Optimal Barrel Length for .223 Rem.

[Wado]

I decided to replace my Remington 700 Tactical Suppressor ready rifle with a nice CZ 527 Kevlar Varmint I bought. I didn't know whether to ask here or on the suppressor forum so I will start here. The 700 has a 16.5" barrel and the CZ is 24" so with my suppressor on that would put it at 30", a bit on the unhandy side. I plan on shooting up to and maybe heavier than sixty grains so I don't want to sacrifice any more velocity than I have to by shortening the barrel prior to threading and in the same time by shortening make the rifle easier to handle. I hope to shoot this rig before I modify it and I would imagine after shortening it and suppressing I will start all over on a load/loads to suit my needs. The rifle has a twist rate of one in nine and that alone I am told is accountable for 1.5% velocity loss so what can I expect from per inch of bore loss, or would the suppressor bore offset the loss of barrel bore to some degree? I don't have a .223 suppressor so it will be passing through a .30 caliber. I realize there is a lot going on when something this heavy is placed at the muzzle, my 700 would shoot 3" low when the suppressor was attached. Any thoughts? I am thinking 20", you can take it off but you sure can't put it back on.

 

[Darkker]

--I plan on shooting up to and maybe heavier than sixty grains
-- I would imagine after shortening it and suppressing I will start all over on a load/loads to suit my needs.
--The rifle has a twist rate of one in nine and that alone I am told is accountable for 1.5% velocity loss --so what can I expect from per inch of bore loss,
--would the suppressor bore offset the loss of barrel bore to some degree? .

-- Alright
--Yes, very wise
--Not true
--Can't say, there is no linear formula that holds true
--Maybe

Twist formula is: MV * 720 / Twist = RPM. Bullet weight isn't direct, what you need to stabilize is the length.

 

[Wado]

Quote: Bullet weight isn't direct, what you need to stabilize is the length.
Ok, let me see if I am following you. I shoot 95 grain Nosler Partition's in my .243 and they stabilize in my one in ten barrel. I shoot 95 grain Berger VLD and they tumble because they are longer, right? I haven't actually tried this but I do have five loads with 95 grain VLD's to do a ladder test one day in my .243. That's another science project I have going. I feel I am good with the CZ as long as I don't take too much off, the Remmy is a 16.5" after all but no bench rest rig by any means. Thanks for responding.

 

[benchracer]

Here is a link to the results of actual testing of the effects of twist rate on muzzle velocity:

http://bulletin.accurateshooter.com/2015/02/does-barrel-twist-rate-affect-muzzle-velocity-litz-test/

Spoiler alert: The 1.5% figure is a bunch of bs someone has pulled from their posterior.

Bottom line: Your 9 twist barrel isn't costing you muzzle velocity.

I don't believe the suppressor bore will do anything to help you in terms of velocity because it will still cause a pressure drop relative to the bore of the longer barrel. I have no way to back that up with hard data, though. That is just my best guess.

I have a 5.56 chambered bolt action with a 24" barrel and a 5.56 chambered AR with a 16" barrel. The difference in muzzle velocity between the two, using the same load, is around 300 fps. Based on that, I would expect you to lose around 150fps by going to the 20" barrel.

BTW, I am a big CZ fan. The 527 Varmint is a great rifle. Good choice!

 

[Darkker]

Correct, and as was just stated; velocity loss by twist is hooey.
There is a calculator on Berger's site for their bullets, but here is universal, can look up any bullet length.
JBM - Calculations - Stability

Just remember that your individual barrel plays a part in the final number. Barrel twists can vary from stated by 1/2 twist. A rough barrel won't act the same as a smooth one.

 

[Wado]

I believe I might have confused the percent value with inch unit, sorry. One point five percent is pretty radical I agree. I have a seven twist AR I just started fooling with also so this will be fun. Thanks guys.

