cutting down a barrel

I doubt if the velocity you'd loose would be noticeable to your trajectory, guys that have cut .375s down to 20" report about 10 fps for each inch of barrel cut that was cut off. Barrel length has a minor effect of accuracy, but shorter stiffer barrels are normally thought to have a greater potential for good accuracy, but this might be overshadowed by other considerations such as the quality of the new crown, the tightness of the bore at the new muzzle, or perhaps a shorter sight radius making good shooting with irons a bit more challenging. What's important is that the rifle is suitable for your uses, and a 22" .375 would hold its resale value IMHO, because so many guys want carbine length .375s, the .375 Ruger Alaskan is a case in point. Take care of shortening the barrel less than 22" though, 22" seems to be the tipping point between a rifle that balances well and one that doesn't.
 
Thanks for the tips. Good point on the shorter sight radius....I have made some nice shots on targets as is with the irons. I would be worried most about the gun smith re attaching the front sight perfectly aligned after. I would also like to get a set of affordable, yet dependable quick detach bases and rings. Any suggestions?
 
Boomer said:
I doubt if the velocity you'd loose would be noticeable to your trajectory, guys that have cut .375s down to 20" report about 10 fps for each inch of barrel cut that was cut off.
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This has not been my experience... I have chopped dozens of barrels... and most of those had loads developed before the chop and retested after the chop... IME you can expect to loose approximately 1.5%/inch of the initial velocity. So a barrel that spits out a bullet at 2000 fps at 22", will launch the same load at 1940 fps at 20" (1.5% of 2000 = 30 fps X 2 = 60 fps)... a firecracker load that launches at 4000 fps at 26" will launch the same load approximately 3760 fps at 22" (1.5% of 4000 = 60 fps X 4 = 240 fps)... you can see that the faster the initial velocity the more velocity that will lost per on a barrel bob... this is not a hard and fast rule that can be applied in all circumstance but it has allowed me to predict post-bob performance pretty accurately.

IMO... you won't notice the loss of velocity, but you will notice the increased ease of handling, and more often than not, improved accuracy (although this may be more attributable to a better crown).
 
SuperCub said:
...... and get a big increase in handling.

I've had 375s in 26", 25", 24" & 22" bbls. I'd never go over 22" again.
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Huh, I loved my 20" 375. Probably the only way I would do it if I was ever to do another.

On that rifle the numbers worked out to an average of 20 feet per second per inch.
 
sharp shooter said:
Thanks for the tips. Good point on the shorter sight radius....I have made some nice shots on targets as is with the irons. I would be worried most about the gun smith re attaching the front sight perfectly aligned after. I would also like to get a set of affordable, yet dependable quick detach bases and rings. Any suggestions?
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The choice of after market sights are dependent upon the make of rifle. I very much like the NECG sights for CZs and the redesigned ones for Rugers, but I don't like the Weaver style as much. Another option is to get Talley bases, QD rings, and their ghost ring.
 
hoytcanon said:
This has not been my experience... I have chopped dozens of barrels... and most of those had loads developed before the chop and retested after the chop... IME you can expect to loose approximately 1.5%/inch of the initial velocity. So a barrel that spits out a bullet at 2000 fps at 22", will launch the same load at 1940 fps at 20" (1.5% of 2000 = 30 fps X 2 = 60 fps)... a firecracker load that launches at 4000 fps at 26" will launch the same load approximately 3760 fps at 22" (1.5% of 4000 = 60 fps X 4 = 240 fps)... you can see that the faster the initial velocity the more velocity that will lost per on a barrel bob... this is not a hard and fast rule that can be applied in all circumstance but it has allowed me to predict post-bob performance pretty accurately.

IMO... you won't notice the loss of velocity, but you will notice the increased ease of handling, and more often than not, improved accuracy (although this may be more attributable to a better crown).
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The .375 bore rifles seem to be quite tolerant of reduced barrel lengths, my .375 Ultras would spit out 270s at 2950 fps from the 20" barrel and 3000 fps from the 22" tube, but the significantly smaller powder charges of the H&H and the Ruger should not be as adversely affected.
 
Boomer said:
The .375 bore rifles seem to be quite tolerant of reduced barrel lengths, my .375 Ultras would spit out 270s at 2950 fps from the 20" barrel and 3000 fps from the 22" tube, but the significantly smaller powder charges of the H&H and the Ruger should not be as adversely affected.
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I am only referring to testing before and after a chop with the SAME barrel, not two different barrels... I don't think you can make relevant comparisons from two different barrels... and the forumla above has applied to all calibers that I have done, including .375 H&H, 9.3X62 and 9.3X74R...
 
There are lots of variables involved in trying to determine velocity loss. Cutting a 28" 257 Wby barrel down to 24" won't net as much of a loss as cutting one 26" long down to 22". It depends on the amount and type of powder in relation to the bore diameter and length (volume), that's why big bores generally lose less velocity than high velocity smaller bore calibers when the bbl. is chopped. It's another reason most 22 LR barrels achieve max velocity at around 16" or so, they don't have much powder to burn.

I once had a Sako AV in 375 H&H with a 20"bbl. in a Brown's Precision stock. That was a nice rifle, handled like a dream. I would say 20-22" is perfect in a 375.
 
Boomer said:
The .375 bore rifles seem to be quite tolerant of reduced barrel lengths, my .375 Ultras would spit out 270s at 2950 fps from the 20" barrel and 3000 fps from the 22" tube, but the significantly smaller powder charges of the H&H and the Ruger should not be as adversely affected.
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Can't rember the web page, but when shorting barrels small bore were more susceptible to speed loss pr inch than large bore. Some large bore gained speed from a long barrel to a mid length.
 
bearkilr said:
There are lots of variables involved in trying to determine velocity loss. Cutting a 28" 257 Wby barrel down to 24" won't net as much of a loss as cutting one 26" long down to 22". It depends on the amount and type of powder in relation to the bore diameter and length (volume), that's why big bores generally lose less velocity than high velocity smaller bore calibers when the bbl. is chopped. It's another reason most 22 LR barrels achieve max velocity at around 16" or so, they don't have much powder to burn.
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This is why I am saying that expressing the velocity loss in fps/inch is a poor way to express what is actually going on... expressing it as 1.5% of original velocity/inch takes into account many of the factors that you are referring to... and it is a pretty accurate rule of thumb.
 
hoytcanon said:
This is why I am saying that expressing the velocity loss in fps/inch is a poor way to express what is actually going on... expressing it as 1.5% of original velocity/inch takes into account many of the factors that you are referring to... and it is a pretty accurate rule of thumb.
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Except it's not a constant percentage. Using the 257 Wby as an example, you might lose only 40 fps going from 26" to 25", but you may lose 80 fps going from 24" to 23".
 
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