Is this too much for a 1 in 9 twist? I have a box given to me and would like to try them but if it won't work there is no point of trying and wasting components and barrel life. The Berger number is 22421. 77 grain is supposedly too much but a number of people have used the Sierra 77 grain with a 1 in 9 twist.
I'd try them, but, you can check length to see if they are longer than the SMK's. Not the whole story but it might get you in the ballpark.
I find that there is a difference between the stated twist from the factory for a caliber and the actual twist that was reamed into the barrel on any particular day.
It can vary by maybe a 0.5 quicker than spec which is enough to allow a 77-grain high BC bullet to stabilize.
I have two .223s that shoot 77 SMKs and TMKs great; one shoots them better than any other caliber.
You really have to test performance in your particular barrel.
I have long since stopped assuming that each barrel will perform like someone else's.
Experience can be misleading, too.
The same rifle that shoots 77 better than any other caliber doesn't shoot some 75 gr bullets very well.
I think it may depend on the bullet shape as well as the bullet weight when you are near the limit of the twist.
That is good advice from both of you. I will load up maybe a half dozen and try them. I guess the money spent if it is wasted won't break me and the 223 barrels last quite a while too. If they do work, I think they are a premium dollar bullet and it would be a shame to waste them if they will work.
I think they will work. I just shot a group and it was 9/16". I have done better with other bullets but I have also done worse. A little wind too so that could have had an effect. I did use the maximum listed powder charge, heard speed helps stabilization some.
Actual stability can be affected by how the bullet is made, eg, how far forward or back the CG is located, length of ogive vs drive band, length and angle of boat tail, etc. When you get to marginal cases it all matters.
The two Berger bullets I have used both like being seated into the lands. A jump of even .005 would open the groups a bit.
If not they would make great sub sonic plinking AR loads
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