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Thread: Ballistics and Barrel lengths?

  1. #1
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    Default Ballistics and Barrel lengths?

    Is there a place to look up ballistics for different calibers with different barrel lengths?Or is there a good book with that info?

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    I don't know of any such published tables to give caliber by caliber, different barrel length velocities. Such info is only generally gathered from time to time in articles and such and then just for one specific caliber.

    I have thousands of loads, for over 100 calibers, in various barrel lengths. The barrel length will include what is generally considered normal or practical lengths for various calibers. Some rifle calibers in pistol barrels of 12" to 15" are included but mostly rifle length barrels for rifles and handgun length for handguns. There have been many rules of thumb published about velocity loss vs barrel length. Some apply to some calibers and some don't get close.

    Do you have a specific question about a particular caliber or barrel length?
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    I was wanting to shorten my 375 hh and wanting to know a good stopping point.And the same on a .280 rem.

    Thanks

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    You'll loose about 25-30 fps/inch of barrel. That's ballpark number, but holds fairly close. So if you chop a 24" barrel to 20", you'll loose about 100 fps.

    Looking at data for running bottle neck cartridges in pistols and from other tests, it looks when you go shorter than 17-18" you loose about 50 fps/inch. But the legal limit for a rifle is 16", and it's advised to keep to 16 1/2" so there's no argument with the authorities.

    That said I find muzzleblast starts getting downright nasty shorter than 18", and I'm hardpressed to see much advantage in rifles with barrels shorter than 20".

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    I like my barrels a little shorter on some rifles but there is a practical limit. For the 375 H&H if you stick with 300 grain bullets you could go down to 20" and probably still be happy with it. The H&H shoots 300 grains at about 2550 fps from a a 24" tube. And as Paul said you'll give up about 25 to 30 fps per inch, it will vary. This will likely give you 2400 to 2450 fps at the muzzle of the 375. That is at the edge of loosing some field performance and some reach on the rifle. Below 2400 fps impact velocity, we are getting close to the Nitro Express velocity and heavier bullets work best. Energy drops quickly with velocity. If you use the 375 as a 100 yard rifle there will be little notice except for the slight increase in muzzle blast. If you hand load you can select powders that help with the blast and flash.

    For the 280 Rem you can turn it into a 7-08 really quickly with a hack saw. A loud and boisterous 7-08. I'd suggest trading it for a 7-08 carbine or maybe a nice 7x57 rather than cut it. I'll bet you'll loose 40 to 45 fps per inch from 24". This has to do with expansion ratio and lower expansion ratios loose more velocity as they give up barrel volume.

    Why do we need to shorten the barrel of the 280? It is a great reach out sheep caliber but if we give up velocity it becomes much less the flat shooting rifle it should be.

    Some time back I posted on here about a fellows 270 WSM cut to 16 inches. It didn't quite make 2400 fps with 130 grain factory ammo. The 6.8 SPC will do that in 16 inches. I asked him why he had it cut to 16 inches? "That's as short as the gunsmith would cut it"! He was told by the smith that he would only loose about 50 fps from the 24" barrel. "Sure I'll still love ya in the morning"
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    I was thinking about rebarreling my 375,and wanted to shorten up,maybe 22" would be better?

    I dont have a 280 but I might in the future and was curious on a good barrel length.I know some rounds need the extra length to perform.

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    Post i've shot a 1885 HW since they made the "new one"

    "and " You do get extra get fps. then there is wt ,i have never seen studys on .".more barrel length " (as in 48" etc) my 1885 has a 28" barrel and shoots a .308 150gr a-eagle fmj at 3100+ fps. that is down rite mean with "bs" amao off the shelf ,from my "testing " u get 20 fps for every inch of barrel...speed and weight,where is the line ....
    WHEN IN DOUBT> THROTTLE OUT.......

  8. #8

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    The last time that I was at Brownell's shooting range there was a fella shooting a Remington model 7 in 243 with an 18 or 18&1/2 inch barrel(what ever the early 7's came with). I asked him if I could shoot my old 77-243 through his feet per second machine and he obliged. My old Ruger has probably had 3-4000 rounds put through it and it showed. When new that gun with the same load of 4064 and a 70 grain Hornady would shoot 3575 fps. It now shoots 3450 fps. The 18 inch barrel on his "7" was pretty much a virgin and with my loads he was getting 3425fps. So in this case 4 inches of barrel meant 25 fps difference. Even when comparing brand splinter new barrels of the same make and length there can be a noticeable difference. Getting a brand new rifle that has had its rifling cut with brand new tooling or getting a brand new rifle that had its rifling cut with tooling that was approaching tolerances near the end of the cutters life cycle is luck of the draw.

    I quit worrying about ringing the most velocity out of my guns along time ago. Giving up a hundred or so fps doesn't concern me in the least. However in the case of one cutting a 270WSM down to 16 inches, thats nonsense, but it would be fun to watch him shoot that thing after dark!

    I plan to replace that old 243 real soon with an Ultra Light 77 with a 20" barrel. My guess is the coyotes won't know the difference!

    Chronographs themselves are not beyond suspicion when it comes down to a gnats ***** as no two of them read exactly the same!

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    Quote Originally Posted by Murphy View Post
    I like my barrels a little shorter on some rifles but there is a practical limit. For the 375 H&H if you stick with 300 grain bullets you could go down to 20" and probably still be happy with it. The H&H shoots 300 grains at about 2550 fps from a a 24" tube. And as Paul said you'll give up about 25 to 30 fps per inch, it will vary. This will likely give you 2400 to 2450 fps at the muzzle of the 375. That is at the edge of loosing some field performance and some reach on the rifle. Below 2400 fps impact velocity, we are getting close to the Nitro Express velocity and heavier bullets work best. Energy drops quickly with velocity. If you use the 375 as a 100 yard rifle there will be little notice except for the slight increase in muzzle blast. If you hand load you can select powders that help with the blast and flash.

    For the 280 Rem you can turn it into a 7-08 really quickly with a hack saw. A loud and boisterous 7-08. I'd suggest trading it for a 7-08 carbine or maybe a nice 7x57 rather than cut it. I'll bet you'll loose 40 to 45 fps per inch from 24". This has to do with expansion ratio and lower expansion ratios loose more velocity as they give up barrel volume.

    Why do we need to shorten the barrel of the 280? It is a great reach out sheep caliber but if we give up velocity it becomes much less the flat shooting rifle it should be.

    Some time back I posted on here about a fellows 270 WSM cut to 16 inches. It didn't quite make 2400 fps with 130 grain factory ammo. The 6.8 SPC will do that in 16 inches. I asked him why he had it cut to 16 inches? "That's as short as the gunsmith would cut it"! He was told by the smith that he would only loose about 50 fps from the 24" barrel. "Sure I'll still love ya in the morning"
    Way to Go, Murphy:

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    For what ever it's worth I have a good load for my 20" .308 that runs 2575fps with a 175gr Berger. That same load with brass sized for my 24" .308 AR rifle runs 2640fps.

    Glad you're back Murphy...

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