Main Menu
Advertisement
Affiliates
Advertisement
Newest Members
Adchunts, CoolCatDaddy, tommy shelton, TexasBuckeye7, Tangi
60412 Registered Users
Top Posters
dogcatcher 77324
stxranchman 52092
RWH24 44568
rifleman 43776
BOBO the Clown 41084
BMD 40539
Big Orn 37484
txshntr 33682
bill oxner 32575
sig226fan (Rguns.com) 30560
facebook
Forum Stats
60412 Members
45 Forums
475563 Topics
6238598 Posts

Max Online: 16728 @ 03/25/12 08:51 AM
Topic Options
#5737978 - 05/10/15 07:18 PM how much loss in ft per sec?
Bigfoot Online   content
Tracker

Registered: 08/06/14
Posts: 586
Loc: Galveston Bay
I have a 30-06 it has a 20 3/4 inch barrel

i assume most of the ballistic charts are for a 24 inch barrel

What am I losing in ft per second?

25 50 100 200 ?

Thanks
_________________________
"No, I am not a good shot, but I shoot often." Teddy Roosevelt

Top
#5738008 - 05/10/15 07:40 PM Re: how much loss in ft per sec? [Re: Bigfoot]
Brother in-law Online   content
THF Celebrity

Registered: 07/08/07
Posts: 24460
30-50

Top
#5738122 - 05/10/15 08:50 PM Re: how much loss in ft per sec? [Re: Bigfoot]
Beaubien Offline
Bird Dog

Registered: 02/18/15
Posts: 473
Loc: In the mountains east of ABQ
I have always used 50 fps per inch. Never tested that with a chrono.
_________________________


Top
#5738152 - 05/10/15 09:10 PM Re: how much loss in ft per sec? [Re: Beaubien]
FiremanJG Offline
THF Celebrity

Registered: 12/16/08
Posts: 17893
Loc: Wolfe City, TX
That's over doing it.

20 fps per inch is the rule of thumb.
_________________________


800 Yard Steel Rifle Range
Long Range Shooting Instruction
Memberships and Classes Available


Top
#5738157 - 05/10/15 09:14 PM Re: how much loss in ft per sec? [Re: Beaubien]
dawaba Offline
Extreme Tracker

Registered: 10/22/06
Posts: 4200
Loc: Big Eddy Road, Noonday
When I shortened my .375 H&H from 24" to 22", I lost 65 fps with my favorite 300 gr bullet. So with this one example, 30-35 fps per barrel inch would apply.
_________________________
"For every complex problem there is an answer that is clear, simple.....and wrong." H. L. Mencken

Top
#5738171 - 05/10/15 09:22 PM Re: how much loss in ft per sec? [Re: Bigfoot]
DStroud Offline
Pro Tracker

Registered: 11/02/11
Posts: 1155
Loc: Waco
It really varies from caliber to caliber but looking in the Berger manual which actually gives that info they show an average of 25 ft per inch for the 30-06.
I also out of curiosity looked at the .308 in the Berger book and it shows 20fps per inch.....well just so happens I checked 3 .308's for velocity last week. Two had 20 inch barrels and one with a 16 inch barrel all shooting factory 168gr Match ammo and yes the 16 inch barrel was almost exactly 80 fps slower so those guys at Berger are pretty good guessers.

Top
#5738595 - 05/11/15 08:28 AM Re: how much loss in ft per sec? [Re: Bigfoot]
ChadTRG42 Offline
THF Trophy Hunter

Registered: 09/16/09
Posts: 9396
Loc: Lewisville, TX
With a 30-06 and using the typical bullet weights (150-180 grains), you are looking right at 25 fps per inch gain/lose. Going from 24 to 20.75", about 80 fps.
_________________________

www.DallasReloads.com
Type 01 and Type 06 FFL

Top
#5740594 - 05/12/15 12:27 PM Re: how much loss in ft per sec? [Re: Bigfoot]
Bigfoot Online   content
Tracker

Registered: 08/06/14
Posts: 586
Loc: Galveston Bay
thank you guys

75 ft/s is like no loss at all for any hunting situation
_________________________
"No, I am not a good shot, but I shoot often." Teddy Roosevelt

Top
#5741927 - 05/13/15 09:28 AM Re: how much loss in ft per sec? [Re: FiremanJG]
deewayne2003 Offline


Registered: 03/19/09
Posts: 4167
Originally Posted By: FiremanJG
That's over doing it.

20 fps per inch is the rule of thumb.


X2 on what FiremanJG said.

I had a .257wby with a 26" barrel that was heavy and hard to maneuver in tight spaces, so I sent it to Kampfeld and part of the custom work he did was cutting the barrel from 26" down to 24".

Everyone was saying I would have a massive loss in velocity with such a fast round; so I took both factory ammo and my hand loads and chronographed the rifle & ammo out of the same 2 boxes of ammo before and after I had the barrel cut down.

The result was an average loss of 50 fps from 3550fps with a 26" barrel to 3500fps with a 24" barrel and the trade off on weight and handling was worth it.

Top
#5743461 - 05/14/15 08:29 AM Re: how much loss in ft per sec? [Re: Bigfoot]
VAFish Offline
Outdoorsman

Registered: 02/09/15
Posts: 99
Loc: Fairfax, VA
From Chuck Hawks page:

http://www.chuckhawks.com/rifle_barrel.htm

Quote:


Velocity loss (or gain)

It is worth noting that the velocity figures published in ammunition brochures and reloading manuals are sometimes taken in barrels different in length from those supplied on many rifles. I have seen various estimates of how much velocity is lost (or gained) when a barrel is not the same length as the test barrel in which a cartridge was chronographed. Here are some of them.

