I have a 16" HBAR (1-9 twist) that I'm considering having cut to 11.5".  Would I have any cycling issues with the shorter barrel.  It looks like that is what Bushmaster does with there 11.5" barrels.  I didn't know if the gas port is the same size or not.

Thanks
Jeremy

I am pretty sure that the gas port on the 11.5-inch upper is larger then on the 16-inch barrel.  Just the same, until you cut it down you really don't know if it will work or not.

Personally, I would buy a 11.5 and sell your 16 or trade your barrel for a used 11.5.

JMHOs

ADCO cut my 16" Del-Ton upper down to 11.5" for me, works great.  

Quoted: Try it and see if it works.  There is a surprising inconsistancy in gas port size, even with the same brands.

Well, you will be trying it.  I was planing on sending the barrel your way to get it done.  Would it be a problem to make the hole larger?  I don't know if it matters, but I am also planing on using the new ARES piston conversion if they keep getting good reviews.

Jeremy

One more practical question for you... Are you planning to be able to use this for self defense of SHTF type use?  If so, you may wish to consider the arrel twist rate of your 16-inch barrel.

If your barrel is a 1:9 twist, you may not be able to shoot the really heavy 75, 77, or heavier bullets.  To do this you will likely want a 1:7 twist barrel.  As I am sure you know, a 11.5-inch barrel has a tough time getting enough velocity to get the smaller 55 and 62 gr bulets moving fast enough to get fragmentation.  The heavier bullets fragment at a slower velocity better but they realy need the faster twist to allow them to shoot accutarely.

If it is a range toy for punching holes in paper, well then it really doesn't matter but for my own 11.5-inch upper I use a 1:7 twist barrel in case I might need the better terminal performance of the heavier bullets.

Just something to think about... good luck!

Quoted: I don't know if it matters, but I am also planing on using the new ARES piston conversion if they keep getting good reviews. Jeremy

With the ARES piston kit on a 11.5 or 16, it will need hot ammo to function.  I have one on a 11.5 that will not function with Wolf or WWB until it was opened up to .083.  BTW, I cut a BM 16" down to 11.5 a long time back and use this barrel for this piston kit; the port definitely has to be opened.

Quoted: If your barrel is a 1:9 twist, you may not be able to shoot the really heavy 75, 77, or heavier bullets.  To do this you will likely want a 1:9 twist barrel.  As I am sure you know, a 11.5-inch barrel has a tough time getting enough velocity to get the smaller 55 and 62 gr bulets moving fast enough to get fragmentation.  The heavier bullets fragment at a slower velocity better but they realy need the faster twist to allow them to shoot accutarely.

I had thought about this.  I can go up to 69grn. with the 1:9 twist, but I have alot of 55grn stuff on hand.  Real use will be for at my range, but it would be used for what ever I would "need" it for, home defense included.  I am building a Mk 12ish clone right now, and wanted to do something different with my other rifle.

Hail Mary:  That is good to know about the ARES.  I'm assuming it was easy to open up the port.  How is the accuracy at 100 yrds with the cut barrel?

Thanks for all the opinions guys.
Jeremy

Quoted: Quoted: If your barrel is a 1:9 twist, you may not be able to shoot the really heavy 75, 77, or heavier bullets.  To do this you will likely want a 1:9 twist barrel.  As I am sure you know, a 11.5-inch barrel has a tough time getting enough velocity to get the smaller 55 and 62 gr bulets moving fast enough to get fragmentation.  The heavier bullets fragment at a slower velocity better but they realy need the faster twist to allow them to shoot accutarely. I had thought about this.  I can go up to 69grn. with the 1:9 twist, but I have alot of 55grn stuff on hand.  Real use will be for at my range, but it would be used for what ever I would "need" it for, home defense included.  I am building a Mk 12ish clone right now, and wanted to do something different with my other rifle. Hail Mary:  That is good to know about the ARES.  I'm assuming it was easy to open up the port.  How is the accuracy at 100 yrds with the cut barrel? Thanks for all the opinions guys. Jeremy

OOpps ... to be clear I meant to say if you want to use the heavier bullets I would want a 1:7 twist!  I use a 1:7 twist Bushmaster 11.5-in BBL on my subcarbine upper so I can use the 77-gr Noslers if I wanted to use it against targets that might shoot back.  It is quite effective out to 100-yrds according to what I have read.

With 55s, 62s, or 69s, you are limited to really close range...  See www.ammo-oracle.com/

Quarterbore:  I knew what you ment.  If you don't mind, where in Pa are you?

Jeremy

I live just north of Valley Forge