keep the ideas coming.