Which barrel length for 450BM

[45r]

I want to get a 450BM upper for my AR.What would you get,16 inch or 20.What are the pros and cons of each choice.

[wildcatter]

I want to get a 450BM upper for my AR.What would you get,16 inch or 20.What are the pros and cons of each choice.

For me it's a question of how skilled you are, meaning, cutting off inches are easier than adding them on, if you've a lathe. Otherwise, 16" is allot more handier, 20" gives you something like 125fps +- more speed. I love carrying the 16", but the 20" is handy enough and I can always cut some off, if I need it, so I always buy the 20"-ers and never get around to cutting them down, I just don't seem to need it..t

[BayouBob]

Mine is a 20". All my other AR's are 16" but the longer barrel just seems right for Thumper. I've carried mine in the woods a bunch and the extra 4 inches and 8 ounces hasn't bothered me at all. As I work on some of the canned dynamite loads Wildcatter talks about I think the longer barrel will also perform a little better.

[Hoot]

Not to get into a Less Filling! Tasts Great! debate, but I love my 20". With my handloads, it delivers sub MOA at 100 yards. I toted it through some God awful thickets this past deer season and the 4 inches were a non-issue. I do not engage in CQB, so I just prefer my rifles to have rifle length barrels. Free velocity is always it's own reward. Since I never shot one in 16", I can not contrast the muzzle blast or perceived recoil difference. Whatever you get,make sure you set aside $40.00 for one of Ross' excellent brakes.



His brake puts that izzy flash hider that comes with the rifle to shame.

Previously Posted:
I'm not ripping on Bushmaster for no good reason. They make a great rifle. I just resent putting accessories on guns for the sake of eye candy. All they had to do to that flash hider was weld a flat washer on the end with a hole ~.010 over bore and it would have made a good brake. Folks with flash hiders have been doing that for a while to turn them into a brake.

Bushmaster Flash Hider:


Izzy:


Bushmaster Brake:


You be the judge...

The closer the size of the hole on the end to the bullet's diameter, the more effective a brake will be as it lets the bullet pass without gasses leaking around it until it's clear of the hole. Those microseconds from when it enters the hole until it clears the hole is the time when the path of least resistance for the gas is sideways. That's also why brakes with multiple constriction chambers or baffles are more effective. Each transition through a choke point diverts more gas. If like in a flash hider, there is no resistance to the gas blowing past the bullet during the time when the sideways exit is available, not much gas will go sideways. Some will, but most just continues forward with the bullet. There is a lot of good reference material on this subject available online, including hyper-speed photography showing what I just said.

A decent brake and a Sims slip-on Limbsaver recoil pad make the 450b comfortable enough to shoot that my friend's 10 year-old who shot it said, "Wow, That's it!? Can i get one Dad!!!?"

Hoot

[Texas Sheepdawg]

Mines a 20". I like the blast out there as far away as possible and the
longer the barrel, the more complete powder burn and less flash
With better accuracy. And as WC says, better FPS.

[wildcatter]

Not to get into a Less Filling! Taste Great! debate, LOL.. Yeah this can become a bit like the thing about the favorites being either Blond, Brunette, or Red Headed.. I guess the answer is, you've got to choose your own poison.. but I love my 20". With my handloads, it delivers sub MOA at 100 yards. I toted it through some God awful thickets this past deer season and the 4 inches were a non-issue. I do not engage in CQB, so I just prefer my rifles to have rifle length barrels. Free velocity is always it's own reward. Since I never shot one in 16", I can not contrast the muzzle blast or perceived recoil difference. Whatever you get,make sure you set aside $40.00 for one of Ross' excellent brakes.

[45r]

I think I'd like to get the 20 inch.I can get a 16 inch for 511 plus 6 bucks shipping and thats 40 to 50 bucks cheaper,but I will wait for a 20.I'm used to the 24 inch Hart barrel on my Colt anyways.Thanx for the replies,I was temted to go the cheaper route but the 20 would be better I think,wish they left the fake block off though.Guess I can take it off when I get the ross break,I want one of those also.

[Hoot]

Red Heads!



Hoot

[bushmeister]

I've found that redheads are hardly worth the temper...uh what?? oh barrel length!! I swear by the 16" barrel for real woods hunting situations on my side of the states. If your are hunting in the western 1/3 of the country, I could see where the longer barrel would be advantageous. But inside 200 yds it's dead regardless.

[BD1]

Here's another vote for the 16" barrel. It's lighter and handles quicker in the brush. I'm easily getting 2,200 fps with the 250 grain FTX, so what do I need with the extra 4" of barrel Actually if I had my preference it would be an 18 inch barrel with a little faster twist, maybe an 18 or 20, because I'm really into the 300 grain cast lead.
BD