24" barrel...is it possible?

[Expatriot]

You will run a HIGH risk of sticking bullets in the bore.

This is both NOT FUN and DANGEROUS. This rifle had a 20" barrel.

[SDB777]

Just how much should I bump up a loading of AA#9(8.1grs) that is fired from a 14" barrel at 1035fps? With the extra 10" of barrel, is there a formula to be had that could approximate the velocity loss due to bore friction?
*Sure is a good reason to use QuickLoad*, but I'm pretty cheap when it comes to buying programs on the 'net.



Was 'itching' to go shooting today, but with a hot turkey coming out of the oven, and a ham....well, you got to do what you got to do! Then it rained all afternoon....good time for a nap!




Scott (start high and work down....) B

[dksd39]

well since you mentioned quickload...it shows you needing to reduce the load as 8.1 will be supersonic. The 24" barrel is allowing a better burn.

[alorton]

Originally Posted by dksd39

well since you mentioned quickload...it shows you needing to reduce the load as 8.1 will be supersonic. The 24" barrel is allowing a better burn.

Most subsonic loads from a 10.5" Whisper will shoot slower in a 16" barrel so I would definitely not reduce the load. The Whisper has such a low powder volume with the larger subsonic bullets that it just runs out of gas. It is set up really well for a 8"-12" barrel and a 16" is really on the long side for subsonics.

If you must shoot subs from the long barrel look at Sierra's tables and start with a known supersonic load and chronograph it. Work down slowly as when you get to the powder charge where the barrel starts slowing the bullets down velocity will drop quickly. Make sure that every bullet fires (check the bore after the shot) because you do not want to fire another round into a stuck bullet.

[BWE Firearms]

Originally Posted by alorton;

Make sure that every bullet fires (check the bore after the shot) because you do not want to fire another round into a stuck bullet.

alorton,

You mean like this.

[pud-knocker]

Originally Posted by dksd39

well since you mentioned quickload...it shows you needing to reduce the load as 8.1 will be supersonic. The 24" barrel is allowing a better burn.

I don't think quickload is a good representation of what happens in a 24" barrel with the Whisper, or takes all of the mechanics of the round into account. I have a 24" bolt gun that was built for running super sonics, but....

I played around with loading up some light (110gr to 125gr) subsonics for backyard rabbit plinkers out of my 24" bolt gun. Keeping the velocity at roughly 1,000fps, once you get below about 150gr bullet weight the pressure drops enough that with the 110 or 125 bullets the brass doesn't grow or seal to the chamber, it's not noticable in a 16" AR but in the 24" bolt-gun there is enough barrel back-pressure that you get a face full of powder, like a dangerous shot of powder to the face.

From what I've seen the Quickload data was 2 to 2.5 grains off from real life in the 24". And there's no way it can take variables like chamber seal or gas loss into account, for that reason I've all but quit using it for the Whisper and other wildcats.