Cutting barrel /velocity testing? Update Feb.3

Brianma65 said:
I plan on testing for accuracy and speed at each length,and then a final accuracy test with the finished 18.5 barrel.

I’m ordering a couple of different bullets today,first thing I’m going to do is find a bullet it likes.

I’m also curious as to what the accuracy will be,with the unfinished barrel.
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http://ww w.accuratereloading.com/crownr.html

Interesting read and may challenge what some believe about the role the crown plays in accuracy.
 
How long is your new barrel going to be from Mystic? I have a Savage Hog Hunter in .308 with a 20 inch barrel and I wound not go shorter in a bolt gun.

Bottom line, I do a lot of shooting at the range from the bench and was surprised at the amount of blast and kick from the .308 with a 20 inch barrel. And I would not say shorter is better with full power loads when shooting 50 or more rounds from a short barrel. Just ask anyone with a Enfield No. 5 Mk I Jungle Carbine if they are fun to shoot from the bench.

Below my 1950 No.4 Long Branch with a 25 inch barrel and a Winchester 30-30 Trapper Model with a 16 1/2 barrel. I like to think the 30-30 is a Contender pistol with a butt stock. ;)

HwPDC8U.jpg


Have fun with your project, I'm sure you will get a "kick" out of it. :evil:
 
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Go for it.

I did a similar test cutting a barrel back from 32" to 28". Lost about 25 fps per inch, as I recall.

24 to 19 would lose a bit more, I suspect. Say, 35 fps/in.

As you do it, pay attention to kick and noise. You might want to stop at 20"
 
My new barrel is going to be finished at 19 inches.
CFW barrel ,6.5 CM
I’m not to concerned about the kick, as I’ve shot 70 to 80 rnds,in one sitting ,with a 7mm :)
 
Brianma65 said:
My new barrel is going to be finished at 19 inches.
CFW barrel ,6.5 CM.
I’m not to concerned about the kick, as I’ve shot 70 to 80 rnds,in one sitting ,with a 7mm :)
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When I was young I would call my shooting buddy and say lets take our pistols to the range and shoot till our hands bleed.

When I call him now I ask him how his arthritis is and if he feels like shooting a few rounds.

So don't worry, it will not be long before age and gravity takes its toll and shooting short barreled rifles knocks your false teeth loose.

Below fire forming .303 British brass using 100 grain pistol bullets with reduced loads. This would make the Enfield's brass butt plate softer when firing 100+ rounds.

HHDfGl9.jpg


Don't forget the rubber o-rings to hold the case against the bolt face and center the rear of the case in the chamber.https://www.airsoftgi.com/images/imagecache/550x393_airsoft-recoil-mag1.jpg

FCHGvIZ.jpg


The Truth About Barrel Length, Muzzle Velocity and Accuracy
http://www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/

Short barrel 16.5 inch 308 Winchester load development
https://rifleshooter.com/2017/01/short-barrel-16-5-inch-winchester-load-development/

Real men subscribe to the magazine below. :stirthepot2:

REC20_350x424.jpg
 
The new gun will be in the mail on Wednesday, it should be in my hands by Jan 15.

I should have all the testing done before the end of the month.

I’m going to try two different loads, testing for accuracy and speed at each interval.

I’ll roll up 6 rnds of each load per inch of barrel. One for the chrony and five for the group.
That sound about right?

I’m betting 19 inches to be the sweet spot.
 
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Brianma65 said:
The new gun will be in the mail on Wednesday, it should be in my hands by Jan 15.

I should have all the testing done before the end of the month.

I’m going to try two different loads, testing for accuracy and speed at each interval.

I’ll roll up 6 rnds of each load per inch of barrel. One for the chrony and five for the group.
That sound about right?

I’m betting 19 inches to be the sweet spot.
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Not enough. A single shot can be 50 fps more or less than average. If you want to know the effect of cutting off an inch, fire 3 for velocity (at least) at each length.
 
My Savage 10 PSR is 18.5"
I am shooting 1/2 moa at 100-300 yards with handloads.
168 Amax @ almost 2800 in Lapua brass with 46 grains of Varget.
 
Brianma65 said:
The new gun will be in the mail on Wednesday, it should be in my hands by Jan 15.

I should have all the testing done before the end of the month.

I’m going to try two different loads, testing for accuracy and speed at each interval.

I’ll roll up 6 rnds of each load per inch of barrel. One for the chrony and five for the group.
That sound about right?

I’m betting 19 inches to be the sweet spot.
Click to expand...

I agree that one shot won't tell you what you want to know. Fire all of them over the chronograph set up so you can shoot for groups at the same time. I do it all the time to save money, and you will need several more shots to get a good average. You will find, as has been pointed out, the extreme spread of any given load can easily exceed the difference you will get as a result of the inch of shortening.

Testing can be fun, but doing a bad test is not worth the effort.
 
I was also thinking that the more uniform the cut,the better it should be.

Gander,should I do five shots, over the chrony,and take the average of those?
 
rral22 said:
I agree that one shot won't tell you what you want to know. Fire all of them over the chronograph set up so you can shoot for groups at the same time. I do it all the time to save money, and you will need several more shots to get a good average. You will find, as has been pointed out, the extreme spread of any given load can easily exceed the difference you will get as a result of the inch of shortening.

Testing can be fun, but doing a bad test is not worth the effort.
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I can do five over the chrony and five for the group.

It’s only for kicks, but I want it to be done right.
 
if your going to test for accuracy the gun must be fired using a vise to eliminate human error - all factors being equal (clean barrel / cooled barrel) with each 5 shot strings. Only then, can you conjecture that a shorter barrel may or may not be more accurate.
 
bigedp51 said:
If you want to save powder, bullets, money and your time a detailed writeup below.


308 Winchester / 7.62x51mm NATO: Barrel Length versus Velocity (28″ to 16.5″)
https://rifleshooter.com/2014/12/308-winchester-7-62x51mm-nato-barrel-length-versus-velocity-28-to-16-5/

308-barrel-velocity-first-cut.jpg
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I’m not looking to save anything. I have a barrel ,that I have no use for, I have lots of spare time, I have some spare cash.
So I thought I’d have some fun,while I’m waiting on my new barrel.
It’s a lonnng winter:)
And I’ve read all the internet pieces on the subject, but thought I’d like to try it myself.
Sometimes you just gotta find out for yourself, how things work.
 
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