PDA

View Full Version : What one bullet is most accurate in a .300 Win Mag?


FLChinook
November 12, 2012, 11:41 PM
I know there are more discussions about this bullet being better or that bullet being better than most of us have had hot breakfasts. But I'm having an accuracy issue with my new Weatherby Accumark in .300 Win Mag. I've tried mostly Berger bullets, 168 and 185 gr., and now find that since Weatherby's have such a large freebore, the Bergers may not be suited to the gun.

If I don't care about killing game and only want to test the accuracy of this gun, which one bullet should I try? Surely, it will be a hollow point; possibly one from Sierra's MatchKing range? What say ye???

big al hunter
November 12, 2012, 11:56 PM
:( Sorry Chinook only your rifle knows what bullet will shoot best. If the bullets you already tried were hollow point, try boat tail soft point. Then try soft point or fmj. I do wish you luck in your search. Maybe someone else has a load that will perform in your rifle, but you wont know for sure until you pull the trigger.:)

FLChinook
November 13, 2012, 12:12 AM
You are right, of course. But I'm only getting 2" groups from a bench rest and want to try another bullet that at least has a chance of doing better.

srfisher3
November 13, 2012, 12:22 AM
It's possible that you're using a bullet that is a little to light for your gun. Do you know what twist the rifling of your barrel is? Try something a bit heavier and see what you get.

Saskhunter
November 13, 2012, 12:22 AM
Try some Ballistic Tips. They often shoot well.

FLChinook
November 13, 2012, 12:49 AM
Do you know what twist the rifling of your barrel is?

I haven't measured the twist but the spec is 10".

Try some Ballistic Tips. They often shoot well.

Even Nosler acknowledges that hollow points are the most accurate bullet type and that BTs are a less expensive way to deal with a bullet tip than to do a hollow point. However, for hunting, I suspect hollow points would be less successful :confused:

Art Eatman
November 13, 2012, 07:02 AM
"What one bullet is most accurate in a .300 Win Mag?"

The one which gives the tightest groups.

(Sorry. It's just a character defect. :D)

I've always had tight groups from Sierras in my 1:10 '06 sporter. Always sub-MOA. Sometimes down around 1/2 MOA. That's through some 4,000 rounds over a bunch of years.

B.L.E.
November 13, 2012, 07:31 AM
I think the Weatherby Magnum calibers have a specified freebore in the chamber dimensions. That doesn't necessarily mean that Weatherby uses freebore in rifles built for Winchester Magnum ammo.

You could experiment with seating the bullets out a little more, though you may have to use it as a single shot if the overall length doesn't fit in the magazine.

FLChinook
November 13, 2012, 09:16 AM
I've always had tight groups from Sierras in my 1:10 '06 sporter

Is there a specific Sierra you can proffer? Thanks

kraigwy
November 13, 2012, 11:37 AM
I've tried mostly Berger bullets, 168 and 185 gr., and now find that since Weatherby's have such a large freebore, the Bergers may not be suited to the gun.

That certainly narrow the range of Berger Bullets. I think you might take advantage of that freebore by trying Berger's 230 grn bullets. They have two, the 230 Gr Hybird (BC G1 .743, G7 380) and the 230 Gr Hybird OTM Tactical (BC G1 .719 G7 .368).

I use to think I could do no better then the 200 Gr SMK in my 300 WM Model 70 1000 yard gun, but I've been working with Berger's 190 VLD and its showing promise in my gun.

Of course all guns are different.

FLChinook
November 13, 2012, 11:59 AM
I think you might take advantage of that freebore by trying Berger's 230 grn bullets.

Yikes, my shoulder is hurting at just the thought of that big bullet :)

There seem to be so many factors to consider. A longer bullet may reach my grooves sooner but a longer bullet is harder to stabilize. And recoil will be greater for a 230 gr. vs. a 165 gr. I'm not a complete wuss when it comes to recoil but I did once sell a .338 WM when it was putting my already-depleted rotator cuffs into jeopardy.. :D

I'd like to find a circa 165 gr. bullet that works...

Now that I consider it, my Berger 168s did badly when my scope was bad. It was only the 185s that I tested with the re-conditioned Swarovski (and did not do well). I could go back and recheck the 165s. But if the 185s did not do well, what are the chances for the 168s?

Lloyd Smale
November 13, 2012, 01:00 PM
if i told you id have to kill you;)

FLChinook
November 13, 2012, 01:06 PM
if i told you id have to kill you

Aha, so you REALLY don't know....:D

kraigwy
November 13, 2012, 01:11 PM
Yikes, my shoulder is hurting at just the thought of that big bullet

I cheated, I put a Badger Ord FTE muzzle brake on my 300 WM, it's about like shooting a light weight 234.

