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Old 04-16-2020, 12:30 PM
shaun1826 shaun1826 is offline
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Default CZ 527 17 Hornet barrel length

I’ve got a 17 hornet that I’m having the barrel cut down and threaded for a suppressor. It’s currently 24 inches and I’m probably going to make it 20 or 18 inch. My question is has anyone went from 24 inch to 18 or 20 inch and what was the loss in velocity? I’m probably splitting hairs but I would like to go 18 inch if there isn’t a big loss in velocity compared to 20 inch.

Thanks
Shaun
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Old 04-16-2020, 01:49 PM
TinMan TinMan is offline
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For a 223 Rem, change is about 30fps/in of barrel length. Don't know the number for a 17 Hornet.
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Old 04-16-2020, 02:17 PM
Bill K Bill K is offline
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Various tests and also comments by posters seem to me anyway, that a mean average for loss or gain, is about 30 FPS per inch on a barrel.
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Old 04-16-2020, 03:49 PM
Wiserfool Wiserfool is offline
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I like short barrels so have a few. If you are going to chop one and velocity loss is a concern, jumping up to a K Hornet while the work is being done might be something to consider.....
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Old 04-16-2020, 03:50 PM
shaun1826 shaun1826 is offline
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Quote:
Originally Posted by Bill K View Post
Various tests and also comments by posters seem to me anyway, that a mean average for loss or gain, is about 30 FPS per inch on a barrel.
I appreciate the responses. But for what caliber is the 30 fps loss per inch? Take a 22 LR for instance. You can go from 22 inch to 16 inch and not have any velocity loss. All the powder is burnt up by 16 inch.

I guess another way of asking my question is at what barrel length for 17 Hornet is all the powder burnt up and you do not get additional velocity? Then once you start cutting it off how much do you lose per inch for this specific caliber.
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Old 04-16-2020, 03:56 PM
Bill K Bill K is offline
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They, of course, will vary somewhat due to FPS, etc. But as I said a mean average, if you read various comments and reports ( Bullberry has a chart, for one ) a mean average will still run around 30 FPS per inch.

As to what length barrel the powder will be burnt up in, that will mostly depend of the burn rate of the powder used. Only way you would know for sure on your barrel and caliber, would be to run a chrony from the length you start with and then by cutting of one inch at a time, see what you are getting. ( google Bullberry's chart and see what you think or what they found)

Last edited by Bill K; 04-16-2020 at 03:58 PM.
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Old 04-16-2020, 05:36 PM
Dean2 Dean2 is offline
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Even if 6" of cut costs you 200 fps, does that really make enough difference to offset how much handier the gun is? Personally, I have never worried about velocity loss. I only ever use long barreled rifles for real long distance shooting and the 17 H is pretty much a max 300 yard gun so the velocity loss on 6" is pretty much irrelevant and on 2" matters not at all. Load using Lil'Gun and it will make up for any velocity loss anyhow and it is more than fast enough to burn in the 18" barrel.
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Old 04-16-2020, 05:38 PM
TinMan TinMan is offline
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Shawn1826. I did the test with all the 223Rem rifles my friends and I had available to us many years ago. The ammo was factory 55gr NATO FMJ. The barrel lengths were from 8 inches on a HK-53, a 14 inch Contender, ARs in 16 and 20 inch, to multiple bolt actions from 20 inch to 26 inch length. We chronographed all the rifles and curve fit the data. We did not cut any barrels. I am sure the different action types made some difference/scatter in the data, but it was cheap (ammo cost only) and fun to do. The curve fit of velocity to barrel length result said 29 fps/in of barrel length change, in the lengths of 8 inch to 26 inches.

Last edited by TinMan; 04-16-2020 at 05:42 PM. Reason: added info
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Old 04-16-2020, 08:25 PM
17tbs 17tbs is offline
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http://varmintal.com/aflut.htm

Shorter(fatter and proportionally stiffer) barrels have less barrel whip.

You'll lose about 40 to 80fps by chopping back to 20 from 22.

Use a more advanced powder, convert to a 17K Hornet.
You will never know the difference. My 18.75" 12.75gr h20
case capacity 40°17VHA still gets 2910fps using a 30gr Kindler over a case full (compredded load ) H4198, at 9.7gr H4198 the load is easy on the brass at somewhere near 45k to 48k PSI.

I don't think that I am losing much behind the 17K hornet, so for me the 18.75" barrel is optimal for my carry rifle, an old TC carbine.

Your mileage may vary, but with heavy woods all around me and no shots presenting themselves over 100 yds I am probably not missing anything.

Last edited by 17tbs; 05-05-2020 at 04:11 AM.
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Old 04-16-2020, 08:44 PM
GLWenzl GLWenzl is offline
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I just ran up a 24” 223 and a 16” 5.56 with same loads. I realize it isn’t apples for apples but the 16” stopped at 2800 FPS where the 24” was still gaining velocity when I stopped at 3125fps. (My goal is to find a 75gr bthp load with a 3k FPS MV, I’m not going to get it).

I think it was Fred at Bullberry who once told me he thought 21” was an optimal length for a 17AH.
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