Based on rifles I have bobbed, I would expect about a 200 fps loss with 8" being cut off.
Thinking about a bush gun...
- Thread starter kolik1
- Start date
Based on rifles I have bobbed, I would expect about a 200 fps loss with 8" being cut off.
Northman999
CGN Ultra frequent flyer
- Location
- Southern Yukon
I checked a batch of .308 cal 165 grain SST's over 45.0 grains if IMR 4895 and CCI #200 primers, in .308 win.
My chrony readings (average of 5 rds) were as follows.
22" - 2760 fps
18.5" - 2590 fps
So that's 170 fps for 3.5" of barrel, so pretty much right on 50 fps loss per inch.
I've also chronied a Swedish M38 (24" bbl) and M96 (29" bbl) using exactly the same batch of handloads and found close to 250 fps difference (so again about 50 fps per inch), and the 24" bbl isn't really "short" to start off with in the first place.
A .358 will likely lose less, but IMO (no offense to anyone) most guys who cut barrels have got some wishful thinking going on in terms of velocity loss.
My chrony readings (average of 5 rds) were as follows.
22" - 2760 fps
18.5" - 2590 fps
So that's 170 fps for 3.5" of barrel, so pretty much right on 50 fps loss per inch.
I've also chronied a Swedish M38 (24" bbl) and M96 (29" bbl) using exactly the same batch of handloads and found close to 250 fps difference (so again about 50 fps per inch), and the 24" bbl isn't really "short" to start off with in the first place.
A .358 will likely lose less, but IMO (no offense to anyone) most guys who cut barrels have got some wishful thinking going on in terms of velocity loss.
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No wishful thinking on my part... I started with one 7mm-08 barrel and tested it before and after... I was happy with the results and so I did a .223 and .30/30... And again I was happy with the results... In my book, the small loss in velocity was a good trade off for the wieldiness of the gun after the bob... And accuracy "improved" in the .223 and .30/30, and was pretty much the same in the 7mm-08... So gradually over the past 3-4 years I have bobbed most of the rest... And I have no regrets.
I shoot T/C Contender carbines one is a 12.5" rifling + muzzle brake = 14" barrel in 45-70 another is a 22" barrel in 45-70 with identical loads/batch of 325gr Hornady FTX I get 1750fps with the 14" barrel and 1850fps in the 22" barrel.
9.5" shorter barrel = a grand total of 100fps velocity loss.
I find the greater the diameter of the bore/bullet the less velocity loss I have to deal with.
9.5" shorter barrel = a grand total of 100fps velocity loss.
I find the greater the diameter of the bore/bullet the less velocity loss I have to deal with.
surplusfan
Member
- Location
- Halifax NS
Well, nobody mentioned the winchester 94 chambered in 32 winchester special yet, so I guess I might as well. Works great in the bush.
Yep it's called cartridge efficiency, the more efficient the cartridge the less it gives up to a shorter barrel. 45-70 is almost the "poster child" for this effect, but cartridges with powder capacities to bore ratios from the 358 win on up lose very little to short barrels because of the optimum burn rate powders that are used in these calibers are quite fast and burn very efficiently in as little as 16" of bore, (read 18" barrel). I was going to get into the mathematics of expansion ratios of the 35 and up bores but who cares, right !! Suffice it to say the larger the bore and the smaller the case the less you lose with shorter barrels. Cartridges like the 458 Win function perfectly through 18-20" barrels with minimal loss of velocity or energy, even in a DG rifle.
Applefarmer
CGN Ultra frequent flyer
- Location
- Lime Stone City
Eighteen inch barrel in a 308 in which ever action you prefer. Really short scope, 150gr Power Point, pause, shoot well, wait a few minutes. Gut deer.
Scope 1-4 or a 2-7 keeping the weight and length down. Good enough for a 300 meter shot.
Knowing a 12ga Winchester 1300 rifled is good enough for swamp and the occasional long 200 meter long shot with a 1-4 scope using 3", not a problem with a 308 with 300 meters.
Scope 1-4 or a 2-7 keeping the weight and length down. Good enough for a 300 meter shot.
Knowing a 12ga Winchester 1300 rifled is good enough for swamp and the occasional long 200 meter long shot with a 1-4 scope using 3", not a problem with a 308 with 300 meters.
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Lever action / sem auto .44 magnum with open sights, preferablly XS or Williams. Winchester 1892, or an older Ruger Carbine Semi Auto. Light weight, easy handling, great for scrambling up and down hills. Lots of knockdown power out to 100 yards. modest recoil, tons of fun!
I have the wide open fields covered with my weatherby, just looking for ideas for something to use when i'm in the willow's in the bottom of the coolie's and ravines.
I'm poking around in the timber with my M1894 Big Bore in .375Win. I loaded up some 220gr Hornady FN for it.
I've got the 'Shifle' in the truck for longer shots (M700 .270Win, 2.5-8X Leupy).
If you listen to certain people you'd come away with the idea that every rifle needs a high powered variable, with turrets on it...