FLChinook
November 13, 2012, 01:15 PM
Did that muzzle break give a big increase in "bang", I.e., did you find shooters at adjacent benches pick up their stuff and move further away from you..?

kraigwy
November 13, 2012, 01:29 PM
Not as bad as you think.

But to be honest, I shoot on my own private range.

hooligan1
November 13, 2012, 03:30 PM
Listen to the captain, try heavier bullets..... circa 200 grn or larger.:)

buckhorn_cortez
November 13, 2012, 03:45 PM
The most accurate bullet I found for my magnum 30 caliber (30-338) is the Sierra 190 grain match HPBT. Not much of a hunting round, but it is accurate.

Art Eatman
November 13, 2012, 10:14 PM
In the Sierra line, I have used 150-grain soft-points, both flat-base and boat-tail. 165-grains, HPBT. 180-grain, SPBT.

All gave sub-MOA groups, regularly. Reliably.

I mostly used the 150s in my deer hunting. I made one bad hit on a buck and lost him via a setting sun in the scope at 4X. I hit one running buck a bit far back and needed a finishing shot. Otherwise, it was bang/whop/flop on a tad over twenty bucks. Some exit wounds; sometimes none. But if they go flop, what difference does it make?

Ranges from 25 to 450 yards, but mostly around 100 to 200 yards.

Another couple of dozen bucks with my .243, using the Sierra 85-grain HPBT, which is also a tack-driving load.

jdillon
November 13, 2012, 11:04 PM
I shoot Berger 155 gr. VLD's out of my 300 WM with excellent results. When I am having a good day, it will group under .5 MOA. Bergers are very sensitive to seating depth and you may want to try different seating depths before giving up. Most people recommend having the bullet in contact with the lands but this is always not possible especially with lighter bullets. They also can perform effectively with a bit of jump and there is an excellent article on Berger's website explaining how to do so. You may want to try their hybrid bullets which are reported not to be as sensitive to seating depth. Also you may want to experiment with different powders since and may have an impact as well. I tried several different powders in my rifle and settled on IMR 4350. Only adjust one variable at a time otherwise you will have difficulty ascertaining which variable provides the best results.

warbirdlover
November 14, 2012, 12:30 AM
I think the Weatherby Magnum calibers have a specified freebore in the chamber dimensions. That doesn't necessarily mean that Weatherby uses freebore in rifles built for Winchester Magnum ammo.

You could experiment with seating the bullets out a little more, though you may have to use it as a single shot if the overall length doesn't fit in the magazine.

B.L.E.

I was going to say this same thing. The long freebore is for the higher pressures from the .300 Weatherby Mag vs. the .300 Win Mag. They would be making a giant mistake if they put that freebore on the Win Mag.

Just for the "heck" of it try a box of factory ammo. And 150 gr. should shoot fine in a .300 Win Mag.

Lloyd Smale
November 14, 2012, 05:57 AM
[QUOTE][Quote:
if i told you id have to kill you

Aha, so you REALLY don't know.... /QUOTE]

nope because ive never seen two differnt guns in the same caliber like exactly the same load best. Not that it couldnt happen but i wouldnt wager any of my money on it. How do you find out. You buy and shoot everything you can find until that majic load somehow appears.

warbirdlover
November 14, 2012, 10:08 AM
I got lucky. My Ruger 77 MkII all-weather .300 Win shoots any factory ammo (and bullet weight) to the same hole and groups with anything I run through it. I quit handloading when I couldn't beat it with my own loads. I'm talking sub-MOA with anything. That's why I kept the rifle for over 20 years. It's one in a million.

mapsjanhere
November 14, 2012, 10:28 AM
Have you measured the length of your chamber with those bullets? Bergers like to be set close to the lands or touching. My method of measuring uses two wooden dowels, one to press the bullet against or into the lands, the other used from the muzzle to measure the distance. Then use the muzzle dowel to measure the length of the empty barrel and chamber - the difference gives you your best OAL for Bergers.
I like the 210gr in 30, but they are making rather long cartridges when set to the right distance. They might not fit into the magazine in your gun.

Bart B.
November 15, 2012, 07:52 AM
Note that a 1:10 twist in a 300 Winny Maggie will spin bullets lighter than 200 grains much too fast for best accuracy. As 97% of all bullets are unbalanced to some tiny amount, it's enough that spinning them too fast creates enough centrifugal force to make 'em jump off the bore axis when they exit.

Which is why 1:12 twists were (and still are) popular for 30 caliber cartridges of that size with heavy bullets for long range matches. I've shot 180 HPMK's from my .300 Win Mag's 1:13 twist with excellent accuracy through 1000 yards.

