How does Barrel length affect velocity?

[Forrest r]

OMG.

Methodologically speaking that site is worthless.

What ever you do, don't consider it to be the "holy grail" for anything other than junk science.

GEE!!!
I wounder why I said it's NOT the holy grail??????

I'm glad to see you've posted other websites that have done testing to cross reverence those data point listed in the ballistics by the inch.

So far all I see is your flapping gums, yada-yada-yada. I'll stick with BBTI, less hot air.

 

[Forrest r]

OMG.

Because of the small sample size and high standard deviations, in many of the tables you'll see bullets getting "faster" in the next one or two shorter barrel lengths.

I was talking about this thread with a fellow reloader and we had such a good laugh I figured might as well share it with everyone else.

Buffalo bore had the same problem with their 40s&w ammo, shorter bbl has a higher velocity.

https://www.buffalobore.com/index.php?l=product_detail&p=299
https://www.buffalobore.com/index.php?l=product_detail&p=301
https://www.buffalobore.com/index.php?l=product_detail&p=301

As bb57 would say OMG!!!!!!

Imagine that, you need to tell them what they're doing wrong there bb57, so they don't mis-lead people.

Another one that has the same problem, shorter bbl's and higher velocities. And to think this guy wasted his time going to college for this, worked for years developing small arms ammo for the gov/army and then started his own ballistics company.

Brass Fetcher Ballistic Testing

OMG!!!!
3 different websites in 1 thread and they all have it wrong!!!!!

yuck-yuck-yuck-yuck BWAAAA-HHHAAAA-HHAAA-HAAAAAA!!!!

Thank you bb57, you made my day!!!!
Got any other good one's??????

 

[aurora40]

Buffalo bore had the same problem with their 40s&w ammo, shorter bbl has a higher velocity.

Those are different firearms at each length, though. BBTI uses the same barrel at each length, they cut it down for each subsequently shorter test.

I don't agree a sample of 3 makes it useless data, though. It is a great resource for what it is. And they explain the reason for the sample size, cost. Shooting 5 or more at each inch increment would significantly increase the number of rounds they had to use.

 

[aurora40]

Then I will find a different projectile and build them for the carbine. I'm looking forward to getting it!

Just FWIW, I don't think I'd try to make it into something it isn't. I wouldn't try to make carbine-only loads or anything. A semi-auto PCC isn't going to have the big gains a magnum revolver chambered PCC will. And with the simple blowback operation of most semi-auto PCC's, you'll possibly beat it up trying to get bigger velocity gains. Nothing delays the bolt's movement, so pushing a given bullet faster will push the bolt faster.