barrel length Q

WhelanLad

WhelanLad

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hello.

so, say i have my 30-06, it was originally a Abolt with 22.? inch barrel........ i had 2 inches cut off it i think.... now overall is say 20 inches.

however with a case like a 30-06, we have a length of 2 inches or so before the rifling starts...

my question here is, we look at ballistics from 24 inch barrels most of the time, then we knock 25fps per inch off each bit we lose of barrel.........

does my rifle now really only run a 18-19 inch length of barrel? so the FPS guestimates an such would be off?

ive chronomy load of varget an 180gr at 2550fps as it currently sits.

does this Q make sense?

say the overall barrel was 20 inch wit ha 308 case.......

V

20 inch 3006, isnt the 06 losing to begin with due to longer case / less barrel? per say
 
The case length is less than half an inch so you may be overthinking this somewhat, also more case volume means more velocity even in shorter barrels though you can get some spectacular muzzle flash in short barreled magnums.
 
Is typical that "barrel length" is measured from the closed bolt face to the muzzle - so that dimension INCLUDES the length of the chamber. Some may chose to measure from wherever they want to wherever else they want, but when inventing your own "rules", do not expect anyone else to know what you are reporting, unless you also explain from where to where you have measured.

I have experienced some Sellers who measure from the barrel muzzle to the front edge of the receiver - that works, if they say what it is what they measured from and to.
 
Every cartridge is going to lose some velocity due to the shorter barrel length, and it will vary dependent upon the cartridge. Some lose more than others, but as each barrel will perform somewhat differently, the only way to know for certain is to chrony your load in your rifle. The end result will be individual to your rifle barrel and ammunition used. The difference in energy and performance on the animal is going to be dependent upon the bullet's BC, SD, initial velocity, and retained energy at the target. This easy to calculate once you have chronied your load, in your rifle. From there, stick to the recommended energy figures for most game e.g., 1000 ft lbs for deer sized game, 1500 ft lbs for moose and other larger game, and 2000 ft lbs for bison, grizzly bears, etc. (some prefer 2000 ft lbs for elk, while others say 1500 ft lbs...I think this is due to the better quality bullets available today compared to the softer cup and core bullets from 70 years ago (most cup and core today work better than their predecessors)).

One item not discussed or written about as much, is the distance of the shot on game, where a cup and core bullet can still be preferred to the bonded or monometal bullets. For most hunters who are going to be facing shorter distance shots e.g. 150 yards and less, I believe that this is where a cup and core bullet still has a lot of merit and useful performance on most big game hunted to today (various deer species, black bear, etc.) Most of the discussion and writing today focuses on longer shots with the bonded and monometal bullets...due to the long range hunting fad.

And since animals are also individuals, each will be reacting somewhat differently when shot. Some species are hardier than others, such as elk are definitely more tenacious of life than moose, but as each individual is also different, some animals in hardier species die quicker than some animals in less hardy species. E.g., Caribou are not usually known to be hardy and tough to kill, but my first took 5 in the boiler room from 100 yards before expiring, while I have had quick, clean one shot kills on elk in the rut. Most of the other caribou (6) taken over the years expired quickly to one shot.

And a variance of 100 fps in a cartridge (for most commonly used small and medium bores used with common bullets weights ) is not going to make a huge difference when it comes to killing most game, we are starting to get into the weeds here. I wouldn't worry about it too much...just my two cents...
 
It not exactly 25 fps per inch.

It varies, 1 inch might be 27 fps where as the next 1 inch reduction may only be 17 fps.

My .308 averaged 19 fps over a 5 inch reduction.

It started off as a 24 inch barrel as was listed with the manufacturer and ended up at 19 inches.
 
I’ve got a 20” 30-06, and realize approximately 75-100 fps velocity loss compared to all the 22” barreled 30-06’s I’ve owned over the years.

In the real world it ain’t no big deal……..
 
In my 20 inch 308 win I'm getting an average of about 2530-2535 fps with federal GGM 168 gr. thats averaged over 5 rounds. but in that five rounds there was a 60 fps extreme spread. According to the manufacturer in a 24 inch barrel it clocks at 2650 fps. this gives me about 30 fps lose per inch of barrel.
 
Here in NZ barrels are getting shorter and shorter. 16" is common amongst the bush hunters and in all sorts of calibres, from the 223 right up to the 358. It appears that the bigger the bore, the less a loss in velocity from short barrels. And some cartridges just seem to work better in shorter barrels than other cartridges. With lots of different powder choices available to the handloader, it is possible to still retain some decent velocity too.
Chopping a 30-06 is reasonably common, but the same can be achieved by using a 308 and shortening it. A lot of our hunters are using shortened barrels with larger projectiles, 2700fps +, and consistently shooting deer out to 400 metres and beyond.
 
Backcountryal said:
Here in NZ barrels are getting shorter and shorter. 16" is common amongst the bush hunters and in all sorts of calibres, from the 223 right up to the 358. It appears that the bigger the bore, the less a loss in velocity from short barrels. And some cartridges just seem to work better in shorter barrels than other cartridges. With lots of different powder choices available to the handloader, it is possible to still retain some decent velocity too.

Chopping a 30-06 is reasonably common, but the same can be achieved by using a 308 and shortening it. A lot of our hunters are using shortened barrels with larger projectiles, 2700fps +, and consistently shooting deer out to 400 metres and beyond.
Click to expand...

Was just going to say… if you’re wanting to cut down a 30-06 to 18-20” you’re better off with just getting a 18-20” .308. Similar performance, less bang.
 
Potashminer said:
Is typical that "barrel length" is measured from the closed bolt face to the muzzle - so that dimension INCLUDES the length of the chamber. Some may chose to measure from wherever they want to wherever else they want, but when inventing your own "rules", do not expect anyone else to know what you are reporting, unless you also explain from where to where you have measured.

