I just got a new A-Bolt in 300 Win Mag. I've never reloaded this caliber before. I have been reloading for 7mm Weatherby Mag for the past several years. Here's what I already have on hand to work with. Hodgden H4831SC, Hornady 165gr BTSP Interlock bullets and Norma brass. I don't have my Hornady reloading manual yet, it's on order. I do have a couple other manuals that I'm using for reference in the mean time. I'm thinking of starting out with 75gr. of powder and maybe working up. Does this sound like a good starting point? or does anyone have experience with the stuff I have on hand and know a better starting point? Thanks.

I have been reloading for a 1963 custom made 300 Win I got from my dad for 20 years. This summer I just got my new Ruger 77 Mark II in stainless chambered in 300 Win.

I just got to try out my new elk loads for this year. I have been using H4831SC for 2 years. I really like this powder.
I weigh all hunting rifle loads, but this powder will meter
very consistent if you go that route, just check every 10th load.

My hunting loads this year are 73.0 grains of H4831SC
using Hornady 180 grain Interbonds. This is a compressed load. I have never shot a 300 Win as accurate as this. It could be the new Burris 4.5x-14x Balisticplex scope I mounted on my new rifle or the loads or maybe a little of both. I'm shooting 5 shot 2" groups at 200 yards off the bench and 5 shot 5"-6" groups off-hand. Anyway I'm ready for the elk this year.

Good Luck

I use 75 grs of h4831sc in my 300 win mag with a 165 gr bullet all the time. Happens to be the load my rifle likes.Good luck but may take alittle tweaking as all rifle are different in their likes and dislikes.

Thanks to both of you for the info. I'll be at the range tomorrow trying them out. With this initial loading, I'm just going to get the barel broke in. After that I'll start tweaking for accuracy. Thanks again, much appreciated.

topgun:

I load both the 300 WM and the 300 H&H and have taken Elk with the latter. I prefer IMR 4350 as I can get factory level velocity with less powder, thus giving me slightly less recoil and muzzle blast. I've had good performance with both 165 and 180 grain bullets. In 1990 I took my first bull elk at 400 plus yards with Sierra's 165 grain Game King.

With the short neck on the 300 Winchester it is important to crimp your bullets as the substantial recoil may push the bullets deeper into the case as they are slammed forward when you fire the rifle - a potentially dangerous situation when a cartridge like this is fired. This being said, during your reloading operation all cases must be trimmed to exactly the same length. Roll crimping the cases also requires care. Too much crimp pressure can alter the shoulder of the case just enough to keep it from chambering. It would be wise to test chamber all of your hunting cartridges before venturing out into the field. Murphey's Law would likely rear it's ugly head just as you need that second shot on a bull elk.

8iowa,

Glad you came along. You mention 2 things that I never did. I measured each case after running through the sizing die and all were below the max but all were not exactly the same. I didn't resize any of them because they were bleow the max length. Second, you mention crimping. I never did this either. I've never loaded a round that needed crimping. What do I need for this? Are the rounds I have loaded safe to fire without being crimped and each case sized to the same length? Thanks.

Most bullet seating dies, ie: RCBS, Redding, Hornady, Lyman, feature roll crimping. After you seat your bullet to the proper overall length, and in the example of the 300 Winchester, the case mouth needs to be about midway up the bullets crimping groove, you then raise the bullet seating stem to get it out of the way and carefully screw the die body deeper into the press until it begins to roll the case mouth into the crimping ridges on the bullet. Just a little bit of crimp is sufficient, As I mentioned before, continuing to screw the die deeper and applying more pressure may buckle the case shoulder. Most new die sets include instructions on this proceedure.

Some shooters purchase a separate seating die just for crimping, leaving the other seating die permanently set just for seating bullets. Lee makes a factory crimp die, which is an alternative to the roll crimp, and Lyman makes a taper crimp die which is mostly for cast lead bullets.

Many 300 Winchester shooters do not crimp their cartridges and have never have any trouble. Dies and bullets of course are manufactured to certain tolerances. The combination of a larger range diameter neck expander in the sizing die and bullets at the lower end of the tolerance on diameter could result in fit too loose for the 300 Winchester's short neck. If you prefer not to crimp, You should at least clean out any lubricant residue from inside the case mouth before seating a bullet.

Before going on a hunting trip I would recommend loading cartridges into the magazine of the rifle and examine the cartridges after firing to see if bullets are being pushed further into the case. I hope that I have not made crimping seem unduly difficult, because it is not.

Crimping does throw a third set of criteria into the determination of the overall all length of your cartridge; the first being the position of the bullet relative to the leade of the rifiling in the chamber, and the second being the maximum length of cartridge that the magazine will permit. Some loading manuals give recommended OAL's for their particular bullets. This will work fine in almost all instances.

I use the Lee Factory Crimp Die with my 300 WM loads. Just be aware the case will move some with the heavy powder loads. I get great results with fire-formed brass and load for a tight chamber fit. I usually only neck size but you have to be mindful of case expansion and fit. It's good advice to check the reworked case in the gun before you load it if you're going for a snug fit. This will ensure the shoulder is bumped back far enough to chamber the round.

I don't get near as good results with H4831SC as I do with Retumbo when loading the 300. I bought 3 pounds of 4831 but get much better performance using it with my 243 Winchester. I use Retumbo for the 300 WM, 7mm Rem Mag, and 25-06. It works well for "over bore" loads.

