Thread: Barrel length vs speed

Originally Posted by Max Headroom

Ok your Honour, i'll rephrase the question.

How much per cubic foot?

You’d have to ask Greg. I think he sells it by the pinch.

Originally Posted by timattalon

As a general (approximate ) rule of thumb, for centrefires it is usually about the 50fps per inch when a barrel is shortened so the estimates of about 150fps would be within reason. As mentioned, in most rifles the projectile is accelerating rght up unto it exits the muzzle at which point the pressure behind it is released and it then relies on momentum.

This can be countered by using a faster burning powder that expends all of its energy in the time it takes to move the projectile to the muzzle, but to be hones, 100-200fps difference at the muzzle will not make much "real world" difference to most hunters.
...

No not really. Faster powder for shorter barrels is a wide spread belief but its a myth, its not how internal ballistics work. The best burn rate for max velocity is dictated by the cartridge and the projectile regardless of barrel length.

Originally Posted by Edunn

Keep in mind the reduction in velocity does not mean you'll kill fewer animals.

I got my 7mm08 cut to 16" and it's a great rifle with plenty of killing power for short - medium distance (300yd or so) and I have found a few loads that the rifle seems to like a lot.

MV for the 139g interlock in front of AR2206H was 2700 fps as measured by chrono, but I am validating that with drops this weekend, assuming the forecast stays OK.

would be interested in knowing the results,as im running a similar set up

I can report 2800 fps from a 18" sporter weight barrel with 140 grn and 3000fps with 120gr and .5" groups. CFE 223 powder. You will do better @Nathan F because I doubt you have a cataract in your right eye.

Water is rocket science!

Originally Posted by Tentman

Water is rocket science!

Yes. I have been involved with dihydrogen monoxide for almost sixty seven years now.

I cut my 7mm08 to 16inch and never looked back,deer are just as dead.

I cut my Tikka 300wsm from 24 inches to 20 inches and only lost 100 fps

https://rifleshooter.com/2014/12/308...ty-28-to-16-5/

Originally Posted by Sako85

I cut my Tikka 300wsm from 24 inches to 20 inches and only lost 100 fps

I be happy if mine works out to be the same as that

Originally Posted by Sako85

I cut my Tikka 300wsm from 24 inches to 20 inches and only lost 100 fps

mine is 20 inches still get 178AMAX doing 2980 fps

From my 7saum 22” barrel I got 2950 with 168vld. Cut the barrel back to 17” and now get 2725 with the same load(validated).
Cheers

I just checked my 16inch Kimber 7mm08 yesterday with Hornady Whitetail and was only getting 2430fps.....same Chrono used for 22 and 284 so it’s real for this rifle.

I didn’t think the 7mm08 would drop that much based on other data I had read.

Will need to speed up a little to get a 400yard over 1000ft pound

Factory superformance 139sst was going 2650 in my 16in 7mm08 if that helps