My 6.8spc upper has an 18" barrel, I mainly use it for hunting under 300m. With an AAC 7.62 SDN on it I might as well be carrying a brown bess . I have been looking at an SBR upper 10.5" - 12.5" but I figured hell why not just have to cut down. Evidently there is a good outfit local Atwell Tactical so I thought I would asked the SF Brain Trust.

I have looked at the velocity loss and if I go from the 120gr SST I have been using to a 95gr or 100gr the difference is not that bad..especially for hog or what they call deer here in NTX.

My big fear is the barrel has been a great performer....last time at 200yd it averaged 2.2" and I don't want to screw it up.

There are always some risks, but a competent gunsmith with good barrel cut experience should be able to do it without much drama.

I had two SCAR barrels cut down, which are supposed to be difficult due to the chrome lining process but they are fine and shoot as well as they did before.

You also might consider the cost difference between a cut down job vs new shorter barrel installed. Depending on factors, it might not be that much different $$ wise.

Looked, its about half the price...if I could find the length I want. Atwell charges $80 to cut and thread. ARP has a.12.5" 5R that is very nice but finding them in stock is hard and they are $185

I will have to buy a new handguard...oh well

Cutting a barrel can be an unknown, per the 'smiths I've spoken to. The shorter barrel will be stiffer, however it will have different harmonics and will produce a lower muzzle velocity. Most likely for your use and distance, any potential accuracy changes won't change the rifle's function.

Reducing your bullet weight from 120 to 100 grains will certain offset some of the velocity loss, however you should compare the terminal ballistics of the two bullets -- it's possible the the lighter bullet will not perform as well as the heavier one. And regardless of what you do, the shorter barrel means less muzzle energy and less terminal energy.

We all have different preferences with barrel lengths and their issues given the terrain in which we carry them. In AR-15 matches I hump 18" and 20" barrels with a 6" can across variable terrain. In precision rifle matches, also in variable terrain, I use a 26" bolt action with a 9" can. YMMV

I've cut several. I had ADCO do it. In an AR it never occurred to me to worry about the barrel being worse off and they were not but the most I've sliced is 2 ish ".

quote:

Originally posted by dewhorse:
My 6.8spc upper has an 18" barrel
I have been looking at an SBR upper 10.5" - 12.5"

I should have thought of gas systems earlier. If you have an 18" AR barrel, I believe your gas port distance will be 9" for a mid-length or 7" for a carbine-length. It's possible your gas port distance of your 18" barrel could be incompatible with a such a significant reduction in barrel length.

quote:

Originally posted by RHINOWSO:
There are always some risks, but a competent gunsmith with good barrel cut experience should be able to do it without much drama.

I had two SCAR barrels cut down, which are supposed to be difficult due to the chrome lining process but they are fine and shoot as well as they did before.

You also might consider the cost difference between a cut down job vs new shorter barrel installed. Depending on factors, it might not be that much different $$ wise.

Hey Rhino, was that local?

quote:

Originally posted by fritz:

quote:

Originally posted by dewhorse:
My 6.8spc upper has an 18" barrel
I have been looking at an SBR upper 10.5" - 12.5"

I should have thought of gas systems earlier. If you have an 18" AR barrel, I believe your gas port distance will be 9" for a mid-length or 7" for a carbine-length. It's possible your gas port distance of your 18" barrel could be incompatible with a such a significant reduction in barrel length.

I will have to go to a mid length gas system, also good point on the bullet construction. Hoping either the 95gr Barnes ttsx or ths 100gr hornady gmx agrees with the barrel as both have shown excellent terminal qualities.

One of our permanently sighting-in shooters here in our gun club bought a nice Tikka T3 with an 18" bbl in 6.5x55. It was a sweet shooter with a SAX mod on it, but still too long for him to wave around in his pickup.

He got it cut down the the legal limit of 16".

I watched him shooting it last Sunday, just for a laff. It has gone from a 10 shots in under an incher, to ten shots in a little under a footer, more often than not.

Beware abut cutting down that barrel, like the man above noted.

tac

You said, "I will have to go to a mid length gas system."

Does that mean your rifle is currently rifle length? Some 18" 223 barrels are. Depending on the gas block journal and contour of your barrel, that may limit how much you can cut off.

Using a can increases back pressure so you will probably be ok if your rifle is already a mid. If it is a rifle that will possibly limit how much you can cut.



Resist the urge to go to a lighter bullet to keep up muzzle velocity. Your velocity will probably still be plenty sufficient for hunting, and lighter bullets sacrifice sectional density and penetration.

Muzzle velocity doesn't mean much for hunting. Beyond a certain point, enough is enough and it's all about placement and a good performing bullet.

I favor the heaviest Barnes TSX that will stabilize well in my small frame guns that will see use on CXP2 class game.

quote:

Originally posted by dewhorse:
My 6.8spc upper has an 18" barrel, I mainly use it for hunting under 300m. With an AAC 7.62 SDN on it I might as well be carrying a brown bess . I have been looking at an SBR upper 10.5" - 12.5" but I figured hell why not just have to cut down. Evidently there is a good outfit local Atwell Tactical so I thought I would asked the SF Brain Trust.

I have looked at the velocity loss and if I go from the 120gr SST I have been using to a 95gr or 100gr the difference is not that bad..especially for hog or what they call deer here in NTX.

My big fear is the barrel has been a great performer....last time at 200yd it averaged 2.2" and I don't want to screw it up.

If you have a local shop that is well regarded and you can save a decent amount of coin, I would advise you to roll the dice and have it cut down.


You don't like it the way that it is, make it the way you want it. There is no guarantee that a purchased NIB short barrel will shoot MOA unless you buy one from someone who offers and accuracy guarantee. And that means $$$.

quote:

Originally posted by tacfoley:
One of our permanently sighting-in shooters here in our gun club bought a nice Tikka T3 with an 18" bbl in 6.5x55. It was a sweet shooter with a SAX mod on it, but still too long for him to wave around in his pickup.

He got it cut down the the legal limit of 16".

I watched him shooting it last Sunday, just for a laff. It has gone from a 10 shots in under an incher, to ten shots in a little under a footer, more often than not.

Beware abut cutting down that barrel, like the man above noted.

tac

Poor guy. All for 2 inches too.......

Maybe he could have the crown recut and bring it back?

anybody can screw up anything. its not like the original mfg. of the barrel didn't cut it, they did. if you get a competent person to cut your barrel you will be fine. I say this for AR barrels since I understand them. Some other barrel with weird harmonics or voodoo OK maybe its a risk.