.450 bushmaster build

[Mdhart79]

New to this forum and looking for help. I have a model 10 .308 looking to re barrel to 450 bushmaster. Looking for barrel contour and twist rate info. Also would there be much lost in 18" vs. 20". Most likely ordering a mcgowen barrel as Apache is not taking orders.

[bsekf]

I have a 17 inch 444 Marlin and couldn't be happier.

[RC20]

No you will not loose much between 18 and 20 inches. 26 to 18 yes.

You are substituting velocity for oomph (heavy bullet and less reach out range) (Carronade of the muzzle loading cannons did the same thing). A bit of velocity loss is zero issue.

You will need to determine what bullets you plan on shooting before a twist can be recommended. The 450 has quite a range of 1-10 to 1-24.

If you are not sure then go 1-16 and you should still be good.

[foxx]

Don't go any longer than 22... its pretty much slowing down by then.

[handirifle]

My Marlin 45-70 uses 1-16 and it stabilizes everything from 300 to 450 wonderfully. Lighter bullets would take slower twist (1-18), and thus better velocities. I would say an 18" barrel would be about ideal.

Nevermind, I didn't realize the 450 used .452 bullets. Carry on.

[squirrel_slayer]

I wouldn't be afraid to go as short as 16.5" honestly. straight walled cartridges do well in short barrels. I'd go 1-16" for a more versitility. if you go 18" and it thumps to much you could have someone machine a brake into the barrel. i'd keep the contour on the lighter side if you want a handy package (face it, it's not going to be a long range precision rig) i'd go ~.750-.780 at the muzzle. people have had good success using .458 bullets ran through 2 lee push through sizers .454 first followed by .451 if my memory serves me well. with jacketed use hornady 1 shot or similar. reason for the .451 sizer is the bullet will end up around .452 due to spring back. this will open a whole new world of bullets for you.

Good Luck and keep us updated on the build

[Mdhart79]

Wouldn't 1:16 be fast since 1:24 seems the standard? Also looks like the can do 1:18 so that could be a meet in the middle?

[squirrel_slayer]

depends what your after. if you see yourself shooting light bullets 200-260 mostly then yes the 1:18 will probably work better for you and you'd gain a little velocity. however part of the fun of the big bruisers is launching heavy slugs out of them 400+gr thats where the 1:16 will help and it gives you a broader spectrum of bullet weights to play with. another thing to factor is stability is also dictated by velocity. so if you plan to shoot heavy subsonic loads again the faster twist will give you more options. really depends on your intended use.

[Mdhart79]

Mainly a deer rifle. Plan is to stay with factory ammo so 250 gr.

[squirrel_slayer]

are you in one of the states where you have to have a straight walled cartridge? if so then yes the 1:18 would be the best comprimise and 18-20" may be for you. you'll want the flattest trajectory you can get. if your area is heavily wooded look to the 16-18" options

[Mdhart79]

Yes I hunt in lower Michigan so 450 is now legal.

[RSMII]

I have a .50 Beowulf and the barrel is 18". Alexander Arms figured out that nothing was really gained and quit making the 20" or 22" barrel, don't remember which it was. The twist rate is 1 in 14 I believe and it's accurate with everything I put thru it. My slug of choice is a 400gn Speer. So, an 18" barrel will be good.