Thread: Myth? - shorter barrel = use faster powder?

A faster burning powder for a shorter barrel or is it an old reloaders myth?

So which statement is correct?

Statement 1 - All a longer barrel does is give the powder more time to burn. Burning all the powder gives you all the speed that load can give you. A shorter barrel simply does not always allow all the powder to burn, therefore you should use a faster burning powder in a short barrel to get high velocities.

Statement 2 - The fastest burning powders burn completely within just a few inches down the barrel. The slowest burning powders in a couple of inches more. However, the gas produced by the burned powder continues to expand down the barrel, so a longer barrel will produce higher velocities. Therefore, slower powders that produce the fastest velocities in long barrels also produce the fastest velocities in short barrels.

The received wisdom I've heard is, the powder that gives top velocity in the long barrel is probably the powder you should use in the short barrel.

Well there's an experiment for someone. Let us know.

Both your "hypothesis" are incorrect.

Results of slow versus fast powder and barrel length can be precisely modeled on any interior ballistics program, have a look at Quickload or GRT.

Originally Posted by Tentman

Both your "hypothesis" are incorrect.

Results of slow versus fast powder and barrel length can be precisely modeled on any interior ballistics program, have a look at Quickload or GRT.

Not the greatest of posts....why are my hypothesis incorrect?...I have to now look it up on a ballistics program?

Too hard basket at moment.

Originally Posted by Allizdog

Well there's an experiment for someone. Let us know.

@Allizdog I'm just about to start that experiment with a Contender 6.8 SPC barrel I have test fired at 23" and now cut and crowned to 18.5"
I have pre and post cut velicities with 2 different factory 110 grain ammunitions
Have Speer Gold Dot 90 grain projectiles as my first chosen deer shooting option
And three different on hand powders to have a play with

This might not be quite the same scenario because I'm going light, fast and short !

Originally Posted by akaroa1

@Allizdog I'm just about to start that experiment with a Contender 6.8 SPC barrel I have test fired at 23" and now cut and crowned to 18.5"
I have pre and post cut velicities with 2 different factory 110 grain ammunitions
Have Speer Gold Dot 90 grain projectiles as my first chosen deer shooting option
And three different on hand powders to have a play with

This might not be quite the same scenario because I'm going light, fast and short !

Speaking of which I modeled Reloader 7 last night, its going to be spot on if you can get it to shoot well

Originally Posted by Hermitage

Not the greatest of posts....why are my hypothesis incorrect?...I have to now look it up on a ballistics program?

Too hard basket at moment.

I can't be fucked typing a long answer. Do you own homework

Originally Posted by Tentman

I can't be fucked typing a long answer. Do you own homework

Dude, this bloody forum is going down hill because of responses like yours.
There are less and less questions being asked in this forum.....it is getting boring...really boring.
But when I do ask a genuine question I don't get a forum boosting answer, instead I get 'I can't be fucked'.

Good going...

Originally Posted by Tentman

if you can get it to shoot well

That requires me to shoot well also !
Not very bloody likely at the moment

Originally Posted by Hermitage

Dude, this bloody forum is going down hill because of responses like yours.
There are less and less questions being asked in this forum.....it is getting boring...really boring.
But when I do ask a genuine question I don't get a forum boosting answer, instead I get 'I can't be fucked'.

Go going...

He ( tentman ) has to vacuum his caravans shag pile carpet to find a vital lost gun part
Hence he does not have the time to model your genuine question

Both of your statements are correct in there own way.
Personally I lean towards the second statement however if running a real short barrel and a suppressor I would take the First statement into account.
Just my opinion though.

If you take the trouble to download and install GRT (Gordons Reloading Tool, its free) you will truly learn something. It will take you an evening. I'm a two finger typist and i don't have an evening to spare. Besides this half the forum who don't think science can give any answers will jump on and try to contradict any specific answer given.

Try a parable, you know the one about teach a man to fish versus give him a fish . . . .

Originally Posted by Hermitage

Dude, this bloody forum is going down hill because of responses like yours.
There are less and less questions being asked in this forum.....it is getting boring...really boring.
But when I do ask a genuine question I don't get a forum boosting answer, instead I get 'I can't be fucked'.

Good going...

If you are genuinely interested in an answer, as he said, do your own research. Are you incapable? Do you expect someone else to do it for you?

Originally Posted by Tentman

If you take the trouble to download and install GRT (Gordons Reloading Tool, its free) you will truly learn something. It will take you an evening..

Yeah this is a friendly post.....that's all it takes (and writing what the 'GRT' means). Cheers.