I have experienced some Sellers who measure from the barrel muzzle to the front edge of the receiver - that works, if they say what it is what they measured from and to.
Click to expand...

Yeah this is what I was getting at aswell, including the chamber in over all means that the so an so 20 inch, is really about 17-17.5 inch rifling with said 30-06 . ?
 
BeaverMeat said:
Was just going to say… if you’re wanting to cut down a 30-06 to 18-20” you’re better off with just getting a 18-20” .308. Similar performance, less bang.
Click to expand...

i use varget aswell, so this puts it just a bit warmer than a 308 , with the 180grain...

but with varget you are only using 45gr V 49? grains in the 3006 for the 180, so all in all, its pretty similiar stuff.

choronod at 2550, i think thats close to 22/24 inch ? 308s ?
 
I used an older Shooting Chrony to measure velocity. The rifle was a push feed Model 70 Winchester in 308 Win - it still has the factory barrel that I called a 22" barrel - I bought that rifle new in a Co-op store in small town Sask in 1976. Over the years I had tried it with IMR 4064, W-W 748 and finally I use Reloder 15 powder and Speer 165 HotCor bullets in that one, since early 1990's - chrono'd my load several dozen times - a bit more or less than 2,800 fps. Almost always Fed 210 primers - was various cases - mostly W-W or Rem brand. You will find that powder listed in both the Speer #14 Manual and in Nosler #9 manual - circa 2,800 fps. The Speer book says they used a 22" Rem 700 rifle for velocity testing; the Nosler book says they used a 24" Lilja barrel for their velocity testing. Some number of grains difference reported by each manual - no doubt a function of different barrels, different cases used, different primers used. Many, many five shot groups on 100 yard target circa 1.25" diameter group - way more "accurate" than needed to take many dozen head of deer at various ranges. Both myself and my son, 25 years later, took our first elk with that load and rifle.

My Dad had a WWI M1917 Enfield in 30-06 that he "sporterized" in 1948 - he described to have removed "several inches" of barrel - originally they were reported to have 26" barrels, so I presume his would have ended up circa 20"-21"-22". He never hand loaded - only used store bought commercial ammo. I did take one deer with his rifle and ammo - was my impression that what he got with commercial 165 grain loads was similar to my hand loads in my 308 Win - deer gets hit by the bullet, not by the head stamp - so when they are dead, is hard to argue one is "better" or "worse" than the other. When he passed on about 10 years ago, that rifle and remnants of his ammo ended up with me - so some 150 grain, 165 grain, 180 grain, 200 grain and a couple 220 grain - a good amount of it got fired off at a 100 yard target from sand bags - could cover the 11 or 12 shot group with palm of your hand - good enough to kill stuff. Oddly, the 3 x 150 grain made their own little group high and right - all the rest of the bullet weights clumped in just about point of aim.
 
Typically barrel length is measured from the closed bolt face to the end of the barrel, easy way to measure is to close the bolt, insert a cleaning rod from muzzle end until it touches the bolt face, mark the rod then pull it out and measure it, no magic involved pretty straight forward, same goes for shotguns, most manufacturers publish barrel lengths using this method and the published length includes the length of the chamber.
 
WhelanLad said:
Yeah this is what I was getting at aswell, including the chamber in over all means that the so an so 20 inch, is really about 17-17.5 inch rifling with said 30-06 . ?
Click to expand...

Yup - there is about 1/2" more rifling in the barrel that is chambered for 308 Win, versus that same barrel chambered for 30-06. However, the case capacity is part of the "combustion chamber" that includes the bore as the bullet moves along - so, when bullet about to exit muzzle, is a small amount more gas volume under pressure - within the case chamber and within that bore, for the 30-06, over the 308 Win. You can alter that by using differing burning rate powders - a very slow powder likely results in faster exit velocity from muzzle for heavier bullets - also bullet weight affects that - about 165 grains or so, I think 308 Win and 30-06 about equal, with components that I have used - especially hand loaded 308 Win versus store bought commercial 30-06 ammo. As bullets go heavier - 180 grain, 200 grain, 220 grain - the 308 Win can not keep up to 30-06 - can not get enough slower burning powder into that smaller case. Case shape also matters - is different with straight walls like 45-70 and 458 Win Mag - versus shouldered cases like 243 Win, 7x57, 308 Win and 30-06.
 
WhelanLad said:
hello.

so, say i have my 30-06, it was originally a Abolt with 22.? inch barrel........ i had 2 inches cut off it i think.... now overall is say 20 inches.

however with a case like a 30-06, we have a length of 2 inches or so before the rifling starts...

my question here is, we look at ballistics from 24 inch barrels most of the time, then we knock 25fps per inch off each bit we lose of barrel.........

does my rifle now really only run a 18-19 inch length of barrel? so the FPS guestimates an such would be off?

ive chronomy load of varget an 180gr at 2550fps as it currently sits.

does this Q make sense?

say the overall barrel was 20 inch wit ha 308 case.......

V

20 inch 3006, isnt the 06 losing to begin with due to longer case / less barrel? per say
Click to expand...

No you're question does not make sense. not sure why you would chop a 30-06 barrel other than going to carbine length for versatility. Range and velocity are not going to very enough to make it all worth crap.
 
threecentsolution said:
No you're question does not make sense. not sure why you would chop a 30-06 barrel other than going to carbine length for versatility. Range and velocity are not going to very enough to make it all worth crap.
Click to expand...

its been done, it is left handed, my only left handed rifle, i use it in bush, but i wanted it shorter, i had it fluted too lol .. its good. i like it. i was just questioning the actual length of it now minus the chamber etc.
 
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