Ruger AR-556

[G Puller]

Just brought home a new Ruger AR-556 (8 inch twist) and curious about how good it is suppose to be and some starting loads. I have plenty of Varget and CFE223 plus Hodgdon 414 and H380 and H335 for powder. Bullets selections are Varmint Grenade 36 gr. -Sierra 50 gr. TNT - Nosler 40 - 50 - 55 gr. ballistic tip - Hornady 50 gr.V-MAX. Will be priming with CCI's in military brass. I have a Colt HBAR with a 7 inch twist that favors Nitemare 55 gr. HP pushed by 25 gr. of CFE223. Just throwing this out to get some ideas. Planning a prairie dog trip the last few days of May so have some time to "cook" up some loads.

 

[ar10ar15man]

what bbl length ?
my ar's like the hornady 50 vmax( actually the zmax green version).
they do have target bbls.

 

[CVCOBRA1]

Have you tried any heavier bullets in your Colt. That 7 twist was made for the high 60 through low 70 gr bullets. The 8 twist is more for the 55 gr. The bolt 223 guns have 12 and 14 twist barrels for the lightweight bullets. The 224 Valkyre has 7.5 twist for 80-90 gr at faster speeds of course. Just some thought for you.

 

[ar10ar15man]

just looking from one side of the math in bbl twist.
an 8 will easily handle 55-80 in 20 rifle config
a 7 the same unless it is short.
try 50's they will likely work in the 8
( you do know the mil shoots 55's and low 60's as in 62's,out of 7's ??)

Have you tried any heavier bullets in your Colt. That 7 twist was made for the high 60 through low 70 gr bullets. The 8 twist is more for the 55 gr. The bolt 223 guns have 12 and 14 twist barrels for the lightweight bullets. The 224 Valkyre has 7.5 twist for 80-90 gr at faster speeds of course. Just some thought for you.

 

[G Puller]

just looking from one side of the math in bbl twist.
an 8 will easily handle 55-80 in 20 rifle config
a 7 the same unless it is short.
try 50's they will likely work in the 8
( you do know the mil shoots 55's and low 60's as in 62's,out of 7's ??)

what bbl length ?
my ar's like the hornady 50 vmax( actually the zmax green version).
they do have target bbls.

Barrel length of the Ruger is 18 inches -- the bullet weights are about what I had figured -- was just looking for confirmation on what I was thinking -- I didn't have any heaver bullet weight on hand to try in the Colt but will pick some shortly.

 

[G Puller]

just looking from one side of the math in bbl twist.
an 8 will easily handle 55-80 in 20 rifle config
a 7 the same unless it is short.
try 50's they will likely work in the 8
( you do know the mil shoots 55's and low 60's as in 62's,out of 7's ??)

 

[G Puller]

Not really "hot rodding" the 55's -- running about 2700 fps per Chrony.

 

[ar10ar15man]

hodrodding...the mil runs them at over 3100.
your 2700 is walking sped.

Not really "hot rodding" the 55's -- running about 2700 fps per Chrony.

 

[G Puller]

hodrodding...the mil runs them at over 3100.
your 2700 is walking sped.

yeah I realize that but it seems like it clusters real good at that speed -- I doubt the prairie dogs will know much difference!!! When I get a hold of some heaver bullets I will try to "refine" the load a little more -- but am satisfied with it for now using military brass.