.300 Win Mag, Getting Started.

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Got a RCBS Rock Chucker loading setup for Christmas, and now things are calming down a little and I can start to find powder, primers and bullets. I was looking for a little help / experience on where to start trying to develop a good load for my .300 Win Mag. Rifle this will be used has a 25'' bbl with 1 in 10" twist. (Winchester Model 70 Alaskan) And so far what I've found that the rifle and I both like best are 165gr Federal Fusion's, Link: http://www.fusionammo.com/ballistics/rifle.aspx?id=662 . I can do a Copenhagen can sized group at about 200 yards with this. Now fast foreward to this Christmas and I open the Speer manual that came with my RCBS kit and here I see about 12 different powder charge options for most of the bullets I am interested in loading with. Something like a 165gr tipped boattail spitzer, or a 168gr match boattail hollow point. So I figured some folks on here could lay some advice on what their .300 Win Mag likes as far as hand loads goes. From what I've read alot of it has to do with individual load development but I would think that some advice could at least get me closer to what I want? Thanks and I appolagize for my 'novel'.
 
IMR 4350 is a good powder to start with for a 300 WM. I shoot both 155 and 168 Berger's in mine and they both perform well with IMR 4350. I would recommend that you get tools to measure headspace so you can properly set up your dies. You will want to adjust your dies so the case head spaces off the shoulder and not the belt. This will extend the life of your brass and most likely result in better accuracy as well.
 
Man, mine sure loves 220 grain bullets.

Over the almost 20 years I've loaded for my 300 win mag, I've gone through about every bullet weight and powder combination - everything from little 110 grain barrel burners up to 240 grain.

H1000 is what my rifle liked best.

IMR4350 is real good though.

4895SC was doing real well too on my new Krieger barrel.

I only neck size, with a redding bushing die (I also neck turn and uniform primer pockets; but neck turning is a complex process and easy to do more harm than good, don't start with it..)

I only full length size brass ONCE, when I get it new from the factory bag. After that it's neck size only.

If you're shooting the ammo ONLY in one rifle, just neck size. Don't full length size 300 Win unless you have more than one rifle and want to make sure all rounds work in all rifles. This will let you get a LOT more out of each case, lifespan wise.

On the second trimming (when brass exceeds the spec length the second time) start watching for signs of case head separation, it'll ruin your day. The Sierra book has a good excerpt on this, and how to check with a feeler tool.

If you have only a full length sizer and don't want to buy another die, just back your sizing die off until it's only sizing the neck. You *might* get a little of the body on some cases, but it won't work the brass as hard.
 
My biggest problem with 7mmRM, 300WM, and 338WM is that they are belted magnums.

The SAAMI spec is .220" minimum from the breech face to the end of belt space. I have not found any brass longer than .215".
This means that those that reload a belted magnum long enough, eventually learn to space off the belt on the first shot, and then only push back the shoulder .001" when resizing [Don't bump the shell holder with the FL sizer die]. The subsequent shots with that brass then headspace off the shoulder.
I have started headspacing rifles, when I rebarrel them, to .215", but I still have factory rifles.

The other problem is the brass right in front of the belt. If more than one rifle uses the same reloads, this will cause problems. That bulge does not get reached by the sizer die because of the thickness of the shell holder and the chamfer of the sizer orifice.
Some people use a belt bulge collet die. http://www.larrywillis.com/
Some people segregate a batch of brass to just one rifle.
Some people buy new brass all the time.
I am in a disorganized state of doing all three, kinda.
 
Trent
300 Win Mag isn't headspaced off the belt, like other belted magnums.
Click to expand...
http://www.fulton-armory.com/\faqs\AR-FAQs\headspace.htm
Belted magnum cases (e.g., .300 Win Mag., .458 Win Mag.) are positioned by the belt resting on the recess provided for it at the rear of the chamber, much as rimmed cartridges are.
Click to expand...
It does on the first shot with new brass.
And there after if the shoulder is pushed back.
You may be thinking of the 300 Win short mag.
It does not have a belt
http://en.wikipedia.org/wiki/.300_Winchester_Short_Magnum
 
My Win M70 in .300 mag likes 150 gr Nosler BT's over IMR 4350. My groups were significantly tighter when using mag primers. YMMV.
 
No, I'm specifically thinking of 300 win Mag, Clark.

I've got three editions of Sierra reloading books that all specifically state it doesn't headspace on the belt, but rather, on the shoulder.
 