The 2001 Edition of the Shooter's Bible states, in the introduction to the Centerfire Rifle Ballistics section, "Barrel length affects velocity, and at various rates depending on the load. As a rule, figure 50 fps per inch of barrel, plus or minus, if your barrel is longer or shorter than 22 inches." However, they do not say what category of load to which this 50 fps average pertains.

Jack O'Connor wrote in The Rifle Book that, "The barrel shorter than standard has a velocity loss which averages about 25 foot-seconds for every inch cut off the barrel. Likewise, there is a velocity gain with a longer barrel." He went on to illustrate this using a .30-06 rifle shooting 180 grain bullets as an example, so his estimate was obviously for rifles in that general performance class.

Other authorities have tried to take into account the different velocity ranges within which modern cartridges operate. The Remington Catalog 2003 includes a "Centerfire Rifle Velocity Vs. Barrel Length" table that shows the following velocity changes for barrels shorter or longer than the test barrel length:

MV 2000-2500 fps, the approximate change in MV per 1" change in barrel length is 10 fps.
MV 2500-3000 fps, the approximate change in MV per 1" change in barrel length is 20 fps.
MV 3000-3500 fps, the approximate change in MV per 1" change in barrel length is 30 fps.

MV 3500-4000 fps, the approximate change in MV per 1" change in barrel length is 40 fps.


The 45th Edition of the Lyman Reloading Handbook also has a table showing Center Fire Rifle Velocity Vs. Barrel Length. Their figures apply to barrels between 20 and 26 inches in length and agree with the Remington figures. The Lyman table shows the following approximate velocity changes:

For rifles with muzzle velocities in the 1000-2000 fps range, the change in velocity for each 1" change in barrel length is 5 fps.
For rifles with muzzle velocities in the 2001-2500 fps range, the change in velocity for each 1" change in barrel length is 10 fps.
For rifles with muzzle velocities in the 2501-3000 fps range, the change in velocity for each 1" change in barrel length is 20 fps.
For rifles with muzzle velocities in the 3001-3500 fps range, the change in velocity for each 1" change in barrel length is 30 fps.
For rifles with muzzle velocities in the 3501-4000 fps range, the change in velocity for each 1" change in barrel length is 40 fps.

The 43rd edition of the Lyman reloading Handbook gave some concrete examples of velocity loss for specific calibers and loads. The Lyman technicians chronographed some high velocity cartridges in rifles with barrels ranging in length from 26 inches down to 22 inches with the following results:

The average loss for the .243 Win./100 grain bullet was 29 fps per inch.
The average loss for the .264 Win. Mag./140 grain bullet was 32 fps per inch.
The average loss for the .300 H&H Mag./220 grain bullet was 25 fps per inch.

For standard high intensity cartridges in the same test, the Lyman technicians chronographed the cartridges in barrel lengths ranging in length from 24 inches down to 20 inches with the following results:

The average loss for the .270 Win./130 grain bullet was 37 fps per inch.
The average loss for the .270 Win./150 grain bullet was 32 fps per inch.
The average loss for the .300 Sav./180 grain bullet was 17 fps per inch.
The average loss for the .30-06/180 grain bullet was 15 fps per inch.
The average loss for the .35 Rem./200 grain bullet was 11 fps per inch.

After a bunch of disclaimers, the Lyman people concluded, "The rule of thumb is that high speed, high pressure cartridges shed more speed in short barrels than do the low speed, large bore types." It's funny, but that is what I had suspected all along!




So I would say that it depends upon what bullet at what speed, pushed by what powder, but probably somewhere in the range of 20-30 fps per inch of length. So somewhere in the range of 60-100 fps for a 3 1/4" shorter barrel. Or in other words like the difference between a .308 and a .30-06 (which really means no animal will be able to tell the difference)


Edited by VAFish (05/14/15 08:35 AM)
_________________________
"If your plan is for one year, plant rice.
If your plan is for ten years, plant trees.
If your plan is for one hundred years, educate children."
-- Confucius

Top
#5743528 - 05/14/15 09:23 AM Re: how much loss in ft per sec? [Re: Bigfoot]
ChadTRG42 Offline
THF Trophy Hunter

Registered: 09/16/09
Posts: 9396
Loc: Lewisville, TX
It totally depends on the weight of the bullet and at what speed the round is going. It's common sense that a magnum round pushing a light weight bullet really fast will have more of a fall off from velocity with a shorter barrel. Your really big caliber rifles, like a 45-70 or 35 Rem, will have less fps fall off since they are not going near as fast.

But for most common hunting calibers in Texas, the general rule is about 20-25 fps per inch. If you went with this, it will put you in the ball park of your velocity on almost all your common hunting calibers.
_________________________

www.DallasReloads.com
Type 01 and Type 06 FFL

Top
#5744028 - 05/14/15 03:10 PM Re: how much loss in ft per sec? [Re: Bigfoot]
parisite Offline
Tracker

Registered: 07/10/11
Posts: 681
Loc: North of the Sulphur
Doesn't however the velocity loss with each inch in length get incrementally larger the shorter you go?

Top



© 2004-2016 OUTDOOR SITES NETWORK all rights reserved USA and Worldwide