450 LM "LeGendre Magnum"

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Re: 450 LM "LeGendre Magnum"

Postby Kiwi Greg » Sun Jan 10, 2016 12:13 am

Kiwi Greg wrote:Very interesting read Gentlemen, thanks for posting :)


Well it took me a while with hold ups with parts, mainly the barrel, was going to use a local manufacturer but got sick of waiting so ordered a Pacnor which took a while to get here with import, export permits etc.

Here is my version of the 450 LM the 450 Terminator I built on my Christensen CA10, mainly for S&G & because I could :D

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22" Pacnor .451, 1-16 twist barrel, T3 Terminator muzzle brake.

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Reasonable performance with the 250 FTX out of a Rattle gun 8-)

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I'm very impressed with its performance.

I'm using Lapua brass which is more of a hassle than the Norma brass to use because of its thickness.

I'm struggling to get as good a performance from the heavier projectiles, this isn't much of a drama because the 250s go so well with Lil-Gun :)
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Re: 450 LM "LeGendre Magnum"

Postby Al in Mi » Sun Jan 10, 2016 6:06 am

nice Greg, very nice :)
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Re: 450 LM "LeGendre Magnum"

Postby Smooth » Tue Jan 12, 2016 7:38 pm

Very nice ?
I was wondering if enough body doing anything with the 450 LM.
Thanks
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Re: 450 LM "LeGendre Magnum"

Postby kottke_35 » Thu Jan 21, 2016 1:26 pm

Super cool. Thanks for posting!

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Re: 450 LM "LeGendre Magnum"

Postby JaredP » Tue Dec 12, 2017 11:12 am

I've spent quite some time reading through this thread a couple times in with the goal of replicating the 450 LeGendre Magnum.

As far as I can tell, 450 LM is:

284 win, necked up in two steps, first to 356, then to 452.
Case Length 2.085
Chamber 2.09
COAL: 2.5-2.8
71.3 gr H2O case capacity
Utilizing a taper crimp, and a side crimp into a cannelure using a modified factory crimp die.

Resized/loaded with 45/70 dies? Or 450 bushmaster?

I typed the above into quickload, using 71.3 case capacity, 230gr .452 FMJ, 64 gr of W296 which was indicated as the starting load.

I was getting close to 100k PSI, before any of the modification to starting pressure to account for the crimp.

Is there something I'm missing here or is this cartridge extremely high pressure? Is it safe?
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Re: 450 LM "LeGendre Magnum"

Postby Hoot » Tue Dec 12, 2017 2:07 pm

Welcome Aboard Jared!

I also use QuickLoad and do a lot of modeling for the 450b. When comparing predicted results using W296 versus real results, it became apparent that QL gets W296 wrong in that caliber. I'm guessing it gets it wrong in the 450 LM as well. I edit the powder characteristics now when doing W296 workups to get it in line with what I see at the shooting bench. IE Dial it down. I'm at work, so I don't have my notes with me, but its quite a bit lower in practice than in theory (see sig). ;)

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Re: 450 LM "LeGendre Magnum"

Postby Texas Sheepdawg » Tue Dec 12, 2017 7:28 pm

Meanwhile, I’m over here drooling.
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Re: 450 LM "LeGendre Magnum"

Postby Hoot » Tue Dec 12, 2017 9:06 pm

Texas Sheepdawg wrote:Meanwhile, I’m over here drooling.


I thought Tim sent you one?

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Re: 450 LM "LeGendre Magnum"

Postby Texas Sheepdawg » Tue Dec 12, 2017 9:54 pm

Hoot wrote:
Texas Sheepdawg wrote:Meanwhile, I’m over here drooling.


I thought Tim sent you one?

Hoot

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Re: 450 LM "LeGendre Magnum"

Postby Bmt85 » Wed Dec 13, 2017 8:59 pm

I'd love to build one of these!
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