I have had my 17-556 kak(18" barrel) since June and here are a few things i have observed. firs off the 17-556 kak has the same relationship to the 17-223 as the 17 Mach IV has to the 17 fireball. virtually identical. i have shot the 17-223 since 1980 in a bolt rifle, Remington 17 Remington (24" barrel) rechambered. it had been a great rifle and cartridge combo.
I dipped my toe into this project of a 17 on a ar platform even though i am somewhat anal about accuracy. Most of my 17's shoot in the .2 and 3"s but my expectations for the kak was some what realistic with 1" groups expected. Needless to say i was able to meet those expectations with 2 out of the 3 bullets i had on hand.
that said let's talk about bullets i had on hand, 25 gr Hornady hp, 25 vmax ,20 vmax, 25 Berger, 25 Remington and 15.5ntx. i have others but have not tried them in the rifle. KAK list the 20 and 25 gr vmax for their loads. in my rifle the 25 gr vmax is a 1.25" grouper, the 20 vmax does a lot better with some .50 groups. the 25 gr Hornady hp did best with an *, i'll explain that in a bit. i had a box of 25 hhp from about 1984 and they shot in the .4-.5 on a regular basis in the mid 3750fos range. the 25 gr burger hp was also consistent at .4-.5" at about the same velocity.
now let's discuss the * in the room. i ran out of that box of bullets and switched to recent production. well all went to hell in a hand basket. matter of fact you couldn't hit a 10" hand basket with those bullets. I'll call them 10" patterns so as not to insult groups. sometimes i did have 1 hole group because that was the one bullet that made it to target. I'm guessing they were blowing up mid-range.
i contacted Kak customer service and they sent a call tag for the barrel, which i promptly sent it back. a few days later i received an email that the barrel was in spec and they test fired it with no groups exceeding 1". they shipped it back and i reassembled the upper. took the rifle to the range yesterday and all was calm with the wind gods. the rifle shot .5 groups with the Berger's and the 20 gr vmax just like before. the 25 gr Hornady hp shot over 10" high and off the target, so i have no idea what the group was.
i had a chat with Hornady as i knew they changed the 25 gr hp a while back. they verified the bullets i was shooting were not seconds as did Midway where they were bought.
conclusion, i will be shooting 25 gr Berger's(3725 fpr) and 20 gr vmax (3989 fps) and not look back at the 25 gr hp. i will shoot those in my other 17 and see what happens.
As to reloading the 17-556 kak, it does present it's challenges. a fired case reloaded with Redding kak dies measure to the same exact specs as though there is zero neck clearance. usually there is about .001 spring back from actual chamber specs and they seem to function just fine. not sure how they will fare with reloading and necks thickening. i turned some cases down by .001 and they defiantly had less neck tension when seating bullets. i am experiment resizing the necks with my 17 viper bushing die to create more bullet to neck tension and loading with a Vickerman straight line seater. don't know if it will chang anything but just thinking like a farm boy.
I dipped my toe into this project of a 17 on a ar platform even though i am somewhat anal about accuracy. Most of my 17's shoot in the .2 and 3"s but my expectations for the kak was some what realistic with 1" groups expected. Needless to say i was able to meet those expectations with 2 out of the 3 bullets i had on hand.
that said let's talk about bullets i had on hand, 25 gr Hornady hp, 25 vmax ,20 vmax, 25 Berger, 25 Remington and 15.5ntx. i have others but have not tried them in the rifle. KAK list the 20 and 25 gr vmax for their loads. in my rifle the 25 gr vmax is a 1.25" grouper, the 20 vmax does a lot better with some .50 groups. the 25 gr Hornady hp did best with an *, i'll explain that in a bit. i had a box of 25 hhp from about 1984 and they shot in the .4-.5 on a regular basis in the mid 3750fos range. the 25 gr burger hp was also consistent at .4-.5" at about the same velocity.
now let's discuss the * in the room. i ran out of that box of bullets and switched to recent production. well all went to hell in a hand basket. matter of fact you couldn't hit a 10" hand basket with those bullets. I'll call them 10" patterns so as not to insult groups. sometimes i did have 1 hole group because that was the one bullet that made it to target. I'm guessing they were blowing up mid-range.
i contacted Kak customer service and they sent a call tag for the barrel, which i promptly sent it back. a few days later i received an email that the barrel was in spec and they test fired it with no groups exceeding 1". they shipped it back and i reassembled the upper. took the rifle to the range yesterday and all was calm with the wind gods. the rifle shot .5 groups with the Berger's and the 20 gr vmax just like before. the 25 gr Hornady hp shot over 10" high and off the target, so i have no idea what the group was.
i had a chat with Hornady as i knew they changed the 25 gr hp a while back. they verified the bullets i was shooting were not seconds as did Midway where they were bought.
conclusion, i will be shooting 25 gr Berger's(3725 fpr) and 20 gr vmax (3989 fps) and not look back at the 25 gr hp. i will shoot those in my other 17 and see what happens.
As to reloading the 17-556 kak, it does present it's challenges. a fired case reloaded with Redding kak dies measure to the same exact specs as though there is zero neck clearance. usually there is about .001 spring back from actual chamber specs and they seem to function just fine. not sure how they will fare with reloading and necks thickening. i turned some cases down by .001 and they defiantly had less neck tension when seating bullets. i am experiment resizing the necks with my 17 viper bushing die to create more bullet to neck tension and loading with a Vickerman straight line seater. don't know if it will chang anything but just thinking like a farm boy.
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