So, for best accuracy with a 1:10 twist in one, I suggest a 220-gr. Sierra HPMK. But it'll only work well accuracy wise if the barrel's groove diameter is smaller than those bullets; they're typically about .3082". Lots of 30 caliber factory sporter barrels have larger groove diameters (Winchester was nororious for that and may still be). If the groove diameter's bigger than that, then I'd try to find some fatter bullets to use.

The 1:10 twist for so many 30 caliber magnum barrels came about when Winchester built their first Model 70's in .300 H&H Mag. They used the same twist as the .30-06 had, but even Harry Pope (famous barrel maker a century ago) said that was way too fast for best accuracy. Roy Weatherby used that twist for his .300 Wby. Mag. 'cause both he and his customers felt if the H&H version's twist was good enough, then so would his be. But Winchester and arsenal engineers were smart enough to make the 7.62 NATO's and .308 Win's twist 1:12 for 150-gr. to 200-gr. bullets leaving slower than the .30-06 shot them. They were more accurate with that slower twist.

Whatever bullet you choose to test, shoot enough shots per test group to be meaningful. At least 15 and 20 is better. Judge accuracy by the largest group for a given load as that's what you can count on all the time. Rarely does anybody shoot a group the size of the smallest one shot with a given load.

old roper
November 15, 2012, 08:38 AM
All the early 300Wby had a 1/12 twist barrel not sure when they switched over to the 1/10 twist.

http://www.weatherbynation.com/spikecamp/conversation/31/300-wby-mag-twist-rate/0/

Sako uses 30 cal 1/11 twist barrels they don't list what they use in 308

http://www.berettausa.com/products/sako-85-classic/ click on spec you get barrel twist

Rifleman1776
November 15, 2012, 09:25 AM
In my Winchester Ranger (plain jane Mod. 70) 30-06, I have beat expensive bench rifles using handloaded Sierra Matchkings.
Very accurate, I have no reason to consider anything else. But, top accuracy also requires proper loading techniques.

FLChinook
November 15, 2012, 09:44 AM
Note that a 1:10 twist in a 300 Winny Maggie will spin bullets lighter than 200 grains much too fast for best accuracy. As 97% of all bullets are unbalanced to some tiny amount, it's enough that spinning them too fast creates enough centrifugal force to make 'em jump off the bore axis when they exit.

Which is why 1:12 twists were (and still are) popular for 30 caliber cartridges of that size with heavy bullets for long range matches. I've shot 180 HPMK's from my .300 Win Mag's 1:13 twist with excellent accuracy through 1000 yards.

So, for best accuracy with a 1:10 twist in one, I suggest a 220-gr. Sierra HPMK. But it'll only work well accuracy wise if the barrel's groove diameter is smaller than those bullets; they're typically about .3082". Lots of 30 caliber factory sporter barrels have larger groove diameters (Winchester was nororious for that and may still be). If the groove diameter's bigger than that, then I'd try to find some fatter bullets to use.

The 1:10 twist for so many 30 caliber magnum barrels came about when Winchester built their first Model 70's in .300 H&H Mag. They used the same twist as the .30-06 had, but even Harry Pope (famous barrel maker a century ago) said that was way too fast for best accuracy. Roy Weatherby used that twist for his .300 Wby. Mag. 'cause both he and his customers felt if the H&H version's twist was good enough, then so would his be. But Winchester and arsenal engineers were smart enough to make the 7.62 NATO's and .308 Win's twist 1:12 for 150-gr. to 200-gr. bullets leaving slower than the .30-06 shot them. They were more accurate with that slower twist.

OH no.. I really don't like to hear this. I don't like shooting big, heavy bullets because of the recoil. I choose the 300 Win Mag because it was at the top end of the acceptable recoil envelope for me for an elk gun. It replaced a .338 that I simply could not shoot because of the recoil. I've avoided muzzle breaks because of the noise and bother to nearby shooters at the range (where I probably shoot 200 rounds for every round in the field).

Maybe I need to start a new thread on the best way to rebarrel my gun... :mad

kraigwy
November 15, 2012, 10:11 AM
I really don't like to hear this. I don't like shooting big, heavy bullets because of the recoil.

Then don't worry about it. The lighter bullets 150 and heavier will shoot just fine out of your 1:10 barrel.

Look at the recommendations bullet makers put on their bullets, "X twist of faster".................Meaning, you can use faster twist but not slower twist.

Hunting bullets, (not varmint but hunting bullets) made for the 300 jackets heavy enough to take the fast 1:10 twist.

Heavier bullets work better at long range because of the weight (wind bucking ablities) and better BC (Longer compared to the cal), not the twist.

