Barrel shortening and weight reduction

just weighed the 4" stub from my 6x47 remington barrel. .665 at the base to .655 at the muzzle end, 6mm hole....weighed 5.35oz
So 2.675ish oz / inch with that taper and bore dia.
I had an 7mm A bolt stub somewhere, but i cant find it right now. ill weigh that one when i get the chance, its tapper is faster so it would weigh less.

I've chopped three .308 barrels down from 22" to 20" now. Sporter profile Savage factory barrels and they were right at 1 oz./inch. The accuracy actually improved each time - I can only guess because of the hand cut crown and stiffer barrel. But I don't know that for sure.

It's amazing how much difference just 2" of barrel can make. It's not so much the weight as the balance. The difference to me, between a hunting rifle with a 22" barrel and a 20" barrel is night and day.

Newtosavage said:

It's amazing how much difference just 2" of barrel can make. It's not so much the weight as the balance

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Agreed, thats the big one, and that cannot be understated.

You really need to cut 1/2 pound or so from the average rifle for me to be able to tell any difference. But cut 4oz of the very front of a gun, especially a gun with a 26" barrel like my Abolt, and the handling completely changes. I still prefer longer barrels for rifles that will be shot from supported positions, or even for general use, but for quick action hunting, or in thick cover where you have to move the rifle around and hold it at weird angles/positions, shorties are really nice.

Oops bad math...i forgot it was 4" not 2....
The stub from my 6x47 would be 1.337oz per inch

I know this isn't .30 caliber, but I just weighed a piece of sporter profile barrel from a .22 WMR barrel I cut down to 16.25" a while back.

The length is 5.46". The smallest outside diameter (at the old muzzle) is 0.55" and the largest outside diameter is 0.62". The weight of that barrel piece on my kitchen scale is 5.5 ounces. So, just over 1 ounce per inch in my example.

I have no idea how much weight was lost in the hacksaw cut and the re-crowning process. Probably not enough to matter.

Accuracy for 5 shot groups has proven to be virtually the same in my example. It's mostly a choice of ammo, just like before.

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I cut the barrel of a Remigton Sendero .308 (it was 28 o 30 inches) down to about 19" (long enough to be legal). Did not notice much weight reduction (heavy rifle to begin with) but it handles much better and is more accurate now.

I have a Norwegian Krag, 6.5 X 55, which the former owner, a nice old gentleman from the Jicarilla Apache Nation, cut down from 29 inches to 16 for some reason. Obviously, it is way lighter and a lot handier. I have often wondered how much muzzle velocity has been lost with factory ammo? As you know, slow burning powder is the standard propellant, so there is much muzzle flash. I do not have access to a chronograph. I guess the original 2,700 FPS is reduced to the neighborhood of 2,100 or so. Any thoughts are appreciated.

I just got done with a 308 hunting rifle that had a very slim 18 1/2 inch barrel.I replaced it with a 20 inch.The shootability of the rifle improved dramatically.With the shorter,lighter barrel,the balance was so butt heavy that the rifle was horrible to shoot offhand.When cutting a barrel,always remember that too much of a good thing can be a bad thing.

(Diameter at cut point - diameter of muzzle) / 2 + diameter of muzzle = Reference diameter

((Reference diameter - bore diameter) / 2) ^2 * pi * length cut off * 0.291

Gives you approximate weight of the stub you're removing.

Accuracy will not be negatively affected unless your smith completely botches the crown job. The balance of the rifle may change, making the rifle less shootable, but the inherent precision should improve.

. I do not have access to a chronograph. I guess the original 2,700 FPS is reduced to the neighborhood of 2,100 or so. Any thoughts are appreciated.

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No where near 600 fps. More likely closer to 100-150 fps.

Here is a study done with 6.5 Creedmoor, they lost 158 fps with 142 gr bullets between 27" and 16". And most of that came after going under 19". Only 73 fps between 27" and 19". The lighter 120 gr bullets saw more speed loss. But once again at 19" or longer there just wasn't much loss of velocity. Plus your gun would have gained almost nothing with a barrel longer than about 22-24". The extra 5-7" of barrel was to get a longer sight radius for iron sights.

https://rifleshooter.com/2016/02/6-...el-length-on-velocity-cutting-up-a-creedmoor/

Blacksmoke said:

I have a Norwegian Krag, 6.5 X 55, which the former owner, a nice old gentleman from the Jicarilla Apache Nation, cut down from 29 inches to 16 for some reason. Obviously, it is way lighter and a lot handier. I have often wondered how much muzzle velocity has been lost with factory ammo? As you know, slow burning powder is the standard propellant, so there is much muzzle flash. I do not have access to a chronograph. I guess the original 2,700 FPS is reduced to the neighborhood of 2,100 or so. Any thoughts are appreciated.

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Most if not all factory, and reloading data velocity is usually given from a 22-26" (most are 24") barrel, so 2700fps is already rated from a barrel much shorter than the original 29".

I used quickloads to match Hornadys 140ss load, using hodgdon h4831 which is about as slow a powder as will run in the 6.5x55 at standard pressures.
From a 24" barrel the theoretical muzzle velocity is 2750
From a 19" barrel the theoretical muzzle velocity is 2590
Your only loosing about 32fps per inch.

This is about the average for velocity loss in most mid size centerfire rifle cartridges, and probably a little on the higher side as the powder used in my ql calculations was as quite slow.

I cut down a cetme barrel with a cutoff wheel. Crowned it with sand paper and valve grinding compound and a carriage bolt. It actually shoots pretty good now. It’s a 2 moa gun, was a 3-4 with whatever was hanging off the barrel from the get go. I cut it off mainly because the sound was too loud.

If the caliber is reasonable through a shorter barrel I wouldn’t hesitate. I’ve never seen a rifle that didn’t handle better shorter.

I took my Savage Axis .30-06 down to 18 inches from 22 inches and recrowned it by hand. It is working pretty well for me, and I've not noticed any accuracy issues.

I used the Brownell's hand cutters, and the important thing is to keep the whole system well-oiled. I used Viper's Venom cutting oil, but there are a ton of other options, too.

I had a factory Rem 700 in .270win trimmed down to an even 20". It sits better and is much nicer in the brush than it was. I don't really recall the factory muzzle and accuracy being very good, never really played with it much before its alteration. So can't tell if it is much better or worse than before but currently stacking homeloads into a quarter at 100.

Accuracy is a result of the rifling not barrel length.. length is about velocity. The difference in velocity from cutting 2" off ( esp. 26 down to 24) is negligible as very few calibers are still building much pressure that far down the barrel.
Keep in mind that 4 oz. 26" out the barrel feels much heavier than 4oz. In close. I don't remember if you said what caliber this is for but ballisticsbytheinch .com has good breakdowns of your velocity loss