Trent
No, I'm specifically thinking of 300 win Mag, Clark.
I've got three editions of Sierra reloading books that all specifically state it doesn't headspace on the belt, but rather, on the shoulder.
Click to expand...
I looked through Sierra I 1971, Sierra II 1978, and Sierra 4,1995.
I can only find a little on the subject in Sierra 4
I find nothing that says the 300 Win Mag head spaces on the shoulder.
So I can't find any mistakes in the Sierra books I have.
Why do I say that?
Because new brass that meets SAAMI specs will be between 2.2630 to 2.2700" to the shoulder.
SAAMI spec chambers will be 2.2791 to 2.2891"
That means the firing pin would have to push the case forward between 0.0091 and 0.0261" to get the shoulder of the brass to touch the shoulder of the chamber.
Meanwhile the SAAMI brass belt is between 0.212 and 0.220"
The SAAMI chamber belt is between 0.220 and 0.227".
That means the firing pin would have to push the case forward between 0.000 and 0.015" for the brass belt to touch the chamber belt.
While it might seem that if we perform convolution of two functions of uniform probability distribution [0 to .0150 and .0091 to .0261] , we would find that the cartridge will headspace on the chamber 6.9% of the time.
That might be true if the distribution were random.
But I have a lot of guns and a lot of brass and the brass is concentrated around .212" and the chambers are around .221".
So in reality the brass and and chambers you buy will almost never headspace on the shoulder on the first shot. They will on the second shot, if you do not push the shoulder back with a FL or bump die.
 

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ALL factory belted magnums headspace on the belt. However, ALL belted magnums handloads must headspace on the shoulder. If your sizing dies are set accurately you'll never experience a case head separation.
 
I don't agree with the post above by "Innovative"

It reads:

"ALL factory belted magnums headspace on the belt. However, ALL belted magnums handloads must headspace on the shoulder. If your sizing dies are set accurately you'll never experience a case head separation. "

All factory belted magnums may headspace on the belt for the first shot.

After that you can adjust your FL die so that, if the round has an adequate shoulder, it can headspace on its shoulder.

For sure you don't need that die that 'Innovative" tries to sell if you can adjust a die.
 
.300

Berger 210 VLD Hunting Bullet with 71 grains Reloader 22, 2" groups at 500 yd.
Bergers do NOT always like to be jammed, after alot of testing, tightest groups were .100 (way) off the lands.
Still longer than any factory loads at 3.460
This out of a weatherby TRR custom.
Should try heavier (@ 200) bullets to get most out of .300 WM...I think
 
I like RL22 in my Remington. I am also partial to 200 gr Accubonds. Shoot really well. I don't feel that your really need the case volume of the winmag to shoot 165 gr bullets. The extra room really is appreciated in the heavier bullets. That being said, I have loaded and killed deer with 165 Ballistic tips. At close range, that is asking for a lot of performance from a bullet moving that fast. Work nice further out but expansion was over optimum to say the least. Killed the deer, but I prefer the heavier bullets
 
Savage99 ........

All factory belted magnum calibers are specifically designed to headspace on the belt.

Don't worry, I'm not trying to sell anything here . . . . just trying to help with the facts.
Any case fired in your chamber will ALWAYS have an edequate shoulder, and handloads SHOULD always be resized to headspace on the shoulder.
 
Don't waste time and money on average quality Winchester or remington brass,try to get Hornady.I also found their A-max bullets outperformed the SMK's.RL-22 worked good for me,IMR 4831 better.One mistake I made drove me nuts was cleaning the barrell too aggessively with a brush,couldn't get the cloverleafs I was expecting from REM 700 5-r milspec.Tightened right up after comp. shooters told me not to! I suggest hornady tool for finding seating lengths to rifling for various shaped bulletts,and rcbs case mic.
 
I think the issue with the head spacing is that old belted magnums were designed to be spaced off the belt for reliability purposes, but nowadays chambers are made to space off the shoulder instead leaving the belt as a useless appendage. There are inherent accuracy issues leaving an empty space between the shoulder and chamber walls and last I checked the 300 Win Mag was no slouch in the accuracy department. All that said I would prefer the WSM because it was designed as a modern beltless magnum without any useless parts, the short action is just an added bonus to me.
BTW there is nothing wrong with Remington or Winchester brass especially after it has been fired one time, Win brass is kinna rough new in the box but I buy it once fired for cheap with no complaints.
 
Kachok
I think the issue with the head spacing is that old belted magnums were designed to be spaced off the belt for reliability purposes, but nowadays chambers are made to space off the shoulder instead leaving the belt as a useless appendage. There are inherent accuracy issues leaving an empty space between the shoulder ...
Click to expand...

I disagree:
1) The chambers have not changed.
2) The best accuracy is when the 300 WM forward push by the firing pin is stopped by the belt.

