Barrel length

[Inksmyth]

New to reloading and am trying to get all the info I can.
I have seen that some reloading data lists barrel length.
This is usually 5". What should be taken into consideration when loading for a different length barrel? Short barrel, faster powder....etc?

 

[arjay]

You lose some velocity with a shorter barrel and the barrel cylinder gap also causes some loss.Two identical guns will also show a difference.I just take their numbers as an approximation and work up loads that group nicely in my guns and I'm happy with that.

 

[Nevada Ed]

+1;
Data per the company and "Their" set up and weapons.............

The old 38/44 had a long 8" plus barrel and the model 10;s a 4" barrel, on the average.
Most try to test with a barrel close to 4" but some use longer and most are with a Universal test barrel while some use a "Vented" system that is more like a revolver in its data.

The old Speer used "K" frames in its 38 special loads, one reason for the high FPS and pressures and why if you have a "J" frame to stop at or below the middle data.

Data can be good or BAD..........
there are a few loads that I would not even try to test from the lower powder results and then there were some starting loads that seemed pretty SLOW and wimpy.

Just match the load to your weapons ability and you should be ok.. and as mention in a lot of post, maximum FPS is not always the most accurate out of a weapon.

Good loading.

 

[fredj338]

Bbl length really doesn't come into play. You will always get max vel, any bbl length, using slower powders. The diff will be blast & flash. The exact vel you get is meaningless unless you are trying to meet a min power factor for gun games. Every gun or test platform will yield diff vel, even if bbl lengths are identical. I have 5 diff 4" 357mags, all will show diff vel with identical loads.

 

[rwsmith]

To get some idea...

Look up "Ballistics by the inch".

 

[Nevada Ed]

Per post #5;

Then look up the song.............. "Dizzy"

 

[Warren Sear]

Bbl length really doesn't come into play. You will always get max vel, any bbl length, using slower powders. The diff will be blast & flash. The exact vel you get is meaningless unless you are trying to meet a min power factor for gun games. Every gun or test platform will yield diff vel, even if bbl lengths are identical. I have 5 diff 4" 357mags, all will show diff vel with identical loads.

^^^That right there.

 

[3five7]

As others have said the only way to know what your load velocity is in your gun is to buy a buy or borrow a chronograph and chronograph the load in your firearm. You can usually estimate a ball park figure by deducting or adding about 50 FPS for each inch of barrel different from what the the original barrel length was. For instance if the book load was 1300 FPS using a 10 inch barrel and you have 4 inch barrel which is 6 inches shorter, 6 X 50 = 300 FPS. So 1300 FPS minus 300 FPS equals 1000 FPS out of your gun. This is not a exact figure but it should put you in the ball park velocity wise.

 

[hard nose street cop]

In General the longer the barrel more spin on the bullet which helps with velocity and accuracy. Heavier the bullet less flash at the muzzle or more complete burn of the powder with longer barrels. Short barrels medium weight bullets and medium burning powders.

 

[bigedp51]

My oldest son who doesn't reload sold me his S&W 29 classic with a 5 inch barrel. I loaded up some light practice loads and he wanted his .44 magnum back.

Please notice the purple dotted line below and "ALL" the powder being burnt at 4.2 inches of barrel length.

Moral of story, LONG barrels like slow burning powders and even Dirty Harry downloaded his .44 magnum.

I'm 65 and when I was young I would say to my shooting buddies lets go out shooting until our hand bleed. Now I tell my old buddies lets go shooting until our arthritis bothers us.
(its got to do with Newtons Third Law and the burning rate of the powder)

 

[Big Cholla]

As a beginner, you should read all published loading data with a jaundiced eye. I am not aware of a single powder company using more than one length test barrel in the development of loading data for a cartridge. And that barrel/receiver just might be a modified bolt action rifle with say a 8" barrel that is being used to develop 357 mag. revolver published loads for a 2.5" barrel handgun. The Thompson Centerfire Rifle action is a popular one for the labs to use while developing loads because of the quick and easy changeability of the barrels. A lot of the top gunsmiths of the USA have been given contracts for a batch of test barrel, both rifle and handgun. They are all sworn to silence about just what they built and for whom.

So, you are working on loads for a 2.5 S&W M 686 and reading the powder company's published data that just might be from a 8" or a 10" test barrel with NO cylinder gap that is bored .358" or even .359" or the rifling might be all but none existent. It all depends on the lab's honesty, the pressures they are getting from the marketing department. There is a lot of 'gaming' going on. The best defense you have is to read data from independent experimenters like Ken Waters and look for data generated by using equipment that is closest to what you are working with. The correct use of a chronograph on your loads is your best indicator of results. Read what you can understand on "Exterior Ballistics". Never take as viable any load data verbalized to you or lifted from the Internet without verifying it from responsible published data. "Bubba's" bragged upon load has blown up many 'other people's guns'. I started handloading when I was 16. I got my first chronograph when I was about 45/46. I didn't realize how much more there was to learn until I started comparing recorded velocities with published data velocities. ..............