Cast in the 450 Bushmaster AR

  • Last Post 05 August 2021
Wheel Weights posted this 15 April 2020

I have a Ruger AR in 450 BM. Will cloverleaf jacketed loads @100 yds.

Cast bullets not so ! Have tried every bullet I can cast or buy from 220 to 475 gr.

Any load that will function the action (H110, 4227, 4198, 5744) is 6" @ 50 yards.

Pooper loads of Unique (hand operated) are very accurate @50 yds.

Guys with TCs and bolt guns are getting fine results with full power loads.

Anyone have the secret ?

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Tom G posted this 15 April 2020


First I would slug the barrel and make certain that your cast bullets are at least .001" larger than the slug diameter. 

Second, if it still won't shoot, try harder bullets. You can water drop right out of the mold or heat treat ww's to get them harder. An alloy of monotype or foundry type will probably be hard enough to allow you to run loads hot enough to work the action. 

Short of that, you could very carefully open up the gas port hole till you can shoot softer bullets and work the action. You could also install a variable gas block where you can open it up for soft loads and close it back down for hunting loads. If you open up the port, use that gas block only for cast bullet loads or you will probably damage the gun shooting hot loads in it.  

My brother did that and cast bullets of linotype shot well in his 223 AR.  I went the route of making harder bullets for my AR and it worked very well with a standard size gas port and a powder that had a burning rate that maximized the peak chamber pressure in the barrel to coincide with the location of the gas port. 

Tom G

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Wheel Weights posted this 16 April 2020

Thanks. I have been using WW bullets. When I get back to WY, I'll get some lino and cast some really hard ones.

Your advice makes sense as velocity seems to be the factor that blows up the groups.

Have to wait until June to see IF we can go home !

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JohnForrest posted this 05 August 2021


Do yo happen to have any updates with your 450? I have a 45 Raptor (a rebated 460 case) That I shoot out of a 308 AR. If mold demand ever eases up I want to try 300-400 grain lead just to see how I can make it shoot. After reading about Jeffnz resizing 277 down to 268 I may try getting 45-70 bullets down to 453


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jr460 posted this 05 August 2021

Not a ar but in bolt gun this works very well I will try in my ar and see how it shoots 

1000 yards easy

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