This is some good info you guys have provided. Thanks.

flashhole,

How do you determine how much retumbo to use. Even the Hodgdon manual I have don't list a load for retumbo in the bullet grain I am using(Hornady 165 gr BTSP Interlock). If I can find some info on this I'd like to give it a try. Thanks.

I cannot comment on the 165 grain load, as I only played around with that bullet weight very briefly.
I fired close to a thousand rounds through my .300 Winchester Magnum, a Model 98, and I never crimped a load. I generally shot 180 grain bullets, at a muzzle velocity of 2980-3000 fps depending on the load. I also fired a box of 200 grain.
I always found that the velocity variation with the various 4831 powders that I used were often 10 fps or less.
I generally shot the rifle from the magazine. I never noticed any sign of bullet movement.
In short, I don't believe you need to worry about crimping most bullets. The only effect the short neck has (as it is plenty long enough to grip most bullets firmly under full power loads), is to cause some worries with some bullets that have very short bearing lengths. The 180 grain bullets usually have a long shank which is fully gripped by the neck. Some others, such as a 165 grain Nosler Ballistic Tip, might not be if it is kept to standard overall length. This might, and I repeat might as I haven't tested or observed it, cause some bullets to slip in the .300 Winchester Magnum.
But, in general, it should not be necessary.

This is some good info you guys have provided. Thanks.

flashhole,

How do you determine how much retumbo to use. Even the Hodgdon manual I have don't list a load for retumbo in the bullet grain I am using(Hornady 165 gr BTSP Interlock). If I can find some info on this I'd like to give it a try. Thanks.

Go to the Hodgdon website. They have load data for the 300 WM and Retumbo. If you are a Hodgdon powder fan (as am I), keep your eye open for their annual magzine they publish updates and a complete listing of load data.

Retumbo was designed for heavy-for-caliber bullets with over bore cases but it works well with good quality (read in high-end) lighter weight bullets that can hold together at the velocities you can get with the cartridge. 165 grains is the lightest weight bullet I will shoot in the 300 and prefer to shoot 200 grain bullets. I'll drop down in caliber to a 7mm if I want a bullet in the 150 - 170 grain range and Retumbo is THE powder for a 7mm Rem Mag. For lighter bullets I shoot a 25-06 and again, Retumbo is an excellent powder choice.

All three cartridges have large capacity cases for the caliber bullet loaded and Retumbo gives me outstanding results.

I don't shoot the 300 wimpchester but I work with fellers that do and reload for them. They both use H4831sc.

Finally maed it out to the range today. I had loaded up several different loads to test. I tested each load with 2 three shot groups and a cleaninig in between each three shot group. My results.

Batch #1- Hornady 165gr BTSP Interlock with 73grs of H4831sc.
Average 3 shot group was 3/4" at 100 yrds.

Batch #2- Same bullet with 74grs of H4831sc.
Average 3 shot group was 1 1/4" at 100 yrds

Batch #3- Same bullet with 75grs of H4831sc
Average 3 shot group was 1 1/2" at 100 yrds.

Batch #4- Same bullet with 76grs of H4831sc
Average 3 shot group was 2" at 100 yrds

Batch #5- Barnes XLC coated 168gr boat tails with 78gr of H4831sc
Average 3 shot group was 1 1/2" at 100 yrds.

Batch #5- Same Barnes bullet with 79grs of H4831sc
Average 3 shot group was 1 3/4" at 100 yrds.

Batch #6- Same Barnes bullet with 80grs of H4831sc
Average 3 shot group was 2 1/4" at 100 yrds.

I don't have any other powder to test the Barnes bullets, maybe they would perform better with something else. They didn't fair too well with my setup. I got my load data for this bullet from the Barnes manual. Why is the starting load of 78grs so high compared with other bullets. Is it due to the coating on the bullets?

rrush, you were right on about the 73grs. It was the best accuracy wise of the bunch and should be good enough for a hunting load on whitetail.

Thanks to everyone for the info they have provided.

How hot was it at the range? If your barrel is heating up (which it is prone to do with all that powder) your accuracy will suffer as you get further into the shooting session. When I shoot my 300 during load development I make sure the barrel is cool between loads. I'm not keen on standing around at the range waiting for the barrel to cool so I take a few guns. It was a pain in the butt to do load development in Florida because it was always hot.

Are you toying with the seating depth of the bullet? I use 0.020" off the lands as a starting point and tighten it up as needed. I usually end up around .010" (ten thousandths) off the lands for all my handloads. Some a little closer, some a little further back, depends on the shape of the bullet.

Are you familiar with the ladder test for load development? It's a little time consuming but it sure works well.

I didn't mention it, but I did let my barrel cool after each 3 shots. As for seating depth, I have a Stoney Point OAL gauge that I have used. However, to get it that close, the bullet would be bearly seated in the brass, I measured the depth it would be seated and it was only .180. I made up a dummy round this length just for fun and it did fit the mag and cycle OK but I just felt that I might run into trouble with that depth. I settled on an OAL of 3.350. It's a little longer than the manuals recommend but I think its got plenty of bullet in the brass.

I'm not familiar with the ladder test but I would be interested in learning. Thanks.

The ladder test is a method of load development similar to what you were doing but with a lot more rigor and explanation. Do a Google search for ladder test and you'll find it.