Next time you go to the gun store, look at the bullets that list the recommended twist. its X or faster, not X or slower.

Or go to the Berger website, they list the recommended twist for their rifles. I've never seen anyone say X is too fast except for light jacketed bullets such as made for the Hornet or small varmits.

Art Eatman
November 15, 2012, 11:42 AM
Max-pressure loads and a long barrel let my '06 do pretty well in the velocity department. 150-grain bullets somewhere near 3,150. Way back when, (okay, 60 years ago) I loaded 80-grain .32-20 bullets ahead of some 54 grains of 3031, which would be up near 4,000. (Ruinacious on jackrabbits).

I've never had any problems for accuracy with the 1:10 twist.

I tend to think that folks worry too much.

old roper
November 15, 2012, 12:59 PM
I agree with the last couple post on the 1/10 twist barrel for the 300mag. I think Wby found that out when they changed over to a 1/10 twist for the 300WbyMag vs using the 1/12 twist. Wby only has one load for a 200gr bullet but 6 loads for the 180gr and 4 loads 165gr and 2 load 150gr bullets for their mag.

If your going to build something maybe use 1 or two bullets you might do better with different twist but you sure want to talk to the barrel guys and get feedback from them also talk to the bullet guys. Nothing wrong with getting education from the guys who build them.

I tend to build around certain bullets.

Bart B.
November 15, 2012, 02:58 PM
For those who think a twist too fast won't impair accuracy may want to investigate the following.

When the Brits finally decided to do something about their .303 SMLE's not-so-great accuracy at long range, something had to be different. They already knew that the barrel whip properties of the SMLE let their cordite-loaded ammo's huge velocity spread compensate and made accuracy better past 500 yards. But the M1903 Springfield's out shot them handily with their 1:12 twist custom barrels and the new 172-gr. FMJBT machine gun bullet was used.

Finally, a smart Brit said the 1:10 twist in those SMLE's spun the 174-gr. bullets about perfect for decent accuracy leaving at 2500 fps, but the 150-gr. ones used later were spun too fast leaving at 2800 fps. He tried 1:11, 1:12 but finally settled on 1:13 twist barrels for the 150's leaving at 2800 fps. The Commonwealth's been using that for their fullbore medium and long range matches ever since with both the .303 Brit. and 7.62 NATO round. A 1:13 twist (and even 1:14) are now popular in Palma rifles shootng 150 to 155 grain bullets out at 2900 to 3100 fps. Faster twists start causing accuracy problems.

However, if you and your stuff can't shoot under 1/4 MOA at 100 yards or 3/4 MOA at 1000, you probably won't be able to tell the difference. For those who can, spinning bullets too fast matters. Best examples are the short range benchrest crowd shooting 22 and 24 caliber bullets; folks make tiny changes in charge weight as ambient temperatures change. They use twists just slow enough to stabilize the bullet and if it gets a few degrees cooler, the gotta add 1 or 2 tenths of a grain of powder to raise muzzle velocity just enough to increase the bullet's rpm's leaving the muzzle to stabilize it as it goes through thicker air. If a bullet's rpm rate didn't matter, they would not do it.

What about the .30BR round used in benchrest? Their 110 to 125 grain 30 caliber bullets leave at 2900 to 3000 fps. Best accuracy's with 1:16 to 1:18 twist barrels.

And yes, Weatherby did make lots of .300 Wby Mag's with 1:12 twist barrels.

old roper
November 15, 2012, 03:22 PM
Here is test done on a 1/13 twist right here in the good old USA

http://riflemansjournal.blogspot.com/2010/06/ballistics-heavy-bullets-in-113-twist.html

Bart B.
November 15, 2012, 04:57 PM
Old Roper, I got similar results Salazar did when I shot 168's, 180's, and 190's from a 1:12.7 twist 29 inch barrel chambered for the .308 Win. cartridge. Did just fine in 75 degrees and higher temperatures. With temperatures in the 30's and 40's, accuracy suffered with the 180's and 190's but the 168's still did pretty good.

sc928porsche
November 16, 2012, 01:41 AM
Since you have the rifle and are probably not looking to rebarrel for competition, but to simply tighten your groups, then you should try something in a spbt or hpbt. 150 to 180 gr should do fine with your current twist. You really cant expect 1/4 MOA 5 shot groups with a factory rifle even with custom reloads. Just remember, each rifle is different. You can have 2 identical rifles 1 serial number apart and they shoot differently. For accuracy, my old M77R likes the Sierra Matchkings the best.

Bart B.
November 17, 2012, 01:57 PM
One interesting thing I learned years ago was Sierra Bullets tended to get best accuracy in factory sporter barrels with flat based bullets. Their boattail ones shot better in high quality match barrels.