Shortround6
Major General
When evaluating military weapons, or other things, a number of factors com into play.
Even for things like rifles they actually have to viewed as a "weapons system" even though a simple one.
The Carcano was a well built rifle that is-- good forgings, well machined, good finish (for the most part, many war time guns from many nations were poorly finished). Many rifles have idiosyncrasies that don't make sense at first glance to people familiar to other guns/tactics.
However as a "system" the rifle is largely dependent on ammunition and here the Carcano was let down, both by Italian military ammunition and in the American market. To deliver good "accuracy" a rifle needs good ammo. Not only good new ammo but good old ammo (ammo that has been in storage for 20-40 years) and here the Carcano ran into trouble, some lots of ammo having poor sealing around the primer allowing moisture to get into the primer and powder making the cartridges inconsistent. It has hard to get a good group if the ammo is going bang, bang, bang. pop, BOOM, bang. The Carcano also used an oddball bullet. It was .268 in diameter instead of the much more common .263-.264 of many other 6.5mm cartridges which meant even American handloaders had trouble making ammunition for it. It was only after about 2002 that an American company offered a .268 bullet so from the end of WW II on even American experimenters were using undersized bullets when trying to evaluate or compare the Carcano to other rifles.
Many countries had problems with ammunition quality during war time and at times accepted some pretty poor stuff.
A 3rd consideration is the sights and ergonomics. The Carcano never got a decent set of sights. They were stuck with the pre turn of 20th century sight system until just before WW II when the Italians turned to the simplified fixed sight setup. Perhaps that was an attempt to simplify things for the troops in combat.
Military rifles were often regulated (or sighted in) at the factory or arsenal by using different height front sight blades (or filing) and drifting the front sight left and right in the front sight base to establish a "zero". However different "lots" of ammunition will often shoot to to different points of impact even if the velocity is the the same. A few inches left or right may be acceptable for military use but leaves civilian users less than impressed. Trying to use different bullets or hand loads can really shift point of impact even if the group size is small.
The Short barreled Carcanos suffer due to the short sight radius. The greater the distance between the sights the less the point of impact will shift for the same sighting error (front sight not in exact center of rear sight). This is true for many of the short carbines but very few of the European short carbines showed up in the US in numbers (except for the Swedish Mauser Carbines).
One source claims the short carbines were built using cut down rifle barrels. The Carcano rifles (long barrel) used gain twist rifling in which the rifling twist started slow (about one turn in 19in of barrel) and the twist changed as the rifling went to the muzzle with the twist ending at somewhere between 1 in 8 or 1 in 9. Cutting the barrel back to just under 18in inches may have left the the final rifling twist to slow to stabilize the long 162 grain bullet.
Point of personal information, My 6.5 Rem bench rest rifle has a 1 in 10 barrel and while phenomenally accurate using 120 grain bullets it threw Sierra 142 grain match kings sideways in a pattern (not group) the one time I tried at 100yds. My 6.5X 308 rifle uses a 1 in 9 barrel and with the higher velocity with it's larger powder charge shoots 142 grain bullets just fine at any range I have tried (1000 yds max).
Later Short rifle Carcanos (1938 and later) used a constant rate of twist rifling.
With the large variety of different Carcanos and the difficulty in making sure you have good ammo ( post war testers or civilians could hand load most different calibers to evaluate different rifles without depending on factory/government ammunition) evaluation of the Carcano in the 50s and 60s could have had very mixed results.
I would note that US practice called for the rifles to be accuracy tested at the factories with certain lots of ammo of known performance while ammo was accuracy tested in special test guns ( universal receivers fasted to heavy duty benches/tables and with very large diameter barrels) in order to reduce the variables. Ammo testing was NOT done with standard service rifles and rifle accuracy testing was NOT done with what ever batch of ammo that was handy. Function tests or durability tests would be done with whatever would go bang.
Even for things like rifles they actually have to viewed as a "weapons system" even though a simple one.
The Carcano was a well built rifle that is-- good forgings, well machined, good finish (for the most part, many war time guns from many nations were poorly finished). Many rifles have idiosyncrasies that don't make sense at first glance to people familiar to other guns/tactics.
However as a "system" the rifle is largely dependent on ammunition and here the Carcano was let down, both by Italian military ammunition and in the American market. To deliver good "accuracy" a rifle needs good ammo. Not only good new ammo but good old ammo (ammo that has been in storage for 20-40 years) and here the Carcano ran into trouble, some lots of ammo having poor sealing around the primer allowing moisture to get into the primer and powder making the cartridges inconsistent. It has hard to get a good group if the ammo is going bang, bang, bang. pop, BOOM, bang. The Carcano also used an oddball bullet. It was .268 in diameter instead of the much more common .263-.264 of many other 6.5mm cartridges which meant even American handloaders had trouble making ammunition for it. It was only after about 2002 that an American company offered a .268 bullet so from the end of WW II on even American experimenters were using undersized bullets when trying to evaluate or compare the Carcano to other rifles.
Many countries had problems with ammunition quality during war time and at times accepted some pretty poor stuff.
A 3rd consideration is the sights and ergonomics. The Carcano never got a decent set of sights. They were stuck with the pre turn of 20th century sight system until just before WW II when the Italians turned to the simplified fixed sight setup. Perhaps that was an attempt to simplify things for the troops in combat.
Military rifles were often regulated (or sighted in) at the factory or arsenal by using different height front sight blades (or filing) and drifting the front sight left and right in the front sight base to establish a "zero". However different "lots" of ammunition will often shoot to to different points of impact even if the velocity is the the same. A few inches left or right may be acceptable for military use but leaves civilian users less than impressed. Trying to use different bullets or hand loads can really shift point of impact even if the group size is small.
The Short barreled Carcanos suffer due to the short sight radius. The greater the distance between the sights the less the point of impact will shift for the same sighting error (front sight not in exact center of rear sight). This is true for many of the short carbines but very few of the European short carbines showed up in the US in numbers (except for the Swedish Mauser Carbines).
One source claims the short carbines were built using cut down rifle barrels. The Carcano rifles (long barrel) used gain twist rifling in which the rifling twist started slow (about one turn in 19in of barrel) and the twist changed as the rifling went to the muzzle with the twist ending at somewhere between 1 in 8 or 1 in 9. Cutting the barrel back to just under 18in inches may have left the the final rifling twist to slow to stabilize the long 162 grain bullet.
Point of personal information, My 6.5 Rem bench rest rifle has a 1 in 10 barrel and while phenomenally accurate using 120 grain bullets it threw Sierra 142 grain match kings sideways in a pattern (not group) the one time I tried at 100yds. My 6.5X 308 rifle uses a 1 in 9 barrel and with the higher velocity with it's larger powder charge shoots 142 grain bullets just fine at any range I have tried (1000 yds max).
Later Short rifle Carcanos (1938 and later) used a constant rate of twist rifling.
With the large variety of different Carcanos and the difficulty in making sure you have good ammo ( post war testers or civilians could hand load most different calibers to evaluate different rifles without depending on factory/government ammunition) evaluation of the Carcano in the 50s and 60s could have had very mixed results.
I would note that US practice called for the rifles to be accuracy tested at the factories with certain lots of ammo of known performance while ammo was accuracy tested in special test guns ( universal receivers fasted to heavy duty benches/tables and with very large diameter barrels) in order to reduce the variables. Ammo testing was NOT done with standard service rifles and rifle accuracy testing was NOT done with what ever batch of ammo that was handy. Function tests or durability tests would be done with whatever would go bang.