300 win mag reloading

[92xj]

Standard large primers or Magnum primers?
Everything I've read and researched is 50/50 on this.  What to use?

[spookgus]

I use magnum primers and 4350 or 4831.

[luvtohnt]

I normally use magnum primers. I am fairly new to reloading and was wondering this also. I would imagine that the magnum primers have a slightly larger charge to them. I use 4350 and 4831 with my rounds as well.

Brandon

[wraithen]

From what I've been reading magnum primers not only have a hotter charge, they make use of the end on the powder side more efficiently and create a more even ignition for the powder in the case. What does your reloading data say to use? Don't most have a specific primer they include in the recipe?

[92xj]

Just getting started into reloading. Doing all my reading and research now.

[spookgus]

What ever bullet you choose, buy their loading manual and use the powder/primer combo recommended for that brand and weight of bullet. Magnum primers with surely be recommended for the slower powders with hunting weight bullets.(especially in cooler climates)

[Huntbear]

Magnum primers...  try looking at the Reloader powders.... the results just may surprise you in a very good way.

Buy multiple reloading manuals, and study them.  If you have a buddy that reloads, work with him for the first couple of times....

great websites for information:

reloadersnest.com

handloads.com

[spookgus]

Magnum primers...  try looking at the Reloader powders.... the results just may surprise you in a very good way.

Buy multiple reloading manuals, and study them.  If you have a buddy that reloads, work with him for the first couple of times....

great websites for information:

reloadersnest.com

handloads.com

You are correct, there are probably better magnum powders on the market today. I just can't seem to stop buying the same powders I was using 20 years ago. Although I have switched to Varget for the .223.

[bobcat]

Hodgdon h1000 is a good powder in the 300 Win Mag. I don't hear of a whole lot of people using it, but it's one step slower than H4831 and you should get more velocity with the h1000. And with it I would use magnum primers.

[GoldTip]

I use magnum primers, reloader 19 at 75.5 grains and 180gr swift scirrocco II's.  They trip the chrono at 3050FPS, with an average 5 shot velocity spread of 14fps.  Plenty accurate and kills everything real well.

[Biggerhammer]

Federal 215 Match is what I have used for years and I have shot more .300 Win Mag than anything else. I had just under 5000 rounds on one heavy barrel. The throat was completely shot out and it would still shoot as long as I didn't clean it.

RL-22 and 165 BT's and Accubonds have been the ticket for me, the last Remington Sendero I had in .300 Win Mag shot everything I fed it well. RL-22 gave me speed and accuracy, I've learned over the years the .300 Win Mag cartridges likes to be pushed, it performs excellent at it's higher velocity range.

My last Sendero .300 Win Mag all factory, I put 2400 rounds through it and sold it. It was a easy rifle to drive and just plain shot well for a out of the box rifle. The .300 Win Mag is not shy of being jumped, the bullet seated a ways off the lands.



Here are some groups I dug up with the load data I always write on the targets and keep in a file for every rifle. I hate digging a rifle out later and not being able to remember the load data.








This was a group shot at 400 yards with my favorite load through a Rem700, with a slight right to left breeze, I know I would be on paper so I didn't correct for any wind. I just wanted to confirm my drop, using my standard 300 yards zero. I wanted to check my real world drop at 400 and make sure my ballistic program was right on. Which it was, the program was right on with my drop. This group was shot from the prone off a bipod. I was using CCI 250 Magnum primers because I had ran out of Fed 215's. The federal and CCI's performed about the same, I felt the Fed 215's may be a bit more accurate with my load but I could have just been slapping the trigger tighter on those days.

[iusmc2002]

Biggerhammer:
You said the 300 likes to be humped quite a bit.  The COAL for the 168gr AMax's I was using today is 3.340.  But when I run a loose case and Sharpie'd bullet into the chamber, I'm getting a COAL of 3.480-3.482.  That was with 5 different bullets and 5 different pre-sized cases.  Is it normal to have THAT big a difference in book COAL and actual COAL?  I'm just wondering if that big jump is why it isn't shooting to what I think it's potential is?  It's a Douglas barrel, if that matters

[wraithen]

Are you talking about the coal of the round vs the space in the throat? If so just realize the book is probably on the shorter end of safe just so it's not going to be touching lands with any maker's firearm. I can't chime in as to what he's experienced but from some of his posts I get the feeling sometimes he talks to the barrel maker and tells him what he want's every aspect of his guns mic'd to.  j/k

[Biggerhammer]

Biggerhammer:
You said the 300 likes to be humped quite a bit.  The COAL for the 168gr AMax's I was using today is 3.340.  But when I run a loose case and Sharpie'd bullet into the chamber, I'm getting a COAL of 3.480-3.482.  That was with 5 different bullets and 5 different pre-sized cases.  Is it normal to have THAT big a difference in book COAL and actual COAL?  I'm just wondering if that big jump is why it isn't shooting to what I think it's potential is?  It's a Douglas barrel, if that matters

Yes, it is perfectly normal to have that much of a difference between the books COAL and the real world COAL of your choice of bullet touching the lands in any particular rifle. What I would do and what I have done with many .300 Win Mags is start with the bullet just " Kissing" the lands.

But remember the COAL now may become a issue. It is loaded to touch your lands and that overall length may not fit down in you mag box. Which most often than not is the case, take a fired cartridge, set a bullet in it and seat it just deep enough so that it will go down in your mag box and measure that.

I can almost bet it's going to be longer than the book COAL but it will get you closer to the lands. Close isn't always better, just like with some Bergers. Some Bergers like to be seated just  " Kissing" the lands or from between .010-.015 "Jammed " into the lands and some I have had to back off in .010 increments until I'm .040 thou off and hit the sweet spot.

What I was saying was that with several of my Accubond loads in a .300 Win mag, I can seat them just kissing the lands or .030 thou off and the rifle will still shoot the same. It's a very forgiving chambering unlike many 7mm cartridges I have loaded for.

For example, bellow are three different targets shot from the same rifle pictured in my post above. I was tinkering with the seating depth with the same bullet, the 165gr Nosler Ballistic tips. I do allot of the load development with the BT's because they are Nosler factory seconds at a fraction of the cost of the 165 Accubonds and they shoot exactly the same.

Also take into consideration your A-Max has a Secant Ogive which in my experience very rarely in .30 cal likes much jump if any. It's a completely different outer ballistics creature from let's say the Accubond, you may have to switch bullets. You would have better luck and accuracy from lets say jumping a Sierra MK then you would a A-Max or a Berger for that matter.

Note the difference " Extreme" in seating depths and for a factory rifle it is still shooting well.

This was a 100 yard group with the 165 BT seated at 3.345 and my rife zeroed @ 300 yards, my preferred zero for the .300 Win Mag. I'm still holding hair a little past 400 yards, also with a different powder than my RL-22 load.



This is a group shot at 300 yards with the 165 BT's. The first shot was out, with a warm but just cleaned bore. Note the seating depth 3.550



This is the same 400 yard group posted above note  the seating depth 3.450. A extreme spread in seating depths with the same bullet but still very capable of MOA of Rockchuck well beond 400 yards. Very forgiving chambering and at extended ranges the BT's flat destroy Mulies. I have killed them a little over 600 yards with the 180 BT, in fact that particular Muley was head down feeding and I flat knocked him of his feet at that distance "Bang/Flop". That was before the arrival the the Accubond.

[grundy53]

I use LR primers and IMR4350 for both of my .300 magnums and they both like it. Especially my Sendero