Barrel shortening

[njc110381]

I've been all over the web looking for answers to this. I'm not sure if I'm looking in the wrong places, or maybe I'm just missing something, but I can't find much info.

 

I want to cut a Hornet down to a more truck friendly length. I know a guy with a CZ cut to 18" and he says that works fine, but is it possible to go shorter? I have read of one guy who cut his rifle down to 13.5" and he recons it still pushes 3000fps with 35grn bullets. I don't want it that short, but 15-16" would be nice.

 

I don't want to spoil the rifle, so I thought I'd ask you guys first. Someone must have tried it, or at least have a good idea what the velocity loss would be? Some of the info coming from the more informed members here just baffles me, so I figured someone would be able to offer an accurate answer!

 

All I can find that made me think it would be ok is that the Hornet case isn't much wider than the bore. Supposely this makes a chopped barrel less likely to cause a major reduction in velocity? Is that right?

[Cornishman]

Normally I'd turn to Quickload and work out the velocity loss but my new computer is reluctant to run this excellent programme and I've not fixed it yet. Generally as a rule of thumb you might lose 25fps for each inch of barrel lost but I think there are some other factors at work here as well:

 

*The reason your Cz has a long barrel may be because many buyers would use iron sights and need a long sight radius, not because the cartridge needed a long barrel. If you use an optical sight this doesn't matter to you.

 

*The powder needs enough barrel length to burn efficiently. This is where Quickload is so useful in that it might suggest that you move to a faster powder if you chop the barrel.

 

*Barrel stiffness improves greatly (third power) with shorter barrels. So, all other things being equal, shorter =stiffer= more accurate

 

*You might suffer from more muzzle flash with a shorter barrel. Are you using a moderator?

 

*Is the barrel choked? Some button-rifled barrels have a slight choke at the muzzle that improves accuracy. Bill Calfee wrote a series of articles in Precision Rifle about this and recommends the crown be placed at the tightest point in the barrel. His work was mainly around rimfire rifles but many of the same issues might apply to the Hornet which is relatively low pressure. Bill used lead laps to measure the slightest variation in barrel contours but I believe you can feel most of this with a tight patch in an oiled barrel. For example I can feel a constriction on my Cz barrel where they've taken out the rearsight dovetail.

 

You might want to have a look at this page where they tested a Sako 223 chopping the barrel shorter and shorter. http://www.accuratereloading.com/223sb.html

 

Personally I think you should go for it!

 

Cornishman

[silentsoulsleave308holes]

chop it mate

[silentsoulsleave308holes]

chop it mate

[njc110381]

I'm definately going to chop it, but I think I'll hold back at 18" for now. I can always take more off later. I will be using a moderator and also fairly mild loads so the muzzle blast isn't going to be too bad. More than could be said for the 10" .223 in that link anyway!