Shortening a barrel and Accuracy ??

T

THE RAVEN

New member
Well,I finally found a rifle I am liking,I had previously overlooked it because of the length......I am in a wheelchair and it's rough to handle a firearm with a long barrel,so I need something as compact as possible....
One member here suggested cutting down a barrel,something I have never thought of....If I have it shortened to the 16-18 inch range how bad will this effect accuracy ?? I am looking to get this rifle in a .308 caliber....I suppose any decent machine shop can do this for me ? There aren't any gunsmiths around my area....If I have a machine shop do it should I have the end of the barrel crowned or leave it flat ?? If crowned what angle(if that's the proper term)should I have put on the barrel ??

Thank you everyone,you have been great !
 
Raven, I can't answer all your questions and I haven't responded prior to this because of the specific rifles you wanted. Yes, you can have a barrel shortened. I'd have a gunsmith do it, and surely there's a competent gunsmith somewhere near you. Or, you could buy a Ruger Compact Model 77 in 308 or one of the other great calibers (260 Remington, for instance) that will work as well and kick less hard. Mine, in 260, has a 16.5 inch barrel and is so easy to carry and handle that I use it more than any other rifle I have. Also as an option would be the Ruger 77 Ultralight, which you may have to buy as a used rifle. Of course, with light weight you'll have a bit more recoil.
 
I am looking to stay with a heavy barrel.....It's not the weight that gives me trouble,it's the combination of a long barrel and bull barrel that does.....A short,compact rifle with a bull barrel would be ideal...
 
It's impossible to tell precisely what the effect on accuracy will be.

If you really like the rifle and want to get the best results, I suggest that you don't shorten it to the shortest length you might want initially. For example, if you think that 18 is probably what you want, start by shortening it to 20 inches and having it recrowned properly. Then shoot it for accuracy. If you're happy with the accuracy, you're done. If not, take off an inch, recrown and try again.

Guns will often have sweet spots where the barrel length really works well for best accuracy and the result can be pretty pronounced.

The chart below is the result of shortening a .223 barrel and shooting for groups at each different length. I created the plot based on the information from this website. Each point is the average group size recorded for a given length. http://www.accuratereloading.com/223sb.html

The gist of the plot is that shortening the barrel really didn't make all that much difference in accuracy across the board. Other than the one outlier at 15", all of the average group sizes could be characterized by 0.58" plus or minus 7 hundredths of an inch. That said, it's also clear that certain lengths (notably 15" for this particular rifle) did seem to perform better than others. The latter is why I suggest not cutting it down to the minimum length you think you might want on the first try.

bblvsgrpchart_small.jpg
 
As to accuracy, depending on who you talk to, shortening the barrel makes it stiffer barrel, so it could be more accurate, but it terms of parctical accuracy, I doubt you will see a measurable difference.

A good machinist can make the cut for you. If you tell him what crown you want cut, he should be able to do that too.
 
The benchresters probably have an "ideal" crown angle that they use, but the specific details of the measurements of the final product aren't as important as that the result is symmetric/square/clean/etc.
 
I have only heard of an 11deg crown. If they're are others, I haven't heard of them. http://www.brownells.com/.aspx/pid=628/Product/79-deg-MUZZLE-CROWNING-CUTTER
I cut one myself once on an old Swedish Mauser, I first cut it to length with a hacksaw and then squared the end of the muzzle with a flat file and a combination square. When I had it perfectly square I took it too a gunsmith and had him cut the crown for me. Saved having to buy the tools to do it myself.
 
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I recrowned the barrel on my TC Encore in .223 because the original crown looked like it had been gnawed by angry beavers.

I did it on the kitchen table using various grits of sandpaper wrapped around a .380 bullet.

Then I shot the three-shot group in the picture using the rifle. I have no idea what the "crown angle" is but I can tell you that the result is clean/square/symmetric/etc. ;)

attachment.php
 
A good gunsmith is hard to find these days. If you have a hard time handling the rifle, does that mean you might be prone to dinging the barrel? If so, then a recessed crown is what you need.
 
I don't have a hard time handling a firearm as long as I can get it down to my size per-say.....But a recessed crown might not be a bad idea just incase...! That sandpaper crown is an interesting concept...However I think if I am going to spend that kind of money on a rifle,I will have a professional do it....Now if it was a $200 clunker,I would experiment annnnd probably end up with a gun that would shoot around corners....:D
 
Accuracy isn't affected by barrel length to a great degree. You might have to change the ammo you use as the harmonics will be different.
Consider cutting the barrel down to a medium length first. Easy to cut it off hard to put it back on.

Somewhere on the intertubes there are instructions for DIY rifle crowning using home made tools. As to angle, a machinist should be able to get that off of the old crown you've removed.
 
I have a Savage 10 Precision Carbine with a 20" barrel that shoots .5" or better groups depending on the trigger puller. I looked to have my 700 7mm08 Varmint shortened for handling as well and was told that it wouldn't hurt accuracy one bit. Never did though, I like the tiny groups it shoots and couldn't risk it.
 
A single shot like a Browning/Winchester or Ruger #1 will be short because of the short action My Browning 1885 came with a 28" barrel .I cut it to 22" [still a normal length] and the total length was just under 37" .A great woods gun !!
A heavy barrel bolt action cut to 18" will still have the stiff barrel for good accuracy and short OAL.
 
There's a few myths floating around in this thread......

A barrel vibrates the same frequency for every shot fired. Whatever its fundamental vibrating frequency is, that's what it wiggles at every time it's fired. The metal doesn't change nor does its dimensions, so the frequency stays the same. It might vibrate a greater amount but still at the same frequency. Exactly the same as a guitar string; pluck it gently with your finger or smack it with a ball peen hammer; its musical note stays the same but the volume is different. Note that harmonics are just higher frequency multiples of the fundamental frequency the barrel vibrates at that's typically 100 Hz or less. And the harmonic frequencies change the bore axis at the muzzle much, much less than the fundamental one does.

Stiff barrels are no more accurate than flimsy ones. As long as the barrel vibrates the same for each shot, it doesn't matter how much nor how fast it vibrates; great accuracy is possible.
 
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Here's an article/experiment on barrel shortening:

http://www.tacticaloperations.com/SWATbarrel/

I shortened my bull barreled Winhester 70 .308 to 18" and it shoots fine.
Couple of things though...it made the rifle lighter so it kicks more, the muzzle blast is closer to me and if I have the muzzle over a shooting bench (and not forward of the benche's edge) I can feel the blast bounce off the bench, if you reload you may need to tweak your loads.

If you don't have a gunsmith nearby you could consider sending your rig to one.

Or go the DIY Savage barrel swap route.
 
what you do (:D) is take the barrel off the action. Then hold it in your hand and bounce a softball off it several times to find the sweet spot (no vibration). Mark it and cut it at that length as long as its longer than 16. Oh come on somebody's gotta try it!
 
If the barrel has a good crown when it's shortened , it will shoot about the same after shortening ! If the barrel had a poor crown before shortening , it will shoot better . An 11% recessed crown should work for you . A rifle barrel has to be 16" to be legal . I don't like to shorten to 16" , just in case the barrel may need recrowning at some point in the future . If the barrel is 16" you can't recrown and still have a legal barrel . Leave an inch or so , for the future !
 
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