.300 Win Mag Accuracy Woes

[coldboreshot]

So a year ago a purchased a Savage 116 Bear Hunter second hand, it was like new. This is a 23" barreled in a 1:10twist rifle with a brake that can be turned on and off, stainless fluted barrel. I replaced the Accustock with a nice Bell and Carlson full aluminum bed stock. They say it is 23" but they count the brake, I say its more like 20 or at most 21"

My bullet of choice was to be the Federal Terminal Ascent 175gr which I scored 200 of these rare birds. I have run through RL25,RL22,RL19,RL16,H1000,4831SC and Reloder 16 has been the most accurate so far, the best group I can get is 1.5" at 100 yards.

I am simply not satisfied with this. I noticed the rifle likes 150gr bullets better than heavier 175gr still not tight enough but better, I am wondering if it is the shorter barrel? Browsing the Internet I found a few other people who are experiencing the same issue with the same model rifle.

I am going to try an experiment, I am going to load a ladder of BARNES 110gr with H4350 and see if it likes it. I see 84.5gr is the MAX at 3807fps in a 24: barrel. I probably should split the difference and load 130gr BARNES but I have the 110gr on hand. All I hunt is White Tail at a max range of 300yards, I think a 110gr Barnes at 3600+ would be devastating if it will shoot them.

Barnes are funny bullets in their own right, some guns LOVE them and some seem to have issues with them, I have a .257 Weatherby Magnum that shoots 1 hole with the Barnes TTSX 100gr.

I am really just thinking out loud, what are your thoughts? If I cannot get this rifle down to at least .5 MOA I am going to rebarrel it, of the many rifles I have built and bought nothing but this one shoots less than that. Frustrating.....

Now that I remember, you mentioned others online are having similar issue. i wonder if the brake is not a good match to the barrel and it is giving a bad harmonic signature to the barrel. Try testing without the brake.

 

[CharlieNC]

A 110gr bullet in a Win Mag, what purpose are you loading for? I would try a known good, forgiving bullet like a 175 SMK. Some barrel and bullet combinations just don't work, don't give up based on one.

 

[MUP]

Excellent advice above from all members. The only thing I could think of to add is the saying I've often heard that the 180 gr bullet was the optimal gr wt bullet for the 300 WinMag. I've got a Remington Model 700 Sendero in 300 WinMag and it shoots really well with 180 NAB's and NBTs over RL 22. I've shot a single group at sub 1/2 MOA at 1000 yards with this combination before, but generally a sub MOA shooter at distance, not that I would hunt at those ranges, but nice to stretch it out to see what it will do. After checking your equipment well, you might try moving up to a heavier bullet, just something else to try. Good luck!

 

[marazzi59]

Not saying there can't be something else going on but saami spec 300 win mag chambers have a crazy large throat diameter that isn't great for accuracy at all. .308 bullet diameter vs ..315"

 

[SixFive]

I think I got it worked out today! The following load is the best yet, shooting 1/2 MOA at 100 Yards.

175gr Federal Terminal Ascent Bullet
RL 16 Powder 69.5grs
Rem 9 1/2 Mag Primer
Winchester Brass
COAL 3.500
.004 Neck Tension
3040 FPS at the Muzzle
That is plenty good enough to hunt with. Just had to keep playing, thanks for all the great ideas guys!

 

[William Vogel]

I think I got it worked out today! The following load is the best yet, shooting 1/2 MOA at 100 Yards.

175gr Federal Terminal Ascent Bullet
RL 16 Powder 69.5grs
Rem 9 1/2 Mag Primer
Winchester Brass
COAL 3.500
.004 Neck Tension
3040 FPS at the Muzzle
That is plenty good enough to hunt with. Just had to keep playing, thanks for all the great ideas guys!

That bullet is a secant ogive. I would try running it really close to the lands and and back away to find it’s sweet spot. Because you’ve got it to 1/2moa with powder, you should be able to get it to tighten up more. All my rifles shoot 1/4moa or less because I’ve adjusted seating depth and load development. I have a 6.5 Creedmoor that I haven’t found the best load yet but that’s it. Here’s a target I shot Sunday with my 6 Dasher.