 

[Trickymissfit]

I decided to replace my Remington 700 Tactical Suppressor ready rifle with a nice CZ 527 Kevlar Varmint I bought. I didn't know whether to ask here or on the suppressor forum so I will start here. The 700 has a 16.5" barrel and the CZ is 24" so with my suppressor on that would put it at 30", a bit on the unhandy side. I plan on shooting up to and maybe heavier than sixty grains so I don't want to sacrifice any more velocity than I have to by shortening the barrel prior to threading and in the same time by shortening make the rifle easier to handle. I hope to shoot this rig before I modify it and I would imagine after shortening it and suppressing I will start all over on a load/loads to suit my needs. The rifle has a twist rate of one in nine and that alone I am told is accountable for 1.5% velocity loss so what can I expect from per inch of bore loss, or would the suppressor bore offset the loss of barrel bore to some degree? I don't have a .223 suppressor so it will be passing through a .30 caliber. I realize there is a lot going on when something this heavy is placed at the muzzle, my 700 would shoot 3" low when the suppressor was attached. Any thoughts? I am thinking 20", you can take it off but you sure can't put it back on.

Years back I was trying to make a 26" Mod. 700 Remington shoot. Barrel was junk, so I later found. Barrel was a 14 twist varmint contour. It was a rock solid 4.25" barrel with the best hand loads I could produce. I should have sent the gun back to Remington, but I'm kinda stubborn. Cut a big chunk of metal off the big end to get a completely new chamber, and did the same off the muzzle. Ended up with a 20" barrel, and lost 74 FPS from the 26" barrel. Seriously thinking about the barrel length, I think a 22" or a 23" is that's needed. I'd probably just do a #7 contour 22" long and be done with it. Plus the short stiff barrel will be more consistent shot to shot due to reduced harmonics alone
gary

 

[MudRunner2005]

Suppressors are not rifled and have a slightly larger bore than the caliber they are designed for, because they are not meant for the bullet to touch the baffles... Therefore, they do not counteract a shorter barrel. They are not designed for you to gain or lose velocity from adding a suppressor. It is simply designed to suppress the decibel level of the report coming out of the muzzle and to reduce muzzle flash...That's it. They do have some other pros as well, such as they reduce recoil, and keep you from going deaf.

They are nothing special, and don't have magical properties, like the gun-grabbers, dems, libs, Hollyweird, and Obama would have you believe. Think of it like a car...It is basically nothing more than a muffler for your gun.

 

[Wado]

Suppressors are not rifled and have a slightly larger bore than the caliber they are designed for, because they are not meant for the bullet to touch the baffles... Therefore, they do not counteract a shorter barrel. They are not designed for you to gain or lose velocity from adding a suppressor. It is simply designed to suppress the decibel level of the report coming out of the muzzle and to reduce muzzle flash...That's it. They do have some other pros as well, such as they reduce recoil, and keep you from going deaf.

They are nothing special, and don't have magical properties, like the gun-grabbers, dems, libs, Hollyweird, and Obama would have you believe. Think of it like a car...It is basically nothing more than a muffler for your gun.

I agree on the hype that they generate, by no means can they silence a firearm. They sure make it comfortable to shoot as long as your groups don't go south. About the best way to describe the noise level of a .223 suppressed with what I use ( SRT Shadow .308 ) is about the same as a .22mag, with less recoil. I am not saying to throw away your ear plugs but at least you have the freedom of taking a spontaneous shot without later having an echo in your ears for two hours. They sure are gaining popularity and are flying off the shelves right now.

 

[MudRunner2005]

I agree on the hype that they generate, by no means can they silence a firearm. They sure make it comfortable to shoot as long as your groups don't go south. About the best way to describe the noise level of a .223 suppressed with what I use ( SRT Shadow .308 ) is about the same as a .22mag, with less recoil. I am not saying to throw away your ear plugs but at least you have the freedom of taking a spontaneous shot without later having an echo in your ears for two hours. They sure are gaining popularity and are flying off the shelves right now.

If they would ever pass the Hearing Protection Act, they would sell them even faster. I'm not paying $200 extra, and waiting for months on end just to get an approval for something I already KNOW I'm approved to own. Soon as the HPA gets passed, I'll be buying about 4 of them from the local store.