Belt relief in Chambering 300 Win Mag
3 posts by 3 authors in rec.guns

Clark Magnuson 10/15/06...
Does anyone have any accuracy experience with the shoulder touching before the belt?

Bart B. 10/16/06
When the 30 caliber belted cases were king of the 1000 yard prone
matches, folks got best accuracy with new cases headspacing on the
belt. Accuracy was based on shooting at least 20 shot strings; 25 was
common. New cases in a minimum SAAMI chamber shot Sierra Match Kings
no worse than 7 inches at 1000 yards. Which means sometimes a 5-shot
group would be 3 to 4 inches and a 10-shot group sometimes in the 4 to
6 inch range.
Both military and civilian top marksmen tried full-length sizing fired
cases such that they would headspace on the belt, but accuracy wasn't
as good. They tried neck only sizing; same results, often worse. Yes,
I know the long range benchresters liked to neck size their cases, but
they also got groups ranging from 4 or 5 inches up to over 12 inches
evidenced by their 3- to 5-group aggregates (averages). The problem
was the fired cases had an extra step in front of the belt. When the
firing pin drove the case forward to stop with its belt against the
chamber headspacing step and burning powder expands the case, the case
shoulder gets pushed forward against the chamber shoulder. Then the
case head gets pushed back against the bolt face taking the belt with
it and the case body immediately in front of the belt expands against
the chamber wall.

Now there's a step in front of the belt that regular full-length and
neck sizing dies won't get rid of. As the extractor in the bolt face
pushes the case head to one side when the round's chambered, that step
interferes with the chamber headspacing step so the belt doesn't easily
seat against it. When the firing pin strikes the primer and drives the
case forward (if the case isn't already as far forward it will go from
ejector spring pressure), that step on the case sliding off the
headspacing step in the chamber sets up unwanted vibrations. Depending
on where that step contacts the chamber, the resultant changes in
barrel whip cause bullets to be launched and greater and more varying
angles than the interference-free headspacing new cases have. It's
much the same thing as an out of square bolt face contacting a
previously fired case at their combined high points; groups open up
quite a bit.

Someone figured out that a way to get rid of that extra step on belted
cases was to cut off the bottom 3/8ths of an inch of a full-length
sizing die and to top of the die just below its body-shoulder junction.
Clean up and slightly radius these cut off areas, then set the die in
the press such that a fired case could be body sized all the way to the
belt reducing that horrible step back to almost new case diameter.
This "belted body die" is best used after running a fired case through
a regular full-length sizing die such that the shoulder's set back
about .005-inch ensuring the case will headspace on the belt. Set the
body sizing die such that its bottom just touches the fired case belt.
If the sized case diameter immediately in front of the belt isn't back
to no more than .001-inch over new case diameter, cut another 1/8th
inch off the bottom of this body die, clean it up then try again.

All the Winchester belted cases I've used are about .217-inch from head
to the front of the belt. Minimum SAAMI headspace is .220-inch;
maximum is .223-inch. Which means the fire case shoulder's got to be
set back at least .003-inch when resized so it'll headspace on the
chamber step; more if your chamber is at the long end of the
headspacing range. In measuring head-to-shoulder headspace on new
belted cases, they're at least .006-inch shorter than SAAMI minimum.
Those new cases do indeed headspace on their belts.

I don't think any extra belt relief on any H & H style cartridge is a
good idea. It'll only let a larger step show up in front of the belt
when a new case is fired. And I think the bigger that step is, the
more accuracy will be degraded.

I asked RCBS to make such a die in the early 1970's but they said there
would be no market for it. Now there's a collet version; checkout
www.larrywillis.com.
Click to expand...

attachment.php

An NRA icon for accuracy is a patch made from a painting based on a picture of Bart at Camp Perry
 
Clark said:
I disagree:
1) The chambers have not changed.
2) The best accuracy is when the 300 WM forward push by the firing pin is stopped by the belt.
Click to expand...

OK I checked IV and V editions, it's not there. Which got me wondering where the heck I read it at, since I remember reading it. :)

It was Dave Campbell's article in American Rifleman on 300 Win Mag loading that I remember reading. I also remembered it wrong. It was (to paraphrase) {to help slow the problem of case head separation} "back off the sizing die so that cases are headspaced off the shoulder, instead of the belt".

Full article here: http://www.americanrifleman.org/ArticlePage.aspx?id=1767&cid=31

Now, I can't speak of his article being applicable across the board, but my personal experience on neck sizing only has yielded good results. My best load with my old 300 Win Mag barrel was yielding .92" 10 shot groups at 300 yards, on 4th generation grouped by weight / neck turned / neck sized / primer pocket uniformed brass, using H1000 and 220 grain Sierra matchkings.

