Sighted in my 300 Win Mag

[jro45]

I've been tring to get this rifle to shoot Serria 180 gr bullets to give me a nice group ar 200 yds. Those boat tail bullets would not group at 200 yds. Sure everything was fine at 100 yds. They go every where at 200. I was shooting them at 3080 Fps. So I changed from boat tail bullets to flat base bullets and now everything is fine. At 200 yds the bullets used the same hole a couple times. No problem with the flat base bullets. Does anybody know why those boat tail bullets do that at 200 yds? Maybe its the powder?
 

[KN]

Gremlins!  I have found that barrels just seem to like one over the other with no rhyme or reason. If your bullets are grouping good at 100 and not at 200 they are probably becoming unstable. Which is not typical of a boat tail over a flat base. I generally just find what ever a rifle likes and stick with it. I don't worry too much about B/T vrs FB.  KN

[Redhawk1]

KN, I have to agree, there is no rhyme or reason. I also shoot until I find what works.  

[jro45]

Thanks guys I guess thats one way to look at it.

[Randy Flowers]

Well, that is why we test this stuff, you never know.

I used to have a 25-06 barrel that did the same kind of thing.  It would not shoot Sierra 117 grain boat tail bullets well at all but would stack the flat based version on top of each other.  

Some barrels just do not stabilize boat tails well.  The barrel that is on that 25-06 now shoots boat tails pretty well, but still prefers flat base versions.

The world of acuracy bullets is sort of puzzling.  If you look at the 22 and 24 caliber bullets shot by most benchrest competitors you will find mostly flat based bullets.  But, if you look at the bullets shot by most guys for long range shooting (high power, silhouette, etc.) you will find most competitors use boat tails.  

The folks at Sierra readily admit that it is generally easier to get flat based bullets to shoot well.  By the way, that flat based 180 grain Sierra is one heck of a good choice.  I shoot them in my 300 Wby Mag some and they perform well for me.

Good testing on your part.  Most guys would have assumed because the 100 yard groups were good that they were finished testing.

R F

[jro45]

I e-mailed Serria about this and Serria said that my barrel must have a deep throut. This is the third barrel on this action the first was no good so the 2nd was good shot bt and fb no problem this third barrel only shoots fb bullets. Serria says that alot of WBY's have deep throuts and can't shoot
bt's also.  :-)