The new Krieger barrel I have hasn't been fully explored yet, and is not yielding the same accuracy as the original Savage barrel. I've only been getting about 1.5" groups at 300 yards with it, but I haven't fully explored all projectile weights and powder combinations.

(300 yards is the longest range I have access to within 3 hours of driving time..)

I will say I don't agree with the above advice; unless you're using a completely custom action. If you resize the casing fully, you won't get much life out of your cases; they'll end up weakening just ahead of the belt and blowing out after a few shots.

On my rebarreled Savage 110, Krieger headspaced it so there is ZERO expansion at the shoulder of the casing. My fired casings are identical in length to the shoulder, as measured from both the belt AND the rear of the case, to the original unfired Winchester 0x cases I loaded. So in my case, it doesn't really matter if I neck size or full length size; there's no tolerance to allow the case to expand when fired. It DOES matter that I neck turn them though, as I elected to have Krieger use a tighter than standard neck diameter reamer, and the Winchester brass is not reknowned at maintaining a uniform wall thickness (most of them were .001 to .002 thicker on one side of the neck than the other; hard to chamber and inconsistent on seating pressure.)
 
Trent,
I can tell that you and Bart are better shots than me.

Krieger used Bart's name without permission and misspelled both his first and last name.
..May 1997 issue of Precision Shooting, I encountered an ad for Krieger Barrels, Inc. that showed an actual-size copy of a 20-shot group shot at 800 yards by "Bert Bobbit [sic] with his Krieger Barrelled PALMA rifle." Now this group has a .942" mean radius, with an extreme spread of 3.325. ..
Click to expand...
I have a factory chambered Krieger 300WM barrel, but I have never put it on an action and shot it.
I have ~3 shooting rifles in 300WM, ~ 1 of of the 338WM, and ~5 or the 7mmRM.
I have the belted mag reamers and lots more barrel and actions to put together.
I consider every 0.75" 3 shot group at 100y to be a good group for a big game hunting rifle.
So it does not matter if I necksize or bump the shoulder back. The accuracy difference is down in noise of my other problems.

I am just glad that after 35 years since college, I got to finally use the math term "convolution", in my post.
 
Haha understood.

I need a real calm day to put together a group that size consistently. My group sizes open up considerably when wind gets involved, especially over uneven terrain. :)

I've just got the one 300 Win Mag, it's on it's second barrel. First barrel finally developed such bad throat erosion it fouled horribly. It'd still shoot spectacular groups; IF I took the time to clean it each.. and every shot.

Anyway I got the Krieger on and haven't got back to those size groups the original barrel was capable of. I haven't experimented too much with different bullet weights or powder types yet, been shooting other stuff this year.

I did take the time to measure some old fired cases I had leftover from the original barrel (I'm not reusing them in the new barrel). The original Savage barrel had stretched casings MUCH more than the new barrel did, about .005" longer from belt to shoulder. (The new barrel, as mentioned, has 0.000" clearance and does not stretch cases).

My best group so far with the Krieger is WORSE than the worst group I put on paper the last year of the Savage barrel. But, as mentioned, I haven't done much laddering yet to find out what it likes. I'm also 1x firing cases prior to doing all of the prep work so I can get them past their first trimming. I found previously that the first firing tends to grow the cases the most, and this saves me time on firings 2+ as I don't have to re-turn the necks for a couple shots. I load on the "light" side of neck tension, .0015", but do not feed rounds from the magazine so the light tension doesn't bother me.

If I were feeding from the magazine I'd use a MUCH heavier tension (otherwise recoil would knock my bullets around), but I found that a heavier tension REALLY hurts accuracy (vertical stringing, greater deviation on velocity).

The downside of the Krieger barrel and such a tight tolerance so far has been a small amount of rejects from factory new brass. I can't get some to chamber (these are 0x fired); they are too long from the front of the belt to the rear of the casing, the bolt won't close. Winchester quality control isn't the best.. Once I get enough of them in a pile I'll chuck them in the lathe and turn the belt down enough to clear, so I can use them. Won't have to remove much material at all.
 
I have not finished fully developing my loadings for my 300 win yet but I have come up with a go to load for 7828ssc and 165, and 180 grain Hornady bullets. I have found that the minimum charges produce some very good groups at 100 yards. They are not barn burners by any stretch but they are accurate and easy on the recoil.

These loads are closer to 308 or 30-06 performance but I am working on getting some faster loads developed.
 
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